Gamma-Ray Luminosity Function of Blazars and the Cosmic Gamma-Ray Background: Evidence for the Luminosity Dependent Density Evolution

Abstract

We present a comprehensive study for the gamma-ray luminosity function (GLF) of blazars and their contribution to the extragalactic diffuse gamma-ray background (EGRB). Radio and gamma-ray luminosity correlation is introduced to take into account the radio detectability which is important for the blazar identification. Previous studies considered only pure luminosity evolution (PLE) or pure density evolution, but we introduce the luminosity dependent density evolution (LDDE) model, which is favored from the evolution of X-ray luminosity function (XLF) of AGNs. The model parameters are constrained by likelihood analyses about the observed redshift and gamma-ray flux distributions of the EGRET blazars. We find that the LDDE model gives a better fit to the observed distributions than the PLE model, indicating that the LDDE model is also appropriate for gamma-ray blazars, and that the jet activity is universally correlated with the accretion history of AGNs. The normalization between the GLF and XLF is consistent with the unified picture of AGNs, when the beaming and a reasonable duty cycle of jet activity are taken into account. We then find that only 25--50% of the EGRB can be explained by unresolved blazars with the best-fit LDDE parameters. Unresolved blazars can account for all the EGRB only with a steeper index of the faint-end slope of the GLF, which is marginally consistent with the EGRET data but inconsistent with that of the XLF. Therefore unresolved AGNs cannot be the dominant source of the EGRB, unless there is a new population of gamma-ray emitting AGNs that evolves differently from the XLF of AGNs. Predictions for the GLAST mission are made, and we find that the best-fit LDDE model predicts about 3000 blazars in the entire sky, which is considerably fewer than a previous estimate.

13 pages, 12 figures, accepted by ApJ; minor typos corrected and some figures revised, main conclusions essentially unchanged

Cited by in corpus (78)

• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• The First Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope
• Bright AGN Source List from the First Three Months of the Fermi Large Area Telescope All-Sky Survey
• The Luminosity Function of Fermi-detected Flat-Spectrum Radio Quasars
• The Fermi-LAT high-latitude Survey: Source Count Distributions and the Origin of the Extragalactic Diffuse Background
• The Evolution of Swift/BAT blazars and the origin of the MeV background
• Constraints on Cosmological Dark Matter Annihilation from the Fermi-LAT Isotropic Diffuse Gamma-Ray Measurement
• Contribution of the Gamma-ray Loud Radio Galaxies Core Emissions to the Cosmic MeV and GeV Gamma-Ray Background Radiation
• The nature of the Diffuse Gamma-Ray Background
• Diffuse $\gamma$-ray emission from misaligned active galactic nuclei
• The Blazar Sequence and the Cosmic Gamma-Ray Background Radiation in the Fermi Era
• Anisotropies in the diffuse gamma-ray background measured by the Fermi LAT
• Cosmogenic photon and neutrino fluxes in the Auger era
• Dark matter annihilation or unresolved astrophysical sources? Anisotropy probe of the origin of cosmic gamma-ray background
• Composition of the Fermi-LAT isotropic gamma-ray background intensity: Emission from extragalactic point sources and dark matter annihilations
• Components of the Extragalactic Gamma Ray Background
• Constraints on Decaying Dark Matter from the Isotropic Gamma-Ray Background
• Diffuse $\gamma$-ray emission from unresolved BL Lac objects
• Statistics of Cosmological Black Hole Jet Sources: Blazar Predictions for GLAST
• Circumscribing Late Dark Matter Decays Model Independently
• The Lyman-alpha forest in a blazar-heated Universe
• Constraints on the annihilation cross section of dark matter particles from anisotropies in the diffuse gamma-ray background measured with Fermi-LAT
• Gamma Rays from Clusters and Groups of Galaxies: Cosmic Rays versus Dark Matter
• Gamma-ray background anisotropy from galactic dark matter substructure
• Cross-Correlation of Cosmic Shear and Extragalactic Gamma-ray Background: Constraints on the Dark Matter Annihilation Cross-Section
• The Cosmic MeV Gamma-ray Background and Hard X-ray Spectra of Active Galactic Nuclei: Implications for the Origin of Hot AGN Coronae
• Deciphering Contributions to the Extragalactic Gamma-Ray Background from 2 GeV to 2 TeV
• Characterization of Dark-Matter-induced anisotropies in the diffuse gamma-ray background
• Robust identification of isotropic diffuse gamma rays from Galactic dark matter
• The Contribution of Blazars to the Extragalactic Diffuse Gamma-ray Background and Their Future Spatial Resolution
• Imprint of galaxy clustering in the cosmic gamma-ray background
• Contribution to the Extragalactic Gamma-ray Background from the Cascades of Very-high Energy Gamma Rays from Blazars
• Models of the Contribution of Blazars to the Anisotropy of the Extragalactic Diffuse Gamma-ray Background
• Balancing the Cosmic Energy Budget: The Cosmic X-ray Background, Blazars and the Compton Thick AGN Fraction
• Angular power spectrum of gamma-ray sources for GLAST: blazars and clusters of galaxies
• The Signature of Large Scale Structures on the Very High Energy Gamma-Ray Sky
• Dissecting the Gamma-Ray Background in Search of Dark Matter
• The Linear Instability of Dilute Ultrarelativistic $e^{\pm }$ Pair Beams
• Dark Matter Annihilation around Intermediate Mass Black Holes: an update
• Angular correlations in the cosmic gamma-ray background from dark matter annihilation around intermediate-mass black holes
• The Luminosity Function and Formation Rate of A Complete Sample of Long Gamma-Ray Bursts
• Angular Anisotropies in the Cosmic Gamma-ray Background as a Probe of its Origin
• Dark matter annihilation from intermediate-mass black holes: Contribution to the extragalactic gamma-ray background
• The Extragalactic Background Light Absorption Feature in the Blazar Component of the Extragalactic Gamma-ray Background
• Revisiting the luminosity and redshift distributions of long gamma-ray bursts
• Implications of Plasma Beam Instabilities for the Statistics of the Fermi Hard Gamma-ray Blazars and the Origin of the Extragalactic Gamma-Ray Background
• The Spectral Shape of the Gamma-ray Background from Blazars
• The detectability of dark matter annihilation with Fermi using the anisotropy energy spectrum of the gamma-ray background
• Black Holes as Dark Matter Annihilation Boosters
• Probing the Cosmic X-ray and MeV Gamma-ray Background Radiation through the Anisotropy
• Source-count Distribution of Gamma-Ray Blazars
• BASS XXXIII: Swift-BAT blazars and their jets through cosmic time
• Prospects for Very High Energy Blazar Survey by the Next Generation Cherenkov Telescopes
• High energy emission component, population, and contribution to the extragalactic gamma-ray background of gamma-ray emitting radio galaxies
• The Effect of Blazar Spectral Breaks on the Blazar Contribution to the Extragalactic Gamma-ray Background
• Astrophysical interpretation of the anisotropies in the unresolved gamma-ray background
• Gamma-ray signatures of annihilation to charged leptons in dark matter substructure
• Prospects for future very high-energy gamma-ray sky survey: impact of secondary gamma rays
• Cosmological Tests with the FSRQ Gamma-ray Luminosity Function
• The contribution from blazar cascade emission to the extragalactic gamma-ray background: What a role does the extragalactic magnetic field play?
• Gamma-ray luminosity function of Gamma-ray bright AGNs
• Searching for the most distant blazars with the Fermi Gamma-ray Space Telescope
• How many radio-loud quasars can be detected by the Gamma-Ray Large Area Space Telescope?
• Contribution from unresolved discrete sources to the Extragalactic Gamma-Ray Background (EGRB)
• Cosmological Evolution of Flat-Spectrum Radio Quasars based on the {\it Swift}/BAT 105-month Catalog and Their Contribution to the Cosmic MeV Gamma-ray Background Radiation
• Astrophysics in 2006
• Unresolved Unidentified Source Contribution to the Gamma-ray Background
• The Stellar-mass Function of Long Gamma-Ray Burst Host Galaxies
• Unidentified EGRET Sources and the Extragalactic Gamma-Ray Background
• Luminosity Function of collapsar Gamma-Ray Bursts:the Progenitor of Long Gamma-Ray Bursts Is Not Singular
• Detecting unresolved moving sources in a diffuse background
• A New Result on the Origin of the Extragalactic Gamma-ray Background
• A New Method to Study the Origin of the EGB and the First Application on AT20G
• BL Lacertae Objects and the Extragalactic Gamma-Ray Background
• Dark Matter implications of the Fermi-LAT measurement of anisotropies in the diffuse gamma-ray background: status report
• The redshift evolution of the luminosity function of type II GRBs
• Constraining the Luminosity Function and Delay-Time Distribution of Short Gamma-Ray Bursts for Multimessenger Gravitational-Wave Detection Rate Estimation
• The Gamma-ray Luminosity Function of Flat-Spectrum Radio Quasars