The origin of the cosmic gamma-ray background in the MeV range

Abstract

There has been much debate about the origin of the diffuse $\gamma$--ray background in the MeV range. At lower energies, AGNs and Seyfert galaxies can explain the background, but not above $\simeq$0.3 MeV. Beyond $\sim$10 MeV blazars appear to account for the flux observed. That leaves an unexplained gap for which different candidates have been proposed, including annihilations of WIMPS. One candidate are Type Ia supernovae (SNe Ia). Early studies concluded that they were able to account for the $\gamma$--ray background in the gap, while later work attributed a significantly lower contribution to them. All those estimates were based on SN Ia explosion models which did not reflect the full 3D hydrodynamics of SNe Ia explosions. In addition, new measurements obtained since 2010 have provided new, direct estimates of high-z SNe Ia rates beyond $z\sim$2. We take into account these new advances to see the predicted contribution to the gamma--ray background. We use here a wide variety of explosion models and a plethora of new measurements of SNe Ia rates. SNe Ia still fall short of the observed background. Only for a fit, which would imply $\sim$150\% systematic error in detecting SNe Ia events, do the theoretical predictions approach the observed fluxes. This fit is, however, at odds at the highest redshifts with recent SN Ia rates estimates. Other astrophysical sources such as FSRQs do match the observed flux levels in the MeV regime, while SNe Ia make up to 30--50\% of the observed flux.

40 pages, 13 Figures, accepted to be published in ApJ

References in corpus (13)

• New Hubble Space Telescope Discoveries of Type Ia Supernovae at z > 1: Narrowing Constraints on the Early Behavior of Dark Energy
• Cosmic X-ray background and Earth albedo Spectra with Swift/BAT
• The Origin of the Extragalactic Gamma-Ray Background and Implications for Dark-Matter Annihilation
• Supernova rates from the Southern inTermediate Redshift ESO Supernova Search (STRESS)
• Early 56Ni decay γ-rays from SN2014J suggest an unusual explosion
• Composition of the Fermi-LAT isotropic gamma-ray background intensity: Emission from extragalactic point sources and dark matter annihilations
• The Extended HST Supernova Survey: The Rate of SNe Ia at z>1.4 Remains Low
• Slow-Speed Supernovae from the Palomar Transient Factory: Two Channels
• A New Determination of the High Redshift Type Ia Supernova Rates with the Hubble Space Telescope Advanced Camera for Surveys
• Resolving Cosmic Gamma Ray Anomalies with Dark Matter Decaying Now
• Revealing Type Ia supernova physics with cosmic rates and nuclear gamma rays
• Expectations for the Hard X-ray Continuum and Gamma-ray Line Fluxes from the Type Ia supernova SN 2014J in M82
• The Rate of Type Ia Supernovae at z~0.2 from SDSS-I Overlapping Fields

Cited by in corpus (16)

• Science with e-ASTROGAM (A space mission for MeV-GeV gamma-ray astrophysics)
• The e-ASTROGAM mission (exploring the extreme Universe with gamma rays in the MeV-GeV range)
• Planck Constraint on Relic Primordial Black Holes
• Breakdown of Hawking Evaporation opens new Mass Window for Primordial Black Holes as Dark Matter Candidate
• The TeV Diffuse Cosmic Neutrino Spectrum and the Nature of Astrophysical Neutrino Sources
• Soft gamma rays from low accreting supermassive black holes and connection to energetic neutrinos
• BASS XXXIII: Swift-BAT blazars and their jets through cosmic time
• Revisiting the constraints on primordial black hole abundance with the isotropic gamma ray background
• Nonthermal processes in hot accretion flows onto supermassive black holes: An inhomogeneous model
• CubeSats for Gamma-Ray Astronomy
• Gamma-rays from kilonovae and the cosmic gamma-ray background
• Evaluation of the performance of a CdZnTe-based soft $\gamma$-ray detector for CubeSat payloads
• Limits on primordial black holes detectability with Isatis: A BlackHawk tool
• Performance Evaluation of a silicon-based 6U Cubesat detector for soft $\gamma$-ray astronomy
• Diffuse continuum emission and large extended sources at MeV energies
• Is a symmetric matter-antimatter universe excluded?