FERMIFHL ivo://nasa.heasarc/fermifhl NASA/GSFC HEASARC Fermi LAT Team 2026-10-02 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source This is a catalog of sources detected above 50 GeV by the Fermi-Large Area Telescope (LAT) in 80 months of data. The newly delivered Pass 8 event-level analysis allows the detection and characterization of sources in the 50GeV-2TeV energy range. In this energy band, Fermi-LAT has detected 360 sources, which constitute the second catalog of hard Fermi-LAT sources (2FHL). The improved angular resolution enables the precise localization of point sources (~1.7-arcminutes radius at 68% confidence level) and the detection and characterization of spatially extended sources. The authors found that 86% of the sources could be associated with counterparts at other wavelengths, of which the majority (75%) are active galactic nuclei and the rest (11%) are Galactic sources. Only 25% of the 2FHL sources have been previously detected by Cherenkov telescopes, implying that the 2FHL provides a reservoir of candidates to be followed up at very high energies. This work closes the energy gap between the observations performed at GeV energies by Fermi-LAT on orbit and the observations performed at higher energies by Cherenkov telescopes from the ground. This database table was first ingested by the HEASARC in September 2015 using electronic data obtained from the Fermi Science Support Center (FSSC). That data is available at <a href="http://fermi.gsfc.nasa.gov/ssc/data/access/lat/2FHL/">http://fermi.gsfc.nasa.gov/ssc/data/access/lat/2FHL/</a>. This is a service provided by NASA HEASARC . 2016ApJS..222....5A https://heasarc.gsfc.nasa.gov/W3Browse/all/fermifhl.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=fermifhl& GET text/xml 180 99999 true 318.144012451172 -86.2966003417969 0.166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=fermifhl GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_fermifhl&Action=More+Options&Action=Parameter+Search&ConeAdd=1 FERMI 0.166666666666667 Gamma-ray public fermifhl Second Catalog of Hard Fermi-LAT Sources (2FHL) name Source Designation 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_radius Position Uncertainty at 68% Confidence Level degree stat.error;pos double nullable test_statistic Test Statistic double nullable spectral_index Spectral Index spect.index double nullable spectral_index_error 1-Sigma Uncertainty on the Spectral Index stat.error;spect.index double nullable flux Integral Photon Flux from 50 GeV to 2 TeV photon/cm^2/s phot.count;em.gamma double nullable flux_error 1-Sigma Uncertainty on Integral Photon Flux from 50 GeV to 2 TeV photon/cm^2/s stat.error;phot.count;em.gamma double nullable energy_flux Energy flux from 50 GeV to 2 TeV erg/cm^2/s phot.flux double nullable energy_flux_error 1-Sigma Uncertainty on Energy Flux from 50 GeV to 2 TeV erg/cm^2/s stat.error;phot.flux double nullable assoc_name Designation of the Most Likely Associated Source meta.id.assoc char nullable source_class Class Designation for the Most Likely Association src.class char nullable redshift Redshift (When Available) of the Most Likely Associated Source src.redshift double nullable sqrt_ts585_2000_gev Square Root of the Test Statistic Between 585 GeV and 2 TeV double nullable hep_prob Probability Highest Energy Photon Is Coming from the Source stat.probability double nullable assoc_3fgl Designation of the Most Likely Associated Source in the 3FGL meta.id.assoc char nullable sqrt_ts50_171_gev Square Root of the Test Statistic Between 50 GeV and 171 GeV double nullable flux50_171_gev_pos_err 1-Sigma Positive Uncertainty on Integral Photon Flux from 50 GeV to 171 GeV photon/cm^2/s stat.error;phot.count;em.gamma double nullable spectral_index_g12_error 1-Sigma Uncertainty on G12 Intrinsic Spectral Index stat.error;spect.index double nullable flux50_171_gev Integral Photon Flux from 50 GeV to 171 GeV photon/cm^2/s phot.count;em.gamma double nullable flux585_2000_gev Integral Photon Flux from 585 GeV to 2 TeV photon/cm^2/s phot.count;em.gamma double nullable spectral_index_d11_error 1-Sigma Uncertainty on D11 Intrinsic Spectral Index stat.error;spect.index double nullable flux171_585_gev Integral Photon Flux from 171 GeV to 585 GeV photon/cm^2/s phot.count;em.gamma double nullable nupeak_obs Observed Synchrotron Peak Frequency Hz em.freq double nullable flux171_585_gev_pos_err 1-Sigma Positive Uncertainty on Integral Photon Flux from 171 GeV to 585 GeV photon/cm^2/s stat.error;phot.count;em.gamma double nullable assoc_prob_lr Probability of Association from the Likelihood Ratio Method stat.probability double nullable roi Region of Interest Number int nullable assoc_prob_bay Probability of Association from the Bayesian Method stat.probability double nullable hep_energy Highest Energy of the Photons from the Source GeV em.energy double nullable assoc_1fhl Designation of the Most Likely Associated Source in the 1FHL meta.id.assoc char nullable flux50_171_gev_neg_err 1-Sigma Negative Uncertainty on Integral Photon Flux from 50 GeV to 171 GeV photon/cm^2/s stat.error;phot.count;em.gamma double nullable flux585_2000_gev_neg_err 1-Sigma Negative Uncertainty on Integral Photon Flux from 585 GeV to 2 TeV photon/cm^2/s stat.error;phot.count;em.gamma double nullable spectral_index_g12 Intrinsic Spectral Index Using Gilmore et al. (2012) Model spect.index double nullable sqrt_ts171_585_gev Square Root of the Test Statistic Between 171 GeV and 585 GeV double nullable flux171_585_gev_neg_err 1-Sigma Negative Uncertainty on Integral Photon Flux from 171 GeV to 585 GeV photon/cm^2/s stat.error;phot.count;em.gamma double nullable npred Predicted Number of Photons from the Source double nullable bii Galactic Latitude degree pos.galactic.lat double nullable spectral_index_d11 Intrinsic Spectral Index Using Dominguez et al. (2011) Model spect.index double nullable assoc_tevcat Designation of the Most Likely Associated Source in the TeVCat meta.id.assoc char nullable lii Galactic Longitude degree pos.galactic.lon double nullable flux585_2000_gev_pos_err 1-Sigma Positive Uncertainty on Integral Photon Flux from 585 GeV to 2 TeV photon/cm^2/s stat.error;phot.count;em.gamma double 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