J/ApJ/722/520 Gamma-ray light curves of Fermi blazars (Abdo+, 2010)
Gamma-ray light curves and variability of bright Fermi-detected blazars.
Abdo A.A., Ackermann M., Ajello M., Antolini E., Baldini L., Ballet J.,
Barbiellini G., Bastieri D., Bechtol K., Bellazzini R., Berenji B.,
Blandford R.D., Bloom E.D., Bonamente E., Borgland A.W., Bouvier A.,
Bregeon J., Brez A., Brigida M., Bruel P., Buehler R., Burnett T.H.,
Buson S., Caliandro G.A., Cameron R.A., Caraveo P.A., Carrigan S.,
Casandjian J.M., Cavazzuti E., Cecchi C., Celik O., Chekhtman A.,
Cheung C.C., Chiang J., Ciprini S., Claus R., Cohen-Tanugi J.,
Cominsky L.R., Conrad J., Costamante L., Cutini S., Dermer C.D.,
de Angelis A., de Palma F., do Couto e Silva E., Drell P.S., Dubois R.,
Dumora D., Farnier C., Favuzzi C., Fegan S.J., Focke W.B., Fortin P.,
Frailis M., Fukazawa Y., Funk S., Fusco P., Gargano F., Gasparrini D.,
Gehrels N., Germani S., Giebels B., Giglietto N., Giommi P., Giordano F.,
Glanzman T., Godfrey G., Grenier I.A., Grondin M.-H., Grove J.E.,
Guiriec S., Hadasch D., Hayashida M., Hays E., Healey S.E., Horan D.,
Hughes R.E., Itoh R., Johannesson G., Johnson A.S., Johnson W.N., Kamae T.,
Katagiri H., Kataoka J., Kawai N., Knodlseder J., Kuss M., Lande J.,
Larsson S., Latronico L., Lemoine-Goumard M., Longo F., Loparco F.,
Lott B., Lovellette M.N., Lubrano P., Madejski G.M., Makeev A., Massaro E.,
Mazziotta M.N., McEnery J.E., Michelson P.F., Mitthumsiri W., Mizuno T.,
Moiseev A.A., Monte C., Monzani M.E., Morselli A., Moskalenko I.V.,
Mueller M., Murgia S., Nolan P.L., Norris J.P., Nuss E., Ohno M.,
Ohsugi T., Omodei N., Orlando E., Ormes J.F., Ozaki M., Panetta J.H.,
Parent D., Pelassa V., Pepe M., Pesce-Rollins M., Piron F., Porter T.A.,
Raino S., Rando R., Razzano M., Reimer A., Reimer O., Ritz S.,
Rodriguez A.Y., Romani R.W., Roth M., Ryde F., Sadrozinski H.F.-W.,
Sander A., Scargle J.D., Sgro C., Shaw M.S., Smith P.D., Spandre G.,
Spinelli P., Starck J.-L., Strickman M.S., Suson D.J., Takahashi H.,
Takahashi T., Tanaka T., Thayer J.B., Thayer J.G., Thompson D.J.,
Tibaldo L., Torres D.F., Tosti G., Tramacere A., Uchiyama Y., Usher T.L.,
Vasileiou V., Vilchez N., Vitale V., Waite A.P., Wallace E., Wang P.,
Winer B.L., Wood K.S., Yang Z., Ylinen T., Ziegler M.
<Astrophys. J., 722, 520-542 (2010)>
=2010ApJ...722..520A 2010ApJ...722..520A
ADC_Keywords: Active gal. nuclei ; Gamma rays ; QSOs ; BL Lac objects
Keywords: BL Lacertae objects: general - gamma rays: galaxies -
gamma rays: general - methods: data analysis - methods: statistical -
quasars: general
Abstract:
This paper presents light curves as well as the first systematic
characterization of variability of the 106 objects in the
high-confidence Fermi Large Area Telescope Bright AGN Sample (LBAS).
Weekly light curves of this sample, obtained during the first 11
months of the Fermi survey (2008 August 4-2009 July 4), are tested for
variability and their properties are quantified through
autocorrelation function and structure function analysis. For the
brightest sources, 3 or 4 day binned light curves are extracted in
order to determine power density spectra (PDSs) and to fit the
temporal structure of major flares. More than 50% of the sources are
found to be variable with high significance, where high states do not
exceed 1/4 of the total observation range. Variation amplitudes are
larger for flat spectrum radio quasars and low/intermediate
synchrotron frequency peaked BL Lac objects. Autocorrelation
timescales derived from weekly light curves vary from four to a dozen
of weeks.
Description:
The LAT Bright AGN sample (LBAS) sample include two radio galaxies
(Cen A and NGC 1275) and 104 blazars of which 58 are flat spectrum
radio quasars (FSRQs), 42 are BL Lac objects, and 4 are blazars with
uncertain classification (Abdo et al. 2009, Cat. J/ApJ/700/597). Data
used in this paper were collected during the first 11 months of the
Fermi LAT all-sky survey, from 2008 August 4 to 2009 July 4 (Modified
Julian Day (MJD) from 54682.655 to 55016.620).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 94 106 Variability indices and amplitudes
table3.dat 43 4982 Tabulated data of the weekly flux light curves
reported in figures 1 and 2
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See also:
J/A+A/538/A26 : BL Lac objects beyond z=1.3 (Rau+, 2012)
J/ApJS/194/29 : Observations of blazars at 15GHz (Richards+, 2011)
J/ApJ/716/30 : SED of Fermi bright blazars (Abdo+, 2010)
J/ApJ/709/1407 : SED of the Fermi blazars (Li+, 2010)
J/ApJ/700/597 : FERMI LAT detected blazars (Abdo+, 2009)
J/ApJS/183/46 : Fermi/LAT bright gamma-ray source list (0FGL) (Abdo+, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- 0FGL 0FGL name (JHHMM.m+DDMM; Cat. J/ApJS/183/46)
14- 33 A20 --- OName Other name
35- 39 A5 --- Ocl Optical class (FSRQ=Flat Spectrum radio quasar,
BLLac, RG=radio galaxy or Un=Unknown)
41- 43 A3 --- Scl SED class (HSP, ISP or LSP) (1)
45 A1 --- l_z Limit flag on z
46- 50 F5.3 --- z [0.002/2.944]? Redshift
52- 53 I2 --- Np [11/47] Number of points in each light
curve having a test statistic
(TS)≥4(∼2σ)
55- 59 F5.2 10-8/cm2/s Mean flux (E>300MeV)
61- 65 F5.2 10-8/cm2/s S Standard deviation of each light curve
67- 72 F6.2 10-8/cm2/s FM Peak flux
74- 77 F4.2 10-8/cm2/s sigM Error in FM
79 A1 --- l_Prob Limit flag on Prob
80- 83 F4.1 % Prob [0/99] Variability probability of χ2
(for Np-1 degrees of freedom)
85- 89 F5.2 --- NXS Normalized excess variance
(σ2NXS) (2)
91- 94 F4.2 --- e_NXS Error in NXS
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Note (1): The spectral energy distribution (SED) class, based on the peak
frequency of the synchrotron component (νSp) of the broadband
SED following the scheme outlined by Abdo et al. (2010,
Cat. J/ApJ/716/30) which is an extension of the classification system
introduced by Padovani & Giommi (1995ApJ...444..567P 1995ApJ...444..567P) for BL Lacs. In
this scheme, we have class as follows:
LSP = low synchrotron peaked (for νSpeak<1014Hz),
ISP = intermediate synchrotron peaked (for 1014Hz<νSpeak<1015Hz),
HSP = high synchrotron peaked (for νSpeak>1015Hz).
Note (2): Negative values of σ2NXS indicate absence or very small
variability and/or slightly overestimated errors.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- 0FGL The 0FGL catalog name (1)
14- 15 I2 --- i [0/46] Weekly index (2)
17- 22 F6.4 10-6/cm2/s Flux Integrated flux above 300MeV; in units of
10-6photons/cm2/s
24- 29 F6.4 10-6/cm2/s e_Flux The 1σ error in Flux (3)
31- 36 F6.1 --- TS [0/3057] Test statistic (4)
38- 43 F6.4 10-6/cm2/s FluxU ?=0 The 2σ upper limit Flux
(0: entries with TS>25)
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Note (1): Contacts for this data set are lott{at}cenbg.in2p3.fr and
stefano.ciprini{at}pg.infn.it.
Note (2): The relation between weekly index and time is as follows. The week
with index 0 begins on Aug. 5, 2008 at 00:00:00 UTC, MJD 54683,
MET 239587200, so the week with index i begins on MJD 54683+7i and
ends on MJD 54690+7i.
Note (3): There might be a few data points with caveats (too small or too
large error bars).
Note (4): TS=2Δlog(likelihood) between models with and without the
source; it is a measure of the source significance
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 10-Jul-2012