English
Related papers

Related papers: Evolving Stellar Background Radiation and Gamma-Ra…

200 papers

We present an updated model of the cosmic ionizing background from the UV to the X-rays. Relative to our previous model (Faucher-Giguere et al. 2009), the new model provides a better match to a large number of up-to-date empirical…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-05 C. -A. Faucher-Giguere

Quantifying the evolution of stellar extreme ultraviolet (EUV, 100 -- 1000 $\overset{\circ}{A}$) emission is critical for assessing the evolution of planetary atmospheres and the habitability of M dwarf systems. Previous studies from the…

Recent optical observations have led to a significant progress in our understanding of galaxy formation and evolution. However, our view on the deep universe is currently limited to the starlight which directly escapes from high-redshift…

Astrophysics · Physics 2007-05-23 B. Guiderdoni

For distant extragalactic sources of gamma-rays in the PeV energy range, interactions of the gamma rays with intergalactic diffuse radiation fields will initiate a pair cascade. Depending on the magnetic fields in the vicinity of the…

Astrophysics · Physics 2007-05-23 HEGRA Collaboration , F. Aharonian

Very high energy (VHE) $\gamma$-rays above 10$'$s of GeV energy, emitted from distant blazars, are attenuated by photons from the extragalactic background light (EBL). Unfortunately, neither the EBL nor the intrinsic blazar spectrum is…

High Energy Astrophysical Phenomena · Physics 2015-06-17 K K Singh , S Sahayanathan , A K Tickoo , N Bhatt

The diffuse extragalactic gamma-ray background (EGRB) above 100 MeV encodes unique information about high-energy processes in the universe. Numerous sources for the EGRB have been proposed, but the two systems which are certain to make some…

Astrophysics · Physics 2009-11-07 Vasiliki Pavlidou , Brian D. Fields

Observations of very-high-energy (VHE, E > 250 GeV) gamma-ray emission from several blazars at z > 0.1 have placed stringent constraints on the elusive spectrum and intensity of the intergalactic infrared background radiation (IIBR).…

Astrophysics · Physics 2009-11-13 Markus Boettcher , Charles D. Dermer , Justin D. Finke

Very high energy (VHE; $E \geq$ 100GeV) $\gamma-$ray from cosmological distances are attenuated by the extragalactic background light (EBL) in the IR to UV band. By contrasting measured versus intrinsic emission, the EBL photon density can…

High Energy Astrophysical Phenomena · Physics 2020-09-01 Longhua Qin , Jiancheng Wang , Quangui Gao , Weiwei Na , Huaizhen Li , Ju Ma , Jianping Yang

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…

High Energy Astrophysical Phenomena · Physics 2017-01-12 Mariangela Lisanti , Siddharth Mishra-Sharma , Lina Necib , Benjamin R. Safdi

We present improved synthesis models of the evolving spectrum of the UV/X-ray diffuse background, updating and extending our previous results. A "minimal cosmic reionization model" is presented in which the galaxy UV emissivity traces…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-29 Francesco Haardt , Piero Madau

As recently shown, Fermi-LAT measurements of the diffuse gamma-ray emission from the Galaxy favor the presence of a smooth softening in the primary cosmic-ray spectrum with increasing Galactocentric distance. This result can be interpreted…

High Energy Astrophysical Phenomena · Physics 2016-06-22 Daniele Gaggero , Dario Grasso , Antonio Marinelli , Alfredo Urbano , Mauro Valli

Evolved stars dominate galactic spectra, enrich the galactic medium, expand to change their planetary systems, eject winds of a complex nature, produce spectacular nebulae and illuminate them, and transfer material between binary…

The last years have seen a revolution in ground-based gamma-ray detectors. We can now detect the spectra of nearby TeV blazars like Mrk 421 and 501 out to approximately 20 TeV, and during the strongest flares, we can now follow fluctuations…

Astrophysics · Physics 2009-10-31 Paolo S. Coppi , Felix A. Aharonian

The current weak lensing measurements of the large scale structure are mostly related to statistical study of background galaxy ellipticities. We consider a possibility to extend lensing studies with intrinsically unresolved sources and…

Astrophysics · Physics 2008-11-26 Asantha Cooray

Diffuse gamma-ray emission has long been established as the most prominent feature in the GeV sky. Although the imaging atmospheric Cherenkov technique has been successful in revealing a large population of discrete TeV gamma-ray sources, a…

High Energy Astrophysical Phenomena · Physics 2019-08-15 K. Egberts , F. Brun , S. Casanova , W. Hofmann , M. de Naurois , O. Reimer , Q. Weitzel , Y. Fukui

We have studied small scale (2 arcmin) spatial variation of the diffuse UV radiation using a set of 11 GALEX deep observations in the constellation of Draco. We find a good correlation between the observed UV background and the IR 100…

Astrophysics of Galaxies · Physics 2015-05-20 N. V. Sujatha , Jayant Murthy , Rahul Suresh , Richard Conn Henry , Luciana Bianchi

To study large-scale structure in the Universe a full census of the contents are required. This is even more important when the processes of galaxy formation are being investigated. In the last year the population of distant galaxies that…

Astrophysics · Physics 2009-10-31 Andrew W. Blain

Context. Star-forming galaxies emit {\gamma}rays with relatively low luminosity, but the study of their emission is no less captivating. While it is known that their {\gamma}-ray luminosity in the GeV band is strongly linked to their star…

High Energy Astrophysical Phenomena · Physics 2025-07-02 P. Kornecki , J. Biteau , C. Boisson , P. Cristofari

With this paper we participate to the call for ideas issued by the European Space Agency to define the Science Program and plan for space missions from 2035 to 2050. In particular we present five science cases where major advancements can…

Instrumentation and Methods for Astrophysics · Physics 2021-01-26 A. Zanella , C. Zanoni , F. Arrigoni-Battaia , A. Rubin , A. Pala , C. Peroux , R. Augustin , C. Circosta , E. Emsellem , E. George , D. Milakovic , R. van der Burg , T. Kupfer

Diffuse $\gamma$-ray emission produced by the interaction of cosmic-ray particles with matter and radiation in the Galaxy can be used to probe the distribution of cosmic rays and their sources in different regions of the Galaxy. With its…