International Astronomical Union Colloquium (5)
Canadian Journal of Mathematics (1)
Proceedings of the Royal Society of Edinburgh Section A: Mathematics (1)
Cambridge Contemporary Astrophysics (5)
Black hole astrophysics with HAWC, the High Altitude Water Cherenkov γ-ray observatory
Alberto Carramiñana, for the HAWC Collaboration
Journal: Proceedings of the International Astronomical Union / Volume 12 / Issue S324 / September 2016
Published online by Cambridge University Press: 23 June 2017, pp. 309-316
The HAWC gamma-ray observatory is a wide field of view and high duty cycle γ-ray detector investigating the 0.1 - 100 TeV energy range. It has detected supermassive black holes in the near Universe, and is seeking to detect black hole related objects like gamma-ray bursts, Galactic binary systems, primordial black holes and gravitational wave mergers. Daily light curves of the BL Lac objects Mrk 421 and Mrk 501 are presented here, together with a compilation of studies of black hole related objects.
Multiwavelength variability analysis of the FSRQ 3C 279
V. Patiño-Álvarez, V. Chavushyan, J. León-Tavares, A. Carramiñana, L. Carrasco, S. Fernandes, E. M. Schlegel, E. López-Rodríguez
Published online by Cambridge University Press: 24 March 2015, pp. 89-90
We present a multifrequency analysis of the variability in the flat-spectrum radio quasar 3C 279 from 2008 to 2014. Our multiwavelength dataset includes gamma-ray data from Fermi/LAT (Abdo et al. 2009), observations in 1mm from SMA (Gurwell et al. 2007), Near Infrared from OAGH (Carramiñana & Carrasco 2009) and SMARTS (Bonning et al. 2012); optical V band from the Steward Observatory (Smith et al. 2009) and SMARTS; optical spectra from OAGH (Patiño-Álvarez et al. 2013) and the Steward Observatory; and polarization spectra from the Steward Observatory. The light curves are shown in Fig. 1. Six out of seven optical activity periods identified within our dataset show clear counterparts in mm, NIR and gamma-rays, however, the late 2011 - early 2012 optical flare does not have a counterpart in the GeV regime. In this contribution, we discuss the flaring evolution of 3C 279 and speculate about the production of the anomalous activity period.
On adjacent complete ideals above a given complete ideal
Maria Alberich-Carramiñana, Jesús Fernández-Sánchez
Journal: Proceedings of the Royal Society of Edinburgh Section A: Mathematics / Volume 140 / Issue 2 / April 2010
Given a complete m-primary ideal J in a local regular two-dimensional ring (R,m), we describe every adjacent complete ideal above J as the integral closure of some ideal (f, g) for suitable f, g associated to J. We also provide a geometrical procedure that gives its base points, thus determining its equisingularity class. We decompose the set IJ of these adjacent ideals in terms of the Rees valuations of J. As a consequence, we obtain a geometrical characterization of the finiteness of IJ.
Enriques Diagrams and Adjacency of Planar Curve Singularities
Maria Alberich-Carramiñana, Joaquim Roé
Journal: Canadian Journal of Mathematics / Volume 57 / Issue 1 / 01 February 2005
Print publication: 01 February 2005
We study adjacency of equisingularity types of planar complex curve singularities in terms of their Enriques diagrams. The goal is, given two equisingularity types, to determine whether one of themis adjacent to the other. For linear adjacency a complete answer is obtained, whereas for arbitrary (analytic) adjacency a necessary condition and a sufficient condition are proved. We also obtain new examples of exceptional deformations, i.e, singular curves of type ${\mathcal{D}}'$ that can be deformed to a curve of type $\mathcal{D}$ without ${\mathcal{D}}'$ being adjacent to $\mathcal{D}$ .
High Time Resolution Observations of the Crab Pulsar with the UCL MIC Detector
R. Much, A. Carramiñana, J.L.A. Fordham, H. Kawakami, R. Michel
Journal: International Astronomical Union Colloquium / Volume 177 / 2000
High time resolution (41.4μs) observations of the Crab Pulsar have been undertaken on the 2.1m telescopes at San Pedro Martir and the Observatorio Astrofisico Guillermo Haro (MX) in January/February 1999. In our prelimenary analysis of the Crab Pulsar's light curve we obtained a slightly narrow widths on the seondary pulse than that reported by Percival et al. Our data indicate the presence of substructures in the pulsar's main pulse, though not statistically convincing.
CLYPOS: the Cananea-Ljubljana Young Pulsar Optical Survey
Alberto Carramiñana, Andrej Čadež, César Alvarez
The Cananea-Ljubljana Young Pulsar Optical Survey, or CLYPOS, is an observational study of ≳ 30 known radio pulsars, in search for pulsed optical emission. The survey is being carried out at the 2.12m telescope of the Observatorio Astrofísico Guillermo Haro, near Cananea, Sonora, using the stroboscopic camera of the University of Ljubljana. We restricted the study to young pulsars with declination δ > −35°, prioritized in terms of E/d 2. Our strategy consists in spending two hours of observing time per pulsar, scanning the whole pulsed-phase interval three times. Further details are given below.
On the Existence of an Universal Spin-down Equation for Pulsars
César Alvarez, Alberto Carramiñana
The Taylor expansion of the generalized spin-down equation = − f(v), derives into the multipolar equation = −gv 5 – rv 3 − sv), which is used here to study pulsar evolution. The coefficients g, r and s can be physically associated to gravitational radiation, magnetic dipolar radiation and particle aceleration. The multipolar expansion with constant coefficients cannot describe the P Ṗ diagram in a consistent manner and therefore it is unlikely a generalized equation of the form = −f(v;t) can be used to describe pulsar evolution. A more general form, = − f(v; t) can be investigated giving to the coefficients g, r and s time dependence. We consider some explicit functional forms for g(t), r(t) and s(t) which are consistent with observational and theoretical constraints.
By José Franco, Tonantzintla, Puebla., Alberto Carramiñana, Tonantzintla, Puebla.
Edited by Jose Franco, Universidad Nacional Autónoma de México, Alberto Carraminana, Instituto Nacional de Astrofisica, Optica y Electronica, Tonantzintla, Mexico
Book: Interstellar Turbulence
Print publication: 28 May 1999, pp xi-xii
Interstellar Turbulence, the second conference organized by the Guillermo Haro International Program on Advanced A strophysical Research, was an excellent forum to review and discuss one of the most intriguing features of cosmic and terrestrial fluids. Turbulence is universal and mysterious, and remains one of the major unsolved problems in physics and astrophysics. It is present in all terrestrial and astrophysical environments: close to our telescopes, it blurs and distorts our view of the skies, and in the interstellar and intergalactic media, somehow, it creates fluctuations and redistributes angular momentum, leading to star formation and large scale structure.
The Guillermo Haro Program was created in 1995 at the Instituto Nacional de Astrofísica, Optica y Electrónica (INAOE), and is named in honor of its founder, the remarkable astronomer-lawyer Guillermo Haro. This second conference was aimed at revising our conceptions on the properties of turbulence, and at summarizing the present status in observational, theoretical, and computational research in interstellar turbulence. It was held in Puebla, México, at the Benemérita Universidad Autónoma de Puebla, during the week of January 12th to 16th, 1998. There were 130 participants, from four continents, and a large fraction of them were very young scientists. The program covered a wide variety of topics, ranging from atmospheric and interstellar turbulent flows, to magnetic fields and cosmic ray transportation, and energy dissipation, fragmentation and star formation.
Print publication: 28 May 1999, pp vii-x
Interstellar Turbulence
Edited by Jose Franco, Alberto Carraminana
Print publication: 28 May 1999
Buy the print book
Turbulence is universal and mysterious. It remains one of the major unsolved problems in physics and astrophysics. From star formation to large-scale outflows, turbulence is present in all interstellar and intergalactic media. With advances in observational techniques (from optical to radio) and the development of more efficient computer codes and faster computers, research in this area has made spectacular progress in recent years. This volume presents a series of review articles covering every aspect of interstellar turbulence - from accretion disks, molecular clouds, atomic and ionized media, through to spiral galaxies - based on a major international conference held in Mexico City. The result is a comprehensive overview of the most important developments in observing and modelling turbulent flows in the cosmos. It provides graduate students and researchers with a state-of-the-art summary of observational, theoretical and computational research in interstellar turbulence.
Print publication: 28 May 1999, pp i-vi
On the timing histories of the crab, PSR1509-58 and PSR0540-69
Alberto Carramiñana, César Alvarez
A simple model of a combined magnetic dipole, gravitational and/or magnetic quadrupole and particle accelerator is applied to simulate the time behaviour of the timing parameters of PSR 0531+21, PSR 1509-58 and PSR0540-69, as well as their energy budget. The model restricts the allowed values for the second braking index and is therefore testable through measurements of .
Pulsar Studies with Comptel
K. Bennett, M. Busetta, A. Carramiñana, R. Diehl, G. Lichti, V. Schönfelder, A. Strong, W. Hermsen, L. Kuiper, A. Connors, J. Ryan, R. Buccheri
The Compton Gamma-Ray Observatory (C-GRO) has completed a full-sky survey during which the number of known γ-ray pulsars has more than doubled. COMPTEL has observed the classical pulsars Crab and Vela on several occasions and has derived detailed pulse patterns and spectral parameters in the 0.7-30 MeV energy interval. The new C-GRO γ-ray pulsars have different properties in terms of energy spectra and light-curve shapes, and, in fact, only the Crab is seen by all four C-GRO instruments. This raises intriguing questions about the particle acceleration processes and beaming taking place in the neutron magnetosphere. We have examined the COMPTEL data to add information on these objects in the 0.7-30 MeV energy interval and present evidence for the detection of one of them, PSR B1509-58. We have also undertaken a search for candidate radio pulsars whose ephemerides are well defined. The results of these analyses are presented.
Subject headings: gamma rays: observations — pulsars: general