text:
Nikol Pashinyan and Abdel... 19:07
Nikol Pashinyan hosts Egyptian... 17:45
I am confident that... 16:47
Artsakh under attack
Eye on the border
18:0608 Dec, 2022
Uzbekistan takes cool line on Russian 'gas union', Reuters
Reuters. Uzbekistan's energy minister on Wednesday poured cold water on a Russian proposal for a "gas union" including the Central Asian country, saying Tashkent would not agree to political conditions that would jeopardise its national interests.
Russia said last month it was discussing a gas union with Kazakhstan and Uzbekistan to support shipments between the three countries and to other buyers including China.
It is part of a shift in Moscow's strategy since its military operations in Ukraine, which prompted the European Union to sharply cut its reliance on Russian energy.
But the Uzbek minister, Jorabek Mirzamahmudov, said Uzbekistan had yet to receive the proposal.
"Even if a gas agreement is concluded with Russia, this does not mean a union," he said. Negotiations were being conducted to deliver Russian gas by pipeline via Kazakhstan but this would be a "technical contract", not a union.
"If we import gas from another country, we cooperate only based on a commercial, sales contract. We will never agree to political conditions in exchange for gas. In short, we will get the gas contract offered to us only if we agree to it, otherwise not," he said.
Uzbekistan's coolness towards the Russian proposal reflects Moscow's increasing difficulties in imposing its will over other former Soviet republics at a time when it is increasingly bogged down by the war in Ukraine.
Uzbekistan remains partly dependent on foreign gas, however. The country, including the capital Tashkent, has experienced gas shortages over the last few days as consumption has spiked due to a cold spell.
Mirzamahmudov said the cold snap had forced Uzbekistan to halt exports of 6 million cubic metres of gas a day to China.
In total, the country produces about 52 billion cubic metres (bcm) of natural gas a year, with imports of 4 bcm and exports of 2.7 bcm, he said.
Kremlin Spokesman Dmitry Peskov on Thursday denied the information that Uzbekistan allegedly abandoned Russia's idea to create a "trilateral gas union."
"Reuters misinterpreted the words. We know what was said. Nobody is talking about gas in exchange for political conditions. This is not being discussed in the context of the idea of creating this union", Peskov told reporters.
18:0930 Nov, 2022 Idea of gas union with Russia, Uzbekistan needs close analysis: Kazakh Foreign Ministry Political
Nikol Pashinyan and Abdel Fattah El-Sisi discuss further development of Armenia-Egypt relations 19:0729 Jan, 2023
Nikol Pashinyan hosts Egyptian President Abdel Fattah El-Sisi in Armenian Government 17:4529 Jan, 2023
I am confident that the cooperation will be further deepened in the near future, President Khachaturyan to the President of Egypt 16:4729 Jan, 2023
Memorandums of understanding signed with the participation of Armenia and Egypt presidents 15:3829 Jan, 2023
Official welcoming ceremony of President of Egypt Abdel Fattah El-Sisi held in Armenian Presidential Palace 13:3329 Jan, 2023
Ararat Mirzoyan briefed Egyptian counterpart on the daily deteriorating humanitarian situation in Nagorno-Karabakh resulting from Azerbaijan's blockade of the Lachin Corridor 13:2529 Jan, 2023
26, G․ Hovsepyan Str., Yerevan, Nork 0011


We are happy to serve our consultation and design clients during the landscape-installation process. As consultants, project managers, and/or general contractors, we charge by the hour at our regular rates. If you are already a client, you will know how to inquire about the installation process. Although we can be of assistance as consultants on projects designed by others, we typically do not install landscapes that are designed by other designers.
Whether you are working with a seriously flawed design, a design that just needs some improvement, or if you simply want a second opinion for a project you are working on, we can help. Click here to get started.


text:
New York Water Science Center
Hurricane Sandy - New York
Science Center Objects
https://www.sciencebase.gov/catalog/item/55dee95ce4b0518e354e0834Gale- to storm-force winds associated with the passage of Sandy across central New Jersey and eastern Pennsylvania that lasted 12 to 18 hours caused major to record coastal flooding in southeastern New York on October 29, 2012. Of 10 real-time tide gages operated by the U.S. Geological Survey (USGS) in coastal areas of Long Island and New York City, all recorded levels above the National Weather Service (NWS) major coastal flood elevation. The locations of tide stations operated by the USGS in the southeastern New York region are shown on the Southeastern New York Coastal Montitoring Sites web page.
The south shore of New York City and western Long Island saw the bulk of the record water elevations, as these areas were to the immediate right of the storm's center of circulation as it made landfall in New Jersey. Widespread record coastal flooding occurred in Lower New York Bay, Jamaica Bay, and the western bays along southern Nassau County. The peak water levels recorded at all stations in these areas also exceeded the Federal Emergency Management Agency (FEMA) 100-year base flood elevations for these sites. In all cases, the peaks from Sandy have surpassed anything documented previously at these sites, including the Oct. 31, 1991 and Dec. 11, 1992 storms and Hurricane Irene.
Record coastal flooding also occurred in western Great South Bay along southern Suffolk County and in the Peconic Estuary of eastern Suffolk County. The peak water levels recorded at most stations in these areas also exceeded the FEMA 100-year stillwater elevations for these sites. In all cases, the peaks from Sandy have surpassed anything documented previously at these sites, including the Oct. 31, 1991 and Dec. 11, 1992 storms.
The Long Island Sound shore of northern Nassau County experienced major coastal flooding. The peak water level recorded at the one real-time station in this area exceeded the FEMA 10-year stillwater elevation for this site. The peak from Sandy was within 0.5 ft of the record previously documented for this site-from the Dec. 11, 1992 storm.
Notice: 14NOV12 - The USGS is monitoring barrier island breaches in cooperation with the National Park Service.The U.S. Geological Survey (USGS) New York Water Science Center (NYWSC) proposes to help evaluate the open breach condition in Federal Wilderness near the Old Inlet area of Fire Island National Seashore, N.Y. The proposed NYWSC evaluation would initially be focused on two activities: measurement of water velocities and depths within the Wilderness breach, and collection of water levels within Great South Bay (GSB) adjacent to the breach.
Measurement of water velocities and depths within the Wilderness breach would be done with a Sontek M9 acoustic Doppler current profiler tethered to an Oceanscience remotely operated Q-boat 1800P. Water velocities would be collected at a rate of 3.0 and/or 1.0 MHz depending on flow conditions with an accuracy of 0.25% of measured velocity and resolution of 0.001 m/s; water depths would be collected at the same frequency as velocity with a vertical accuracy of 1% and resolution of 0.001 m. Approximately 3 to 5 sections perpendicular to the channel axis would be collected within the breach and geo-referenced using RTK GPS. Another section would be collected perpendicular to the flood tidal channel(s) bayward of the former GSB shoreline. An additional section would be collected roughly parallel and seaward of the former ocean shoreline, as conditions permit. For each deployment, these sections would be measured once during the last 2-3 hours of the incoming ocean tide and a second time during the last 2-3 hours of the outgoing ocean tide. Velocity and depth measurements would be imported into a geographic information system (GIS) and exported as one or more geo-referenced shapefiles. Instantaneous discharge also would be computed from one of the breach sections for incoming and outgoing tide conditions.
Collection of water levels within GSB adjacent to the breach would be done with a modified USGS storm surge sensor (SSS). This sensor, which normally collects 7 days of 30-second-interval data, would be reprogrammed to collect about 2 months of routine (6-minute-interval) tide-gage observations. The modified SSS would be affixed to a remnant piling of the Old Inlet dock. At the end of the 2-month period, the SSS would be recovered and its record processed and displayed on the USGS Hurricane Sandy Storm Tide Mapper.
Coastal Storm Surge
Notice: 17DEC12 - A provisional table of peak storm-tide elevations produced by Hurricane Sandy and historical peak water-level elevations, dates of occurrence, and periods of record at 13 U.S. Geological Survey estuary stations in southeastern New York has been made available.
Notice: 14NOV12 - The USGS has recovered most of the 38 storm-surge sensors, 4 wave-high sensors, 10 barometric-pressure sensors, and 4 rapid-deployment gages that were deployed prior to Hurricane Sandy's arrival. This work will be carried out by teams from the New York, Georgia, and North Carolina Water Science Centers. In addition, these teams marked and are surveying over 300 high-water marks in the region to document this record flooding event. Information about high-water marks and data retieved from these instruments are posted for display on the storm tracker found on the Hurricane Sandy Storm Tide mapper.
Tidal water-elevation stations, rapid deployment streamgages and some streamgages recorded water level data and transmitted those data on a real time basis. A list of those gages can be found on the USGS Storm tide and Rapid deployment streamgages page.
Provisional peak data from 10 existing USGS coastal gages in southeastern New York are shown below. All USGS these tidal water-elevation stations recorded levels above the National Weather Service major coastal flood elevation.
West Pond at Glen Cove, NY (01302600): 10.96 ft (above FEMA 10-year stillwater elevation)
Orient Harbor at Orient, NY (01304200): 7.38 ft (approached FEMA 50-year stillwater elevation)
Peconic River at County Hwy 105 at Riverhead, NY (01304562): 8.60 ft (above FEMA 100-year stillwater elevation)
Great South Bay at Lindenhurst, NY (01309225): 7.73 (approached FEMA 100-year base flood elevation)
Hudson Bay at Freeport, NY (01310521): 10.12 ft (above FEMA 100-year base flood elevation)
Reynolds Channel at Point Lookout, NY (01310740): 10.10 ft (above FEMA 100-year base flood elevation
Hog Island Channel at Island Park, NY (01311143): 10.89 ft (above FEMA 100-year base flood elevation
East Rockaway Inlet at Atlantic Beach, NY (01311145): 10.80 ft (above FEMA 100-year base flood elevation)
Jamaica Bay at Inwood, NY (01311850): 11.65 ft (above FEMA 100-year base flood elevation)
Rockaway Inlet near Floyd Bennett Field, NY (01311875): 11.75 ft (above FEMA 100-year base flood elevation
Hudson River - Hurricane Sandy storm-surge high-water-marks are plotted here relative to historic water elevations.
Many good references and resources can be found on our Floodwatch page. Other storm related links are;
National Oceanic and Atmospheric Administration StormCentral
National Weather Service National Hurricane Center
National Weather Service Northeast River Forecast Center
National Weather Service Watches, Warnings or Advisories for New York
USGS Current Conditions for New York: Streamflow
USGS Hurricane Sandy Information
Google Super Storm Sandy
From Montauk to Manhattan – Measuring Storm Tide and High-Water Marks caused by Hurricane Sandy in New York
Hurricane Sandy -- Science to support coastal resilience
Status - Completed
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Coastal Hydrology and Storm Surge
Below are publications associated with this project.
Filter Total Items: 3
logstash-usgs-pw:palladium_root_publication_year_date
Select Year2015 (2)2013 (1)
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Analysis of storm-tide impacts from Hurricane Sandy in New York
The hybrid cyclone-nor'easter known as Hurricane Sandy affected the mid-Atlantic and northeastern United States during October 28-30, 2012, causing extensive coastal flooding. Prior to storm landfall, the U.S. Geological Survey (USGS) deployed a temporary monitoring network from Virginia to Maine to record the storm tide and coastal flooding...
Schubert, Christopher E.; Busciolano, Ronald J.; Hearn, Paul P.; Rahav, Ami N.; Behrens, Riley; Finkelstein, Jason S.; Monti, Jack; Simonson, Amy E.
Attribution: New York Water Science Center, Water Resources, Hurricane Sandy
Schubert, C.E., Busciolano, Ronald, Hearn, P.P., Jr., Rahav, A.N., Behrens, Riley, Finkelstein, Jason, Monti, Jack, Jr., and Simonson, A.E., 2015, Analysis of storm-tide impacts from Hurricane Sandy in New York: U.S. Geological Survey Scientific Investigations Report 2015–5036, 75 p., http://dx.doi.org/10.3133/sir20155036.
Measuring storm tide and high-water marks caused by Hurricane Sandy in New York: Chapter 2
In response to Hurricane Sandy, personnel from the U.S. Geological Survey (USGS) deployed a temporary network of storm-tide sensors from Virginia to Maine. During the storm, real-time water levels were available from tide gages and rapid-deployment gages (RDGs). After the storm, USGS scientists retrieved the storm-tide sensors and RDGs and...
Simonson, Amy E.; Behrens, Riley
Attribution: New York Water Science Center, Water Resources, Groundwater and Streamflow Information Program, United States of America
A.E. Simonson and R. Behrens, Measuring Storm Tide and High-water Marks Caused by Hurricane Sandy in New York. In: J. Bret Bennington and E. Christa Farmer, editors: Learning from the Impacts of Superstorm Sandy, Oxford: Academic Press; 2015, p. 7-19.
Monitoring storm tide and flooding from Hurricane Sandy along the Atlantic coast of the United States, October 2012
The U.S. Geological Survey (USGS) deployed a temporary monitoring network of water-level and barometric pressure sensors at 224 locations along the Atlantic coast from Virginia to Maine to continuously record the timing, areal extent, and magnitude of hurricane storm tide and coastal flooding generated by Hurricane Sandy. These records were...
McCallum, Brian E.; Wicklein, Shaun M.; Reiser, Robert G.; Busciolano, Ronald J.; Morrison, Jonathan; Verdi, Richard J.; Painter, Jaime A.; Frantz, Eric R.; Gotvald, Anthony J.
Attribution: South Atlantic Water Science Center (SAWSC), Water Resources, Region 2: South Atlantic-Gulf (Includes Puerto Rico and the U.S. Virgin Islands), Hurricane Sandy
Monitoring storm tide and flooding from Hurricane Sandy along the Atlantic coast of the United States, October 2012; 2013; OFR; 2013-1043; McCallum, Brian E.; Wicklein, Shaun M.; Reiser, Robert G.; Busciolano, Ronald ; Morrison, Jonathan ; Verdi, Richard J.; Painter, Jaime A.; Frantz, Eric R.; Gotvald, Anthony J.

redpajama_set_name: RedPajamaCommonCrawl


I've been a fiber artist for 10 years, but clay has always intrigued me. I've been pursuing clay now for 5 years.
None currently, but I'm sure they will come.
The movement of the potter's wheel is relaxing and mesmerizing to me. I am challenged by seeing how far I can "stretch" a wheel thrown piece. Just as the years of creating traditional forms in fiber art led me to creating colorful, abstract forms, my work with clay strives to push the limits of the medium by altering the form in a way that maintains its functionality.
Karen has worked in a variety of mediums in the last 25 years. She studied clay at the University of California La Jolla and was later awarded a position as apprentice at Art Center West in Roswell, GA. Both of these schools gave her an opportunity to look at a variety of approaches to the medium and influenced her in different ways. After studying basic shapes in depth, she worked on a variety of techniques to develop her personal style. Through much exploration, altering forms in diverse and artistic ways became her primary interest, and continues to challenge her today.
Before working in clay, Karen was a fiber artist. She had a studio at the Torpedo Factory in Alexandria, VA for 10+ years and taught at the Smithsonian Art School in Washington, DC. Her fiber work was sold to designers, galleries, and hotels as well as to the public who visited the Torpedo Factory. Karen also showed her fiber work at American Craft Council shows in Baltimore, Reinbeck, NY and San Francisco in addition to juried shows in Florida. She has been published in Better Homes and Gardens and other publications.


text:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;

namespace UserInterface {
	class ViewModel : INotifyPropertyChanged {

		private List<INode> _nodes = new List<INode>();

		public ViewModel() {

		}

		public List<INode> Nodes {
			get { return _nodes; }
			set {
				_nodes = value;
				NotifiyPropertyChanged("Nodes");
			}
		}

		void NotifiyPropertyChanged(string property) {
			if (PropertyChanged != null)
				PropertyChanged(this, new PropertyChangedEventArgs(property));
		}

		public event PropertyChangedEventHandler PropertyChanged;
	}
}

redpajama_set_name: RedPajamaGithub


An entire housing complex built in a crescent shape!
Bath – a UNESCO world heritage site and a city made of all the same stone! There really is only reason to come to this city which is to check out the roman baths! Just kidding there are some architectural delights to visit along the way.
3.1 Something Something? Nothing Nothing?
Bath is a relatively easy town to get to from all sides. From Cardiff I took a train which is within 10 minutes of the city center. The central bus station is also located right outside of the train station so its quite convenient no matter which form of transportation you take. The train was about 30 minutes from Cardiff. If you are coming from London, where most visitors come from, the journey is about 1.5 hours.
Surprisingly this small little town had a free walking tour and it was quite high quality. The tour was actually led by a long time resident of the city so the history lessons were quite accurate. The actual tour will lead you to see all of the main sites of the city including: the royal crescent, the abbey square, the church, the old town walled areas, and the outside of the roman baths. The tour presents some interesting information about how Bath was developed as a city and some of the funny history behind Bow Nash. Can you find the yellow door?
Now this is what I came here for, the first part of the tour reveals some mini models on what the bath probably looked like during the Roman times. The actual baths themselves are disgusting and hence why they haven't been used in years. The baths actually house multiple rooms including some for cooling, heating, super heating, and rinse off. The best part is seeing the heated room as it was built above a stove oven essentially. Anyone getting a massage in the heated room actually needed to wear Sandals because the floor would get so hot it could burn your feet. At the end of the tour you get to taste some of the water tasted like blood to me. Overall I liked the amount of extra history that the attraction tries to provide for you and I think its worth the high cost.
Sitting at the Bottom of the Roman Baths!
The View of the Roman Baths From the Entrance!
Real Ruins left from the Roman Times!
I tried some small mini dishes at this restaurant to see if what English tapas were about! The first dish was some green harassa spice chicken wings. The actual harassa gave it a smoky dry taste but not like BBQ sauce. The taste was also very shortlived surprisingly with absolutely no aftertaste. I wouldn't recommend this to everyone especially because the texture of the chicken wing was also changed due to this seasoning. The second small dish was pork with pea mush! The pork cut was pork belly that was actually deep fried. I loved how crispy the pork was and how well it complemented the pea mush. Definitely a recommended dish to try!
Fried Pork Belly with Green Pea Mush!
My time in Bath was so short but I was able to hit the main attraction of the city as well as learn the history in different parts of the city. Coming to this city really only takes a day and can be easily completed as a day trip while visiting London. During this time I met a friend called Ming-Han who I ended up spending time with in London (coming up in the next post)!


text:
"US Must Have Immigration, but Israel Not"—Leading Jewish Supremacist
by Staff	 August 27, 2013 438 Views
America must have "open immigration" but "non-Jewish immigration to Israel" will "challenge the Jewish character of the state"," a leading Jewish Supremacist and executive director of the Jewish Community Relations Council (JCRC) of Boston, Jeremy Burton has said on his Twitter account.
Twittering about the immigration debate currently underway in the US, Burton stated that "Fairly open US immigration supports and sustains the immigrant character of our nation."
Another Twitter user, identified by his Twitter account name as "Daniel Sieradski" answered back "And Israel's not an immigrant nation?"
Burton, whose JCRC is a member organization of the Jerusalem Center for Public Affairs (JCPA), one of the leading pro-Zionist lobby groups based in Israel, then tweeted back "Non-Jewish immigration to Israel has the potential to challenge the Jewish character of the state."
Sieradski tweeted back "That's the same thing white nationalists say about immigration to the U.S. and its effect on the whiteness of America" to which Burton responded "All of which is to say that the nuances of US and Israel are different and it is simplistic thinking to accuse orgs of hypocrisy."
Burton then added as an afterthought: "And we Jews, by and large, don't support the American whiteness argument."
Indeed they don't! In fact, the 50 largest Jewish activist organizations in America have a unified pro-immigration stance for America. Their coordinating body is called the Council of Presidents of Major Jewish Organizations and there member groups have literally billions of dollars at their disposal. The Council supports wide open borders for the U.S. while at the same time supports the State of Israel which has one of the most stringent ethnic (racial) immigration policies of any nation on earth!
So what gives? How do policies that the same Jewish dominated media and Jewish-influenced political establishment would describe as "racist" if promoted by any European nation, not face any serious criticism. In fact they get billions of American taxpayers' dollars to support their racist state built on terrorism, ethnic supremacism and Jewish supremacism!
Any clear thinking person can see this hypocrisy as proof of those powers that are truly supreme in the American establishment.
Burton is no small player in the Jewish Supremacist establishment. According to his official biography, Burton's was the Senior Vice President of Programs at the Jewish Funds for Justice, and Vice President of Programs at the Jewish Funders Network. He has also served as Executive Director of Amos: The National Jewish Partnership for Social Justice, housed at the Jewish Council for Public Affairs.
In addition, the Jewish Telegraphic Agency "included him in their 2010 'Twitter 100' list of the most influential Jewish voices on Twitter."
#Immigration #Jewish Supremacist hypocrisy
Previous Post The Next Big Lie and the Next War: This Time Syria!
Next Post Jewish Press Confirms that Zionist Supremacists are Behind War Propaganda
Today Dr Duke and Andy Hitchcock – Kushner & the ZioCrazies who Prepare for the Jewish Anti-Christ!
by Staff	 April 3, 2019
Dr. David Duke: No! I Did not Endorse Tulsi Gabbard for President.
by Staff	 February 6, 2019
Zionists Expose "Dual Loyalty," as Single Loyalty – Only to Israel and the Tribal Agenda


Will the New CFPB Even Crawl?
Last July, the new Consumer Financial Protection Bureau (CFPB), conceived by Congress in the post-crash financial regulatory overhaul, came into being with great fanfare, carrying hopes it would champion consumer interests against the types of predatory practices that had helped bring about the "Great Recession." Six months later, the question can be asked: was the CFPB stillborn, a victim of "infanticide" by the same Congress that gave it birth?
Under its statute, the CFPB cannot carry out its most important functions, including regulating "non-bank" financial businesses, such as payday lenders, mortgage companies and debt collection agencies, until it has a director. Exploiting this leverage, Republican senators recently filibustered the nomination of President Obama's choice to head the agency, former Ohio Attorney General Richard Cordray, a highly qualified candidate whose credentials were not in dispute. These senators opposed the appointment of a director until the structure and powers of the CFPB were fundamentally altered by replacing a single head with a bipartisan commission, subject the agency's budget to the congressional appropriation process (funding currently comes from the Federal Reserve), and making it easier for other banking regulators to veto the CFPB's rules.
With Democrats unwilling to bow to these demands, the Cordray nomination seemingly died, leaving the CFPB leaderless and powerless. Without a director, it can do little more than take consumer complaints, promote consumer financial education and issue reports. Its most concrete action has been to propose simplified mortgage forms. These and other initiatives would remain unenforceable, however, and the ambitious reform agenda of its backers still stymied, until a director was appointed.
Defiantly, President Obama has now done just that, without Senate confirmation. On January 4, exercising his constitutional appointment power while Congress is in recess, he named Cordray to the CFPB post. The appointment is only short-term, however, and more problematically, Congress technically was not in "recess," (thanks to GOP wrangling of Senate procedure), which places the appointment in uncharted legal territory and invites an almost certain court challenge. Thus, even with the President's daring end run maneuver, the effectiveness and future of the CFPB are still very much in doubt.
Consequently, this could still leave the FTC as the primary cop on the consumer financial protection beat – a duty this hyper-aggressive FTC will be only too eager to discharge. Alone or with state authorities, the FTC has brought nearly 500 cases during the past three years aimed at protecting the "Great Recession" consumer from allegedly dubious schemes, including debt relief, foreclosure rescue, payday lending, grants and business opportunities. Most recently, it obtained multi-million dollar judgments in a mortgage modification and foreclosure relief action; a court order requiring a payday lender to pay nearly $300,000 for illegally trying to garnish borrowers' wages; and a $29.8 million judgment in a government grants case.
With 13 million Americans still unemployed, and millions more still struggling to get by, the FTC has said that consumer financial protection will continue to be a top priority. DR financial marketers should remain on high alert. While the CFPB may be handcuffed for now, the fiercely energized FTC remains on the enforcement prowl.


text:
package alien4cloud.orchestrators.events;

import alien4cloud.events.AlienEvent;
import lombok.Getter;

/**
 * Event dispatched before deleting an orchestrator.
 */
@Getter
public class BeforeOrchestratorDeleted extends AlienEvent {
    private final String orchestratorId;

    public BeforeOrchestratorDeleted(Object source, String orchestratorId) {
        super(source);
        this.orchestratorId = orchestratorId;
    }
}


text:
US media resembling Pravda (The Sunday Guardian)
"Pravda" (truth) was the official newspaper of the Communist Party of the Soviet Union, and the "truth" detailed in its columns was reality as defined by the CPSU. The clearly capable White House Press Secretary has ensured that not just the mainstream media but leading social media influencers reflect the conflict with Russia as defined by the White House. Jen Psaki deserves a raise. There is no need any more for the followers of mainstream media or influencers to access their favourites. All that they need to do is view clips on YouTube of Jen Psaki, Joe Biden, Antony Blinken and other officials who present the "truth" in the manner that the White House regards as advantageous for the Democratic Party in the 2020 midterms. It has not been a secret that media in the Russian Federation is overall respectful of President Putin. They apparently do not share the view, couched in terms that these days passes for diplomacy in the NATO bloc, that Putin is at best insane and at worst, an incarnation of Adolf Hitler. NATO channels endlessly repeated the clip of a charming lady holding a placard against the war and state propaganda in a Russian news channel. The young lady has apparently been persuaded by her VPN access to NATO channels that it is only a matter of weeks if not days before Putin gets toppled in Moscow in the manner that President Viktor Yanukovich was toppled by street violence in Kyiv in 2014. When that happy event occurs, she expects that Putin's successor Alexei Navalny will appoint her as Information & Culture Minister. This would win the support of Joe Biden and Boris Johnson, both of whom have become ardent admirers of the comely media personality after her 15 seconds of fame on a Russian television channel. Should Putin not oblige those predicting his imminent doom, the young lady is likely to earn the ire of ordinary Russians for embracing the views of western media so publicly. Following the same rulebook, prominent voices in the US who are talking truth to power such as Tulsi Gabbard or Tucker Carlson are being branded as traitors. Exactly the way those who protested against the US rush to disaster in Vietnam initially were. Tucker Carlson and Tulsi Gabbard need to be in the US Senate, which appears to be sinking in credibility as an independent wing of governance because of being programmed to follow the narrative presented by the White House and mainstream media. The rising blood lust against Russia has risen to such a pitch that voters are calling for yet more escalatory steps than the many carried out rather than favouring the path towards an outcome that would protect the world from the damage that the present course would cause just a few months from now.
Decades ago, after the Iraq invasion of 2003 against Saddam Hussein, this writer had the privilege of meeting Andrew Marshall, one of the finest strategic minds of the 20th century. In the Pentagon, when presented with the view by an ordinary Indian professor that US troops in uniform should leave Iraq's population centres alone and concentrate on border security (or that having a US Administrator rather than a lifelong citizen of Iraq was certain to create public resentment at such alien domination), Marshall was attentive, while others were dismissive of such conclusions at the early stage of the US-UK (aka the former colonial power) occupation of Iraq. Media in the US and in other countries active in the post-invasion occupation of Iraq uniformly bought the NATO narrative, much as they are doing now in the case of the war in Ukraine. Labelling dissenting voices as treason and adopting the same degree of objectivity as Pravda in its heyday are certain steps towards disaster. During the Vietnam War, when it became clear that metrics of success such as body counts were giving a misleading impression of the conflict's trajectory, Senator J. William Fulbright held hearings in which he brought to account the White House for the war. It is difficult to imagine Chuck Schumer or Mitch McConnell showing similar moral courage. If the McConnell was the lapdog of President Trump, Shumer has accepted that role under President Biden. Their absence of moral courage fused with a paucity of common sense is ensuring that the US lead NATO towards a disaster that may scar the remainder of this century. Were Biden as fortunate as Clinton, he may in time leave the White House in the hands of a Republican successor and escape responsibility for the catastrophe begun under his watch, in the manner Bill Clinton dodged the responsibility for nurturing terrorism in Afghanistan and in turbocharging the PRC economy through generous unilateral trade concessions that caused the trade deficit between China and the US to soar. Clinton left the White House in the nick of time, although Biden and his party may not be so lucky. Latest around the time last year that Biden re-installed the Taliban in power in Afghanistan last year, the folly of his policy on Afghanistan and Russia will become inescapable to voters. There seems no longer any point in trying to get across even a mildly alternative view than NATO "truth" to the Guardian, the New York Times or too many other publications. They claim to print "all the news that's fit to print", when what is meant by that is "all the news that NATO leaders considers fit to print". Poor world.
US media resembling Pravda
Nothing official about it, but PRC Foreign Ministe...
Don't oppose K-Rail Silverline project (The Sunday...
President Biden, India is not shaky, your base is ...
India's stance independent on NATO-Russia row (CHI...
Sino-Russian currency war on Atlantic powers gets ...
President Biden needs a reality check on Ukraine (...
Double Engine power succeeds (The Sunday Guardian)
Biden's folly: Recreating Afghanistan in Ukraine (...


text:
Manchester United manager Jose Mourinho changes his philosophy ahead of transfer window
Man Utd manager Jose Mourinho believes he will need to make major changes to mount a title challenge next season.
James Robson
Jose Mourinho's summer rebuilding at Old Trafford will focus on his search for players he can trust, rather than 'like.'
The Manchester United manager believes his squad is in need of significant surgery after ending the season empty-handed.
Despite securing second place in the Premier League - United's highest finish since Sir Alex Ferguson's retirement - Mourinho's faith in his squad has been pushed to the point that he believes only an overhaul can turn them into title winners. Misgivings that took hold in December were confirmed in the final weeks of the campaign that saw points dropped against West Brom, Brighton and West Ham.
Defeat to Chelsea in the FA Cup final was the last chance of a trophy - and potentially the final straw in relation to the futures of a number of players.
EXCLUSIVE Yaya Toure: I want to play with Paul Pogba
Mourinho had long-accepted his squad was not populated with elite-quality players. But he hoped the character of a squad - albeit in transition - could make a genuine tilt at the title.
Ultimately, he believed a mental fragility prevented United from seriously rivalling Manchester City.
"For me it is not easy because I am very consistent," he said last month. "Sometimes when I see that some kids - for me they are still kids - are a little bit up and down. Sometimes after a good moment, the bad moment will arrive as a consequence of not the correct reaction to the big moment, I feel quite frustrated. I don't forget the points we lost against Newcastle, Huddersfield, Stoke City, West Bromwich."
Mourinho believes major surgery is required this summer.
Mourinho's increasing criticism of his players underlines his growing frustrations - and a change in attitude.
On the eve of last season, he spoke of his affection for his players after delivering two trophies in his first 12 months at United.
"I like the guys," he said. "I keep saying the same thing. We are not the best squad in the world and don't have the best players in the world, or of we do then we have some, not eight or nine or ten like some other big clubs have.
"But I like them all. I like to work with them, I like to live with them and I like them."
Manchester United close to Fred transfer
Sentimentality will make way for ambition as Mourinho aproaches his third season in charge.
As many as three defenders are on his wanted list after telling executive vice chairman Ed Woodward he needs to emulate City's incredible backing of Pep Guardiola in the transfer market.
Two midfielders and another forward will also be needed to give him the depth he believes it will take to overturn the 19 points difference between first and second this season.
Manchester United - key information
Crucially, he is targeting experience.
Toby Alderweireld - the top central defensive target - is 29.
Juventus left back Alex Sandro is 27 and long-term forward targets Gareth Bale and Willian are 28 and 29 respectively.
Mourinho is targeting winning knowhow and a steeliness his side simply didn't show enough of last season.
Whether he 'likes' them or not - is not high on his list of priorities.
Get all the latest Manchester United news first with our new app. Download it here now


text:
German report criticizing Turkey highlights growing tensions within NATO
Johannes Stern
Relations between Ankara and the Western powers—particularly Berlin—have reached new lows, more than four weeks after the aborted military coup against Turkish President Recep Tayyip Erdoğan, which by all indications enjoyed at least the tacit backing of Washington and sections of the German ruling elite.
On Wednesday, German Interior Minister Thomas De Maizière told German regional broadcaster RBB: "There's nothing to regret," when asked if he regretted the release of a paper prepared by his ministry. The Interior Ministry document accuses Turkey of having been "a central platform in the Middle East" for Islamist groups since 2011 and criticizes Erdoğan for having an "ideological affinity" to Hamas in Gaza, the Muslim Brotherhood in Egypt, and armed Islamist forces in Syria.
The report, largely drawn up by the German Federal Intelligence Service (BND), came as a confidential answer to a parliamentary query by the Left Party (Die Linke). It unleashed fury within the Turkish government after it was disclosed by German public broadcaster ARD earlier this week.
"The allegations are a new manifestation of the twisted mentality, which for some time has been trying to wear down our country by targeting our president and government," the Turkish Foreign Ministry said in an official statement. It also accused Berlin of double standards, demanding that the German government offer Turkey more support against the Kurdistan Workers Party (PKK).
"It is obvious that behind these allegations are some political circles in Germany known for their double-standard attitudes in the fight against terror," the statement continued. "As a country which sincerely fights against terror of every sort whatever its source, Turkey expects that its other partners and allies act in the same way."
The hostile exchange between the German interior ministry and the Turkish foreign ministry—each openly accusing the other of supporting terrorism—highlights the stark deterioration in relations between the Western powers and Ankara that had already developed prior to the July 15 coup attempt.
As far back as June, a resolution passed by the German parliament (Bundestag) describing the mass deaths of up to 1.5 million Armenians in the Ottoman Empire as "genocide" led to a sharp reaction in Ankara. Erdogan warned that Berlin's move could "damage… diplomatic, economic, political, commercial and military relations between the two countries."
Another row followed weeks later, when Turkey blocked a visit by German parliamentarians to 250 German soldiers stationed at Incirlik air base in southern Turkey. Not only does Incirlik serve as the main base for the US-led bombing campaign against Syria and Iraq, but it turned out to be at the center of the failed putsch against Erdoğan.
The coup attempt took place amid a stark shift in Turkish foreign policy towards Russia, after Erdoğan became increasingly concerned that the Western-backed regime change operation in Syria is strengthening separatist Kurdish forces backed by the US and Germany.
The tensions that have continued to grow since the failed coup between Washington and Berlin on the one side, and their nominal NATO ally Turkey on the other, confirm the analysis of the World Socialist Web Site. It explained from the beginning that the coup has been organized to prevent a possible alliance between Russia and Turkey and possibly Iran and China that would cut across Western foreign policy in the Middle East—in particular, plans to overthrow Russia's last remaining Arab ally, Syrian President Bashar al-Assad.
In the past days, Western officials and foreign policy strategists attacked Ankara sharply for purging pro-Western putschists in the Turkish army, and raised concerns over Ankara's rapprochement with Moscow after Erdoğan met with Russian president Vladimir Putin in St. Petersburg last week.
"Coup-proofing doesn't work except that it fractures and divides armed forces," complained Aaron Stein, a Turkey expert at the Washington-based think tank Atlantic Council.
Soner Cagaptay, an expert on Turkish security issues at the Washington Institute for Near East Policy warned: "For the first time in recent memory, some in Ankara are questioning Turkey's NATO membership and discussing whether the country should instead move toward becoming a 'friend' of Russia."
NBC's foreign correspondent Matt Bradley reported that "among the newly promoted leaders are a group of officers who are typically distrustful of the U.S. and NATO and seek a closer relationship with Russia and military powers further east."
On August 12, Iranian Foreign Minister Javad Zarif visited Ankara. Unlike Western leaders, he congratulated "the Turkish nation for the defiance they showed against the coup-plotters." He praised the improvement of Russia-Turkey relations and their new efforts to stem the conflict in Syria. "We also have great ties with Russia on the [Syrian] issue, and we believe that all parties must cooperate to provide security and peace and stop the conflicts [in the region]. We are ready to co-operate with both Turkey and Syria on this issue," he said.
In an interview with the Turkish Hurriyet Daily News this week, Turkish defense minister Fikri Işık indicated that Ankara is indeed considering a closer strategic and military alliance with Russia and China: "Our priority is our allies, but that cannot prevent us from cooperating with Russia or China when necessary. If our allies' approach remains to keep Turkey at arm's length, that will force us to develop our own capacity with other types of cooperation. We can't shut the door to non-NATO countries like Russia or China."
As relations warm between Russia, Iran, China and Turkey in the Middle East, and with US-backed Islamist forces on retreat in the northern Syrian city of Aleppo, the Western powers are increasingly building up Kurdish militias as proxies to further their imperialist interests in the region.
On August 12 the strategically important Syrian town of Manbij near the Turkish border was reconquered from the Islamic State of Iraq and Levant (ISIL) by the Syrian Democratic Forces (SDF) under the coordination of the US Central Command. The strongest force within the SDF are the Kurdish People's Protection Units (YPG). At the same time Germany began resupplying the Kurdish Peshmerga fighters in Northern Iraq.
According to the Suddeutsche Zeitung, around 70 tonnes of German weaponry—including 1,500 G36 assault rifles, 100 anti-tank missiles and three armoured vehicles—arrived on Tuesday in Erbil, the capital of the autonomous Kurdish region.
In Turkey itself a series of bombings targeting Turkey's security forces, blamed on Kurdish rebels, killed at least 11 people and wounded 226 others, Turkish media reported on Thursday. Two of the attacks were car bombings targeting police stations in eastern Turkey, while the third—a roadside blast—hit a military vehicle carrying soldiers in the southeast of the country.
The independent European media platform EurActiv reported yesterday that, in a move which could amount to virtual breakdown of the US-Turkish alliance, Washington has started transferring its nuclear weapons stationed at Incirlik air base in Turkey to Deveselu air base in Romania. According to an anonymous source, the transfer is very challenging in technical and political terms: "It's not easy to move 20+ nukes."
As the danger of direct conflict between the great powers grows in the Middle East, tensions are not only exploding between NATO member states, but also within the Western governments themselves.
In an unprecedented move, the German foreign ministry led by Frank-Walter Steinmeier (SPD) dismissed the German interior ministry's report attacking Ankara. After the meeting between Erdogan and Putin, Steinmeier had declared: "There won't be a solution to the civil war in Syria without Moscow and without Iran, Saudi Arabia or Turkey."
TurkeyGermanyNATOWestern EuropeEuropeWar and militarism


text:
\section{Introduction}

Superluminous supernovae \citep[SLSNe;][]{Gal-Yam2012} are rare stellar explosions, radiating $10 - 100$ times more energy than normal supernovae.  Their extreme peak luminosities and slowly evolving light curves (LC) cannot be explained by standard models based on radioactive decay of $^{56}$Ni.  Although the detailed physics of SLSNe is not understood, a general consensus from published studies is that their progenitors are massive stars, $>30 - 100\,M_\odot$ \citep{Quimby2011,Gal-Yam2009,Smith2007,Ofek2007,Nicholl2014,Yan2015}.  Observations of SLSNe have highlighted our poor understanding of the late stages of massive star evolution, especially mass loss processes. According to standard stellar evolutionary models, massive stars ($>30\,M_\odot$) are thought to have very little hydrogen at the time of supernova explosion \citep{Georgy2012,Smith2014,Langer2012}. However, detections of two types of SLSNe -- one with and one without  H and He (SLSN-II and SLSN-I respectively, Gal-Yam et al. 2012) --
illustrate a much more complex picture of massive star evolution, and indicate
that their massive progenitors must have two distinctly different mass loss histories. Progenitors of SLSN-I lose their H-envelope long before core explosion.
In contrast, for a progenitor of a SLSN-II, the stripping of its H-envelope must be incomplete, and the bulk of the H-rich medium is still either loosely bound to or very close to the progenitor at the time of the supernova explosion.

The observational appearance of a SLSN is largely affected by its progenitor mass loss history. Broadly speaking, at the time of explosion, the progenitor star of a SLSN-II still retains a substantial H-envelope, and its early-time spectra show the characteristic H$\alpha$ emission with both narrow and broad components, indicating ejecta interaction with extended, dense H-rich circumstellar medium (CSM), like a SN\,IIn.  In contrast, the progenitor star of a SLSN-I must have lost most of its H and helium material long before the supernova explosion,  and its early-time spectra detect no H and helium features. However, there must be some SLSNe falling between these two simple categories. For example, a progenitor star could retain a small amount of H material and has no substantial CSM. When such a star explodes, its early-time spectrum would have H$\alpha$ emission, but not like SN\,IIn with both narrow and broad components indicating ejecta-CSM interaction. This type of transient may have been detected already, for example, SN\,2008es, SN\,2013hx, PS15br and possibly CSS121015 \citep{Miller2009,Gezari2009, Benetti2014,Inserra2016a}, which show only broad H$\alpha$ emission in the photospheric phase. Another example would be a SLSN-I progenitor which has lost all of the H-envelopes, but only shortly before the supernova explosion. In such a case, the H-rich material would not have enough time to be completely dispersed into the interstellar medium (ISM) and would be located close enough so that when the supernova explodes, the SN ejecta would be able to catch up with this H-shell, and the subsequent interaction would produce broad H$\alpha$ emission in late-time spectra.  Our observation of SLSN-I iPTF13ehe suggests that indeed such events exist \citep{Yan2015}.

Systematic follow-up observations have led to discoveries of  new features from SLSNe-I, including double peak LCs at early times \citep{Nicholl2015, Vreeswijk2016, Smith2016}, and broad H$\alpha$ and [O\,III]\,4363 \&\ 5007\AA\ emission in late-time spectra of SLSNe-I \citep{Yan2015,Lunnan2016}.
Well sampled light curves of SN\,2015bn and iPTF13dcc have also resulted in discoveries of LC undulations of SLSNe-I, suggesting possible ejecta interaction with H-poor CSM \citep{Nicholl2016,Vreeswijk2016}.

In this paper, we report two new SLSNe-I events, iPTF15esb and iPTF16bad, showing late-time H$\alpha$ emission, similar to iPTF13ehe.  In addition, the LC of iPTF15esb shows strong light curve undulations. This paper reports the new observations and presents a coherent analysis of all three events.  We also discuss the implication for various physical models and the whole SLSN-I population.
Throughout the paper, we adopt a $\Lambda$CDM cosmological model with
$\Omega_{\rm{M}}$\,=\,0.286, $\Omega_{\Lambda}$\,=\,0.714, and $H_0$\,=\,69.6\,$\rm{km}\rm{s}^{-1}\rm{Mpc}^{-1}$ \citep{Planck2015}.

\section{Targets and Observations }
\label{sec_obs}

We discuss a sample with three SLSNe-I discovered by the Intermediate Palomar Transient Factory (iPTF), including two new events (iPTF15esb and iPTF16bad) and one already published event \citep[iPTF13ehe;][]{Yan2015}.  The basic properties and  the coordinates are summarized in Table~\ref{sample}.  These three events are at a similar distance, $z\sim 0.224 - 0.3434$), the median redshift of PTF SLSNe, due to the survey sensitivity limit.

All three events have the identical Galactic extinction of E($B - V)=$0.04\,magnitude (Schlafly \&\ Finkbeiner 2011). All fluxes are corrected
assuming the extinction law of \citet{Cardelli1989} with $R_V =  A_V/E(B - V) = 3.1$.  The host galaxies have either pre-explosion photometry from SDSS or measurements after the supernova has faded in the case of iPTF13ehe.  The host of iPTF15esb was detected by SDSS and has AB magnitudes of 23.65, 22.61, 21.90, 21.50 and 21.44\,mag in $u,g,r,i,z$ respectively. The host of iPTF16bad was not detected by SDSS in any band, and is fainter than 50\%\ completeness limits  of 22.4, 22.6, 22.6, 21.7, 20.9 in $u,g,r,i,z$ respectively \citep{Abazajian2003}. The absolute $r$ magnitudes are $>-18.5$ and $-18.5$\,mag for iPTF16bad and iPTF15esb respectively.  Compared with $M_r = -21.23$ for a L$^*$ galaxy at $z=0.1$ \citep{Blanton2003}, these two host galaxies are low luminosity dwarfs, typical of SLSN-I host galaxies as found by \citet{Lunnan2014}, \citet{Leloudas2015}, and \citet{Perley2016}.

Photometric observations of iPTF15esb and iPTF16bad were obtained with the Palomar 48 \&\ 60\,inch (P48 \&\ P60), the 4.3\,meter Discovery Channel Telescope (DCT) and the Las Cumbres Observatory Global Telescope Network (LCOGT).  All reported photometry in Table~\ref{tab:phot} and \ref{tab:phot2} is in AB magnitudes and calibrated to the SDSS $g, r, i$ filters. The P60 and LCOGT photometry is measured using a custom image subtraction software \citep{Fremling2016} and the P48 using the PTF Image Differencing Extraction (PTFIDE) software \citep{Masci2016}.

iPTF15esb and iPTF16bad have spectra at 12 and 4 epochs, covering the rest-frame phase (relative to the peak date) from +0 to +320 and +3 to +242\,days respectively (Table~\ref{tab:spec}).
These data were taken with the Double Beam SPectrograph \citep[DBSP;][]{Oke1982} on the 200\,inch telescope at Palomar Observatory (P200), the Low-Resolution Imaging Spectrometer \citep[LRIS;][]{Oke1995} and the DEep Imaging Multi-Object Spectrograph \citep[DEIMOS;][]{Faber2003} on the Keck telescopes.
The absolute flux calibration of these spectra is set by the broad band photometry at the corresponding phase.

\section{Analysis and Results}
\label{sec_results}

\subsection{Emergence of H$\alpha$ emission from H-poor SLSNe}
\label{sub_halpha}

The main result of this paper is the detection of broad H$\alpha$ emission in the late-time spectra of the three H-poor SLSNe.
Figure~\ref{samplespec} displays all of the available spectra for these three events, except two spectra of iPTF15esb at +270 and 320\,days, which show only features from the host galaxy.   In this figure, the spectra have not been host subtracted.  It is apparent that broad H$\alpha$ emission lines start to emerge at late-times between photospheric and nebular phases. And they persist until fairly late-times, $+123$, $+242$ and $251$\,days for iPTF15esb, iPTF16bad and iPTF13ehe respectively, as shown in  Figure~\ref{discoverfig}.
It is worth noting here that the LCs of iPTF15esb and iPTF16bad decline $\sim3$ times faster than that of iPTF13ehe (see \S\ref{subsec_LC} for details). Therefore, the last spectrum from iPTF15esb at $+123$\,d could be at a similar late phase as that of iPTF13ehe.
In addition, Figure~\ref{discoverfig} compares our late-time spectra with the spectrum of SLSN-I SN2015bn \citep{Nicholl2016b}, showing prominent broad H$\alpha$ emission and apparent weak [O\,I]\,6300\,\AA\ lines from our three events.  Quantitative discussion on [O\,I]\,6300\,\AA\ is included in \S\ref{sec_interp}.

\begin{figure*}
\plotone{fig1.pdf}
\caption{The plot displays all of the available spectra from our three SLSNe-I. We also plot the spectrum of SLSN-I Gaia16apd for comparison \citep{Yan2016}.  For visual clarity, we multiplied scaling factors to shift spectra apart, and very noisy pixels near 7800\AA\ are clipped in order to reduce the spectral overlapping.
\label{samplespec}}
\end{figure*}

One important constraint is when H$\alpha$ is first detected in the available spectra. The answer affects how we calculate the distance the ejecta have traveled since the explosion.
We display all of the available spectra for these three events in Figure~\ref{samplespec}.  All spectroscopic  data are listed in Table~\ref{tab:spec}, and will be made available via WISeREP \citep{Yaron2012}. For comparison, we also
include the high SNR spectrum of Gaia16apd, which is the second closest SLSN-I ever discovered \citep{Yan2016}.

It is clear from Figure~\ref{samplespec} that the answer to the above question is not obvious because before a spectrum becomes fully nebular, broad absorption features can make it difficult to determine where the true continuum is.  For examples, does the $+52$\,d spectrum for iPTF15esb (Figure~\ref{samplespec}) have H$\alpha$ emission?  And is the broad bump near 6500\AA\ in the $+0d$\,day spectrum of iPTF16bad H$\alpha$, or continuum between two broad absorption features?

\begin{figure*}[ht!]
\includegraphics[width=1\textwidth]{fig2.pdf}
\caption{The plot displays the late time spectra of iPTF15esb, iPTF16bad, iPTF13ehe, in comparison with that of SLSN-I SN2015bn. Strong H$\alpha$ emission are detected in the spectra of the first three events.
\label{discoverfig}}
\end{figure*}

To identify possible absorption features near the 6563\AA\ region, we run SYNOW, the spectral synthesis code \citep{Thomas2013}. This is a highly parametric code, including ion species, temperature, opacity, photospheric velocity, and the velocity distribution. However, it nevertheless provides a useful consistency check for line identifications. Figure~\ref{synow} illustrates the two model fits to the $+52$\,day and $+0$\,day spectra for iPTF15esb and iPTF16bad. Clearly, the observed features near $6000 - 6700$\,\AA\ can be well fit by a combination of Na\,I, FeII\,6299, 6248\AA, Si\,II\,6347, 6371\AA\ and CII\,6580, 7234\AA\ {\it absorption}, without any H$\alpha$ emission.
This is confirmed by the actual detections of these lines at $+30$\,day in SLSN-I Gaia16apd \citep{Yan2016}.
The broad bumps around 6500\AA\ in post-peak and pre-nebular spectra are also seen in SN\,2007bi and SN\,2015bn \citep{Gal-Yam2009, Nicholl2016}, and are considered to be a result of multiple absorption features.

By visual inspection of the available spectra, we take $+73$, $+97$ and $+251$\,day as the first dates when H$\alpha$ emission lines are clearly detected.  This method seems to be subjective, however, lack of full spectroscopic coverage gives much larger uncertainties in determining the true times when H$\alpha$ first appears.

\begin{figure}[!h]
\includegraphics[width=0.48\textwidth]{fig3.pdf}
\caption{Synow model fits to the $+52$\,day and $+0$\,day spectra of iPTF15esb and iPTF16bad. The important wavelength region is near $6300 - 6700$\,\AA\ where the H$\alpha$ emission is.  The apparent features at early times near 6500\,\AA\ are not due to H$\alpha$ emission, but produced by other broad absorptions surrounding that wavelength region. \label{synow}}
\end{figure}

\subsection{Light Curves: Are these three SLSNe-I special?  \label{subsec_LC}}

Figure~\ref{obsLC} presents the observed $g,r,i$ light curves of iPTF15esb and iPTF16bad. The derived bolometric light curves are shown in Figure~\ref{bolo} and Figure~\ref{3LC}.  It is immediately clear that the LCs of iPTF15esb are different from a typical SLSN LC, showing prominent undulations, stronger in the bluer bands. The three peaks are roughly separated by $\sim22$\,days. Detailed discussion on the iPTF15esb LC morphology is presented in \S\ref{subsec_15esbLC}.

The peak date for iPTF15esb is chosen as the first peak at MJD\,=\,57363.5\,days. iPTF16bad has very limited photometric data. However, its $r$ and $i$-band LCs in Figure~\ref{obsLC} are initially flat, suggesting we discovered this event just before peak.
Thus we set the peak date as MJD\,=\,57540.4\,days, the epoch of the first data.
We construct the bolometric light curve for iPTF15esb
using the following procedure.  We start with a pseudo-bolometric light curve which is an integral of the broad band photometry. At each epoch with a spectrum, we calculate a bolometric luminosity using a blackbody fit. The ratio between the bolometric and pseudo-bolometric luminosity gives the bolometric correction.  Without sufficient early-time photometry, we fit a power-law $L \propto t^2$ form to the pre-peak data points, and derived a minimum $t_{rise} \ge 10$\,days. The late-time decay rate follows $\propto \Delta t^{-2.5}$, much steeper than the $^{56}$Co decay rate (solid line in Figure~\ref{bolo}).
The bolometric LC for iPTF15esb is shown in Figure~\ref{bolo}.  The similar method was used for iPTF13ehe to get the bolometric light curve. iPTF16bad does not have many spectra. We derive its bolometric LC by assuming similar bolometric corrections to the pseudo-bolometric LC as that of iPTF15esb.

\begin{figure}[!ht]
\includegraphics[width=0.48\textwidth,height=0.59\textwidth]{fig4.pdf}
\caption{This figure presents the monochromatic light curves for $g,r,i$ bands. The Y-axis is observed flux densities in erg/sec/cm$^2/\AA$.  The $r$-band peak date is MJD=57363.5,  57540.4 and 56670.3\,days for iPTF15esb, iPTF16bad and iPTF13ehe respectively.
The black vertical lines at the bottom of the figure mark the dates of spectroscopic observations. The dashed line indicates the date when the H$\alpha$ emission feature starts to appear.  \label{obsLC}}
\end{figure}

One important question is: are these three SLSNe-I with late-time H$\alpha$ emission special and have distinctly different photometric properties compared to other SLSNe-I? The answer is relevant to understanding the nature of these events.  Figure~\ref{3LC} makes comparison of these three LCs with other events, including two slow evolving SLSN-I PTF12dam, SN2015bn and one fast evolving SLSN-I SN2010gx \citep{Vreeswijk2016, Nicholl2016, Pastorello2010}.

iPTF15esb and iPTF16bad have peak bolometric luminosities of $\sim$4$\times10^{43}$\,erg\,s$^{-1}$ ($-20.57$\,mag), whereas iPTF13ehe is more energetic, with $L_{peak}$$\sim$$1.3\times10^{44}$\,erg\,s$^{-1}$ ($-21.6$\,mag\footnote{Here we assume a solar bolometric magnitude of $4.74$.}).
Although an unbiased SLSN-I sample does not yet exist,  a simple compilation of 19 published SLSNe-I \citep{Nicholl2015} has a median $<L_{peak}> \sim 5.7\times10^{43}$\,erg\,s$^{-1}$ ($-20.7$\,mag).

In addition, one striking feature in Figure~\ref{3LC} is the large difference in evolution rates between the three LCs.  For iPTF15esb and iPTF16bad, their post-peak decay rates are fast, $\sim 0.05$\,mag/day, 3 times faster than that of iPTF13ehe, which is $0.016$\,mag/day. For comparison, $^{56}$Co decay rate is 0.0098\,mag/day.
The LC evolution of iPTF15esb and iPTF16bad is similar to the fast evolving SLSN-I SN2010gx \citep{Pastorello2010}, and iPTF13ehe is more like the extremely luminous, slowly evolving SLSN-I SN2007bi \citep{Yan2015,Gal-Yam2009}.  For a naive comparison with the compiled SLSN-I sample by \citet{Nicholl2015},  67\%\ have decay rates of $0.03 - 0.05$\,mag/day, and 33\%\ of $0.01-0.02$\,mag/day.  In addition, iPTF13ehe has a rise time scale of $83-148$\,days, implying a large ejecta mass of $70-220\,M_\odot$. The other two events do not have sufficient pre-peak data, but $t_{rise}$ in iPTF15esb is likely short, as suggested by the rising rate of the first two available observations before the peak.

We conclude that the photometric properties of these three events are clearly very different from each other. However, they are within the diverse ranges represented by the published SLSNe-I so far, with the possible exception of the unique LC morphology  of iPTF15esb. Therefore, it is possible that whatever physical processes responsible for late-time H$\alpha$ emission could also be relevant to the whole population.

\begin{figure}[!h]
\includegraphics[width=0.48\textwidth,height=0.35\textwidth]{fig5.pdf}
\caption{The derived bolometric light curve for iPTF15esb. The three peaks are separated from each other by roughly 22\,days.  The very late decay rate is $\propto t^{-2.5}$(dashed line), steeper than the $^{56}$Co rate (solid line). The vertical bars with $s$ at the bottom mark the dates with spectroscopic observations. \label{bolo}}
\end{figure}

\begin{figure}[!h]
\includegraphics[width=0.48\textwidth,height=0.39\textwidth]{fig6.pdf}
\caption{ The comparison of the three bolometric light curves.  The dashed vertical lines mark the dates when broad H$\alpha$ emission lines are detected. We also plot the bolometric LCs of SN2010gx (green line), a fast evolving SLSN-I and SN2015bn (yellow) and PTF12dam(cyan), two slow evolving SLSNe-I \citep{Pastorello2010, Vreeswijk2016, Nicholl2016}. \label{3LC}}
\end{figure}

\subsection{Other Spectral Properties}
In the following sections, we describe other properties measured from the full spectral dataset.
\subsubsection{Rapid Spectral Evolution}

As shown in Figure~\ref{samplespec}, the spectra of these three events are similar to each other at both early and late-time.  However, they are very different from the spectra of Gaia16apd in two aspects.  First, our spectra at maximum light do not have the full O\,II absorption series (5 features, as seen in Gaia16apd) at 4000\AA, the hallmark of a typical SLSN-I at early phases \citep{Quimby2011}.  Instead, their absorption features at 4200\AA\ could be one or two features of the full O\,II absorption series. This is supported by the matching between the early-time spectrum of Gaia16apd and that of our events. However, we caution
that in iPTF16bad, this identification of the partial O\,II absorption is uncertain. More detailed analyses and modelings are discussed in \citep{Quimby2017} and \citep{Gal-Yam2017}.

As pointed out by \citet{Mazzali2016},  O\,II absorptions arise from highly excited O$^+$ with an excitation potential of $\sim25$\,eV.  Such a high energy level implies that the excitation of O\,II levels is not in thermal equilibrium with the local radiation field. For example, $\gamma$-ray photons from radioactive decays could be a source of excitation energy. This effect is generally represented by a tunable parameter in models, for more details see \citet{Mazzali2016}.

The second prominent difference is that spectroscopically, iPTF13ehe and iPTF15esb seem to evolve faster than Gaia16apd, developing strong Mg\,I and Fe\,II blends at $-5$ and $+7$\,days, characteristics of a SLSN-I at later times, such as the Gaia16apd spectrum at $+30$\,day.  Naively, this may seem to suggest a lower ejecta mass because less material could cool down faster. This may be the case for iPTF15esb, but is not correct for iPTF13ehe at all because the slow rise time of its LC requires a very high ejecta mass \citep{Yan2015}.  This suggests that spectral evolution is affected by many other factors.
The situation for iPTF16bad is not clear due to lack of sufficient spectroscopic data.

\subsubsection{Higher Ejecta Velocities}
Figure~\ref{veltime} shows the ejecta velocity and the blackbody temperature as a function of time.
When possible, we use FeII\,5169\AA, a commonly used feature, to measure the velocity evolution with time. Other Fe\,II lines, such as FeII\,4924, 5018, 5276\AA\ are also used to cross check the results, as what is done in \citep{Liu2016}.
The exception is iPTF15esb at +0\,day, whose spectrum does not have a strong FeII absorption, and the ejecta velocity is estimated using O\,II. The O\,II feature in iPTF15esb is blue-shifted by $40$\AA\ relative to that of PTF09cnd at $-30$\,day with a velocity of 15000\,km\,s$^{-1}$ \citep{Quimby2011}. This implies the velocity of iPTF15esb at $+0$\,day is roughly 17,800\,km\,s$^{-1}$.  The same method is applied to iPTF13ehe and iPTF16bad.  We find that at maximum light, our three SLSNe-I have higher ejecta velocities than those of other published SLSNe-I, ranging between $9000 - 12000$\,km\,s$^{-1}$ \citep{Nicholl2015}.

The blackbody temperatures ($T_{BB}$) are estimated by fitting a blackbody function to the spectral continua.
At maximum light, the blackbody temperatures of these three SLSNe-I range from $\sim8000 - 14000$\,K, with iPTF13ehe being the coolest whereas iPTF16bad the hottest.  Compared with other SLSNe-I with strong O\,II absorption series such as PTF09cnd, SN2015bn, PTF11rks and Gaia16apd with maximum light $T_{BB} \sim 13000 - 15000$\,K \citep{Inserra2013,Quimby2011,Nicholl2016,Yan2015},  iPTF15esb and iPTF13ehe are indeed cooler at peak phase.  At the peak phase, iPTF16bad has a hotter temperature, which is shown by its steeper and bluer spectra in the early-times (Figure~\ref{samplespec}). This difference is confirmed by their broad band $(g - r)$ color versus time shown by Figure~\ref{colors}.
The lack of the full O\,II absorption series should not be associated with blackbody temperatures at the peak phase.  This is because the excitation of O\,II levels are certainly non-thermal.

\begin{figure}[h]
\includegraphics[width=0.47\textwidth,height=0.4\textwidth]{fig7.pdf}
\caption{The broad-band $(g-r)$ color as a function of time, showing the time evolution of the spectral slopes. \label{colors}}
\end{figure}

\begin{figure}
\includegraphics[width=0.5\textwidth,height=0.55\textwidth]{fig8.pdf}
\caption{Blackbody temperature and ejecta velocity as a function of time. The velocity is measured from FeII\,5169\AA. The details are discussed in the text.
\label{veltime}}
\end{figure}

\subsubsection{Broad H$\alpha$ Line Luminosities and  Velocity Offsets}

We perform simultaneous spectral fitting to the spectral continuum plus both narrow and broad H$\alpha$ components assuming a Gaussian profile. The narrow line fluxes are iteratively measured from the unsmoothed data.
Table~\ref{tab_linefit} lists the measured line luminosities and velocity widths.

One important question is whether the narrow H$\alpha$ line comes from the host or from the supernova.  The top panel in Figure~\ref{Halpha-flux} shows the integrated line luminosities as a function of time.  The narrow H$\alpha$ and [O\,II] lines show slight variations with time, and the changes are less than a factor of 2.
In contrast, the broad H$\alpha$ line luminosities vary by a factor of 10 with time. Furthermore, the centroids of the narrow H$\alpha$ emission are always at 6563\AA, whereas the centroids of the broad components change with time (see below).  In the case of iPTF13ehe, the spatially resolved 2-D spectrum shows that the narrow emission appears to be at the center of the host galaxy \citep{Yan2015}. We conclude that the narrow H$\alpha$ and [O\,II] emission lines are likely dominated by the host galaxies. Narrow H$\alpha$ emission from the supernovae may exist, but is too low luminosity to be detected by our data. The observed small variations are due to the combined effects of variable seeing and slit losses.

The middle panel in Figure~\ref{Halpha-flux} shows the broad H$\alpha$ line width (FWHM) as a function of time.  The FWHM of $\sim 6000 - 4000$\,km\,s$^{-1}$ should not be interpreted as the shell expanding velocity.  Similar to well studied SNe\,II powered by ejecta interaction with Circumstellar Medium (CSM),  the broad line widths likely indicate the velocities of the shocked material.  The H-rich CSM expansion velocity is probably much smaller, of an order of a few 100\,km\,s$^{-1}$.

These three events show an interesting trend in their velocity offsets between the broad and narrow H$\alpha$ components, as shown in the bottom panel in Figure~\ref{Halpha-flux}.  We find that initially the broad components appear to be blue-shifted relative to the narrow components (assuming host emission), and at later-times, become red-shifted.  The velocity offset for iPTF15esb at $+73$\,days is as high as +1000\,km\,s$^{-1}$, and decreases to $\sim -400$\,km\,s$^{-1}$ at later epochs.  Similarly in iPTF16bad, the offset varies from $+400$ to $-500$\,km\,s$^{-1}$ at +125 and $242$\,days. iPTF13ehe shows only positive velocity offsets (blue-shifted).

Figure~\ref{redwing} shows the +122\,d and +242\,d spectra for iPTF15esb and iPTF16bad.  Although noisy, the spectra show the excess emission at the red side of H$\alpha$ 6563\,\AA.  One possible explanation  is that initially the expanding H-shell could obscure the H$\alpha$ photons from the back side which is moving away from us. So we initially see more H$\alpha$ emission from the material moving toward us (blue-shifts).  In this model, at later-times when ejecta become more transparent, we should see more symmetric line profiles with no velocity offsets.  This is clearly not what we see at very late-times in our data.  So the red excess emission can not be explained by obscuration.
We also note that the observed positive velocity offsets in all three events could be in tension with the binary model proposed by \citet{Moriya2015} for iPTF13ehe, which predicts the equal probability of observing both positive and negative velocity offsets relative to the host galaxies.

\begin{figure}
\includegraphics[width=0.5\textwidth,height=0.6\textwidth]{fig9.pdf}
\caption{In three panels, we plot the H$\alpha$ line luminosities, line widths (FWHM) and line centroid shifts in km\,s$^{-1}$ as a function of time for the three events discussed in this paper. The X-axis shows the time in days in the rest-frame, relative to the peak date for each SLSN-I.
\label{Halpha-flux}}
\end{figure}

\begin{figure}
\includegraphics[width=0.48\textwidth]{fig10.pdf}
\caption{ Two spectra for iPTF15esb and iPTF16bad showing some excess emission red-ward of H$\alpha$ 6563\,\AA.  \label{redwing}}
\end{figure}

\section{Implications and Discussions }
\label{sec_interp}

\subsection{Nature of the H$\alpha$ emission and implication for helium in the ejecta}

One important question is where this hydrogen material producing the late-time H$\alpha$ emission is located.  One possibility is a residual hydrogen layer left over from incomplete stripping of the H-envelope.
This scenario can be ruled out because if there is any hydrogen in the ejecta, it is very difficult not to have any H$\alpha$ absorption at all near maximum light, as shown in the detailed modelings carried out by \citet{Hachinger2012}.  This is because ejecta density is usually much higher than $10^{7}$\,cm$^{-3}$, and the H recombination time scale is $\propto 10^{13}/n_e$\,seconds $\sim 11(n_e/10^{7})^{-1}$\,days, quite short.
An actual example is SN\,1993J, which is a type IIb SN with a very low mass of H ($<0.9M_\odot$). Although its pre-peak spectra have high blackbody temperatures, a weak H$\alpha$ emission is present at early phases \citep{Filippenko1993}.
For our three events, at post-peak before $+70$\,days, the photosphere temperatures are already low and there are no detectable H$\alpha$ features in all three events, even with ample spectral coverage between $+0$\,days and $+122$\,days for iPTF15esb.

The second possibility is a neutral, detached H-rich shell located at a distance from the progenitor star, possibly produced by a violent mass loss episode some time prior to the supernova explosion.  When the ejecta eventually run into this shell, the shock interaction ionizes H atoms, and subsequent recombination produces H$\alpha$ emission.  This idea was initially proposed for iPTF13ehe in \citet{Yan2015}.

The third possibility is proposed by \citet{Moriya2015}, where the progenitor is in a binary system with a massive, H-rich companion star ($>20M_\odot$). The explosive ejecta strip off a small amount of H from the companion star, which is then mixed in the inner regions of  the ejecta. This H-rich material becomes visible only when the inner layers of ejecta are transparent in the nebular phases.  This model predicts that depending on the orientation of the binary, there should be equal probability of seeing H-emitting material moving toward or away from us. The fact that we see blueshifts in all three events could be in tension with this prediction and disfavors this model.

Some quantitative parameters for the H-shell model can be derived from our observations.
In this scenario, the progenitor is a massive star, prone to violent mass losses.
Several decades before the explosion, it undergoes an eruptive episode,  ejecting all of the remaining H envelope.  Let us assume that the ejecta average speed is $<$$v_{ej}$$>$ and the time between the explosion and the time H$\alpha$ is first detected is $\Delta t$. The distance traveled by the ejecta, {\it i.e.} the radius of this shell, is thus $R = 8.6$$\times$$10^{15}({v \over 10^4\,km/s})$$\times$$({\Delta t \over 100d})$\,cm.   Our measured ejecta velocities range from $18000 - 15000$\,km\,s$^{-1}$ at maximum light to $\sim 6000 - 7000$\,km\,s$^{-1}$ at $+100$ to $+250$\,days.  So the baseline assumption of $<$$v_{ej}$$>\sim10,000$\,km\,s$^{-1}$ is not too far off.

The values of $\Delta t$ are not well measured for both iPTF15esb and iPTF16bad due to poorly constrained explosion dates. For iPTF15esb, a rough estimate of $\Delta t$ (Figure~\ref{obsLC}) is $73+20 \sim 93$\,days.  iPTF13ehe is a slowly evolving SLSN-I \citep{Yan2015}, with $\Delta t \sim 332$\,days.  Therefore, for these three events, the sizes of the H-rich shells range between $9 - 40\times 10^{15}$\,cm.  If the shell expansion speed is 100\,km\,s$^{-1}$, the time since the last episode of mass loss before explosion is $t_{erupt} \sim R/v_{shell} \sim R/100$\,km\,s$^{-1} \sim 30$\,yrs.  So approximately, the last episode of mass loss is only 30 years before the supernova explosion. This time could be as short as 10 years if the expansion speed is faster.  Such violent instabilities shortly before the supernova explosion could be a very common phenomenon for massive stars in general, as demonstrated for example by flash-spectroscopy of SN\,IIP iPTF13dqy and precursor outbursts in SNe\,IIn such as SN2009ip \citep{Yaron2017, Ofek2014, Margutti2014,Martin2013}.  At lower luminosities,  a similar and well studied example as our three events is SN2014C, which was initially discovered as an ordinary SN Ib, then evolved into a strongly interacting SN IIn over $\sim1$ year time scale \citep{Milisavljevic2015, Margutti2017a}.

Two commonly asked questions are:  (1) if this H-shell is present, why don't we see any H emission in the early-time spectra?  (2) why are our spectra not being obscured or absorbed by this shell?
This H-shell is likely to be neutral but optically thin during early-times. However,
if spectra were taken just hours after explosion, neutral H should have been ionized and we would have detected flash spectral features \citep{Gal-Yam2014,Yaron2017}, including H$\alpha$ emission .  For these three events, we don't  detect any early-time H$\alpha$ emission because by the time that our first optical spectrum is taken, the H-shell has already recombined. At a density of $n\geq10^7$\,cm$^{-3}$, the H recombination time $t_{rec} \leq 10^{13}/n$\,sec $\leq11$\,days.  For a H-shell with $R \sim 10^{16}$\,cm and a width of 10\%\,R, this density limit corresponds to a mass limit of $\geq0.01M_\odot$.

If the H-shell is neutral at pre-peak,  why don't we observe any H$\alpha$ absorption? H$\alpha$ absorption is produced when an excited H atom at $n=2$ absorbs a photon with $\lambda=6563$\AA, and moves up to $n=3$ level.  At temperatures of several thousands degree, most H atoms are in the ground state ($n=1$) because the excitation energy from $n=1$ to $n=2$ requires 10\,eV, implying a much higher temperature (100,000\,K). Without excited $n=2$ H atoms, there is no H$\alpha$ absorption. However, we predict that Ly$\alpha$ absorption ($n=1$ -$>$ $n=2$ transition) should be strong. Future late-time UV spectroscopy may confirm this for events such as ours.

The mass of this H-shell can be constrained by two other factors. When the ejecta run into the shell, H atoms are ionized again by the thermalized kinetic energy. One constraint is that this ionized H-rich CSM can not have very high electron scattering opacity, {\it i.e.} Thomson scattering opacity,  $\tau_{thomson} = \sigma_T n_e \Delta R \leq 1$ with $\Delta R$ being the width of the shell. Otherwise,  photons from the central supernova would have been absorbed.  This condition implies $M_{shell} \leq {4\pi f m_H R^2 \over \sigma_T}$, and $f$ is the filling factor, $R$ is the radius of this shell. Here $\Delta R$ is cancelled out when computing the total mass.
With the Thomson cross section $\sigma_T = 6.65\times10^{-25}$\,cm$^{2}$, we have $M_{shell} \leq 1.6f({R\over10^{16}\,cm})M_\odot$.  Assuming the width of this shell is only 10\%\ of the radius $R$, the implied electron volume density $n_e \sim 7\times10^9 ({R\over1.0^{16}\,cm})$\,cm$^{-3}$.  The H-shell upper mass limits range from $(1.6 - 30)f M_\odot$ for the three events discussed in this paper. In the case of a small filling factor $f\sim10\%$, the shell mass would be less than $0.2-3M_\odot$.  One scenario which could naturally explain such a powerful mass loss is the Pulsational Pair-Instability model \citep[PPISN;][]{Woosley2007, Woosley2016}.  Further support of this model is from the weak [O\,I]6300\AA\ emission in the nebular phase spectra, as discussed below.

In the H-shell scenario, the time interval between the supernova explosion and the mass loss episode which ejected all of the H-envelope is not very long, only several decades. During this period of time, additional mass loss episodes could remove some helium layers from the progenitor star, but it is very unlikely that all of the helium can be completely removed.  For example, \citet{Woosley2002} presented a model for a star with $M_{ZAM} \sim 25M_\odot$. Their Figure 9 shows before the supernova explosion, the most outer layer has roughly $5M_\odot$ of mixture of H and He, and just underneath that, there is a pure He layer with a mass of $\sim 1.5M_\odot$.   If we assume the mass loss rate of $10^{-4}$ to $10^{-6}M_\odot$/yr, similar to nominal wind mass loss rates, the time required to completely remove the pure He layer is $1.5\times(10^4  - 10^6)$\,yrs, much longer than several decades set by our observational constraint.

This implies that the ejecta of our three events may contain helium. Observationally, our early-time spectra do not detect significant helium features. However,  we caution that presence of weak helium absorption features is very difficult to confidently rule out because He\,I3888, 4417 and 6678\AA\ lines tend to be blended with other features such as strong Fe\,II4515\AA\, Si\,II3856, and C\,II6580\AA, as shown in Figure~\ref{16badHe}.  On another hand, the non-detection of helium features might not be very surprising because helium ionization potential is high, 24.58\,eV. This would require much higher temperatures than what our spectra show, or more likely,  non-thermal ionization conditions, for example, mixing with radioactive material such as $^{56}$Ni.

Indeed, this condition for non-thermal ionization of He probably exist for SLSNe-I, as suggested by commonly detected five O\,II absorption series around 4000\,\AA.
As argued in \citet{Mazzali2016},  the excitation of O\,II levels is from non-thermal process, such as  energetic particles from radioactive decays. What is relevant here is that these particles can also ionized He\,I (ionization potential of 24.6\,eV). So if helium is present in the ejecta, it is a puzzle why we do not detect any spectral signatures in the early-time data.

Another possible explanation for weak or absence of He features is that all helium is mixed into the outer H-envelope and the H+He outer layers were completely stripped off the progenitor stars before the supernova explosions. The ejecta contain no helium material.

\begin{figure}
\center{
\includegraphics[width=0.49\textwidth]{fig11.pdf}
}
\caption{ The iPTF16bad spectrum at $+0$\,day. We show that weak helium features are difficult to  rule out because they could be blended with other stronger features. As shown, HeI and other features are blued shifted by 14000\,km\,s$^{-1}$. \label{16badHe}}
\end{figure}

\subsection{Weak [O\,I]\,6300 doublet emission}

The [O\,I]\,6300 doublet emission is usually very strong for SLSNe-I and SNe\,Ic because of the following two reasons. First, these supernovae are thought to result from the explosions of massive C+O cores.  The ejecta should naturally contain a lot of oxygen.
 Second, the [O\,I]\,6300 line is a very efficient coolant in the nebular phase \citep{Jerkstrand2017}.  Therefore, it is common to see very strong [O\,I]\,6300\,\AA\ emission in core collapse SNe.
Figure~\ref{discoverfig} visually illustrates an apparent lack of [O\,I]\,6300\,\AA\ emission in the late time spectra of our three events. Given the noise level in our spectra, it is not immediately clear whether this apparent discrepancy is significant, however.

To address this question, we take three late-time spectra from SLSN-I SN2015bn at $+315$ and $+392$\,day \citep{Nicholl2016b}, SN2007bi at $+367$\,day \citep{Gal-Yam2009}, which all have prominent [O\,I]\,6300\,\AA\ emission.  We scale these three spectra to the distance of iPTF16bad, {\it i.e.} multiply by the square of the luminosity distance ratios, and then add the noise measured from the $+242$\,day spectrum for iPTF16bad.  The simulated spectra from this procedure are shown in Figure~\ref{simspec}.  Here the noise added to the input spectra is $\sigma \sim 9\times10^{-19}$\,erg\,s${-1}$\,sec$^{-2}$\,\AA$^{-1}$, measured from the 240\,\AA\ region centered at 6300\,\AA\ (excluding H$\alpha$) in the $+242$\,day spectrum of iPTF16bad.  This noise is then added as a Gaussian random noise to the input spectra. We note that because the input spectra do have their own noises,  the output simulated spectra may have slightly higher RMS than the true value.

From this simple simulation, we conclude that if the $+242$\,day spectrum from iPTF16bad were to have the same [O\,I] luminosity as that of the three input spectra, we would have detected this feature in our data.
This implies that our spectra at $\sim +240$\,days likely have intrinsically weaker [O\,I]\,6300\,\AA\ emission than the late-time spectra of the three comparison SLSNe-I. Unfortunately, at $z\sim 0.2 - 0.3$, the Ca\,II triplet at 8498\AA\ is redshifted out of the optical range,  so we do not know if the Ca\,II triplet is strong, and serves as an alternative cooling line for these three events. In the simulated spectra, the Ca\,II triplet is quite strong in SN2015bn, and absent in SN2007bi  (see \citealt{Gal-Yam2009}).

\begin{figure}
\center{
\includegraphics[width=0.49\textwidth]{fig12.pdf}
}
\caption{ The simulated late-time spectra at the distance of iPTF16bad and with the noise of the $+241$\,day spectrum of iPTF16bad.  The input late-time spectra are from SN2007bi and SN2015bn. The dashed line marks the [O\,I]\,6300\,\AA\ emission. \label{simspec}}
\end{figure}

The [O I] 6300, 6364 lines at nebular phase are very useful diagnostics of supernova ejecta. This is because these lines are  efficient coolant and typically re-emit a large fraction of heating energy of the O-material. More importantly, these lines become optically thin, and line luminosity $\propto M_{OI} n_e e^{-\Delta E/T(t)} $ in the Non-local thermal equilibrium (NLTE) phase, as discussed in details in \citep{Jerkstrand2017b}.

The apparent weakness of the [O\,I]\,6300 doublet and other ionized O emissions in our three events seem to suggest that there is less oxygen emitting at late-times.  This is puzzling because SLSNe-I are thought to be explosive events of C+O cores with masses $>$ several tens of solar masses.  There could be several explanations. First, the ejecta of our three events may have lower
oxygen masses, and perhaps also lower progenitor masses than that of SN2015bn and SN2007bi. The recent modeling of the nebular spectra of SN2015bn and SN2007bi by \citet{Jerkstrand2016} has derived $M(O) \sim 10 - 30\,M_\odot$.  The second possible explanation is that these three events could be pulsational pair-instability supernova (PPISN).  Calculated optical spectra at nebular phase based on pair-instability supernova (PISN) models seem to show a relatively weak [O\,I]\,6300 doublet \citep{Jerkstrand2016}. At face value, this could be considered as supporting evidence for a PISN or PPISN model for these events. However, as shown by \citet{Jerkstrand2016},  the calculated nebular spectra show very strong [Ca\,II]\,7300\AA\ emission lines, which are also not detected in our late-time spectra, but are present in the simulated spectra (Figure\ref{simspec}).  The probability of these three events being PPISN or PISN is small. First is because the required progenitor mass is very high, and secondly, as pointed by \citet{Woosley2016}, PPISN still has difficulties producing very energetic SLSNe-I, and iPTF13ehe is such an example.

The third possible explanation is that Oxygen in these three events is detached from $^{56}$Ni, and with very little mixing.  If the O-zone is above $^{56}$Ni,  $\gamma$-ray photons from $^{56}$Ni decay will be effectively absorbed by Fe group elements before reaching O. In this case, there is not sufficient photon heating to produce [O\,I] emission.  If ejecta density is very high, it would result in high opacity, and the [O\,I] line may cool inefficiently.  Future better modeling of nebular spectra of SLSNe-I would narrow down these possible explanations.

\subsection{Nature of the LC undulations in iPTF15esb}
\label{subsec_15esbLC}

What makes iPTF15esb stand out is its peculiar LC with strong undulations, particularly in bluer bands. We note that the three peaks are separated from each other equally by $\sim22$\,days.  After the first peak, its $g$-band and also bolometric LC have two additional small bumps (Figure~\ref{obsLC} \&\ \ref{bolo}).

LC undulations are also seen in other SN types, such as SN2012aa (between SN\,Ibc and SLSN-I), other SLSNe-I (SN2015bn), SN\,IIn (PTF13z  and SN2009ip) \citep{Roy2016, Nicholl2016,Pastorello2013, Nyholm2017,Inserra2017}. They are probably even present in SN 2007bi and PS1-14bj \citep{Gal-Yam2009, Lunnan2016}.
SN2009ip is either a SN\,IIn or a SN imposter \citep{Fraser2013,Graham2014,Margutti2014,Martin2013}.  Figure~\ref{LCcomp} makes a LC comparison between iPTF15esb, SN2012aa and SN2015bn. The LC undulation in iPTF15esb is quite strong, with some similarity to that of SN2012aa.  These LC undulations are clearly very different from the double-peak LCs with initial weak bumps followed by prominent main peaks seen in LSQ14bdq, SN2006oz, PTF12dam and iPTF13dcc \citep{Leloudas2012, Nicholl2015,Smith2016, Vreeswijk2016}.  Their physical nature may also be different.

Several ideas were proposed by previous studies to explain the light curves. This includes (1) successive collisions between ejecta and mass shells expelled by previous episodic mass losses; (2)  magnetar UV-breakout predicted by \citet{Metzger2014}; (3) recombination of certain ionized elements; (4) variable continuum optical/UV opacities which could modulate the photon diffusion, thus affecting LC morphology, as proposed for ASASSN-15lh \citep{Godoy-Rivera2017, Margutti2017}.

In the case of iPTF15esb, interaction based models may explain the data.  The second peak has a duration of 20\,days and with a net luminosity of $1.5\times10^{43}$\,erg\,s$^{-1}$. The total extra energy in this peak is $\sim 2\times10^{49}$\,erg.
This implies an excess luminosity of $\sim 10^{43}$\,erg\,s$^{-1}$ over 10\,days.
Using a simple scaling relation $L \sim {1\over2}M_{csm} v^2/\delta t$ and taking the ejecta velocity $v_{ej}\sim 17,000$\,km\,s$^{-1}$, we estimate $M_{csm} \sim 0.01M_\odot$. Eruptive mass losses could produce such mass shells.  PPISN models \citep{Woosley2016} could produce various successive H-poor shells, and the subsequent collisions between shells and/or ejecta-shell would generate additional energy producing the observed LC undulations.

The second possible explanation is due to the change in recombination of elements such as C and O, as shown in \citet{Piro2014},  CSM with pure CO can undergo recombination at temperatures of roughly 8000\,K.  Another similar idea is the change of continuum opacity, which can naturally explain the stronger undulation in bluer bands \citep{Godoy-Rivera2017, Margutti2017}.
Finally, models with central power sources, such as magnetars or fall-back accretion onto a neutron star or black hole,
have an energy input function, such as ${E_p \over \tau_p} {1 \over (1 + t/\tau_p)^2}$, with $E_p$ and $\tau_p$ as the magnetic dipole spin-down energy and the spin-down time scale respectively \citep{Dexter2013,Kasen2010}. At late-times, the luminosity should scale like t$^{-2}$, close to $(t-50)^{-2.5}$, measured from the data (Figure~\ref{bolo}).  These models seem to be able to explain some data. However, the real test requires detailed calculations which can meet the challenges of all observed features.

\begin{figure}
\includegraphics[width=0.5\textwidth,height=0.5\textwidth]{fig13.pdf}
\caption{This plot compares the bolometric light curves of iPTF15esb, SN2012aa and SLSNe-I SN2015bn and iPTF13dcc. SN2012aa is a SN between SN\,Ibc and SLSN-I \citep{Roy2016}.
\label{LCcomp}}
\end{figure}

\section{Summary and conclusions  }
\label{sec_summ}

We report two new SLSNe-I with broad H$\alpha$ emission in their late-time spectra discovered by iPTF. Together with iPTF13ehe \citep{Yan2015}, we now have three such events at $z\sim0.2 - 0.3$.
The H$\alpha$ line luminosities reach as high as $(1-3)\times10^{41}$\,erg\,s$^{-1}$ and the line widths range from $4000 - 10,000$\,km\,s$^{-1}$.   We highlight four key observational results from our data.

First, we interpret the late-time H$\alpha$ emission as a result of ejecta interaction with a neutral H-shell. The shock heating ionizes the neutral H atoms, which subsequently recombine and produce H$\alpha$ emission.
The detection of H$\alpha$ lines around $100-300$\,days since explosion imply that the H-shell must be at a distance not much farther than $10^{16}$\,cm from the progenitor star.  This shell with mass $\le 30\,M_\odot$ and an expansion speed of several 100\,km\,s$^{-1}$  indicates a very energetic mass loss, which must have happened not much longer than $10-30$ years prior to the supernova explosion. Such a tight timing provides a strong constraint on evolutionary models of massive stars.

The short time interval inferred from our H-shell model also implies that progenitor stars can not have had time to also lose all of the helium envelope. Therefore, it is likely that the ejecta of these three SLSNe-I may have some helium.  The real mystery is why we do not detect any He features in the early-time spectra, even though at early times, our three events may have sufficient non-thermal energy sources to ionize He in the ejecta, as suggested by the detections of a partial O\,II absorption series.

Second, the $\sim 250$\,day spectra of two of our events show no detectable [O\,I]\,6300\,\AA\ emission. Using simulations, we demonstrate that at these late phases, our events have intrinsically lower [O\,I]\,6300\,\AA\ luminosities in comparison with $200 - 395$\,day spectra of SLSN-I SN2007bi and SN2015bn. Several different  scenarios could explain this observation. The simplest one is that the ejecta of our three events may have oxygen masses
less than $10 - 30\,M_\odot$, which was estimated for SN2015bn and SN2007bi \citep{Jerkstrand2017}.

The third result is that for all three events, we initially see that the broad H$\alpha$ lines are blue-shifted relative to the hosts.  This may be in tension with the massive binary model because it predicted that we should see both red-shifted and blue-shifted H$\alpha$ emission lines relative to the host galaxies \citep{Moriya2015}. Interestingly, the velocity offsets between the broad H$\alpha$ and the host galaxies change from positive to negative with time for two of the events.  The very late-time spectra ($+125$ and $+242$\,days) of iPTF15esb and iPTF16bad show a weak signal of excess emission red-ward of 6563\,\AA.  We propose that a decrease of obscuration with time could be a possible explanation for seeing through more H$\alpha$ emission from the back side of the H-shells.

Finally,  the LC of iPTF15esb has a distinct morphology with significant undulations and three peaks are separated equally by $\sim22$\,days. Together with the evidence of H-shells,  these observations paint a picture of extended and multiple CSM shells, or CSM clumps,  at different radii.
The LC undulation could be explained by H-poor-ejecta CSM interaction.  This would require some mechanisms which can eject multiple layers of material from massive progenitor stars within a time interval of several decades before supernova explosion. One possibility is Pulsational Pair-instability supernova \citep{Woosley2016}.  Quantitative modelings of our data are needed.

With these intriguing results, one important question is how representative these three objects are among other SLSNe-I.  Are they unique compared to other SLSNe-I?  Photometrically, these three events are very different from each other, in their peak luminosities, and post-peak decay rates and LC morphology. However, their LC properties fall within the diverse range shown by published SLSNe-I, and are not much different from the general population of SLSN-I.  Spectroscopically, these three events are very similar to each other at both early and late-times. However, they show some marked differences from other SLSNe-I, with their lack of full O\,II absorption series in the early-time spectra, and their higher ejecta velocities.
In conclusion, our three events are not completely peculiar, but probably represent a subset of the general SLSN-I population. At face value, these three events represent (10-15)\%\ of the PTF SLSN-I sample, although the number of events with good late-time follow-up is not large. The situation is definitely improving.

\acknowledgments

We thank N. Blagorodnova, A. Ho, Y. Cao, H. Vedantham, V. Ravi at Caltech, Virginia Cunningham at University of Maryland, Antonino Cucchiara at Goddard Space Flight Center (GSFC),  J. Mauerhan, I. Shivvers and P. Kelly at University of Berkeley for taking some of the data for iPTF15esb.  This paper benefitted from discussions with Anthony Piro at Carnegie Observatories.
The intermediate Palomar Transient Factory project is a scientific collaboration among the California Institute of Technology, Los Alamos National Laboratory, the University of  Wisconsin, Milwaukee,  the  Oskar  Klein  Center,  the Weizmann Institute of Science, the TANGO Program of the  University  System  of  Taiwan,  and  the  Kavli  Institute  for  the  Physics  and  Mathematics  of  the  Universe. LANL participation in iPTF is supported by the US Department of Energy as a part of the Laboratory Directed Research and Development program. A portion of this work was carried out at the Jet Propulsion Laboratory under a Research and Technology Development Grant, under contract with the National Aeronautics and Space Administration. This paper made use of Lowell Observatory's Discovery Channel Telescope (DCT). Lowell operates the DCT in partnership with Boston University, Northern Arizona University, the University of Maryland, and the University of Toledo. Partial support of the DCT was provided by Discovery
Communications. Large Monolithic Imager (LMI) on DCT was built by Lowell Observatory using funds from the National Science Foundation (AST-1005313). DAH, CM, and GH are funding by NSF grant AST-1313484.  This paper makes use of data from Las Cumbres Observatory.
This work was partially supported by the GROWTH project funded by the National Science Foundation under Grant No 1545949. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community.  We are most fortunate to have the opportunity to conduct observations from this mountain.

{\it Facilities:} \facility{Palomar}, \facility{Keck}, \facility{Discovery Channel Telescope}.

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