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J/ApJ/789/135   Gamma-ray bright blazars spectrophotometry   (Williamson+, 2014)

Comprehensive monitoring of gamma-ray bright blazars. I. Statistical study of optical, X-ray, and gamma-ray spectral slopes. Williamson K.E., Jorstad S.G., Marscher A.P., Larionov V.M., Smith P.S., Agudo I., Arkharov A.A., Blinov D.A., Casadio C., Efimova N.V., Gomez J.L., Hagen-Thorn V.A., Joshi M., Konstantinova T.S., Kopatskaya E.N., Larionova E.G., Larionova L.V., Malmrose M.P., McHardy I.M., Molina S.N., Morozova D.A., Schmidt G.D., Taylor B.W., Troitsky I.S. <Astrophys. J., 789, 135 (2014)> =2014ApJ...789..135W (SIMBAD/NED BibCode)
ADC_Keywords: Spectrophotometry ; X-ray sources ; Gamma rays ; Ultraviolet ; Photometry, UBVRIJKLMNH ; BL Lac objects ; QSOs Keywords: BL Lacertae objects: general - galaxies: active - galaxies: jets - quasars: general Abstract: We present γ-ray, X-ray, ultraviolet, optical, and near-infrared light curves of 33 γ-ray bright blazars over 4 years that we have been monitoring since 2008 August with multiple optical, ground-based telescopes and the Swift satellite, and augmented by data from the Fermi Gamma-ray Space Telescope and other publicly available data from Swift. The sample consists of 21 flat-spectrum radio quasars (FSRQs) and 12 BL Lac objects (BL Lacs). We identify quiescent and active states of the sources based on their γ-ray behavior. We derive γ-ray, X-ray, and optical spectral indices, αγ, αX, and αo, respectively (Fν∝να), and construct spectral energy distributions during quiescent and active states. We analyze the relationships between different spectral indices, blazar classes, and activity states. We find (1) significantly steeper γ-ray spectra of FSRQs than for BL Lacs during quiescent states, but a flattening of the spectra for FSRQs during active states while the BL Lacs show no significant change; (2) a small difference of αX within each class between states, with BL Lac X-ray spectra significantly steeper than in FSRQs; (3) a highly peaked distribution of X-ray spectral slopes of FSRQs at ∼ -0.60, but a very broad distribution of αXof BL Lacs during active states; (4) flattening of the optical spectra of FSRQs during quiescent states, but no statistically significant change of αo of BL Lacs between states; and (5) a positive correlation between optical and γ-ray spectral slopes of BL Lacs, with similar values of the slopes. We discuss the findings with respect to the relative prominence of different components of high-energy and optical emission as the flux state changes. Description: Since 2007, we have been collecting multi-waveband fluxes, polarization measurements, and radio images of blazars to provide the data for understanding the physics of the jets (see, e.g., Marscher 2012, arXiv:1201.5402). This study includes 28 of the original 30 objects selected for the monitoring campaign, confirmed as γ-ray sources by EGRET (Energetic γ-Ray Experiment Telescope) on the Compton Gamma Ray Observatory, have an R-band brightness exceeding 18 mag (bright enough for optical polarization measurements at a 1-2 m class optical telescope without needing excessive amounts of telescope time), exceed 0.5 Jy at 43 GHz, and have a declination accessible to the collaboration's observatories (> - 30°). Three additional BL Lacs (1055+018, 1308+326, and 1749+096) and two FSRQs (3C345 and 3C446) included in this analysis were among those added when they were detected as γ-ray sources by the Fermi LAT (Abdo et al. 2009, J/ApJ/700/597). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 78 33 Sources Analyzed table4.dat 251 33 Weighted Mean Flux and Weighted Standard Deviations table7.dat 69 114 Epochs Selected For Study table8.dat 102 114 Computed Spectral Indices
See also: III/157 : An Ultraviolet Atlas of Quasar and Blazar Spectra (Kinney+, 1991) J/A+AS/114/337 : CCD photometric observations of blazars (Jia Guibin+, 1995) J/A+A/436/799 : X- and gamma-ray fluxes of γ-ray-loud blazars (Fan+, 2005) J/ApJS/175/97 : CGRaBS: survey of γ-ray blazar candidates (Healey+, 2008) J/ApJ/722/520 : Gamma-ray light curves of Fermi blazars (Abdo+, 2010) J/ApJ/732/116 : IR spectra of γ-ray bright blazars (Malmrose+, 2011) J/ApJ/743/171 : The 2LAC catalog (Ackermann+, 2011) J/ApJ/761/125 : X and γ spectral indexes of Fermi blazars (Fan+, 2012) J/MNRAS/439/690 : Optical/γ-ray variability in blazars (Hovatta+, 2014) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 2 I2 --- Seq Sequential number 4- 14 A11 --- Name Object identifier 16- 23 A8 --- AName Commonly used name 25- 36 A12 --- 2FGL Catalog Object's name as listed in the 2FGL catalog (1) 38- 42 F5.3 --- z Redshift (2) 43 A1 --- n_z [d?] Note on z (3) 45- 46 I2 h RAh Hour of Right Ascension (J2000) (4) 48- 49 I2 min RAm Minute of Right Ascension (J2000) (4) 51- 55 F5.2 s RAs Second of Right Ascension (J2000) (4) 57 A1 --- DE- Sign of the Declination (J2000) (4) 58- 59 I2 deg DEd Degree of Declination (J2000) (4) 61- 62 I2 arcmin DEm Arcminute of Declination (J2000) (4) 64- 67 F4.1 arcsec DEs Arcsecond of Declination (J2000) (4) 69- 74 A6 --- Class Object's optical classification (1) 76- 78 A3 --- SEDclass SED classification (1)
Note (1): Ackermann et al. (2011, J/ApJ/743/171). Note (2): Information taken from the NASA/IPAC Extragalactic Database ( Note (3): Note on redshift as follows : d = Danforth et al. (2013ApJ...764...57D) set 0.2315 < z < 0.372 (99.7%). ? = uncertain Note (4): Simbad resolver as reported in
Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 11 A11 --- Name Object identifier 14- 21 E8.2 ct/cm2/s Fgamma Mean Fermi Γ-ray flux; photons/s/cm2 23- 30 E8.2 ct/cm2/s e_Fgamma Weighted standard deviation of Fgamma 32- 35 I4 --- o_Fgamma Number of observations used for Fgamma 37- 44 E8.2 mW/m2 FX ? Mean Swift/XRT X-ray flux; erg/s/cm2 46- 53 E8.2 mW/m2 e_FX ? Weighted standard deviation of FX 55- 57 I3 --- o_FX Number of observations used for FX 59- 64 F6.3 mJy Fuvw2 ? Mean Swift/UVOT w2 band flux 66- 70 F5.3 mJy e_Fuvw2 ? Weighted standard deviation of Fuvw2 72- 74 I3 --- o_Fuvw2 Number of observations used for Fuvw2 76- 81 F6.3 mJy Fuvm2 ? Mean Swift/UVOT m2 band flux 83- 87 F5.3 mJy e_Fuvm2 ? Weighted standard deviation of Fuvm2 89- 91 I3 --- o_Fuvm2 Number of observations used for Fuvm2 93- 98 F6.3 mJy Fuvw1 ? Mean Swift/UVOT w1 band flux 100-104 F5.3 mJy e_Fuvw1 ? Weighted standard deviation of Fuvw1 106-108 I3 --- o_Fuvw1 Number of observations used for Fuvw1 110-114 F5.3 mJy FU ? Mean Johnson U band flux 116-120 F5.3 mJy e_FU ? Weighted standard deviation of FU 122-124 I3 --- o_FU Number of observations used for FU 126-131 F6.3 mJy FB Mean Johnson B band flux 133-137 F5.3 mJy e_FB Weighted standard deviation of FB 139-141 I3 --- o_FB Number of observations used for FB 143-148 F6.3 mJy FV ? Mean Johnson V band flux 150-154 F5.3 mJy e_FV ? Weighted standard deviation of FV 156-159 I4 --- o_FV Number of observations used for FV 161-166 F6.3 mJy FR Mean Johnson R band flux 168-173 F6.3 mJy e_FR Weighted standard deviation of FR 175-178 I4 --- o_FR Number of observations used for FR 180-185 F6.3 mJy FI ? Mean I band flux 187-192 F6.3 mJy e_FI ? Weighted standard deviation of FI 194-196 I3 --- o_FI Number of observations used for FI 198-203 F6.3 mJy FJ ? Mean J band flux 205-210 F6.3 mJy e_FJ ? Weighted standard deviation of FJ 212-214 I3 --- o_FJ ? Number of observations used for FJ 216-221 F6.3 mJy FH ? Mean H band flux 223-228 F6.3 mJy e_FH ? Weighted standard deviation of FH 230-232 I3 --- o_FH ? Number of observations used for FH 234-239 F6.3 mJy FK ? Mean K band flux 241-246 F6.3 mJy e_FK ? Weighted standard deviation of FK 248-251 I4 --- o_FK ? Number of observations used for FK
Byte-by-byte Description of file: table7.dat
Bytes Format Units Label Explanations
1- 11 A11 --- Name Object identifier 14 I1 --- Num Epoch number 16- 23 F8.3 d RJD-Non Earliest RJD date within epoch of non-gamma-ray observations 25- 29 F5.3 d Span Elapsed timespan of non-gamma-ray observations 31- 38 F8.3 d RJD-Obs RJD of Fermi observation, mid-bin 40- 43 F4.1 d Bin Fermi observation bin size 45 A1 --- G-Act Activity state code in gamma-rays (1) 47 A1 --- X-Act Activity state code in X-rays (1) 49 A1 --- W2-Act Activity state code in uvw2 (1) 51 A1 --- M2-Act Activity state code in uvm2 (1) 53 A1 --- W1-Act Activity state code in uvw1 (1) 55 A1 --- U-Act Activity state code in U band (1) 57 A1 --- B-Act Activity state code in B band (1) 59 A1 --- V-Act Activity state code in V band (1) 61 A1 --- R-Act Activity state code in R band (1) 63 A1 --- I-Act Activity state code in I band (1) 65 A1 --- J-Act Activity state code in J band (1) 67 A1 --- H-Act Activity state code in H band (1) 69 A1 --- K-Act Activity state code in K band (1)
Note (1): Flag as follows : Q = Quiescent; T = Transitory; A = Active; F = Flaring; Blank = No data; I = Insufficient number of observations to calculate a mean flux value.
Byte-by-byte Description of file: table8.dat
Bytes Format Units Label Explanations
1- 11 A11 --- Name Object identifier 14 I1 --- Num Epoch number 16- 23 F8.3 d RJD-Non Earliest RJD date within epoch of non-gamma-ray observations 25- 30 F6.3 --- agamma Gamma-ray spectral index 32- 36 F5.3 --- e_agamma ? The 1σ uncertainty in agamma 38- 43 F6.3 --- aX ? X-ray spectral index 45- 49 F5.3 --- e_aX ? The 1σ uncertainty in aX 51- 56 F6.3 --- aO Optical spectral index 58- 62 F5.3 --- e_aO The 1σ uncertainty in aO 64- 65 I2 --- Npts Number of UV/Opt/NIR points used 67- 71 F5.3 --- StDev ? Standard deviation of the data 73- 78 F6.3 --- aOX ? X-ray/optical spectral index 80- 84 F5.3 --- e_aOX ? The 1σ uncertainty in aOX 86- 91 F6.3 --- aXgamma ? Gamma-ray/X-ray spectral index 93- 97 F5.3 --- e_aXgamma ? The 1σ uncertainty in aXgamma 99-102 A4 --- Band UV/Opt/NIR band used if no V-band data available
History: From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 10-Mar-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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