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J/ApJS/194/29        Observations of blazars at 15GHz          (Richards+, 2011)

Blazars in the Fermi era: the OVRO 40m telescope monitoring program. Richards J.L., Max-Moerbeck W., Pavlidou V., King O.G., Pearson T.J., Readhead A.C.S., Reeves R., Shepherd M.C., Stevenson M.A., Weintraub L.C., Fuhrmann L., Angelakis E., Anton Zensus J., Healey S.E., Romani R.W., Shaw M.S., Grainge K., Birkinshaw M., Lancaster K., Worrall D.M., Taylor G.B., Cotter G., Bustos R. <Astrophys. J. Suppl. Ser., 194, 29 (2011)> =2011ApJS..194...29R
ADC_Keywords: Active gal. nuclei ; Radio continuum ; Surveys ; Gamma rays Keywords: BL Lacertae objects: general - galaxies: active - methods: statistical - quasars: general - radio continuum: galaxies Abstract: The Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope provides an unprecedented opportunity to study gamma-ray blazars. To capitalize on this opportunity, beginning in late 2007, about a year before the start of LAT science operations, we began a large-scale, fast-cadence 15GHz radio monitoring program with the 40m telescope at the Owens Valley Radio Observatory (OVRO). This program began with the 1158 northern (δ>-20°) sources from the Candidate Gamma-ray Blazar Survey and now encompasses over 1500 sources, each observed twice per week with about 4mJy (minimum) and 3% (typical) uncertainty. Here, we describe this monitoring program and our methods, and present radio light curves from the first two years (2008 and 2009). As a first application, we combine these data with a novel measure of light curve variability amplitude, the intrinsic modulation index, through a likelihood analysis to examine the variability properties of subpopulations of our sample. Description: Blazars were selected mainly from the Candidate Gamma-Ray Blazar Survey (CGRaBS; Healey et al., 2008, Cat. J/ApJS/175/97). Five bright, stable non-blazar sources are included in our program to provide flux density calibration and to monitor instrumental variability. These are 3C 48, 3C 161, 3C 274, 3C 286, and DR 21. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table4.dat 85 1163 Program source data table5.dat 36 149085 15 GHz flux densities
See also: J/ApJ/715/429 : First Fermi-LAT AGN catalog (1LAC) (Abdo+, 2010) J/ApJ/700/597 : FERMI LAT detected blazars (Abdo+, 2009) J/ApJS/175/97 : CGRaBS: survey of γ-ray blazar candidates (Healey+, 2008) J/ApJ/626/95 : Gamma-ray blazar candidates (Sowards-Emmerd+, 2005) J/ApJ/590/109 : Gamma-ray blazar in northern sky (Sowards-Emmerd+, 2003) J/A+A/379/755 : Radio data of X- and gamma-ray loud blazars (Venturi+, 2001) Byte-by-byte Description of file: table4.dat
Bytes Format Units Label Explanations
1- 10 A10 --- Name Source name (<CGRaBS JHHMM+DDMM> in Simbad for the 1158 Candidate Gamma-ray Blazar Survey sample) 12- 13 I2 h RAh Hour of Right Ascension (J2000) 15- 16 I2 min RAm Minute of Right Ascension (J2000) 18- 22 F5.2 s RAs Second of Right Ascension (J2000) 24 A1 --- DE- Sign of the Declination (J2000) 25- 26 I2 deg DEd Degree of Declination (J2000) 28- 29 I2 arcmin DEm Arcminute of Declination (J2000) 31- 34 F4.1 arcsec DEs Arcsecond of Declination (J2000) 36- 40 F5.3 --- z ? Redshift (1) 42- 47 A6 --- OType Optical classification (AGN, BLL, GALAXY, FSRQ (flat-spectrum radio quasar) or NLRG (narrow-line radio galaxy)) 49- 51 I3 --- Nobs Number of observations (2) 53 A1 --- 1LAC [Y/N] Source associated with gamma-ray source in Fermi 1LAC catalog Abdo et al. 2010, Cat. J/ApJ/715/429 55 I1 --- Var [0,5] Variability analysis flag, 0=variable (3) 57 A1 --- V2 [C/V] Result of 3-σ χ^2^ variability test (4) 59- 64 F6.3 Jy S0 ? Intrinsic source mean flux density at 15GHz 66- 70 F5.3 Jy e_S0 ? The 1-σ uncertainty in S0 72 A1 --- l_m Limit flag on m (5) 73- 77 F5.1 % m ? Intrinsic modulation index 79- 81 F3.1 % E_m ? Upper limit uncertainty in m 83- 85 F3.1 % e_m ? Lower limit uncertainty in m
Note (1): For the CGRaBS sample, redshift and optical classifications are repeated here from Healey et al. (2008, Cat. J/ApJS/175/97) for convenience. Note (2): That survived data editing and were used in our variability analysis. Note (3): Flag as follows: 0 = a non-zero intrinsic modulation is found; 1 = the source is non-variable; 2 = insufficient observations for variability analysis; 3 = flux density too faint for variability analysis; 4 = the source was a calibrator used in the spline fit to remove long-term trends; 5 = the source was a calibrator not used in the spline fit. Note (4): C (V) indicates the source is (is not) consistent with a constant flux density. Note (5): Values for non-variable sources indicate 3-σ upper limits and no uncertainties are quoted for S0 and m.
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 10 A10 --- Name Source name (<CGRaBS JHHMM+DDMM> in Simbad for the 1158 Candidate Gamma-ray Blazar Survey sample) 12- 23 F12.6 d MJD Modified Julian Date of the observation 25- 30 F6.3 Jy S15GHz The 15GHz flux density 32- 36 F5.3 Jy e_S15GHz Uncertainty in S15GHz
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 25-Jul-2011
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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