- ID:
- ivo://nasa.heasarc/fermilhesc
- Title:
- Fermi LAT High-Energy Source Catalog (1FHL)
- Short Name:
- FERMILHESC
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 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 .
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- ID:
- ivo://nasa.heasarc/fermiltrns
- Title:
- Fermi LAT Long-Term Transient Source Catalog
- Short Name:
- FERMILTRNS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- 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 .
- ID:
- ivo://nasa.heasarc/fermille
- Title:
- Fermi LAT Low-Energy Events Catalog
- Short Name:
- FERMILLE
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- LAT Low-Energy events (LLE) are automatically produced for each GBM GRB in the GBM Trigger Catalog if the GBM GRB has a position within 90 degrees of the LAT boresight. LLE data are generated for a given position in the sky (RA, DEC) and for a given interval of time (T0, T1) corresponding to the GBM Burst. The standard LLE selection applied to the downloaded events is the following: (FswGamState==0 && TkrNumTracks>0 && (GltEngine==6 || GltEngine==7) && EvtEnergyCorr > 0) && (FT1ZenithTheta<90.0) && (FT1Theta<=90.0) && (((cos(FT1Dec*0.0174533)*(FT1Ra - (RA)))<sup>2</sup> + (FT1Dec - (DEC))<sup>2</sup>) < PSF(EvtEnergyCorr, Theta) where <pre> * FswGamState is the status of the Flight Sofware Gamma filter. We require that the event is a gamma-ray (FswGamState==0). * TkrNumTracks is the number of tracks in the tracker. We require that there is at least one track. This requires the event to have a reconstructed direction. * GltEngine is the status of the <a href="https://oraweb.slac.stanford.edu/pls/slacquery/DOCUMENTS.DetailedIndex?PROJECT=GLAST&P_DOC_ID=776972">Global LAT Trigger</a>. We require that GltEngine equals 6 or 7, which corresponds to taking all the events that trigger in the tracker TKR but did not have a region of interest (ROI) associated (GltEngine 7) or all the events that pass the CalHI (at least 1 GeV in one crystal). * EvtEnergyCorr is the best estimation of the reconstructed energy, especially at low energy. * Theta is the reconstructed source direction (Theta) with respect the LAT boresight. * PSF(EvtEnergyCorr, Theta) represents the functional form of the containment radius of the Point Spread Function (PSF) of the LAT. </pre> The exact cut used to select the events is saved in the keyword LLECUT in the primary header of each LLE file. If the GBM catalog position of the burst is updated (due to a refined localization from LAT or Swift or from subsequent on ground analysis), the LLE data are automatically updated and new versions of the LLE files are produced. In some cases, LLE data are manually generated (using a better localization which may or may not have been used in the GBM Trigger Catalog). For each updated position, the version of the corresponding LLE files increases by one. There are six FITS files provided for each entry: the LLE event file, the time-binned spectrum (CSPEC) file, the CSPEC response (RSP) file, and the extracted burst spectrum (the PHA-I file) for the entire duration of the burst, an LLE event file with same time cut as the RSP and PHA-I files, and a LAT pointing and livetime history file. There are six FITS files provided for each entry: the LLE event file (gll_lle_bnNNNNNNNNN_vMM.fit), the time-binned spectrum (CSPEC) file (gll_cspec_bnNNNNNNNNN_vMM.pha), the CSPEC response (RSP) file (gll_cspec _bnNNNNNNNNN_vMM.rsp), and the extracted burst spectrum (the PHA-I file) for the entire duration of the burst (gll_pha_bnNNNNNNNNN_vMM.fit), an LLE event file with same time cut as the RSP and PHA-I files (gll_selected_bnNNNNNNNNN_vMM.fit), and a LAT pointing and livetime history file (gll_pt_bnNNNNNNNNN_vMM.fit). The LLE event file format is similar to the LAT photon file format with some exceptions. Because the LLE data are tightly connected to a particular object (position and time), the FITS keyword OBJECT has been added to the file. Generally, OBJECT will correspond to the entry of the GBM Trigger Catalog used to generate LLE data and corresponds to the "name" column in the FERMILLE table (and in the GBM Trigger Catalog table). For similar reasons, the position of the object used to select LLE file is written in the header of each extension of each LLE file. PROC_VER corresponds to the iteration of the analysis of LLE data. PASS_VER corresponds to the iteration for the reconstruction and the general event classification (Pass6, Pass7, etc.). VERSION corresponds to the version of the LLE product for this particular event. The update of a location of a GRB will increase the number of VERSION in the file, but will leave the PASS_VER and PROC_VER unchanged. The CSPEC file is obtained from directly binning the TTE files. It provides a series of spectra, accumulated every second, from -1000 to 1000 seconds around the burst. Each spectrum is binned in 50 energy channels, ranging typically from 10 MeV to 100 GeV. The format of the CSPEC file is tailored to satisfy rmfit standards, and it is not directly usable in XSPEC. The CSPEC Response file (the RSP file) is the detector response matrix calculated from Monte Carlo simulation, and it corresponds to a single response matrix for each Gamma-Ray Burst or Solar Flare. The PHA-I file contains the count spectrum. The PHA-I file is created from the same time interval used to compute the response matrix. The selected events file is identical to the LLE event file with an additional time selection applied to match the cut used to compute response matrix and PHA-I files. The LAT pointing and livetime history file is identical to the standard LAT file but with entries every second (instead of every 30 seconds). It spans 4600 seconds before and 4600 after the trigger time. The information in this table is provided by the Fermi LAT Instrument Science Operations Center (LISOC) and the Fermi Science Support Center (FSSC). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/fermilasp
- Title:
- Fermi LAT Monitored Source List
- Short Name:
- FERMILASP
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Fermi LAT table of monitored sources provides daily and weekly fluxes for sources of interest as described in <a href="http://fermi.gsfc.nasa.gov/ssc/data/policy/LAT_Monitored_Sources.html">http://fermi.gsfc.nasa.gov/ssc/data/policy/LAT_Monitored_Sources.html</a>. In addition, similar information will be released for any source which flares above 2x10<sup>-6</sup> photons cm<sup>-2</sup> s<sup>-1</sup> until the flux drops below 2x10<sup>-7</sup> photons cm<sup>-2</sup> s<sup>-1</sup>. Fermi is currently in survey mode and observes the entire sky every day. However, if a source does not exceed the detection threshold, no entry will appear in this catalog. The tabulated fluxes are derived at the LAT Instrument Science Operations center in a 'quick look' analysis to produce results quickly to facilitate follow-up multi-wavelength observations of flaring sources. The table of released fluxes will be updated as analysis and calibrations improve. <b>These early flux estimates do not include systematic uncertainties and do not</b> <b>have an absolute flux calibration</b>. Use of these data as absolute flux measurements for constraining models or for comparison to other data is strongly discouraged at this time. In addition to overall normalization uncertainties, source fluxes may have variations of up to 10% due to currently-uncorrected dependencies of the gamma-ray detection efficiency on variations of the particle background in orbit. Please note that these results are produced using preliminary instrument response functions and calibrations. The quality and stability of these results will improve when updated calibrations become available over the coming months. This database table is created by the HEASARC from FITS tables received from the Fermi Science Support Center (FSSC). The ASP FITS files are produced by the LAT Instrument Science Operations Center (LISOC) and transferred from the LISOC to the FSSC about once per week. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/fermil2psr
- Title:
- Fermi LAT Second Catalog of Gamma-Ray Pulsars (2PC)
- Short Name:
- FERMIL2PSR
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This catalog summarizes 0.1 GeV gamma-ray pulsar detections using data acquired by the Large Area Telescope (LAT) on the Fermi satellite. These pulsars are neutron stars identified using LAT data through periodicity searches in gamma-ray and radio data around LAT unassociated source positions. The catalogued pulsars are divided into three groups: millisecond pulsars, young radio-loud pulsars, and young radio-quiet pulsars. This catalog summarizes results of the analysis of pulse profiles and energy spectra, and analysis of the off-peak phase intervals, and compares the gamma-ray properties with those in the radio, optical, and X-ray bands. Flux limits for pulsars with no observed gamma-ray emission are provided. This database was constructed by the HEASARC by combining the tabulated data in the psrcat.dat, spec.dat, offpk.dat and refs.dat obtained from <a href="http://adsabs.harvard.edu/abs/2013yCat..22080017A">http://adsabs.harvard.edu/abs/2013yCat..22080017A</a>. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/fermilgrb
- Title:
- Fermi LAT Second Gamma-Ray Burst Catalog
- Short Name:
- FERMILGRB
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The LAT routinely observes high-energy emission from gamma-ray bursts (GRBs). Here we present the second catalog of LAT-detected GRBs. Initially, the second catalog covered the only the first 10 years of operations, from 2008 August 4 to 2018 August 4. The table given here has been supplemented to add later GRBs that were analyzed using the same procedure as the original catalog. It will be updated periodically with new GRBs. This database table was last updated by the HEASARC in April 2022 using electronic data obtained from the Fermi Science Support Center (FSSC). This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/fermilatra
- Title:
- Fermi LAT Sources Refined Associations Catalog
- Short Name:
- FERMILATRA
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Fermi-Large Area Telescope (LAT) First Source Catalog (1FGL: Abdo et al. 2010, ApJS, 188, 405) was released in 2010 February and the Fermi-LAT 2-Year Source Catalog (2FGL: Nolan et al. 2012, ApJS, 199, 31) appeared in 2012 April, based on data from 24 months of operations. Since they were released, many follow up observations of unidentified gamma-ray sources have been performed and new procedures for associating gamma-ray sources with potential counterparts at other wavelengths have been developed. In the reference paper, the authors review and characterize all of the associations as published in the 1FGL and 2FGL catalogs on the basis of multi-frequency archival observations. In particular, they locate 177 spectra for the low-energy counterparts that were not listed in the previous Fermi catalogs, and in addition they present new spectroscopic observations of eight gamma-ray blazar candidates. Based on their investigations, the authors introduce a new counterpart category of "candidate associations" and propose a refined classification for the candidate low-energy counterparts of the Fermi sources. They compare the 1FGL-assigned counterparts with those listed in 2FGL to determine which unassociated sources became associated in later releases of the Fermi catalogs. The authors also search for potential counterparts to all of the remaining unassociated Fermi sources. Finally, they prepare a refined and merged list of all of the associations of 1FGL plus 2FGL that includes 2219 unique Fermi objects. This is the most comprehensive and systematic study of all the associations collected for the gamma-ray sources available to the date of this study. The authors conclude that 80% of the Fermi sources have at least one known plausible gamma-ray emitter within their positional uncertainty regions. This table was created by the HEASARC in May 2015 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/217/2">CDS Catalog J/ApJS/217/2</a> file table4.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/fermilweek
- Title:
- Fermi LAT Weekly Data
- Short Name:
- FERMILWEEK
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Fermi LAT Weekly Data database table provides access to LAT data binned into weekly files by the FSSC's data servers. For each week, the FSSC provides two FITS files: an all-sky file of photons containing positions, energies, etc. and a spacecraft pointing history file. The underscore separated fields in the file names indicate the file type (photon or spacecraft), the Fermi mission week (e.g., w009 = week 9), the processing version (which will change with each major reprocessing of LAT data), and a version number for the file itself. Note that currently the data may include events from slightly after the official week boundaries, which will be reflected in the start and stop times in the table. Any "run" of LAT data the FSSC receives that starts in a given week is put into the weekly file for that week and not broken up. Note additional selections must be applied to the weekly files prior to use in a data analysis. See <a href="http://fermi.gsfc.nasa.gov/ssc/data/analysis/documentation/Cicerone/Cicerone_Data_Exploration/Data_preparation.html">LAT Data Selection Recommendations</a> and <a href="http://fermi.gsfc.nasa.gov/ssc/data/analysis/LAT_caveats.html">Caveats About Analyzing LAT Data</a> for more information. For queries based on position, energy, and exact times, use the <a href="http://fermi.gsfc.nasa.gov/cgi-bin/ssc/LAT/LATDataQuery.cgi">FSSC's LAT data server</a>. This database table is created by the HEASARC from FITS tables received from the Fermi Science Support Center (FSSC). It is updated on a weekly basis. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/fermi3fgl
- Title:
- Fermi LAT 4-Year Point Source Catalog
- Short Name:
- FERMI3FGL
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Fermi LAT 4-Year Point Source Catalog (3FGL) is a catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (Fermi) mission during the first 48 months of the science phase of the mission, which began on 2008 August 4. Compared to the 2FGL catalog, the 3FGL catalog incorporates twice as much data as well as a number of analysis improvements, including improved calibrations at the event reconstruction level, an updated model for Galactic diffuse gamma-ray emission, a refined procedure for source detection, and improved methods for associating LAT sources with potential counterparts at other wavelengths. Sources were detected and characterized in the 100 MeV to 300 GeV range. Source detection was based on a threshold likelihood Test Statistic of 25, corresponding to a significance of just over 4 sigma. This catalog includes source location regions, defined in terms of elliptical fits to the 95% confidence regions and spectral fits with three different spectral forms; power-law for most sources, log-parabola for significantly curved sources, and power-law with exponential cutoff for known gamma-ray pulsars. It also includes flux measurements in 5 bands for each source. The Fermi LAT Team has evaluated the populations of gamma-ray sources that are represented in the catalog using a protocol defined before launch. Individual LAT-detected sources have been provided identifications or plausible associations with sources in other astronomical catalogs. Care was taken to characterize the sensitivity of the results to the model of interstellar diffuse gamma-ray emission used to model the bright foreground, and a number of sources at low Galactic latitudes and toward bright local interstellar clouds are flagged as having positions that are strongly dependent on the model or as potentially entirely due to incorrectly modeled structure in the Galactic diffuse emission. This catalog has been superseded by the <a href="fermilpsc.html">Fermi LAT 8-Year Point Source Catalog</a>, also known as 4FGL. Please refer to that if you want the latest version. This database table was originally ingested by the HEASARC in May, 2015, as FERMILPSC. With the release of the 4FGL catalog in March, 2019, this catalog was renamed FERMI3FGL. The electronic data for this catalog was obtained from the Fermi Science Support Center (FSSC) at <a href="http://fermi.gsfc.nasa.gov/ssc/data/access/lat/4yr_catalog/">http://fermi.gsfc.nasa.gov/ssc/data/access/lat/4yr_catalog/</a>. This is a service provided by NASA HEASARC .
- ID:
- ivo://nasa.heasarc/fermilpsc
- Title:
- Fermi LAT 14-Year Point Source Catalog (4FGL-DR4)
- Short Name:
- FERMILPSC
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The Fermi Point Source Catalog (4FGL) is a catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. The 14-year catalog is an incremental version (4FGL-DR4, for Data Release 4) of the fourth Fermi-LAT catalog of gamma-ray sources. Based on the first fourteen years of science data in the energy range from 50 MeV to 1 TeV, it uses the same analysis methods as the 4FGL- DR3 catalog did for 12 years of data. The spectral parameters, spectral energy distributions, light curves and associations are updated for all sources. This database table was last updated by the HEASARC in February 2024, using the latest electronic data obtained from the Fermi Science Support Center (FSSC) available at <a href="http://fermi.gsfc.nasa.gov/ssc/data/access/lat/14yr_catalog/">http://fermi.gsfc.nasa.gov/ssc/data/access/lat/14yr_catalog/</a>. This is a service provided by NASA HEASARC .
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