IX/72 Fermi LAT Fourth Source Cat. DR4 (4FGL-DR4) (Ballet+, 2023)
Fermi Large Area Telescope Fourth Source Catalog Data Release 4 (4FGL-DR4).
Ballet J., Bruel P., Burnett T.H., Lott,B., The Fermi-LAT collaboration
<astro-ph, arXiv:2307.12546 (2023)>
=2023arXiv230712546B 2023arXiv230712546B
=2026yCat.9072....0B 2026yCat.9072....0B
ADC_Keywords: Gamma rays; Surveys
Mission_Name: Fermi
Keywords: Gamma rays: general ; surveys ; catalogs
Abstract:
We present an incremental version (4FGL-DR4, for Data Release 4) of
the fourth Fermi-LAT catalog containing 7194 gamma-ray sources. Based
on the first 14 years of science data in the energy range from 50MeV
to 1TeV, it uses the same analysis methods as the 4FGL-DR3 catalog did
for 12 years of data, with only a few improvements. The spectral
parameters, spectral energy distributions, light curves and
associations are updated for all sources.
We add four new extended sources and modify two existing ones. Among
the 6658 4FGL-DR3 sources, we delete 14 and change the localization of
10, while 32 are newly associated, eleven associations are changed and
three associations are discarded. We add 546 point sources, among
which 8 are considered identified and 229 have a plausible counterpart
at other wavelengths. Most are just above the detection threshold, and
14 are transient sources below the detection threshold that can affect
the light curves of nearby sources.
Description:
The data for the fourth source catalog (4FGL) DR4 catalog were taken
during the period 4-Aug-2008 (15:43 UTC) to 2 August 2022 (21:53 UTC)
covering 14 years.
The current version of the Large Area Telescope (LAT) data and
Instrument Response Functions remains P8R3_V3. The energy range
remains 50MeV to 1TeV, and the data are split over the same
19 components with the same zenith angle selections as in DR3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
4fgldr4.dat 2058 7195 The Fermi LAT 14-year source catalog (4FGL-DR4)
lcs/* . 7194 The individual 1yr light curves (PDF format)
sp/* . 7194 The individual spectral fits (PDF format)
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Description of file:
gllpscv35.fit is the LAT 14-year Source Catalog (4FGL-DR4 in FITS format) as
downloaded from: https://fermi.gsfc.nasa.gov/ssc/data/access/lat/14yr_catalog/
See also:
IX/67 : Incremental Fermi LAT 4th source cat. (4FGL-DR3) (Fermi-LAT col., 2022)
https://fermi.gsfc.nasa.gov/ssc/data/access/lat/14yr_catalog/ : Fermi SSC page
Byte-by-byte Description of file: 4fgldr4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [4FGL]
6- 18 A13 --- 4FGL The 4FGL name (JHHMM.m+DDMMa)
(Source_Name) (1)
20 I1 --- DR [1/4] Data release number
(DataRelease) (2)
22- 29 F8.4 deg RAdeg Right ascension (J2000) (RAJ2000)
31- 38 F8.4 deg DEdeg Declination (J2000) (DEJ2000)
40- 49 F10.6 deg GLON [0/360] Galactic longitude (GLON)
51- 60 F10.6 deg GLAT [-88/89] Galactic latitude (GLAT)
62- 69 F8.6 deg amaj68 [0.004/0.6]? Long radius of error
ellipse at 68% confidence
(Conf68SemiMajor)
71- 78 F8.6 deg bmin68 [0.004/0.4]? Short radius of
error ellipse at 68% confidence
(Conf68SemiMinor)
80- 90 F11.6 deg PA68 [-90/119]? Position angle of
error ellipse at 68% confidence
(Conf68PosAng)
92- 97 F6.4 deg amaj95 [0.007/0.9]? Long radius of
error ellipse at 95% confidence
(Conf95SemiMajor) (3)
99- 104 F6.4 deg bmin95 [0.007/0.7]? Short radius of
error ellipse at 95% confidence
(Conf95SemiMinor) (3)
106- 116 F11.6 deg PA95 [-90/119]? Position angle of
error ellipse at 95% confidence
(Conf95PosAng) (3)
118- 121 I4 --- ROI [1/1991] ROI number (ROI_num)
123- 139 A17 --- Name Cross-reference to the
ExtendedSources extension
(ExtendedSourceName)
141- 150 F10.6 --- Sig [0.02/898]? Source significance
in σ units over the
100MeV to 1TeV band (Signif_Avg)
152- 161 F10.3 MeV E0 [54/173797] Energy at which
error on differential flux is
minimal (Pivot_Energy)
163- 174 E12.6 ph/cm2/s F1000i [1e-11/1.4e-06] Integral photon
flux from 1 to 100GeV (Flux1000)
176- 187 E12.6 ph/cm2/s e_F1000i [7e-12/3.7e-09]? F1000i
uncertainty (Unc_Flux1000)
189- 200 E12.6 mW/m2 EF100 [1.4e-13/9.3e-09] Energy flux
from 100MeV to 100GeV obtained
by spectral fitting in
erg/cm2/s (Energy_Flux100)
202- 213 E12.6 mW/m2 e_EF100 [1.1e-13/2.9e-11]? EF100
uncertainty (UncEnergyFlux100)
215- 230 A16 --- Mod Spectral type in the global
model (PowerLaw, LogParabola,
PLSuperExpCutoff) (SpectrumType)
232- 243 E12.6 ph/cm2/s/MeV/s FpivPL [2.5e-17/1.5e-07]? Differential
flux at Pivot Energy in
PowerLaw fit (PLFluxDensity)
245- 256 E12.6 ph/cm2/s/MeV/s e_FpivPL [1e-17/1.3e-08]? FpivPL
uncertainty (UncPLFlux_Density)
258- 264 F7.5 --- PLGam [1/3.4]? Photon index when
fitting with PowerLaw (PL_Index)
266- 273 F8.6 --- e_PLGam [0.001/0.8]? PLGam uncertainty
(UncPLIndex)
275- 286 E12.6 ph/cm2/s/MeV/s FpivLP [3.1e-17/1.2e-07]? Differential
flux at Pivot Energy in
LogParabola fit (LPFluxDensity)
288- 299 E12.6 ph/cm2/s/MeV/s e_FpivLP [1.4e-17/10e-09]? FpivLP
uncertainty (UncLPFlux_Density)
301- 308 F8.6 --- LPalpha [0.8/3.8]? Photon index at
Pivot Energy (α of Eq. 1)
when fitting with LogParabola
(LP_Index) (4)
310- 317 F8.6 --- e_LPalpha [0.002/2.7]? LPalpha
uncertainty (UncLPIndex)
319- 327 F9.6 --- LPbeta [-0.14/1]? Curvature parameter
(β of Eq. 1) when fitting
with LogParabola (LP_beta) (4)
329- 336 F8.6 --- e_LPbeta [1.3e-05/2]? LPbeta uncertainty
(UncLPbeta)
338- 347 F10.6 --- SigCurv1 [0/254] Significance (in
σ units) of the fit
improvement between PowerLaw
and LogParabola (LP_SigCurv)
349- 360 E12.6 MeV LPEPk [0.02/1.4e+08]? Peak energy in
nuFnu estimated from the
LogParabola model (LP_EPeak)
362- 373 E12.6 MeV e_LPEPk [0.3/6.3e+09]? LPEPk
uncertainty (UncLPEPeak)
375- 386 E12.6 ph/cm2/s/MeV/s FpivPLEC [3.3e-17/1.1e-07]? Differential
flux at Pivot Energy in
PLSuperExpCutoff fit
(PLECFluxDensity)
388- 399 E12.6 ph/cm2/s/MeV/s e_FpivPLEC [1.7e-17/8.6e-09]? FpivPLEC
uncertainty
(UncPLECFlux_Density)
401- 408 F8.6 --- PLECGamS [0.2/3.4]? Photon index at
Pivot Energy (ΓS of
Eq. 2) when fitting with
PLSuperExpCutoff
(PLEC_IndexS) (5)
410- 417 F8.6 --- e_PLECGamS [0.0038/2.9]? PLECGamS
uncertainty (UncPLECIndexS)
419- 427 F9.6 --- PLECCd [-0.28/2.25]? Spectral
curvature at Pivot Energy (d of
Eq. 2) when fitting with
PLSuperExpCutoff
(PLEC_ExpfactorS) (5)
429- 436 F8.6 --- e_PLECCd ? PLECCd uncertainty
(UncPLECExpfactorS)
438- 445 F8.6 --- PLECCb [0.22/1]? Exponential index (b
of Eq. 2) when fitting with
PLSuperExpCutoff
(PLECExpIndex) (5)
447- 454 F8.6 --- e_PLECCb [0.01/0.15]? PLECCb uncertainty
(UncPLECExp_Index)
456- 465 F10.6 --- SigCurv2 [0/258] Significance (in
σ units) of the fit
improvement between PowerLaw
and PLSuperExpCutoff
(PLEC_SigCurv)
467- 478 E12.6 MeV PLECEPk [0.039/4.6e+07]? Peak energy in
nuFnu estimated from the
PLSuperExpCutoff model
(PLEC_EPeak)
480- 491 E12.6 MeV e_PLECEPk [8.7/5.7e+09]? PLECEPk
uncertainty (UncPLECEPeak)
493- 504 E12.6 --- Npred [11.9/284295] Predicted number
of events in the model (Npred)
506- 517 E12.6 ph/cm2/s F50 [3.3e-20/5.4e-06] Integral
photon flux in 50-100MeV
(Band 1) (Flux_Band1)
519- 530 E12.6 ph/cm2/s F100 [1.6e-20/5.7e-06] Integral
photon flux in 100-300MeV
(Band 2) (Flux_Band2)
532- 543 E12.6 ph/cm2/s F300 [5.3e-19/3.4e-06] Integral
photon flux in 300MeV-1GeV
(Band 3) (Flux_Band3)
545- 556 E12.6 ph/cm2/s F1000 [1.9e-18/1.1e-06] Integral
photon flux in 1-3GeV (Band 4)
(Flux_Band4)
558- 569 E12.6 ph/cm2/s F3000 [1.1e-21/2.3e-07] Integral
photon flux in 3-10GeV (Band 5)
(Flux_Band5)
571- 582 E12.6 ph/cm2/s F10000 [8.7e-23/1.2e-08] Integral
photon flux in 10-30GeV (Band 6)
(Flux_Band6)
584- 595 E12.6 ph/cm2/s F30000 [0/4.6e-09] Integral photon
flux in 30-100GeV (Band 7)
(Flux_Band7)
597- 608 E12.6 ph/cm2/s F100000 [0/1.7e-09] Integral photon
flux in 100GeV-1TeV (Band 8)
(Flux_Band8)
610- 621 E12.6 ph/cm2/s e_F50 [-8.2e-07/-5.4e-09]? Lower
uncertainty on F50
(LoUncFluxBand1) (6)
623- 634 E12.6 ph/cm2/s E_F50 [3.8e-09/6e-07]? Upper
uncertainty on F50
(UpUncFluxBand1) (6)
636- 647 E12.6 ph/cm2/s e_F100 [-1.6e-07/-6.2e-10]? Lower
uncertainty on F100
(LoUncFluxBand2) (6)
649- 660 E12.6 ph/cm2/s E_F100 ? Upper uncertainty on F100
(UpUncFluxBand2) (6)
662- 673 E12.6 ph/cm2/s e_F300 [-4.3e-08/-5.8e-11]? Lower
uncertainty on F300
(LoUncFluxBand3) (6)
675- 686 E12.6 ph/cm2/s E_F300 ? Upper uncertainty on F300
(UpUncFluxBand3) (6)
688- 699 E12.6 ph/cm2/s e_F1000 [-4.2e-09/-9.4e-12]? Lower
uncertainty on F1000
(LoUncFluxBand4) (6)
701- 712 E12.6 ph/cm2/s E_F1000 ? Upper uncertainty on F1000
(UpUncFluxBand4) (6)
714- 725 E12.6 ph/cm2/s e_F3000 [-1.1e-09/-2.8e-12]? Lower
uncertainty on F3000
(LoUncFluxBand5) (6)
727- 738 E12.6 ph/cm2/s E_F3000 ? Upper uncertainty on F3000
(UpUncFluxBand5) (6)
740- 751 E12.6 ph/cm2/s e_F10000 [-4.2e-10/-8.5e-13]? Lower
uncertainty on F10000
(LoUncFluxBand6) (6)
753- 764 E12.6 ph/cm2/s E_F10000 ? Upper uncertainty on F10000
(UpUncFluxBand6) (6)
766- 777 E12.6 ph/cm2/s e_F30000 [-1.6e-10/-7.6e-13]? Lower
uncertainty on F30000
(LoUncFluxBand7) (6)
779- 790 E12.6 ph/cm2/s E_F30000 ? Upper uncertainty on F30000
(UpUncFluxBand7) (6)
792- 803 E12.6 ph/cm2/s e_F100000 [-9.1e-11/-7.5e-13]? Lower
uncertainty on F100000
(LoUncFluxBand8) (6)
805- 816 E12.6 ph/cm2/s E_F100000 ? Upper uncertainty on F100000
(UpUncFluxBand8) (6)
818- 829 E12.6 mW/m2 nuFnu50 [5.3e-24/8.9e-10] Spectral
energy distribution over
50-100MeV in erg/cm2/s
(nuFnu_Band1)
831- 842 E12.6 mW/m2 nuFnu100 [4e-24/1.5e-09] Spectral energy
distribution over 100-300MeV in
erg/cm2/s (nuFnu_Band2)
844- 855 E12.6 mW/m2 nuFnu300 [4.5e-22/2.5e-09] Spectral
energy distribution over
300MeV-1GeV in erg/cm2/s
(nuFnu_Band3)
857- 868 E12.6 mW/m2 nuFnu1000 [5.4e-21/2.6e-09] Spectral
energy distribution over 1-3GeV
in erg/cm2/s (nuFnu_Band4)
870- 881 E12.6 mW/m2 nuFnu3000 [8.6e-24/1.4e-09] Spectral
energy distribution over
3-10GeV in erg/cm2/s
(nuFnu_Band5)
883- 894 E12.6 mW/m2 nuFnu10000 [1.7e-24/2.3e-10] Spectral
energy distribution over
10-30GeV in erg/cm2/s
(nuFnu_Band6)
896- 907 E12.6 mW/m2 nuFnu30000 [0/3.2e-10] Spectral energy
distribution over 30-100GeV in
erg/cm2/s (nuFnu_Band7)
909- 920 E12.6 mW/m2 nuFnu100000 [0/2.6e-10] Spectral energy
distribution over 100GeV-1TeV
in erg/cm2/s (nuFnu_Band8)
922- 931 F10.6 --- TS50 [0/27]? Square root of the Test
Statistic in 50-100MeV
(SqrtTSBand1)
933- 942 F10.6 --- TS100 [0/145]? Square root of the
Test Statistic in 100-300MeV
(SqrtTSBand2)
944- 953 F10.6 --- TS300 [0/389]? Square root of the
Test Statistic in 300MeV-1GeV
(SqrtTSBand3)
955- 964 F10.6 --- TS1000 [0/582]? Square root of the
Test Statistic in 1-3GeV
(SqrtTSBand4)
966- 975 F10.6 --- TS3000 [0/518]? Square root of the
Test Statistic in 3-10GeV
(SqrtTSBand5)
977- 986 F10.6 --- TS10000 [0/202]? Square root of the
Test Statistic in 10-30GeV
(SqrtTSBand6)
988- 997 F10.6 --- TS30000 [0/117]? Square root of the
Test Statistic in 30-100GeV
(SqrtTSBand7)
999- 1008 F10.6 --- TS100000 [0/74]? Square root of the Test
Statistic in 100GeV-1TeV
(SqrtTSBand8)
1010- 1021 E12.6 --- VarInd [2.28/96039]? Variability
(Variability_Index) (7)
1023- 1030 F8.6 --- fVar [0/3.7]? Fractional variability
computed from the fluxes in
each year (Frac_Variability)
1032- 1040 F9.6 --- e_fVar [0.002/10]? fVar uncertainty
(UncFracVariability)
1042- 1050 F9.5 --- SigPk [2.6/401]? Source significance
in peak interval in σ
units (Signif_Peak)
1052- 1063 E12.6 ph/cm2/s FPk [1.8e-10/5.1e-06]? Peak
integral photon flux from
100MeV to 100GeV (Flux_Peak)
1065- 1076 E12.6 ph/cm2/s e_FPk [7.3e-11/3.5e-08]? FPk
uncertainty (UncFluxPeak)
1078- 1086 I9 s TPk [255223712/665390016]? Time of
center of interval in which
peak flux was measured
(Time_Peak)
1088- 1099 E12.6 s IntPk [3.1e+07/3.2e+07]? Length of
interval in which peak flux was
measured (Peak_Interval)
1101- 1112 E12.6 ph/cm2/s F100y1 [1.7e-19/1.1e-05] Integral
photon flux from 100 MeV to 100
GeV in year 1 (Flux_History1)
1114- 1125 E12.6 ph/cm2/s F100y2 Integral photon flux from 100
MeV to 100 GeV in year 2
(Flux_History2)
1127- 1138 E12.6 ph/cm2/s F100y3 Integral photon flux from 100
MeV to 100 GeV in year 3
(Flux_History3)
1140- 1151 E12.6 ph/cm2/s F100y4 Integral photon flux from 100
MeV to 100 GeV in year 4
(Flux_History4)
1153- 1164 E12.6 ph/cm2/s F100y5 Integral photon flux from 100
MeV to 100 GeV in year 5
(Flux_History5)
1166- 1177 E12.6 ph/cm2/s F100y6 Integral photon flux from 100
MeV to 100 GeV in year 6
(Flux_History6)
1179- 1190 E12.6 ph/cm2/s F100y7 Integral photon flux from 100
MeV to 100 GeV in year 7
(Flux_History7)
1192- 1203 E12.6 ph/cm2/s F100y8 [6.1e-20/1.1e-05] Integral
photon flux from 100 MeV to 100
GeV in year 8 (Flux_History8)
1205- 1216 E12.6 ph/cm2/s F100y9 [1e-20/1.1e-05] Integral photon
flux from 100 MeV to 100 GeV in
year 9 (Flux_History9)
1218- 1229 E12.6 ph/cm2/s F100y10 Integral photon flux from 100
MeV to 100 GeV in year 10
(Flux_History10)
1231- 1242 E12.6 ph/cm2/s F100y11 Integral photon flux from 100
MeV to 100 GeV in year 11
(Flux_History11)
1244- 1255 E12.6 ph/cm2/s F100y12 [4.8e-21/1.1e-05] Integral
photon flux from 100 MeV to 100
GeV in year 12 (Flux_History12)
1257- 1268 E12.6 ph/cm2/s F100y13 [1.3e-19/1.1e-05] Integral
photon flux from 100 MeV to 100
GeV in year 13 (Flux_History13)
1270- 1281 E12.6 ph/cm2/s F100y14 [2.6e-22/1.1e-05] Integral
photon flux from 100 MeV to 100
GeV in year 14 (Flux_History14)
1283- 1294 E12.6 ph/cm2/s e_F100y1 [-6.4e-08/-2e-11]? Lower
uncertainty on F100y1
(LoUncFluxHistory1)
1296- 1307 E12.6 ph/cm2/s E_F100y1 [3.4e-11/6.4e-08]? Upper
uncertainty on F100y1
(UpUncFluxHistory1)
1309- 1320 E12.6 ph/cm2/s e_F100y2 [-6.3e-08/-2.2e-11]? Lower
uncertainty on F100y2
(LoUncFluxHistory2)
1322- 1333 E12.6 ph/cm2/s E_F100y2 ? Upper uncertainty on F100y2
(UpUncFluxHistory2)
1335- 1346 E12.6 ph/cm2/s e_F100y3 [-6.3e-08/-1.5e-11]? Lower
uncertainty on F100y3
(LoUncFluxHistory3)
1348- 1359 E12.6 ph/cm2/s E_F100y3 ? Upper uncertainty on F100y3
(UpUncFluxHistory3)
1361- 1372 E12.6 ph/cm2/s e_F100y4 [-6.3e-08/-2.5e-11]? Lower
uncertainty on F100y4
(LoUncFluxHistory4)
1374- 1385 E12.6 ph/cm2/s E_F100y4 ? Upper uncertainty on F100y4
(UpUncFluxHistory4)
1387- 1398 E12.6 ph/cm2/s e_F100y5 [-6.4e-08/-1.8e-11]? Lower
uncertainty on F100y5
(LoUncFluxHistory5)
1400- 1411 E12.6 ph/cm2/s E_F100y5 ? Upper uncertainty on F100y5
(UpUncFluxHistory5)
1413- 1424 E12.6 ph/cm2/s e_F100y6 [-6.5e-08/-2.8e-11]? Lower
uncertainty on F100y6
(LoUncFluxHistory6)
1426- 1437 E12.6 ph/cm2/s E_F100y6 ? Upper uncertainty on F100y6
(UpUncFluxHistory6)
1439- 1450 E12.6 ph/cm2/s e_F100y7 [-6.5e-08/-2e-11]? Lower
uncertainty on F100y7
(LoUncFluxHistory7)
1452- 1463 E12.6 ph/cm2/s E_F100y7 ? Upper uncertainty on F100y7
(UpUncFluxHistory7)
1465- 1476 E12.6 ph/cm2/s e_F100y8 [-6.3e-08/-2.5e-11]? Lower
uncertainty on F100y8
(LoUncFluxHistory8)
1478- 1489 E12.6 ph/cm2/s E_F100y8 ? Upper uncertainty on F100y8
(UpUncFluxHistory8)
1491- 1502 E12.6 ph/cm2/s e_F100y9 [-6.3e-08/-2.1e-11]? Lower
uncertainty on F100y9
(LoUncFluxHistory9)
1504- 1515 E12.6 ph/cm2/s E_F100y9 ? Upper uncertainty on F100y9
(UpUncFluxHistory9)
1517- 1528 E12.6 ph/cm2/s e_F100y10 [-5.9e-08/-2.8e-11]? Lower
uncertainty on F100y10
(LoUncFluxHistory10)
1530- 1541 E12.6 ph/cm2/s E_F100y10 ? Upper uncertainty on F100y10
(UpUncFluxHistory10)
1543- 1554 E12.6 ph/cm2/s e_F100y11 [-6.2e-08/-3.1e-11]? Lower
uncertainty on F100y11
(LoUncFluxHistory11)
1556- 1567 E12.6 ph/cm2/s E_F100y11 ? Upper uncertainty on F100y11
(UpUncFluxHistory11)
1569- 1580 E12.6 ph/cm2/s e_F100y12 [-5.8e-08/-1.7e-11]? Lower
uncertainty on F100y12
(LoUncFluxHistory12)
1582- 1593 E12.6 ph/cm2/s E_F100y12 ? Upper uncertainty on F100y12
(UpUncFluxHistory12)
1595- 1606 E12.6 ph/cm2/s e_F100y13 [-5.8e-08/-1.7e-11]? Lower
uncertainty on F100y13
(LoUncFluxHistory13)
1608- 1619 E12.6 ph/cm2/s E_F100y13 ? Upper uncertainty on F100y13
(UpUncFluxHistory13)
1621- 1632 E12.6 ph/cm2/s e_F100y14 [-5.8e-08/-3.1e-11]? Lower
uncertainty on F100y14
(LoUncFluxHistory14)
1634- 1645 E12.6 ph/cm2/s E_F100y14 [3.3e-11/5.8e-08]? Upper
uncertainty on F100y14
(UpUncFluxHistory14)
1647- 1656 F10.6 --- TSy1 [0/415] Square root of the Test
Statistic in year 1
(SqrtTSHistory1)
1658- 1667 F10.6 --- TSy2 [0/382] Square root of the Test
Statistic in year 2
(SqrtTSHistory2)
1669- 1678 F10.6 --- TSy3 [0/378] Square root of the Test
Statistic in year 3
(SqrtTSHistory3)
1680- 1689 F10.6 --- TSy4 [0/376] Square root of the Test
Statistic in year 4
(SqrtTSHistory4)
1691- 1700 F10.6 --- TSy5 [0/379] Square root of the Test
Statistic in year 5
(SqrtTSHistory5)
1702- 1711 F10.6 --- TSy6 [0/375] Square root of the Test
Statistic in year 6
(SqrtTSHistory6)
1713- 1722 F10.6 --- TSy7 [0/372] Square root of the Test
Statistic in year 7
(SqrtTSHistory7)
1724- 1733 F10.6 --- TSy8 [0/380] Square root of the Test
Statistic in year 8
(SqrtTSHistory8)
1735- 1744 F10.6 --- TSy9 [0/401] Square root of the Test
Statistic in year 9
(SqrtTSHistory9)
1746- 1755 F10.6 --- TSy10 [0/339] Square root of the Test
Statistic in year 10
(SqrtTSHistory10)
1757- 1766 F10.6 --- TSy11 [0/347] Square root of the Test
Statistic in year 11
(SqrtTSHistory11)
1768- 1777 F10.6 --- TSy12 [0/350] Square root of the Test
Statistic in year 12
(SqrtTSHistory12)
1779- 1788 F10.6 --- TSy13 [0/352] Square root of the Test
Statistic in year 13
(SqrtTSHistory13)
1790- 1799 F10.6 --- TSy14 [0/348] Square root of the Test
Statistic in year 14
(SqrtTSHistory14)
1801- 1818 A18 --- Asso4FGL Correspondence to 4FGL-DR3 source
catalog, if any (ASSOC_4FGL)
1820- 1837 A18 --- FGL Most recent correspondence to
FGL source catalogs prior to
4FGL, if any (ASSOC_FGL)
1839- 1856 A18 --- FHL Most recent correspondence to
previous FHL source catalogs,
if any (ASSOC_FHL)
1858- 1873 A16 --- 2AGL Name of likely corresponding
2AGL source, if any (ASSOC_GAM1)
1875- 1888 A14 --- 3EG Name of likely corresponding
3EG source, if any (ASSOC_GAM2)
1890- 1904 A15 --- EGR Name of likely corresponding
EGR source, if any (ASSOC_GAM3)
1906 A1 --- f_TeVCat [ENP] Flag on TeVCat
(TEVCAT_FLAG)
1908- 1928 A21 --- TeVCat Name of likely corresponding
TeV source from TeVCat, if any
(ASSOC_TEV)
1930- 1934 A5 --- Cl1 Class designation for
associated source (CLASS1) (8)
1936- 1940 A5 --- Cl2 Class designation for
low-confidence association
(CLASS2)
1942- 1969 A28 --- Assoc1 Name of identified or likely
associated source (ASSOC1)
1971- 1995 A25 --- Assoc2 Name of low-confidence
association or of enclosing
extended source (ASSOC2)
1997- 2004 F8.6 --- ProbBy [0/1]? Probability of
association according to the
Bayesian method
(ASSOCPROBBAY) (9)
2006- 2013 F8.6 --- ProbLR [0/1]? Probability of
association according to the
Likelihood Ratio method
(ASSOCPROBLR) (10)
2015- 2028 F14.10 deg RACdeg [0/360]? Right ascension in
decimal degrees (J2000)
(RA_Counterpart)
2030- 2043 F14.10 deg DECdeg [-88/89]? Declination in
decimal degrees (J2000)
(DEC_Counterpart)
2045- 2052 F8.6 deg errPos [0/2.5]? 95% precision of the
counterpart localization
(Unc_Counterpart) (11)
2054- 2058 I5 --- Flags [0/12592] Source flags
(Flags) (12)
--------------------------------------------------------------------------------
Note (1): The coordinates are rounded, following the International Astronomical
Union convention. The letter at the end can be c (coincident with
interstellar clump), e (extended source), i (for Crab nebula inverse
Compton) or s (for Crab nebula synchrotron).
Note (2): 1 for DR1, 2 for new in DR2, 3 for new or changed in DR3, 4 for new or
changed in DR4.
Note (3): From the 95% ellipse, assuming a Gaussian distribution.
Note (4): Curved sources are still fit with a lognormal function
(LogParabolaunderSpectrumType in the FITS table, hereafter LP):
dN/dE=K(E/E0)-α-βln(E/E0_)^
See Section 3.4 in Abdollahi+, 2022, IX/67 (4FGL-DR3)
Note (5): See Section 3.4 in Abdollahi+, 2022, IX/67 (4FGL-DR3)
Note (6): Separate 1σ errors are computed from the likelihood profile
toward lower and larger fluxes. The lower error is set equal to NULL,
and the upper error is derived from a Bayesian upper limit if the 1σ
interval contains 0 (TS<1).
Note (7): Sum of 2xlog(Likelihood) difference between the flux fitted in each
time interval and the average flux over the full catalog interval; a
value greater than 24.72 over 12 intervals indicates <1% chance of
being a steady source.
Note (8): Designations shown in capital letters are firm identifications.
Code as follows:
GC = Galactic center (1 occurrence)
PSR = Young pulsar, identified by pulsations (137 occurrences)
MSP = Millisecond pulsars, identified by pulsations (139 occurrences)
PWN = Pulsar wind nebula (13 occurrences)
SNR = Supernova remnant (26 occurrences)
SFR = Star-forming region (3 occurrences)
HMB = High-mass binary (8 occurrences)
LMB = Low-mass binary (2 occurrences)
BIN = Binary (1 occurrence)
NOV = Nova (8 occurrences)
BLL = BL Lac type of blazar (22 occurrences)
FSRQ = FSRQ type of blazar (44 occurrences)
RDG = Radio galaxy (6 occurrences)
AGN = Non-blazar active galaxy (1 occurrence)
BCU = Blazar candidate of uncertain type (1 occurrence)
NLSY1 = Narrow-line Seyfert 1 (4 occurrences)
GAL = Normal galaxy (or part) (2 occurrences)
Designations shown in lower case letters indicate associations:
psr = Young pulsar, no pulsations seen in LAT yet (4 occurrences)
msp = Millisecond pulsars, no pulsations seen in LAT yet (40 occurrences)
pwn = Pulsar wind nebula (9 occurrences)
snr = Supernova remnant (18 occurrences)
spp = Supernova remnant/Pulsar wind nebula (126 occurrences)
glc = Globular cluster (41 occurrences)
sfr = Star-forming region (3 occurrences)
hmb = High-mass binary (3 occurrences)
lmb = Low-mass binary (7 occurrences)
bll = BL Lac type of blazar (1468 occurrences)
fsrq = FSRQ type of blazar (776 occurrences)
rdg = Radio galaxy (47 occurrences)
agn = Non-blazar active galaxy (7 occurrences)
ssrq = Steep spectrum radio quasar (2 occurrences)
css = Compact Steep Spectrum radio source (6 occurrences)
bcu = Blazar candidate of uncertain type (1622 occurrences)
nlsy1 = Narrow-line Seyfert 1 (4 occurrences)
sey = Seyfert galaxy (4 occurrences)
sbg = Starburst galaxy (8 occurrences)
gal = Normal galaxy (or part) (4 occurrences)
unk = Unknown (137 occurrences)
Note (9): Blank values in this column when Assoc1 is defined means that the
probability could not be computed, either because the source is
extended or because the counterpart is the result of dedicated follow-up.
Note (10): Probabilities <0.8 are formally set to 0.
Note (11): For extended counterparts, this reports their extension radius.
Note (12): Each condition is indicated by one bit among the 16 bits forming
Flags. The bit is raised (set to 1) in the dubious case, so that
sources without any warning sign have Flags =0. Binary coding as in Table 4
of Abdollahi+, 2022, IX/67 (4FGL-DR3)
--------------------------------------------------------------------------------
History:
Downloaded at:
https://fermi.gsfc.nasa.gov/ssc/data/access/lat/14yr_catalog/
(4FGL-DR4 in FITS format and Plots of 1-year light curves in PDF format
and Plots of spectral fits in PDF format)
(End) Emmanuelle Perret [CDS] 19-Jun-2026