J/ApJ/892/105 Fourth catalog of Fermi LAT-detected AGNs (4LAC) (Ajello+, 2020)
The fourth catalog of Active Galactic Nuclei detected by the Fermi Large Area
Telescope.
Ajello M., Angioni R., Axelsson M., Ballet J., Barbiellini G., Bastieri D.,
Becerra Gonzalez J., Bellazzini R., Bissaldi E., Bloom E.D., Bonino R.,
Bottacini E., Bruel P., Buson S., Cafardo F., Cameron R.A., Cavazzuti E.,
Chen S., Cheung C.C., Ciprini S., Costantin D., Cutini S., D'Ammando F.,
de la Torre Luque P., de Menezes R., de Palma F., Desai A., Di Lalla N.,
Di Venere L., Dominguez A., Dirirsa F.F., Ferrara E.C., Finke J.,
Franckowiak A., Fukazawa Y., Funk S., Fusco P., Gargano F., Garrappa S.,
Gasparrini D., Giglietto N., Giordano F., Giroletti M., Green D.,
Grenier I.A., Guiriec S., Harita S., Hays E., Horan D., Itoh R.,
Johannesson G., Kovac'evic' M., Krauss F., Kreter M., Kuss M., Larsson S.,
Leto C., Li J., Liodakis I., Longo F., Loparco F., Lott B., Lovellette M.N.,
Lubrano P., Madejski G.M., Maldera S., Manfreda A., Marti-Devesa G.,
Massaro F., Mazziotta M.N., Mereu I., Meyer M., Migliori G., Mirabal N.,
Mizuno T., Monzani M.E., Morselli A., Moskalenko I.V., Negro M., Nemmen R.,
Nuss E., Ojha L.S., Ojha R., Omodei N., Orienti M., Orlando E., Ormes J.F.,
Paliya V.S., Pei Z., Pena-Herazo H., Persic M., Pesce-Rollins M., Petrov L.,
Piron F., Poon H., Principe G., Raino S., Rando R., Rani B., Razzano M.,
Razzaque S., Reimer A., Reimer O., Schinzel F.K., Serini D., Sgro C.,
Siskind E.J., Spandre G., Spinelli P., Suson D.J., Tachibana Y.,
Thompson D.J., Torres D.F., Torresi E., Troja E., Valverde J., van Zyl P.,
Yassine M.
<Astrophys. J., 892, 105 (2020)>
=2020ApJ...892..105A 2020ApJ...892..105A
ADC_Keywords: Active gal. nuclei ; Gamma rays ; Redshifts ; Radio sources ;
X-ray sources ; BL Lac objects ; QSOs ; Cross identifications
Keywords: Active galactic nuclei; Blazars; Gamma-ray sources; Relativistic jets;
Quasars; BL Lacertae objects
Abstract:
The fourth catalog of active galactic nuclei (AGNs) detected by the
Fermi Gamma-ray Space Telescope Large Area Telescope (4LAC) between
2008 August 4 and 2016 August 2 contains 2863 objects located at high
Galactic latitudes (|b|>10°). It includes 85% more sources than
the previous 3LAC catalog based on 4yr of data. AGNs represent at
least 79% of the high-latitude sources in the fourth Fermi-Large Area
Telescope Source Catalog (4FGL), which covers the energy range from
50MeV to 1TeV. In addition, 344 gamma-ray AGNs are found at low
Galactic latitudes. Most of the 4LAC AGNs are blazars (98%), while the
remainder are other types of AGNs. The blazar population consists of
24% Flat Spectrum Radio Quasars (FSRQs), 38% BL Lac-type objects, and
38% blazar candidates of unknown types (BCUs). On average, FSRQs
display softer spectra and stronger variability in the gamma-ray band
than BL Lacs do, confirming previous findings. All AGNs detected by
ground-based atmospheric Cerenkov telescopes are also found in the 4LAC.
Description:
The 4LAC analysis was performed in the context of the 4FGL catalog
(The Fermi-LAT collaboration 2020, J/ApJS/247/33). The data were
collected over the first 8yr of the mission, from 2008 August 4
(MJD 54682) to 2016 August 2 (MJD 57602).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
highlat.dat 436 2863 4LAC high Galactic latitude sources (|b|>10deg)
lowlat.dat 436 344 4LAC low Galactic latitude sources (|b|<10deg)
table5.dat 44 93 3LAC sources not present in 4LAC
table6.dat 66 69 Non-blazar objects and misaligned AGN
table7.dat 70 78 Properties of the 4LAC Very-High-Energy (VHE) AGN
--------------------------------------------------------------------------------
See also:
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
VIII/81 : Sydney University Molonglo Sky Survey (SUMSS V2.1) (Mauch+ 2008)
VII/259 : 6dF galaxy survey final redshift release (Jones+, 2009)
VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)
V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)
VII/274 : The Roma BZCAT - 5th edition (Massaro+, 2015)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/PASP/113/10 : Sub-mJy radio sources complete sample (Masci+, 2001)
J/MNRAS/329/877 : The CLASS blazar survey. II. (Caccianiga+, 2002)
J/ApJS/171/61 : All-Sky Survey of Flat-Spectrum Radio Sources (Healey+, 2007)
J/ApJS/175/97 : CGRaBS: survey of γ-ray blazar cand. (Healey+, 2008)
J/AJ/138/1032 : Filling in the gaps in the 4.85GHz sky (Healey+, 2009)
J/ApJ/716/30 : SED of Fermi bright blazars (Abdo+, 2010)
J/ApJS/188/405 : Fermi-LAT first source catalog (1FGL) (Abdo+, 2010)
J/MNRAS/402/2403 : Australia Telescope 20GHz Survey Cat., AT20G (Murphy+, 2010)
J/ApJ/743/171 : The 2LAC catalog (Ackermann+, 2011)
J/ApJ/742/27 : 15GHz and jet properties of MOJAVE blazars (Lister+, 2011)
J/MNRAS/432/1294 : Fermi unassociated sources ATCA observations (Petrov+, 2013)
J/ApJ/764/135 : Spectroscopic redshifts of BL Lac objects (Shaw+, 2013)
J/ApJS/215/14 : WISE cand. γ-ray blazar radio sources (D'Abrusco+, 2014)
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/576/A126 : The 2009 multiwavelength campaign on Mrk421 (Aleksic+, 2015)
J/ApJS/217/2 : Refined associations of Fermi/LAT sources (Massaro+, 2015)
J/ApJS/217/4 : 2FGL sources observed between 5-9GHz (Schinzel+, 2015)
J/A+A/588/A103 : 2nd ROSAT all-sky survey (2RXS) source catalog (Boller+, 2016)
J/MNRAS/462/3180 : 3FGL Blazar of Unknown Type classification (Chiaro+, 2016)
J/A+A/596/A45 : Radio light curves of 8 AGN (Fuhrmann+, 2016)
J/ApJ/833/77 : gamma-ray bright blazars optical polarization (Itoh+, 2016)
J/ApJ/846/34 : Flaring gamma-ray sources; LAT 7.4yr (2FAV) (Abdollahi+, 2017)
J/A+A/598/A134 : γ-ray signature in WHSP blazars (1BIGB) (Arsioli+, 2017)
J/A+A/598/A49 : FRICAT. FIRST catalog of FR I radio galaxies (Capetti+, 2017)
J/A+A/601/A81 : FIRST catalog of FR II radio galaxies (Capetti+, 2017)
J/A+A/598/A17 : The 2WHSP catalog (Chang+, 2017)
J/ApJ/851/33 : Multi-wavelength analysis of CGRaBS blazars (Paliya+, 2017)
J/ApJS/229/39 : Narrow line Seyfert 1 galaxies from SDSS-DR12 (Rakshit+, 2017)
J/ApJ/838/139 : Radio follow-up on 3FGL unassociated sources (Schinzel+, 2017)
J/ApJS/238/9 : Catalog of giant radio sources known to date (Kuzmicz+, 2018)
J/ApJ/861/130 : BL Lac objects GTC low res. spectroscopy (Landoni+, 2018)
J/ApJ/874/43 : MOJAVE. XVII. Jet kinematics of AGNs (Lister+, 2019)
J/ApJS/247/33 : The Fermi LAT fourth source catalog (4FGL) (Abdollahi+, 2020)
Byte-by-byte Description of file: highlat.dat lowlat.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [4FGL]
6- 18 A13 --- 4FGL 4FGL name (JHHMM.m+DDMMa) (Source_Name)
20- 27 F8.4 deg RAdeg Right ascension (J2000) (RAJ2000)
29- 36 F8.4 deg DEdeg Declination (J2000) (DEJ2000)
38- 45 F8.4 deg GLON Galactic longitude
47- 54 F8.4 deg GLAT Galactic latitude
56- 64 F9.5 --- Sig [4/444] Source significance in σ
units over the 50MeV-1TeV band (Signif_Avg)
66- 77 E12.6 ph/cm2/s F1000i [8.8e-12/9.9e-8] Integral photon flux from
1 to 100GeV (Flux1000)
79- 90 E12.6 ph/cm2/s e_F1000i [4.9e-12/6e-10] F1000i 1σ error
(Unc_Flux1000)
92- 103 E12.6 mW/m2 EF100 [6.4e-13/1.2e-9] Energy flux from 100MeV
to 100GeV obtained by spectral fitting in
erg/cm2/s units (Energy_Flux100)
105- 116 E12.6 mW/m2 e_EF100 [1.7e-13/6.5e-12] EF100 1σ error
(UncEnergyFlux100)
118- 134 A17 --- Mod Spectral type in the global model
(PowerLaw, LogParabola, PLSuperExpCutoff)
(SpectrumType)
136- 142 F7.5 --- PLGam [1.39/3.5] Photon index when fitting with
PowerLaw (PL_Index)
144- 151 F8.6 --- e_PLGam [0.003/0.33] PLGam 1σ error
(UncPLIndex)
153- 161 F9.3 MeV Epiv [137.8/25099.3] Pivot Energy (Pivot_Energy)
163- 171 F9.6 --- LPalpha [-0.34/3.6] Photon index at Pivot_Energy
(α) when fitting with LogParabola
(LP_Index)
173- 180 F8.6 --- e_LPalpha [0.004/3] LPalpha 1σ error
(UncLPIndex)
182- 190 F9.6 --- LPbeta [-0.17/1] Curvature parameter (β)
when fitting with LogParabola (LP_beta)
192- 199 F8.6 --- e_LPbeta [0.001/1.5]?=- LPbeta 1σ error
(UncLPbeta)
201- 204 I4 --- Flags [0/2096] Analysis flags (0=no warning)
206- 210 A5 --- Class Class designation for associated source
212- 239 A28 --- Assoc1 Name of identified or likely associated
source
241- 248 F8.6 --- ProbBY [0/1]?=- Probability of association
according to the Bayesian method
(ASSOCPROBBAY)
250- 257 F8.6 --- ProbLR [0/1] Probability of association according
to the Likelihood Ratio method
(ASSOCPROBLR)
259- 268 A10 --- CCat Counterpart catalog driving the
association (Counterpart_Catalog) (1)
270- 279 F10.6 deg RACdeg Right ascension of the counterpart Assoc1
(J2000) (RA_Counterpart)
281- 290 F10.6 deg DECdeg Declination of the counterpart Assoc1
(J2000) (DEC_Counterpart)
292- 302 E11.6 deg errCPos [3.8e-8/2.5] 95% precision of the
counterpart localization (Unc_Counterpart)
304- 306 A3 --- --- [RFC]
308- 317 A10 --- RFC Name of the VLBI counterpart (JHHMM+DDMM)
(VLBI_Counterpart)
319- 327 A9 --- --- [Gaia DR2:]
329- 347 I19 --- Gaia ? Name of the Gaia DR2 counterpart
established via the VLBI position
(Gaia_Counterpart)
349- 355 F7.4 mag Gmag [12.8/21.5]?=- Gaia G-band magnitude
(GaiaGMagnitude)
357- 364 F8.6 --- z [1.7e-5/4.4]?=- Redshift (Redshift)
366- 368 A3 --- SEDCl SED-based class (HSP, ISP or LSP)
(SED_class)
370- 381 E12.6 Hz nu [0/1.2e+19] Synchrotron-peak frequency in
observer frame (nu_syn)
383- 394 E12.6 mW/m2 nuFnu [0/7.9e-10] Spectral energy distribution
at synchrotron-peak frequency in
erg/cm2/s units (nuFnu_syn)
396- 407 F12.6 --- Var [0.3/50906] Variability index
(Variability_Index)
409- 416 F8.6 --- fVar [0/2.6] Fractional variability
(Frac_Variability)
418- 426 F9.6 --- e_fVar [0.02/10] FVar 1σ error
(UncFracVariability)
428- 436 F9.5 GeV Emax [4.1/913]?=- Energy of the highest-energy
ULTRACLEANVETO photon with association
probability P>0.95 (Highest_energy)
--------------------------------------------------------------------------------
Note (1): Catalog as follows:
bzcat = Massaro et al. 2015, VII/274
rfc = Petrov et al. 2019MNRAS.485...88P 2019MNRAS.485...88P
bllac = BL Lac in Veron-Cetty & Veron 2010, VII/258
cgrabs = Healey et al. 2008, J/ApJS/175/97
crates = Healey et al. 2007, J/ApJS/171/61
whsp2 = 2WHSP, Chang et al. 2017, J/A+A/598/A17
wise = WISE blazar catalog, D'Abrusco et al. 2014, J/ApJS/215/14
at20g = ATCA 20GHz southern sky survey, Murphy+ 2010, J/MNRAS/402/2403
rass = ROSAT All Sky Survey (RASS) Bright and Faint Source Catalogs
(Voges et al. 1999, IX/10 and 2000, IX/29)
nvss = NRAO VLA Sky Survey; Condon et al. 1998, VIII/65
sumss = The Sydney University Molonglo Sky Survey
(Mauch+ 2003MNRAS.342.1117M 2003MNRAS.342.1117M, see VIII/81)
qso = QSO in Veron-Cetty & Veron 2010, VII/258
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- 3FGL 3FGL Name
14- 37 A24 --- CName Counterpart Name
39- 42 A4 --- Class 3LAC Class (1)
44- 44 A1 --- n_3FGL Reason for 3LAC source not present in 4LAC (2)
--------------------------------------------------------------------------------
Note (1): Class as follows:
agn = other active galactic nucleus
bcu = blazar candidate
bll = BL Lac object
css = compact steep-spectrum source
fsrq = flat-spectrum radio quasar
rdg = radio galaxy
ssrq = steep-spectrum radio quasar
Note (2): Reason for 3LAC source not present in 4LAC as follows:
M = missing gamma-ray source in 4FGL
L = 3FGL source present in 4FGL but now unassociated
C = 3FGL source present in 4FGL but now associated with a non-AGN counterpart
D = duplicate counterpart in 3LAC now missing in 4LAC
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1 A1 --- Group [hl] Latitude grouping
3- 15 A13 --- 4FGL 4FGL Name (JHHMM.m+DDMMa)
17- 37 A21 --- OName Other name
39- 43 A5 --- Class Class (1)
45- 48 F4.2 --- Photon [1.44/2.85] Photon Index
50- 53 F4.2 --- e_Photon [0.01/0.24] Uncertainty in Photon Index
55- 59 F5.3 --- z [0.013/1.1]? Redshift
61- 66 F6.2 Mpc Dist [0.69/171]? Distance
--------------------------------------------------------------------------------
Note (1): Class as follows:
agn = other active galactic nucleus (11 occurrences)
css = compact steep-spectrum source (5 occurrences)
nlsy1 = narrow-line Seyfert 1 (9 occurrences)
rdg = radio galaxy (41 occurrences)
sey = Seyfert galaxy (1 occurrence)
ssrq = steep-spectrum radio quasar (2 occurrences)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- 4FGL 4FGL Name
15- 35 A21 --- OName Very-High-Energy Name
37 A1 --- LL [*] * = low-latitude sources not in 4LAC
39- 42 A4 --- Class Class (1)
44- 46 A3 --- SED SED Class (2)
48- 51 F4.2 --- z [0.01/0.94]? Redshift
53- 56 F4.2 --- Photon [1.53/2.65] Photon Index
58- 61 F4.2 --- e_Photon [0.01/0.18] Uncertainty in Photon Index
63- 70 F8.2 --- Var [1.77/17567] Variability Index
--------------------------------------------------------------------------------
Note (1): Class as follows:
bcu = blazar candidate (3 occurrences)
bll = BL Lac object (62 occurrences)
fsrq = flat-spectrum radio quasar (7 occurrences)
rdg = radio galaxy (6 occurrences)
Note (2): SED Class as follows:
HSP = high synchrotron peaked (54 occurrences)
ISP = intermediate synchrotron peaked (8 occurrences)
LSP = low synchrotron peaked (15 occurrences)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 30-Jul-2021