DECIPHERING CONTRIBUTIONS to the EXTRAGALACTIC GAMMA-RAY BACKGROUND from 2 GeV to 2 TeV
Mariangela Lisanti, Siddharth Mishra-Sharma, Lina Necib, Benjamin R. Safdi
Astrophysical sources outside the Milky Way, such as active galactic nuclei and star-forming galaxies, leave their imprint on the gamma-ray sky as nearly isotropic emission referred to as the extragalactic gamma-ray background (EGB). While the brightest of these sources may be individually resolved, their fainter counterparts contribute diffusely. In this work, we use a recently developed analysis method, called the Non-Poissonian Template Fit, on up to 93 months of publicly available data from the Fermi Large Area Telescope to determine the properties of the point sources (PSs) that comprise the EGB. This analysis takes advantage of photon-count statistics to probe the aggregate properties of these source populations below the sensitivity threshold of published catalogs. We measure the source-count distributions and PS intensities, as a function of energy, from ∼2 GeV to 2 TeV. We find that the EGB is dominated by PSs, likely blazars, in all seven energy sub-bins considered. These results have implications for the interpretation of IceCube's PeV neutrinos, which may originate from sources that contribute to the non-blazar component of the EGB. Additionally, we comment on implications for future TeV observatories such as the Cherenkov Telescope Array. We provide sky maps showing locations most likely to contain these new sources at both low (≲50 GeV) and high (50 GeV) energies for use in future observations and cross-correlation studies.
https://doi.org/10.3847/0004-637X/832/2/117
BL Lacertae objects: general
galaxies: active
galaxies: statistics
gamma rays: diffuse background
10.3847/0004-637X/832/2/117
Fingerprint Dive into the research topics of 'DECIPHERING CONTRIBUTIONS to the EXTRAGALACTIC GAMMA-RAY BACKGROUND from 2 GeV to 2 TeV'. Together they form a unique fingerprint.
gamma radiation Earth & Environmental Sciences
gamma rays Physics & Astronomy
point source Earth & Environmental Sciences
point sources Physics & Astronomy
sky Physics & Astronomy
telescopes Physics & Astronomy
blazars Physics & Astronomy
Lisanti, M., Mishra-Sharma, S., Necib, L., & Safdi, B. R. (2016). DECIPHERING CONTRIBUTIONS to the EXTRAGALACTIC GAMMA-RAY BACKGROUND from 2 GeV to 2 TeV. Astrophysical Journal, 832(2), [117]. https://doi.org/10.3847/0004-637X/832/2/117
Lisanti, Mariangela ; Mishra-Sharma, Siddharth ; Necib, Lina ; Safdi, Benjamin R. / DECIPHERING CONTRIBUTIONS to the EXTRAGALACTIC GAMMA-RAY BACKGROUND from 2 GeV to 2 TeV. In: Astrophysical Journal. 2016 ; Vol. 832, No. 2.
@article{27d9a47954514b938c59f5dcddc9653d,
title = "DECIPHERING CONTRIBUTIONS to the EXTRAGALACTIC GAMMA-RAY BACKGROUND from 2 GeV to 2 TeV",
abstract = "Astrophysical sources outside the Milky Way, such as active galactic nuclei and star-forming galaxies, leave their imprint on the gamma-ray sky as nearly isotropic emission referred to as the extragalactic gamma-ray background (EGB). While the brightest of these sources may be individually resolved, their fainter counterparts contribute diffusely. In this work, we use a recently developed analysis method, called the Non-Poissonian Template Fit, on up to 93 months of publicly available data from the Fermi Large Area Telescope to determine the properties of the point sources (PSs) that comprise the EGB. This analysis takes advantage of photon-count statistics to probe the aggregate properties of these source populations below the sensitivity threshold of published catalogs. We measure the source-count distributions and PS intensities, as a function of energy, from ∼2 GeV to 2 TeV. We find that the EGB is dominated by PSs, likely blazars, in all seven energy sub-bins considered. These results have implications for the interpretation of IceCube's PeV neutrinos, which may originate from sources that contribute to the non-blazar component of the EGB. Additionally, we comment on implications for future TeV observatories such as the Cherenkov Telescope Array. We provide sky maps showing locations most likely to contain these new sources at both low (≲50 GeV) and high (50 GeV) energies for use in future observations and cross-correlation studies.",
keywords = "BL Lacertae objects: general, dark matter, galaxies: active, galaxies: statistics, gamma rays: diffuse background, neutrinos",
author = "Mariangela Lisanti and Siddharth Mishra-Sharma and Lina Necib and Safdi, {Benjamin R.}",
note = "Publisher Copyright: {\textcopyright} 2016. The American Astronomical Society. All rights reserved.. Copyright: Copyright 2018 Elsevier B.V., All rights reserved.",
doi = "10.3847/0004-637X/832/2/117",
Lisanti, M, Mishra-Sharma, S, Necib, L & Safdi, BR 2016, 'DECIPHERING CONTRIBUTIONS to the EXTRAGALACTIC GAMMA-RAY BACKGROUND from 2 GeV to 2 TeV', Astrophysical Journal, vol. 832, no. 2, 117. https://doi.org/10.3847/0004-637X/832/2/117
DECIPHERING CONTRIBUTIONS to the EXTRAGALACTIC GAMMA-RAY BACKGROUND from 2 GeV to 2 TeV. / Lisanti, Mariangela; Mishra-Sharma, Siddharth; Necib, Lina; Safdi, Benjamin R.
In: Astrophysical Journal, Vol. 832, No. 2, 117, 01.12.2016.
T1 - DECIPHERING CONTRIBUTIONS to the EXTRAGALACTIC GAMMA-RAY BACKGROUND from 2 GeV to 2 TeV
AU - Lisanti, Mariangela
AU - Mishra-Sharma, Siddharth
AU - Necib, Lina
AU - Safdi, Benjamin R.
N1 - Publisher Copyright: © 2016. The American Astronomical Society. All rights reserved.. Copyright: Copyright 2018 Elsevier B.V., All rights reserved.
N2 - Astrophysical sources outside the Milky Way, such as active galactic nuclei and star-forming galaxies, leave their imprint on the gamma-ray sky as nearly isotropic emission referred to as the extragalactic gamma-ray background (EGB). While the brightest of these sources may be individually resolved, their fainter counterparts contribute diffusely. In this work, we use a recently developed analysis method, called the Non-Poissonian Template Fit, on up to 93 months of publicly available data from the Fermi Large Area Telescope to determine the properties of the point sources (PSs) that comprise the EGB. This analysis takes advantage of photon-count statistics to probe the aggregate properties of these source populations below the sensitivity threshold of published catalogs. We measure the source-count distributions and PS intensities, as a function of energy, from ∼2 GeV to 2 TeV. We find that the EGB is dominated by PSs, likely blazars, in all seven energy sub-bins considered. These results have implications for the interpretation of IceCube's PeV neutrinos, which may originate from sources that contribute to the non-blazar component of the EGB. Additionally, we comment on implications for future TeV observatories such as the Cherenkov Telescope Array. We provide sky maps showing locations most likely to contain these new sources at both low (≲50 GeV) and high (50 GeV) energies for use in future observations and cross-correlation studies.
AB - Astrophysical sources outside the Milky Way, such as active galactic nuclei and star-forming galaxies, leave their imprint on the gamma-ray sky as nearly isotropic emission referred to as the extragalactic gamma-ray background (EGB). While the brightest of these sources may be individually resolved, their fainter counterparts contribute diffusely. In this work, we use a recently developed analysis method, called the Non-Poissonian Template Fit, on up to 93 months of publicly available data from the Fermi Large Area Telescope to determine the properties of the point sources (PSs) that comprise the EGB. This analysis takes advantage of photon-count statistics to probe the aggregate properties of these source populations below the sensitivity threshold of published catalogs. We measure the source-count distributions and PS intensities, as a function of energy, from ∼2 GeV to 2 TeV. We find that the EGB is dominated by PSs, likely blazars, in all seven energy sub-bins considered. These results have implications for the interpretation of IceCube's PeV neutrinos, which may originate from sources that contribute to the non-blazar component of the EGB. Additionally, we comment on implications for future TeV observatories such as the Cherenkov Telescope Array. We provide sky maps showing locations most likely to contain these new sources at both low (≲50 GeV) and high (50 GeV) energies for use in future observations and cross-correlation studies.
KW - BL Lacertae objects: general
KW - dark matter
KW - galaxies: active
KW - galaxies: statistics
KW - gamma rays: diffuse background
KW - neutrinos
U2 - 10.3847/0004-637X/832/2/117
DO - 10.3847/0004-637X/832/2/117
Lisanti M, Mishra-Sharma S, Necib L, Safdi BR. DECIPHERING CONTRIBUTIONS to the EXTRAGALACTIC GAMMA-RAY BACKGROUND from 2 GeV to 2 TeV. Astrophysical Journal. 2016 Dec 1;832(2). 117. https://doi.org/10.3847/0004-637X/832/2/117