FERMILHESC ivo://nasa.heasarc/fermilhesc NASA/GSFC HEASARC Ackermann et al. 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This table contains the catalog of gamma-ray sources at energies above 10 GeV based on data from the Large Area Telescope (LAT) accumulated during the first 3 years of the Fermi Gamma-ray Space Telescope mission. The first Fermi-LAT catalog of > 10 GeV sources (1FHL) has 514 sources. For each source, the authors present location, spectrum, a measure of variability,and associations with cataloged sources at other wavelengths. They found that 449 (87%) could be associated with known sources, of which 393 (76% of the 1FHL sources) are active galactic nuclei. Of the 27 sources associated with known pulsars, they find 20 (12) to have significant pulsations in the range > 10 GeV (> 25 GeV). In this work, the authors also report that, at energies above 10 GeV, unresolved sources account for 27% +/- 8% of the isotropic gamma-ray background, while the unresolved Galactic population contributes only at the few percent level to the Galactic diffuse background. The authors also highlight the subset of the 1FHL sources that are the best candidates for detection at energies above 50 - 100 GeV with current and future ground-based gamma-ray observatories. The time interval analyzed here is from the beginning of Fermi LAT science operations on 2008 August 4 (MET 239557447) to 2011 August 1 (MET 333849586), covering very nearly 3 years. In this work, the authors analyze gamma rays with energies in the range 10-500 GeV. To limit the contamination from gamma rays produced by cosmic-ray interactions in the upper atmosphere, gamma rays with zenith angles greater than 105 degrees were excluded. To further reduce the residual gamma rays from the upper atmosphere only data for time periods when the spacecraft rocking angle was less than 52 degrees were considered. See Section 2 of the reference paper for further explanations. This table was created by the HEASARC in April 2015 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/209/34/">CDS Catalog J/ApJS/209/34/</a> files table3.dat and table7.dat. This is a service provided by NASA HEASARC . 2013ApJS..209...34A https://heasarc.gsfc.nasa.gov/W3Browse/all/fermilhesc.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=fermilhesc& GET text/xml 180 99999 true 157.253 -85.73 0.333333333333333 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=fermilhesc GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_fermilhesc&Action=More+Options&Action=Parameter+Search&ConeAdd=1 FERMI 0.333333333333333 Gamma-ray public fermilhesc Fermi LAT High-Energy Source Catalog (1FHL) name The 1FHL Catalog Source Identifier (1FHL JHHMM.s+DDMM) meta.id;meta.main char nullable ra Right Ascension degree pos.eq.ra;meta.main double nullable dec Declination degree pos.eq.dec;meta.main double nullable error_semimajor_axis Semi-Major Axis of 95% Confidence Source Location Region degree stat.error;pos double nullable error_semiminor_axis Semi-Minor Axis of 95% Confidence Source Location Region degree stat.error;pos double nullable photon_flux The 10-500 GeV Photon Flux photon/cm^2/s phot.flux;em.gamma.hard double nullable photon_flux_error The 1-Sigma Uncertainty in the 10-500 GeV Photon Flux photon/cm^2/s stat.error;phot.flux;em.gamma.hard double nullable flux Energy Flux from 10-500 GeV from Power-Law Spectral Fit erg/s/cm^2 phot.flux;em.gamma.hard double nullable flux_error The 1-Sigma Uncertainty in the Energy Flux erg/s/cm^2 stat.error;phot.flux;em.gamma.hard double nullable assoc_name_1 Primary Name of Associated Source meta.id.assoc char nullable source_type_1 Primary Astrophysical Class of Associated Source src.class char nullable "__x_ra_dec" System unit vector column double nullable "__y_ra_dec" System unit vector column double nullable "__z_ra_dec" System unit vector column double nullable "__row" System index column char nullable lii Galactic Longitude degree pos.galactic.lon double nullable sed_class_1 Primary SED Classification src.class char nullable tev_assoc_flag TeV Association Flag, If Any meta.code char nullable agn_optical_class_2 Secondary AGN Optical Classification src.class char nullable alt_redshift Second Distinct Redshift Found in Literature src.redshift double nullable sed_class_2 Secondary SED Classification src.class char nullable agn_optical_class_1 Primary AGN Optical Classification src.class char nullable error_position_angle Position Angle of Major Axis of 95% Confidence Ellipse from North through East degree pos.posAng short nullable spectral_index Photon Power-Law Index, Gamma spect.index;em.gamma.hard double nullable bii Galactic Latitude degree pos.galactic.lat double nullable class Browse Object Classification src.class short nullable num_bayesian_blocks Number of Change Points in Bayesian Blocks Light Curve (1 for Non-Variable) stat.param;src.var;em.gamma.hard short nullable assoc_name_2 Secondary Name of Associated Source meta.id.assoc char nullable extent_flag Flag [e] Indicates Extended Source meta.code;phys.angSize char nullable significance Source Significance sigma stat.likelihood double nullable redshift Redshift src.redshift double nullable source_type_2 Secondary Astrophysical Class of Associated Source src.class char nullable alt_redshift_flag Flag [l] Indicates Redshift Violates Spectroscopic Lower Limit meta.code;src.redshift char nullable spectral_index_error The 1-Sigma Uncertainty in Gamma stat.error;spect.index;em.gamma.hard double nullable alt_gammaray_name Association with Other Catalogs of GeV Gamma-Ray Sources, If Any meta.id.assoc char nullable