FERMILTRNS ivo://nasa.heasarc/fermiltrns NASA/GSFC HEASARC FSSC; HEASARC 2026-10-09 NASA/GSFC HEASARC help desk heasarc-vo at athena.gsfc.nasa.gov Survey Source The First Catalog of Long-Term Transient Sources detected by Fermi Large Area Telescope (LAT) comprises of 142 unique, transient sources that were detected on monthly time intervals during Fermi-LAT operations. The monthly time scale allows to identify transient and variable sources that were not yet reported in other Fermi-LAT catalogs. The monthly datasets were analyzed using a wavelet-based source detection algorithm that provided the candidate new transient sources. The search was limited to the extragalactic regions of the sky to avoid the dominance of the Galactic diffuse emission at low Galactic latitudes. The transient candidates were then analyzed using the standard Fermi-LAT maximum likelihood analysis method. All sources detected with a statistical significance above 4 sigma in at least one monthly bin were listed in the final catalog. This database table was ingested by the HEASARC in September 2021 and is based upon file downloaded from the Space Science Data Center (SSDC) Fermi-1FLT <a href="https://www.ssdc.asi.it/fermi1flt/">website</a>. This is a service provided by NASA HEASARC . 2021ApJS..256...13B https://heasarc.gsfc.nasa.gov/W3Browse/all/fermiltrns.html Catalog Research served-by HEASARC TAP https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=fermiltrns& GET text/xml 180 99999 true 292.364 -79.151 0.166666666666667 https://heasarc.gsfc.nasa.gov/xamin/vo/tap https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/getvotable.pl?name=fermiltrns GET text/xml https://heasarc.gsfc.nasa.gov/cgi-bin/W3Browse/w3query.pl?tablehead=name=heasarc_fermiltrns&Action=More+Options&Action=Parameter+Search&ConeAdd=1 FERMI 0.166666666666667 Gamma-ray public fermiltrns Fermi LAT Long-Term Transient Source Catalog source_number Unique, Sequential Identification Number for Each Source in Catalog meta.id;src short nullable 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 semi_major_axis Semi-Major Axis of Error Ellipse at 95% Confidence arcmin phys.angSize.smajAxis;pos.errorEllipse double nullable semi_minor_axis Semi-Minor Axis of Error Ellipse at 95% Confidence arcmin phys.angSize.sminAxis;pos.errorEllipse double nullable photon_flux Photon Flux As Determined from the Fit to the Power Law Spectrum photon/s/cm^2 phot.flux;em.gamma double nullable photon_flux_error 1-Sigma Uncertainty in the Photon Flux photon/s/cm^2 stat.error;phot.flux;em.gamma double nullable flux Energy Flux for 100MeV-300GeV Range from the Spectral Fit erg/s/cm^2 phot.flux;em.gamma double nullable flux_error 1-Sigma Uncertainty in the 100-MeV to 300-GeV Energy Flux erg/s/cm^2 stat.error;phot.flux;em.gamma double nullable source_type Class Designation of the Associated Source src.class char nullable assoc_name Designation of the Likely Associated Source meta.id.assoc char nullable time_bin Time Bin in Which Source Detected with Largest Likelihood Test Statistic meta.code;time double nullable plaw_photon_index Photon Index (Gamma) for the Power Law Fit of the Spectrum spect.index;em.gamma double nullable fava_name Designation of Associated Source in the 2FAV Catalog meta.id.assoc char nullable flux_1420_mhz Radio Flux Density at 1420 MHz mJy phot.flux.density;em.radio.750-1500MHz double nullable bii Galactic Latitude degree pos.galactic.lat double nullable low_confidence_flag Flag [YN] Indicates Low Confidence meta.code.qual char nullable lmc_flag Flag [YN] Indicates Source Is Located in the Large Magellanic Cloud (LMC) Region meta.code.member char nullable gamma_name Designation of Associated Source in Other Gamma-Ray Catalogs meta.id.assoc char nullable assoc_redshift Redshift of the Associated Source src.redshift double nullable num_flares Number of Flares for This Source meta.number short nullable fermi_name Designation of Associated Source in Fermi-LAT or FL8Y Catalogs meta.id.assoc char nullable assoc_ra Right Ascension of the Associated Source degree pos.eq.ra double nullable likelihood Likelihood Test Statistic of Source Detection stat.likelihood double nullable plaw_photon_index_error 1-Sigma Uncertainty in the Photon Index for the Power Law Fit of the Spectrum stat.error;spect.index;em.gamma double nullable log_freq_peak Logarithm of the Synchrotron Peak Frequency from Polynomial Fit to Broadband SED log(Hz) em.freq double nullable assoc_dec Declination of the Associated Source degree pos.eq.dec double nullable position_angle Position Angle of the 95% Semi-Major Axis, East of North degree pos.posAng;pos.errorEllipse double nullable class Browse Object Classification src.class short nullable pred_number Number of Predicted Events in the Model meta.number double nullable lii Galactic Longitude degree pos.galactic.lon double nullable assoc_prob_bay Probability of Association from the Bayesian Method stat.probability double nullable cena_flag Flag [YN] Indicates Source Is Located Near Cen A meta.code.member 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