The Fermi GBM Daily Data database table contains entries for each day for which GBM data has been processed. The daily data products consist of GBM data that are produced continuously regardless of whether a burst occurred. Thus these products are the count rates from all detectors, the monitoring of the detector calibrations (e.g., the position of the 511 keV line), and the spacecraft position and orientation. Some days may also have event lists known as time-tagged event (TTE) files associated with them. These TTE files have the same format as those produced for bursts. Due to the large data volume associated with TTE files, only certain portions of the day considered of scientific interest to the instrument team will have TTE data. The underlying Level 0 data arrive continuously with each Ku band downlink. However, the GBM Instrument Operations Center (GIOC) will form FITS files of the resulting Level 1 data covering an entire calendar day (UTC); these daily files are then sent to the FSSC. Consequently, the data latency is about one day: the first bit from the beginning of a calendar day may arrive a few hours after the day began while the last bit will be processed and added to the data product file a few hours after the day ended. These data products may be sent to the FSSC file by file as they are produced, not necessarily in one package for a given day. Note that the data may include events from slightly before and slightly after the day official boundaries, which will be reflected in the start and stop times in the table. Consequently, some events may be listed in files for two consecutive days (e.g., at the end of one and the beginning of the next). Due to the continuous nature of GBM processing, new data files may arrive after the day has been included in Browse and reprocessed version may also arrive at any time. The reprocessed data will have the version number incremented (see file name conventions below). Browse will automatically download the latest versions of the data files. This database table was created by and is updated by the HEASARC based on information supplied by the Fermi Project. It is updated on a daily basis. The tte_flag parameter was added to the table in July 2010. This is a service provided by NASA HEASARC .
These data represent the Fermi GBM Solar Flare Catalog. Data in this catalog are targeted specifically at Fermi observations of high-energy solar phenomena, primarily solar flares, in order to facilitate the use of Fermi data by the international solar physics community. This table catalogs Fermi Gamma-Ray Burst Monitor (GBM) triggers associated with known solar flares. The Fermi GBM Solar Flare Catalog is supported by a Fermi Guest Investigator program and maintained at <a href="http://hesperia.gsfc.nasa.gov/fermi_solar">http://hesperia.gsfc.nasa.gov/fermi_solar</a>. Please include the following acknowledgment if you use these facilities in a paper or presentation: "We acknowledge the use of the Fermi Solar Flare Observations facility funded by the Fermi GI program (<a href="http://hesperia.gsfc.nasa.gov/fermi_solar/">http://hesperia.gsfc.nasa.gov/fermi_solar/</a>)." The information in this table is provided independently by a Fermi Guest Investigator grant. The tabulated data come from <a href="http://hesperia.gsfc.nasa.gov/fermi/gbm/qlook/fermi_gbm_flare_list.txt">http://hesperia.gsfc.nasa.gov/fermi/gbm/qlook/fermi_gbm_flare_list.txt</a>. This table is updated automatically within a day or so of a new data file being made available. This is a service provided by NASA HEASARC .
This table lists all of the triggers observed by one or more of the 14 GBM detectors (12 NaI and 2 BGO). Note that there are two Browse catalogs resulting from GBM triggers. All GBM triggers are entered in the Trigger Catalog, but only those triggers classified as bursts are entered in the <a href="/W3Browse/fermi/fermigbrst.html">Fermi GBM Burst Catalog</a>. Thus, a burst will be found in both the Trigger and Burst Catalogs. The Burst Catalog analysis requires human intervention; therefore, GRBs will be entered in the Trigger Catalog before the Burst Catalog. The latency requirements are 1 day for triggers and 3 days for bursts. The GBM consists of an array of 12 sodium iodide (NaI) detectors which cover the lower end of the energy range up to 1 MeV. The GBM triggers off of the rates in the NaI detectors, with some Terrestrial Gamma-ray Flash (TGF)-specific algorithms using the bismuth germanate (BGO) detectors, sensitive to higher energies, up to 40 MeV. The NaI detectors are placed around the Fermi spacecraft with different orientations to provide the required sensitivity and FOV. The cosine-like angular response of the thin NaI detectors is used to localize burst sources by comparing rates from detectors with different viewing angles. The two BGO detectors are placed on opposite sides of the spacecraft so that all sky positions are visible to at least one BGO detector. The signals from all 14 GBM detectors are collected by a central Data Processing Unit (DPU). This unit digitizes and time-tags the detectors' pulse height signals, packages the resulting data into several different types for transmission to the ground (via the Fermi spacecraft), and performs various data processing tasks such as autonomous burst triggering. The information in this table is provided by the Fermi Gamma-ray Burst Monitor Instrument Operations Center (GIOC) and the Fermi Science Support Center (FSSC). The values come from a trigger catalog entry file or a burst catalog entry file provided by the GIOC. These are FITS files which may contain additional data in extensions for bursts (see the spectrum_flag and fit_flag columns) and are available for download. This table is updated automatically within a day or so of new data files being processed and made available. This is a service provided by NASA HEASARC .
The Fermi LAT table of bright sources is a list of bright LAT sources that have statistical significances of 10 sigma or higher, based on the first three months of survey data. The primary purpose of this list is to assist proposers for Guest Investigator Cycle 2 (due date 6 March). This list will eventually be superseded by the LAT Source Catalog, to be released about one year after launch. This database table was created by the HEASARC in February 2009 based on the electronic data obtained from the Fermi Science Support Center (FSSC) available at <a href="http://fermi.gsfc.nasa.gov/ssc/data/access/lat/bright_src_list/">http://fermi.gsfc.nasa.gov/ssc/data/access/lat/bright_src_list/</a>. This is a service provided by NASA HEASARC .
This is the third update to the fourth catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (LAT). This version (4LAC-DR3) derives from the third data release of the 4FGL catalog based on 12 years of gamma-ray data with energies greater than 50 MeV. The spectral parameters, spectral energy distributions (SEDs), yearly light curves, and associations have been updated for all sources. The catalog contains includes 3407 AGN located at high Galactic latitudes (|b| > 10 degrees). This database table was first ingested by the HEASARC in February 2010. It was last updated (to the 4LAC-DR3 version) in June 2023 using electronic data obtained from the Fermi Science Support Center (FSSC). That data is available at <a href="https://fermi.gsfc.nasa.gov/ssc/data/access/lat/4LACDR3/">https://fermi.gsfc.nasa.gov/ssc/data/access/lat/4LACDR3/</a>. Note that this table does not contain the low-latitude sources given in a separate file there, which are not formally a part of the catalog. This is a service provided by NASA HEASARC .
This database table contains a catalog of classifications for blazar candidates of uncertain type (BCU) detected by the Fermi Large Area Telescope gamma-ray instrument. These classifications have been determined by an Artificial Neural Network machine learning method. The aim of the authors' study was to develop an optimized version of this Artificial Neural Network machine learning method for classifying these blazar candidates. The final result of this study increased the classification performance by about 80% with respect to the method previously used for the classification of uncertain blazars in Chiaro et al. (<a href="https://ui.adsabs.harvard.edu/abs/2016MNRAS.462.3180C">2016MNRAS.462.3180C</a>, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/462/3180/">CDS Cat. J/MNRAS/462/3180</a>), leaving only 15 unclassified blazars out of 573 blazar candidates of uncertain type listed in the Fermi LAT 4-Year Source Catalog. Looking beyond the gamma-ray features of blazars, interesting information can be obtained from a multiwavelength study of the sources and particularly from X-ray and radio flux. In this study the authors tested the possibility to use those two parameters to improve the performance of the network. They did not consider any optical spectroscopy data because, when considering uncertain sources, optical spectra are very often not available or not sufficiently descriptive of the nature of the source. The gamma-ray flux was obtained by adding five time-integrated fluxes in five bands (0.1-0.3, 0.3-1, 1-3, 3-10, 10-100 GeV) from the <a href="/W3Browse/fermi/fermi3fgl.html">3FGL Catalog</a> (Acero et al. <a href="https://ui.adsabs.harvard.edu/abs/2015ApJS..218...23A">2015ApJS..218...23A</a>, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/218/23/">CDS Cat. J/ApJS/218/23</a>). Radio and X-ray data were obtained from the Fermi LAT 4-Year AGN Catalog 3LAC (Ackermann et al. <a href="https://ui.adsabs.harvard.edu/abs/2015ApJ...810...14A">2015ApJ...810...14A</a>, <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJ/810/14/">CDS Cat. J/ApJ/810/14</a>). Radio fluxes used were measured at frequencies of 1.4 and 0.8 GHz; the X-ray fluxes were measured in the 0.1-2.4keV range. The complete list of 567 classified BCUs is presented in this table in which sources are ordered by increasing likelihood of a source being a BL Lac. This database table was ingested by the HEASARC in May 2023 based upon the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/490/4770">CDS Catalog J/MNRAS/490/4770</a> file table1.dat. This is a service provided by NASA HEASARC .
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 .
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 .
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 .
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 .
