FERMIFHL - Second Catalog of Hard Fermi-LAT Sources (2FHL)

Overview

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.

Catalog Bibcode

2016ApJS..222....5A

Bulletin

The FERMIFHL database table was last updated on 18 September 2015.

References

A full description of the catalog is given by the Fermi LAT team in "The Second Catalog of Hard Fermi-LAT Sources". Additional information for which is available at http://fermi.gsfc.nasa.gov/ssc/data/access/lat/2FHL/.

Provenance

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 http://fermi.gsfc.nasa.gov/ssc/data/access/lat/2FHL/.

Parameters

Name
The source designation, 2FHL JHHMM.m+DDMM[e], constructed according to the IAU Specifications for Nomenclature, in which the Right Ascension and Declination have been truncated to 0.1 decimal minutes and 1', respectively. The '2' refers to the second catalog and 'FHL' represents "Fermi Hard LAT". A name ending with 'e' indicates an extended source.

RA
The Right Ascension of the gamma-ray source in the selected equinox in J2000 decimal degrees.

Dec
The Declination of the gamma-ray source in the selected equinox in J2000 decimal degrees.

LII
The Galactic Longitude of the gamma-ray source in decimal degrees.

BII
The Galactic Latitude of the gamma-ray source in decimal degrees.

Error_Radius
The position uncertainty at 68% confidence level in decimal degrees.

Test_Statistic
The test statistic.

Spectral_Index
The observed spectral index from a power-law fit.

Spectral_Index_Error
The 1-sigma uncertainty on the observed spectral index.

Spectral_Index_D11
The intrinsic spectral index (unattenuated by EBL) using the observationally-based Dominguez et al. (2011) model.

Spectral_Index_D11_Error
The 1-sigma uncertainty on the intrinsic spectral index using the observationally-based Dominguez et al. (2011) model.

Spectral_Index_G12
The intrinsic spectral index (un-attenuated by EBL) using the observationally-based Gilmore et al. (2012) model.

Spectral_Index_G12_Error
The 1-sigma uncertainty on the intrinsic spectral index using the observationally-based Gilmore et al. (2012) model.

Flux
The integral photon flux between 50 GeV and 2 TeV, in photon/cm²/s.

Flux_Error
The 1-sigma uncertainty on integral photon flux between 50 GeV and 2 TeV, in photon/cm²/s.

Energy_Flux
The energy flux from 50 GeV to 2 TeV, in erg/cm²/s.

Energy_Flux_Error
The 1-sigma uncertainty on energy flux from 50 GeV to 2 TeV, in erg/cm²/s-1.

Flux50_171_GeV
The integral photon flux from 50 GeV to 171 GeV, in photon/cm²/s.

Flux50_171_GeV_Neg_Err
The lower (negative) uncertainty on integral photon flux from 50 GeV to 171 GeV, in photon/cm²/s.

Flux50_171_GeV_Pos_Err
The upper (positive) uncertainty on integral photon flux from 50 GeV to 171 GeV, in photon/cm²/s.

Sqrt_Ts50_171_GeV
The square root of the Test Statistic between 50 GeV and 171 GeV.

Flux171_585_GeV
The integral photon flux from 171 GeV to 585 GeV, in photon/cm²/s.

Flux171_585_GeV_Neg_Err
The lower (negative) uncertainty on integral photon flux from 171 GeV to 585 GeV, in photon/cm²/s.

Flux171_585_GeV_Pos_Err
The upper (positive) uncertainty on integral photon flux from 171 GeV to 585 GeV, in photon/cm²/s.

Sqrt_Ts171_585_GeV
The square root of the Test Statistic between 171 GeV and 585 GeV.

Flux585_2000_GeV
The integral photon flux from 585 GeV to 2 TeV, in photon/cm²/s.

Flux585_2000_GeV_Neg_Err
The lower (negative) uncertainty on integral photon flux from 585 GeV to 2 TeV, in photon/cm²/s.

Flux585_2000_GeV_Pos_Err
The upper (positive) uncertainty on integral photon flux from 585 GeV to 2 TeV, in photon/cm²/s.

Sqrt_Ts585_2000_GeV
The square root of the Test Statistic between 585 GeV and 2 TeV.

Npred
The detected number of photons from the source as predicted from the best fit.

HEP_Energy
The highest photon energy, in GeV.

HEP_Prob
The probability that the highest-energy photon is coming from the source, >= 0.85.

Roi
The region of interest number

Assoc_Name
The name of the most likely associated source.

Assoc_Prob_Bay
The probability of association from the Bayesian method.

Assoc_Prob_LR
The probability of association from the likelihood ratio method.

Source_Class
The class designation for the most likely association. Refer to the accompanying paper for details of class designations and the association method. The following abbreviations are used:

            psr     = pulsar
            pwn     = pulsar wind nebula
            snr     = supernova remnant
            spp     = supernova remnant/pulsar wind nebula
            hmb     = high-mass binary
            bin     = binary
            sfr     = star-forming region
            bll     = BL Lac type of blazar
            bll-g   = BL Lac type of blazar with prominent galaxy emission
            fsrq    = FSRQ type of blazar
            agn     = non-blazar active galaxy
            rdg     = radio galaxy
            rdg/bll = radio galaxy / BL Lac
            bcu I   = Blazar candidate of uncertain type I
            bcu II  = Blazar candidate of uncertain type II
            bcu III = Blazar candidate of uncertain type III
            gal     = normal galaxy (or part)
            galclu  = galaxy cluster

Redshift
The redshift (when available) of the most likely associated source.

Nupeak_Obs
The observed synchrotron peak frequency.

Assoc_3FGL
The name of the most likely associated source in the 3FGL.

Assoc_1FHL
The name of the most likely associated source in the 1FHL.

Assoc_TeVCat
The name of the most likely associated source in the TeVCat.

Contact Person

Questions regarding the FERMIFHL database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:27:23 EDT