English
Related papers

Related papers: A new model for the extragalactic gamma-ray backgr…

200 papers

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

I discuss how measurements of the absorption of $\gamma$-rays from GeV to TeV energies via pair production on the extragalactic background light (EBL) can probe important issues in galaxy formation. We use semi-analytic models (SAMs) of…

Astrophysics · Physics 2007-05-23 Joel R. Primack

We study the capabilities of the Fermi-LAT instrument on board of the Fermi mission to constrain particle dark matter properties, as annihilation cross section, mass and branching ratio into dominant annihilation channels, with gamma-ray…

High Energy Astrophysical Phenomena · Physics 2017-02-22 Nicolas Bernal , Sergio Palomares-Ruiz

We investigate the extent to which the uncertainties associated with the propagation of Galactic cosmic rays impact upon estimates for the gamma-ray flux from the mid-latitude region. We consider contributions from both standard…

High Energy Astrophysical Phenomena · Physics 2010-11-18 Daniel T. Cumberbatch , Yue-Lin Sming Tsai , Leszek Roszkowski

Ground-based observatories have been collecting 0.2 - 20 TeV gamma rays from blazars for about twenty years. These gamma rays can experience absorption along the line of sight due to interactions with the extragalactic background light…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-14 Jonathan Biteau , David A. Williams

Observations by the Large Area Telescope (LAT) on the \textit{Fermi} mission of diffuse $\gamma$-rays in a mid-latitude region in the third quadrant (Galactic longitude $l$ from $200\arcdeg$ to $260\arcdeg$ and latitude $| b |$ from…

High Energy Astrophysical Phenomena · Physics 2009-12-04 A. A. Abdo

The TANAMI (Tracking AGN with Austral Milliarcsecond Interferometry) and associated programs provide comprehensive radio monitoring of extragalactic gamma-ray sources south of declination -30 degrees. Joint quasi-simultaneous observations…

We analyze the angular power spectrum (APS) of the unresolved gamma-ray background (UGRB) emission and combine it with the measured properties of the resolved gamma-ray sources of the Fermi-LAT 4FGL catalog. Our goals are to dissect the…

High Energy Astrophysical Phenomena · Physics 2023-07-07 Michael Korsmeier , Elena Pinetti , Michela Negro , Marco Regis , Nicolao Fornengo

The GALPROP model for cosmic-ray propagation is able to make explicit predictions for the distribution of galactic diffuse gamma-rays. We compare different propagation models with gamma-ray spectra measured by EGRET for various regions of…

Astrophysics · Physics 2009-11-11 Andrew W. Strong , Igor V. Moskalenko , Olaf Reimer

The spectrum of an isotropic extragalactic {\gamma}-ray background (EGB) has been measured by the Fermi-LAT telescope at high latitudes. Two new models for the EGB are derived from the subraction of unresolved point sources and…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-15 Francesca Calore , Valentina De Romeri , Fiorenza Donato

We present models of the extragalactic background light (EBL) based on several scenarios of galaxy formation and evolution. We have treated galaxy formation with the Press-Schecter approximation for both cold dark matter (CDM) and cold+hot…

Astrophysics · Physics 2009-12-10 D. MacMinn , J. R. Primack

The Extragalactic Background Light (EBL) is the main radiation field responsible for attenuating extragalactic gamma-ray emission at very high energies, but its precise spectral intensity is not fully determined. Therefore, disentangling…

High Energy Astrophysical Phenomena · Physics 2024-03-21 M. Genaro , L. A. Stuani Pereira , D. R. de Matos Pimentel , E. Moura Santos

We describe the properties of the blazars detected by EGRET and summarize the results on the calculations of the evolution and luminosity function of these sources. Of the large number of possible origins of extragalactic diffuse gamma-ray…

Astrophysics · Physics 2009-10-31 R. Mukherjee , J. Chiang

The all-sky surveys in gamma-rays by the imaging Compton telescope (COMPTEL) and the Energetic Gamma Ray Experiment Telescope (EGRET) on board the Compton Gamma Ray Observatory for the first time allows detailed studies of the extragalactic…

Astrophysics · Physics 2009-10-30 P. Sreekumar , F. W. Stecker , S. C. Kappadath

Context. Measurements of the Extragalactic Background Light (EBL) are a fundamental source of information on the collective emission of cosmic sources. Aims. At infrared wavelengths, however, these measurements are precluded by the…

High Energy Astrophysical Phenomena · Physics 2019-08-28 A. Franceschini , L. Foffano , E. Prandini , F. Tavecchio

High energy photons from blazars can initiate electromagnetic pair cascades interacting with the extragalactic photon background. The charged component of such cascades is deflected and delayed by extragalactic magnetic fields (EGMF),…

High Energy Astrophysical Phenomena · Physics 2010-12-23 K. Dolag , M. Kachelriess , S. Ostapchenko , R. Tomas

We make a new estimate of the extragalactic radio background down to kHz frequencies based on the observed luminosity functions and radio spectra of normal galaxies and radio galaxies. We have constructed models for the spectra of these two…

Astrophysics · Physics 2010-11-30 R. J. Protheroe , P. L. Biermann

The extragalactic background light (EBL) is of fundamental importance both for understanding the entire process of galaxy evolution and for gamma-ray astronomy. However, the overall spectrum of the EBL between 0.1 and 1000 microns has never…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Alberto Domínguez

Notwithstanding the advent of the Gamma-ray Large Area Telescope, theoretical models predict that a significant fraction of the cosmic gamma-ray background (CGB), at the level of 20% of the currently measured value, will remain unresolved.…

Astrophysics · Physics 2009-11-13 Francesco Miniati , Savvas M. Koushiappas , Tiziana Di Matteo

Recently, a new measurement of the auto- and cross-correlation angular power spectrum (APS) of the isotropic gamma-ray background was performed, based on 81 months of data of the Fermi Large-Area Telescope (LAT). Here, we fit, for the first…

High Energy Astrophysical Phenomena · Physics 2017-06-21 Shin'ichiro Ando , Mattia Fornasa , Nicolao Fornengo , Marco Regis , Hannes-S. Zechlin
‹ Prev 1 8 9 10 Next ›