J/ApJS/256/13 The Fermi-LAT long-term transient sources (1FLT) (Baldini+, 2021)
Catalog of long-term transient sources in the first 10yr of Fermi-LAT data.
Baldini L., Ballet J., Bastieri D., Becerra Gonzalez J., Bellazzini R.,
Berretta A., Bissaldi E., Blandford R.D., Bloom E.D., Bonino R.,
Bottacini E., Bruel P., Buson S., Cameron R.A., Caraveo P.A., Cavazzuti E.,
Chen S., Chiaro G., Ciangottini D., Cibario N., Ciprini S.,
Cristarella Orestano P., Crnogorcevic M., Cutini S., D'Ammando F.,
De La Torre Luque P., De Palma F., Digel S.W., Di Lalla N., Dirirsa F.,
Di Venere L., Dominguez A., Fiori A., Fleischhack H., Franckowiak A.,
Fukazawa Y., Funk S., Fusco P., Gargano F., Gasparrini D., Germani S.,
Giglietto N., Giordano F., Giroletti M., Green D., Grenier I.A.,
Griffin S., Guiriec S., Gustafsson M., Hewitt J.W., Horan D., Imazawa R.,
Johannesson G., Kerr M., Kocevski D., Kuss M., Larsson S., Latronico L.,
Li J., Liodakis I., Longo F., Loparco F., Lovellette M.N., Lubrano P.,
Maldera S., Manfreda A., Marti-Devesa G., Matake H., Mazziotta M.N.,
Mereu I., Meyer M., Mirabal N., Mitthumsiri W., Mizuno T., Monzani M.E.,
Morselli A., Moskalenko I.V., Nagasawa S., Negro M., Ojha R., Orienti M.,
Orlando E., Palatiello M., Paliya V., Paneque D., Pei Z., Persic M.,
Pesce-Rollins M., Petrosian V., Poon H., Porter T.A., Principe G.,
Racusin J.L., Raino S., Rando R., Rani B., Razzano M., Razzaque S.,
Reimer A., Reimer O., Saz Parkinson P.M., Scotton L., Serini D., Sgro C.,
Siskind E.J., Spandre G., Spinelli P., Suson D.J., Tajima H., Tak D.,
Torres D.F., Tosti G., Troja E., Wood K., Yassine M., Zaharijas G.,
(The Fermi-LAT Collaboration)
<Astrophys. J. Suppl. Ser., 256, 13-13 (2021)>
=2021ApJS..256...13B 2021ApJS..256...13B (SIMBAD/NED BibCode)
ADC_Keywords: Gamma rays; Active gal. nuclei; Redshifts; GRB; Sun; Stars, flare
Keywords: High energy astrophysics; Active galactic nuclei; Gamma-ray bursts
Solar flares; Solar gamma-ray emission; Gamma-rays; Gamma-ray sources
Catalogs; Gamma-ray telescopes; Gamma-ray transient sources; Blazars
Quasars
Abstract:
We present the first Fermi Large Area Telescope (LAT) catalog of
long-term γ-ray transient sources (1FLT). This comprises sources
that were detected on monthly time intervals during the first decade
of Fermi-LAT operations. The monthly timescale allows us to identify
transient and variable sources that were not yet reported in other
Fermi-LAT catalogs. The monthly data sets 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
4σ in at least one monthly bin were listed in the final catalog.
The 1FLT catalog contains 142 transient γ-ray sources that are
not included in the 4FGL-DR2 catalog. Many of these sources (102) have
been confidently associated with active galactic nuclei (AGNs): 24 are
associated with flat-spectrum radio quasars, 1 with a BL Lac object,
70 with blazars of uncertain type, 3 with radio galaxies, 1 with a
compact steep-spectrum radio source, 1 with a steep-spectrum radio
quasar, and 2 with AGNs of other types. The remaining 40 sources have
no candidate counterparts at other wavelengths. The median γ-ray
spectral index of the 1FLT-AGN sources is softer than that reported in
the latest Fermi-LAT AGN general catalog. This result is consistent
with the hypothesis that detection of the softest γ-ray emitters
is less efficient when the data are integrated over year-long
intervals.
Description:
The Fermi-LAT data used in this work encompass a 10yr period from
2008 August 4 15:43:36 UTC (Mission Elapsed Time (MET) 239557417) to
2018 August 5 10:23:32 UTC (MET 555157417).
They are analyzed in monthly time bins, where one time bin (TBIN) is
defined as 2,630,000s (∼30 days). The 1FLT is constructed in the
energy range from 100MeV to 300GeV.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tableb1.dat 379 142 Catalog of Fermi-LAT long-term transient
sources (1FLT)
tableb2.dat 68 60 Sun detection list
tableb3.dat 83 27 GRB detection list
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Description of file:
1FLTfinalV23.fits is the FITS version of the 1FLT catalog described
in tables A1-A3:
The extension SOURCES (#1) has all of the information about the sources
(see Table A1 and Table B1 which also has all the information).
The extension FLARES (#2) contains the information about all the
monthly detections, including multiple monthly flares of the same 1FLT
source reported with the same assigned number. It includes also SED
data points (see Table A2).
The extension EnergyBounds (#3) contains the definitions of the bands in
which the SED data points were computed and the settings of the
analysis (see Table A3).
See also:
VII/178 : Optical Extragalactic Emission-line Objects (Hewitt+ 1991)
VII/259 : 6dF galaxy survey final redshift release (Jones+, 2009)
VII/274 : The Roma BZCAT - 5th edition (Massaro+, 2015)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
J/MNRAS/204/151 : Bright radio sources at 178 MHz (3CRR) (Laing+ 1983)
J/ApJ/715/429 : First Fermi-LAT AGN catalog (1LAC) (Abdo+, 2010)
J/ApJ/716/30 : SED of Fermi bright blazars (Abdo+, 2010)
J/ApJS/188/405 : Fermi-LAT first source catalog (1FGL) (Abdo+, 2010)
J/ApJ/722/520 : Gamma-ray light curves of Fermi blazars (Abdo+, 2010)
J/ApJ/741/30 : Radio/γ-ray correlation in AGN (Ackermann+, 2011)
J/ApJ/743/171 : The 2LAC catalog (Ackermann+, 2011)
J/ApJS/199/31 : Fermi LAT second source catalog (2FGL) (Nolan+, 2012)
J/A+A/541/A160 : Planck + X/γ observations of blazars (Giommi+, 2012)
J/ApJ/771/57 : Fermi-LAT flaring sources from FAVA (Ackermann+, 2013)
J/ApJS/209/14 : The Swift/BAT hard X-ray transient monitor (Krimm+, 2013)
J/ApJS/218/23 : Fermi LAT third source catalog (3FGL) (Acero+, 2015)
J/ApJ/810/14 : Third catalog of LAT-detected AGNs (3LAC) (Ackermann+, 2015)
J/A+A/588/A146 : The gNLS1 galaxy PKS 2004-447. VLBI images (Schulz+, 2016)
J/MNRAS/460/19 : Update of INTEGRAL/IBIS AGN catalogue (Malizia+, 2016)
J/ApJ/846/34 : Flaring gamma-ray sources; LAT 7.4yr (2FAV) (Abdollahi+, 2017)
J/ApJS/235/4 : The 105-month Swift-BAT all-sky hard X-ray survey (Oh+, 2018)
J/A+A/618/A22 : Fermi-LAT sources below 100MeV catalog (Principe+, 2018)
J/A+A/627/A13 : Second AGILE catalog of gamma-ray sources (Bulgarelli+, 2019)
J/ApJ/881/154 : BAT AGN spectroscopic survey. XVI. Blazars (Paliya+, 2019)
J/ApJS/247/33 : The Fermi LAT fourth source catalog (4FGL) (Abdollahi+, 2020)
J/ApJ/892/105 : 4th catalog of Fermi LAT-detected AGNs (4LAC) (Ajello+, 2020)
J/A+A/641/A152 : TANAMI radio galaxies II (Angioni+, 2020)
Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [1FLT]
6- 15 A10 --- 1FLT Source name (JHHMM+DDMM, according to
IAU Specifications for Nomenclature)
17- 19 I3 --- Seq [1/142] Source number (SRCNUM)
21- 25 F5.1 --- TBIN [0/119.5] Time Bin in which the source
was detected with the greatest TS
(TBIN_1m) (1)
27 I1 --- Nfl [1/7] Number of flares of this source
29- 39 F11.7 deg RAdeg Right Ascension (J2000)
41- 52 F12.8 deg DEdeg Declination (J2000)
54- 64 F11.7 deg GLON Galactic longitude
66- 76 F11.7 deg GLAT Galactic latitude
78- 87 F10.8 deg C95a [0.16/1.6] Semimajor axis of the error
ellipse at 95% confidence
89- 98 F10.8 deg C95b [0.14/1.2] Semiminor axis of the error
ellipse at 95% confidence
100- 111 F12.8 deg C95PA [0/178] Position angle of the
95%-confidence semi-major axis (2)
113- 122 F10.6 --- TS [25/177] Likelihood test statistic for
100MeV-300GeV analysis
124- 133 F10.6 --- Npred [36/480] Number of predicted events in
the model
135- 143 F9.7 --- PL [1.7/4.2] Photon index for the PowerLaw fit
145- 155 F11.9 --- e_PL [0.12/0.75] Uncertainty in PL
157- 169 E13.8 ph/cm2/s Flux [1.5e-8/2.3e-7] Integral photon flux for
0.1 to 300GeV
171- 183 E13.8 ph/cm2/s e_Flux [6e-9/6.3e-8] Uncertainty in Flux
185- 197 E13.8 MeV/cm2/s EFlux [1.1e-5/5.7e-5] Energy Flux (3)
199- 210 E12.8 MeV/cm2/s e_EFlux [2.7e-6/1.7e-5] Uncertainty in EFlux
212- 229 A18 --- Fermi Name, correspondence to Fermi-LAT xFGL
and FL8Y catalog (ASSOC_FERMI) (4)
231- 250 A20 --- Gamma Name, correspondence to γ-ray
source catalog (ASSOC_GAM)
252- 255 A4 --- --- [2FAV]
257- 266 A10 --- 2FAV Name, correspondence to 2FAV source catalog
(Abdollahi+, 2017, J/ApJ/846/34)
(ASSOC_FAVA)
268- 272 A5 --- LMC True if the source is in the LMC region
(3 occurrences)
274- 278 A5 --- CenA True if the source is near Cen A
(2 occurrences)
280- 284 A5 --- Class Class of the most likely counterpart (5)
286- 309 A24 --- Assoc Designation of the most likely associated
counterpart (Assoc_Name)
311- 320 F10.8 --- PAssoc [0/1] Probability of association
(AssocProbBay) (6)
322- 332 F11.7 deg RAAdeg ? Right Ascension (J2000), most likely
counterpart (Assoc_RA)
334- 344 F11.7 deg DEAdeg ? Declination (J2000), most likely
counterpart (Assoc_Dec)
346- 353 F8.6 --- z [0.002/3.7]? Most likely counterpart
redshift
355- 365 F11.6 mJy RFlux [24.9/4204]? Most likely counterpart flux
density at 1.4GHz (Radio_flux)
367- 373 F7.3 [Hz] lognupk [-12.6/14.7]? Log10 Synchrotron peak
frequency (7)
375- 379 A5 --- LowConf True if a source has a TS<30 and only
one monthly detection (72 occurrences)
--------------------------------------------------------------------------------
Note (1): Time Bin in which the source was detected with the greatest TS,
where 0-119 stand for first 120 months starting August 04, 2018 UTC
(MET 239557417), 0.5-119.5 stands for 120 15-day shifted months staring
August 19, 2018 UTC (MET 240846000).
Note (2): The position angle of the 95%-confidence semi-major axis, from
celestial North, positive toward increasing R.A. (eastward), in degrees
Note (3): The energy flux in MeV/cm2/s, in the 100 MeV to 300 GeV range
obtained by spectral fitting from 100 MeV to 300 GeV.
Note (4): FL8Y = the preliminary 8yr Fermi-LAT source list
(http://fermi.gsfc.nasa.gov/ssc/data/access/lat/fl8y/)
Note (5): Class of most likely counterpart as follows:
fsrq = Flat Spectrum Radio Quasar (24 occurrences);
bll = BL Lacertae object (1 occurrence);
css = Compact Steep Spectrum radio source (1 occurrence);
ssrq = Steep Spectrum Radio Quasar (1 occurrence);
rg = Radio Galaxy (3 occurrences);
bcu = Blazars of Uncertain Type (70 occurrences);
agn = Active Galactic Nuclei of other type (2 occurrences);
unass = Unassociated (40 occurrences).
Note (6): The probability of association according to the Bayesian method.
It is set to 0 for point sources with only positional association
(see Sect. 3).
Note (7): Log10 Synchrotron peak frequency measured with a third degree
polynomial fit function; Units: Hz (Ackermann+ 2015, J/ApJ/810/14).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 F5.1 --- TBIN [0/109] Time Bin in which the source was
detected with the greatest TS
7- 12 F6.2 deg RAdeg Detection localization, Right Ascension
(J2000)
14- 19 F6.2 deg DEdeg Detection localization, Declination (J2000)
21- 25 A5 --- repROI Overlapping ROI flag (1)
27- 32 I6 --- TS [25/168860] Likelihood test statistic for
100MeV-300GeV analysis
34- 39 E6.3 ph/cm2/s Flux [3e-8/2.2e-5] Integral photon flux for 0.1
to 300GeV
41- 46 E6.3 ph/cm2/s e_Flux [1.2e-8/1.8e-7] Uncertainty in Flux
48- 50 F3.1 --- PL [1.9/3.5] Photon index for the PowerLaw fit
52- 54 F3.1 --- e_PL [0.1/0.4] Uncertainty in PL
56- 68 A13 --- FLSF Name of the associated solar flare (2)
--------------------------------------------------------------------------------
Note (1): A flag indicating whether the source is detected in overlapping ROIs
Note (2): The name of the associated solar flare as reported in The First
Fermi-LAT Solar Flare Catalog (Ajello+ 2021ApJS..252...13A 2021ApJS..252...13A).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 F5.1 --- TBIN [7/119] Time Bin in which the source was
detected with the greatest TS
7- 12 F6.2 deg RAdeg Detection localization, Right Ascension
(J2000)
14- 19 F6.2 deg DEdeg Detection localization, Declination (J2000)
21- 25 A5 --- repROI Overlapping ROI flag (1)
27- 29 I3 --- TS [26/895] Likelihood test statistic for
100 MeV-300 GeV analysis
31- 36 E6.3 MeV/cm2/s EFlux [1.8e-5/0.00024] Energy Flux
38- 43 E6.3 MeV/cm2/s e_EFlux [4.2e-6/5.6e-5] Uncertainty in EFlux
45- 50 E6.3 ph/cm2/s Flux [1.9e-8/2.3e-7] Integral photon flux for
0.1 to 300GeV, in photons/cm2/s
52- 57 E6.3 ph/cm2/s e_Flux [1e-8/3.9e-8] Uncertainty in Flux
59- 61 F3.1 --- PL [1.6/3] Photon index for the PowerLaw fit
63- 65 F3.1 --- e_PL [0.1/0.3] Uncertainty in PL
67- 75 I9 --- Trigger GRB trigger number
77- 83 A7 --- GRB GRB name (Ajello+ 2019ApJ...878...52A 2019ApJ...878...52A)
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Note (1): A flag indicating whether the source is detected in overlapping ROIs
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Dec-2021