skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The Fermi -Lat High-Latitude Survey: Source Count Distributions And The Origin Of The Extragalactic Diffuse Background

Abstract

This is the first of a series of papers aimed at characterizing the populations detected in the high-latitude sky of the Fermi-LAT survey. In this work, we focus on the intrinsic spectral and flux properties of the source sample. We show that when selection effects are properly taken into account, Fermi sources are on average steeper than previously found (e.g., in the bright source list) with an average photon index of 2.40 ± 0.02 over the entire 0.1-100 GeV energy band. We confirm that flat spectrum radio quasars have steeper spectra than BL Lacertae objects with an average index of 2.48 ± 0.02 versus 2.18 ± 0.02. Using several methods, we build the deepest source count distribution at GeV energies, deriving that the intrinsic source (i.e., blazar) surface density at F 100 ≥ 10 –9 ph cm –2 s –1 is 0.12 +0.03 –0.02 deg –2. The integration of the source count distribution yields that point sources contribute 16(±1.8)% (±7% systematic uncertainty) of the GeV isotropic diffuse background. At the fluxes currently reached by LAT, we can rule out the hypothesis that pointlike sources (i.e., blazars) produce a larger fraction of the diffuse emission.

Authors:
 [1]
  1. Naval Research Lab. (NRL), Washington, DC (United States); et al.
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1357530
Grant/Contract Number:  
AC02-76SF00515
Resource Type:
Accepted Manuscript
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 720; Journal Issue: 1; Journal ID: ISSN 0004-637X
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS

Citation Formats

Abdo, A. A. The Fermi -Lat High-Latitude Survey: Source Count Distributions And The Origin Of The Extragalactic Diffuse Background. United States: N. p., 2010. Web. doi:10.1088/0004-637X/720/1/435.
Abdo, A. A. The Fermi -Lat High-Latitude Survey: Source Count Distributions And The Origin Of The Extragalactic Diffuse Background. United States. doi:10.1088/0004-637X/720/1/435.
Abdo, A. A. Wed . "The Fermi -Lat High-Latitude Survey: Source Count Distributions And The Origin Of The Extragalactic Diffuse Background". United States. doi:10.1088/0004-637X/720/1/435. https://www.osti.gov/servlets/purl/1357530.
@article{osti_1357530,
title = {The Fermi -Lat High-Latitude Survey: Source Count Distributions And The Origin Of The Extragalactic Diffuse Background},
author = {Abdo, A. A.},
abstractNote = {This is the first of a series of papers aimed at characterizing the populations detected in the high-latitude sky of the Fermi-LAT survey. In this work, we focus on the intrinsic spectral and flux properties of the source sample. We show that when selection effects are properly taken into account, Fermi sources are on average steeper than previously found (e.g., in the bright source list) with an average photon index of 2.40 ± 0.02 over the entire 0.1-100 GeV energy band. We confirm that flat spectrum radio quasars have steeper spectra than BL Lacertae objects with an average index of 2.48 ± 0.02 versus 2.18 ± 0.02. Using several methods, we build the deepest source count distribution at GeV energies, deriving that the intrinsic source (i.e., blazar) surface density at F 100 ≥ 10–9 ph cm–2 s–1 is 0.12+0.03 –0.02 deg–2. The integration of the source count distribution yields that point sources contribute 16(±1.8)% (±7% systematic uncertainty) of the GeV isotropic diffuse background. At the fluxes currently reached by LAT, we can rule out the hypothesis that pointlike sources (i.e., blazars) produce a larger fraction of the diffuse emission.},
doi = {10.1088/0004-637X/720/1/435},
journal = {Astrophysical Journal},
number = 1,
volume = 720,
place = {United States},
year = {2010},
month = {8}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 146 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

BRIGHT ACTIVE GALACTIC NUCLEI SOURCE LIST FROM THE FIRST THREE MONTHS OF THE FERMI LARGE AREA TELESCOPE ALL-SKY SURVEY
journal, July 2009


FERMI LAT OBSERVATION OF DIFFUSE GAMMA RAYS PRODUCED THROUGH INTERACTIONS BETWEEN LOCAL INTERSTELLAR MATTER AND HIGH-ENERGY COSMIC RAYS
journal, September 2009


DETECTION OF GAMMA-RAY EMISSION FROM THE STARBURST GALAXIES M82 AND NGC 253 WITH THE LARGE AREA TELESCOPE ON FERMI
journal, January 2010


FERMI LARGE AREA TELESCOPE FIRST SOURCE CATALOG
journal, May 2010

  • Abdo, A. A.; Ackermann, M.; Ajello, M.
  • The Astrophysical Journal Supplement Series, Vol. 188, Issue 2
  • DOI: 10.1088/0067-0049/188/2/405

SPECTRAL PROPERTIES OF BRIGHT FERMI -DETECTED BLAZARS IN THE GAMMA-RAY BAND
journal, January 2010


Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived from First-Year Fermi Large Area Telescope Data
journal, March 2010


THE FIRST CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE
journal, April 2010


THE VELA PULSAR: RESULTS FROM THE FIRST YEAR OF FERMI LAT OBSERVATIONS
journal, March 2010


Impact of astrophysical processes on the gamma-ray background from dark matter annihilations
journal, July 2007


BAT X‐Ray Survey. I. Methodology and X‐Ray Identification
journal, May 2008

  • Ajello, M.; Greiner, J.; Kanbach, G.
  • The Astrophysical Journal, Vol. 678, Issue 1
  • DOI: 10.1086/529418

THE EVOLUTION OF SWIFT /BAT BLAZARS AND THE ORIGIN OF THE MeV BACKGROUND
journal, June 2009


THE LARGE AREA TELESCOPE ON THE FERMI GAMMA-RAY SPACE TELESCOPE MISSION
journal, May 2009


Energy spectra of X-ray clusters of galaxies
journal, November 1976


Non-baryonic dark matter: observational evidence and detection methods
journal, April 2000


Nonthermal Particles and Radiation Produced by Cluster Merger Shocks
journal, September 2003

  • Berrington, Robert C.; Dermer, Charles D.
  • The Astrophysical Journal, Vol. 594, Issue 2
  • DOI: 10.1086/376981

The XMM‐Newton Wide‐Field Survey in the COSMOS Field. II. X‐Ray Data and the log  N ‐log  S Relations
journal, September 2007

  • Cappelluti, N.; Hasinger, G.; Brusa, M.
  • The Astrophysical Journal Supplement Series, Vol. 172, Issue 1
  • DOI: 10.1086/516586

The Luminosity Function of the EGRET Gamma‐Ray Blazars
journal, April 1998

  • Chiang, J.; Mukherjee, R.
  • The Astrophysical Journal, Vol. 496, Issue 2
  • DOI: 10.1086/305403

A multidimensional unfolding method based on Bayes' theorem
journal, August 1995

  • D'Agostini, G.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 362, Issue 2-3
  • DOI: 10.1016/0168-9002(95)00274-X

Statistics of Cosmological Black Hole Jet Sources: Blazar Predictions for the Gamma-Ray Large Area Space Telescope
journal, April 2007

  • Dermer, Charles D.
  • The Astrophysical Journal, Vol. 659, Issue 2
  • DOI: 10.1086/512533

The Correction of Statistics for Accidental Error
journal, March 1940

  • Eddington, A. S.
  • Monthly Notices of the Royal Astronomical Society, Vol. 100, Issue 5
  • DOI: 10.1093/mnras/100.5.354

The pulsar contribution to the gamma-ray background
journal, January 2010

  • Faucher-Giguère, Claude-André; Loeb, Abraham
  • Journal of Cosmology and Astroparticle Physics, Vol. 2010, Issue 01
  • DOI: 10.1088/1475-7516/2010/01/005

High-energy gamma-ray results from the second small astronomy satellite
journal, May 1975

  • Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.
  • The Astrophysical Journal, Vol. 198
  • DOI: 10.1086/153590

The gamma ray background from large scale structure formation
journal, September 2003


The Third EGRET Catalog of High‐Energy Gamma‐Ray Sources
journal, July 1999

  • Hartman, R. C.; Bertsch, D. L.; Bloom, S. D.
  • The Astrophysical Journal Supplement Series, Vol. 123, Issue 1
  • DOI: 10.1086/313231

On the Normalization of the Cosmic Star Formation History
journal, November 2006

  • Hopkins, Andrew M.; Beacom, John F.
  • The Astrophysical Journal, Vol. 651, Issue 1
  • DOI: 10.1086/506610

THE BLAZAR SEQUENCE AND THE COSMIC GAMMA-RAY BACKGROUND RADIATION IN THE FERMI ERA
journal, August 2009


The Cosmic MeV Gamma-Ray Background and Hard X-Ray Spectra of Active Galactic Nuclei: Implications for the Origin of Hot AGN Coronae
journal, November 2007

  • Inoue, Yoshiyuki; Totani, Tomonori; Ueda, Yoshihiro
  • The Astrophysical Journal, Vol. 672, Issue 1
  • DOI: 10.1086/525848

Supersymmetric dark matter
journal, March 1996


Gamma Rays from Intergalactic Shocks
journal, March 2003

  • Keshet, Uri; Waxman, Eli; Loeb, Abraham
  • The Astrophysical Journal, Vol. 585, Issue 1
  • DOI: 10.1086/345946

Cosmic γ-ray background from structure formation in the intergalactic medium
journal, May 2000


Optical spectroscopy and polarization of a new sample of optically bright flat radio spectrum sources
journal, July 1996

  • Marcha, M. J. M.; Browne, I. W. A.; Impey, C. D.
  • Monthly Notices of the Royal Astronomical Society, Vol. 281, Issue 2
  • DOI: 10.1093/mnras/281.2.425

Intergalactic shock acceleration and the cosmic gamma-ray background
journal, November 2002


The contribution of unresolved radio-loud AGN to the extragalactic diffuse gamma-ray background
journal, February 2000


Gamma‐Ray Luminosity Function of Blazars and the Cosmic Gamma‐Ray Background: Evidence for the Luminosity‐Dependent Density Evolution
journal, May 2006

  • Narumoto, Takuro; Totani, Tomonori
  • The Astrophysical Journal, Vol. 643, Issue 1
  • DOI: 10.1086/502708

The Guaranteed Gamma-Ray Background
journal, August 2002

  • Pavlidou, Vasiliki; Fields, Brian D.
  • The Astrophysical Journal, Vol. 575, Issue 1
  • DOI: 10.1086/342670

Simulating cosmic rays in clusters of galaxies – II. A unified scheme for radio haloes and relics with predictions of the γ-ray emission
journal, April 2008

  • Pfrommer, Christoph; Enßlin, Torsten A.; Springel, Volker
  • Monthly Notices of the Royal Astronomical Society, Vol. 385, Issue 3
  • DOI: 10.1111/j.1365-2966.2008.12956.x

EGRET Observations of the Extragalactic Gamma‐Ray Emission
journal, February 1998

  • Sreekumar, P.; Bertsch, D. L.; Dingus, B. L.
  • The Astrophysical Journal, Vol. 494, Issue 2
  • DOI: 10.1086/305222

The Gamma-Ray Background from Blazars: A New Look
journal, June 1996

  • Stecker, F. W.; Salamon, M. H.
  • The Astrophysical Journal, Vol. 464
  • DOI: 10.1086/177348

The Einstein Observatory Extended Medium-Sensitivity Survey. II - The optical identifications
journal, May 1991

  • Stocke, John T.; Morris, Simon L.; Gioia, I. M.
  • The Astrophysical Journal Supplement Series, Vol. 76
  • DOI: 10.1086/191582

A New Determination of the Extragalactic Diffuse Gamma‐Ray Background from EGRET Data
journal, October 2004

  • Strong, Andrew W.; Moskalenko, Igor V.; Reimer, Olaf
  • The Astrophysical Journal, Vol. 613, Issue 2
  • DOI: 10.1086/423196

The Starburst Contribution to the Extragalactic γ‐Ray Background
journal, January 2007

  • Thompson, Todd A.; Quataert, Eliot; Waxman, Eli
  • The Astrophysical Journal, Vol. 654, Issue 1
  • DOI: 10.1086/509068

Cosmological dark matter annihilations into γ rays: A closer look
journal, December 2002


Unified Schemes for Radio-Loud Active Galactic Nuclei
journal, June 1995

  • Urry, C. Megan; Padovani, Paolo
  • Publications of the Astronomical Society of the Pacific, Vol. 107
  • DOI: 10.1086/133630

The Large-Sample Distribution of the Likelihood Ratio for Testing Composite Hypotheses
journal, March 1938


    Works referencing / citing this record:

    Active galactic nuclei: what’s in a name?
    journal, August 2017

    • Padovani, P.; Alexander, D. M.; Assef, R. J.
    • The Astronomy and Astrophysics Review, Vol. 25, Issue 1
    • DOI: 10.1007/s00159-017-0102-9

    The gamma-ray spectral index changes for blazars
    journal, September 2012

    • Yang, JiangHe; Fan, JunHui; Nie, JianJun
    • Science China Physics, Mechanics and Astronomy, Vol. 55, Issue 11
    • DOI: 10.1007/s11433-012-4901-8

    Current and future constraints on dark matter from prompt and inverse-Compton photon emission in the isotropic diffuse gamma-ray background
    journal, February 2012


    Constraining extended gamma-ray emission from galaxy clusters: Extended gamma-ray emission in clusters
    journal, November 2012