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J/AZh/85/314  Complete sample of flat-spectrum radio sources   (Gorshkov+, 2008)

Long-term variability of a complete sample of flat-spectrum radio sources at declinations of 4°-6° (B1950). Gorshkov A.G., Konnikova V.K., Mingaliev M.G. <Astron. Zh. 85, 314 (2008)> =2008AZh....85..314G =2008ARep...52..278G
ADC_Keywords: Radio sources Abstract: We present the results of twenty-year observations of a complete sample of 68 flat-spectrum radio sources with flux densities S3.9GHz>200mJy carried out at centimeter wavelengths with the RATAN-600 radio telescope. Since 1995, we have observed simultaneously at six frequencies between 0.97 and 21.7GHz. Of the 56 sources identified with optical objects, 41 are quasars with redshifts between 0.293 and 3.263. Based on our analysis of the spectral shapes, we divide the sources into four classes. Changes of spectral class for individual sources are fairly rare. Based on the light curves and spectra, in most cases,a flare's evolution is in accordance with a model in which the variations result from the evolution of a shock in the radio jet. The main result of our study is that there is no redshift dependence for the true linear sizes of the radiating regions, the variability indices derived for all 20 years of data or for individual flares, or the peak frequencies of the spectra of the compact radio emission. We suggest that this testifies to an absence of cosmological evolution of the sample quasars, at least to z∼3. Description: We observed the flat-spectrum radio sources in our sample in April and September 1984, September 1985, May and July 1987, July and December 1988, March 1989, August and September 1990, August and December 1991, and February-March 1992 at 3.9 and 7.7GHz (on some runs, also at 7.5GHz), using the southern sector of the RATAN-600 with the telescope's periscope. The sources were also observed on the northern sector of the RATAN-600 at 4.85 and 11.1 GHz in August 1990. In 1995, after a break due to renovation of the telescope, we continued simultaneous observations at 0.97, 2.3, 3.9, 7.7, 11.1, and 21.7GHz. Observations were performed on the western sector of the telescope at an azimuth of 270° in October 1996 and April 1997, and on the northern sector in April and November 1995, July 1996, and May, August, and November 1997, with some sources being observed on the southern sector with the periscope. Sources were observed daily, in series covering from 10 to 30 days. Beginning in 1998, we obtained long series of observations covering from 60 to 100 days. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 80 68 Coordinates, identifications, and variability amplitudes of the sources table2.dat 59 43 Parameters of sources derived from the long-term flux-density variations
See also: VIII/60 : Interferometer phase calibration sources (Patnaik+ 1998) VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 10 A10 --- Name Name (JHHMM+DDMM) 12- 13 I2 h RAh Right ascension (J2000) (1) 15- 16 I2 min RAm Right ascension (J2000) (1) 18- 23 F6.3 s RAs Right ascension (J2000) (1) 25 A1 --- DE- Declination sign (J2000) (1) 26- 27 I2 deg DEd Declination (J2000) (1) 29- 30 I2 arcmin DEm Declination (J2000) (1) 32- 36 F5.2 arcsec DEs Declination (J2000) (1) 38- 40 A3 --- Cl Classification (G1) 42- 46 F5.3 --- z ? Redshift 48- 51 F4.1 mag Bmag ? B magnitude (2) 53- 54 I2 --- r_z ? Reference for redshift (3) 56- 59 F4.2 --- V3.9 ? Variability index at 3.9GHz (4) 61 A1 --- --- [(] 62- 65 F4.2 --- V3.9c ? Variability index at 3.9GHz after subtracting the extended component (4) 66 A1 --- --- [)] 68- 71 F4.2 --- V7.7 ? Variability index at 7.7GHz (4) 73 A1 --- --- [(] 74- 77 F4.2 --- V7.7c ? Variability index at 7.7GHz after subtracting the extended component (4) 78 A1 --- --- [)] 80 I1 --- Sp [1/4] Spectrum class (5)
Note (1): J2000 coordinates from the Jodrell Bank VLA Astrometric Survey (JVAS) at 8.4GHz (Cat. VIII/60) or the NRAO VLA Sky Survey (NVSS) at 1.4GHz (Cat. VIII/65). Note (2): Magnitude from USNO-A1.0 (1996, see Cat. I/284) or APM (1993PASP..105..521P) astrometric surveys. Note (3): References for redshift as follows: 29 = Veron-Cetty and Veron, 2003A&A...412..399V, See Cat. VII/248 19 = Richards et al., Cat. J/AJ/131/2766 20 = NED database, http://nedwww.ipac.caltech.edu 21 = Gorshkov and Konnikova, 1993PAZh...19..136G 22 = Chavushyan et al., 2000AstL...26..339C 23 = Chavushyan et al., 2001ARep...45...79C 24 = Afanas'ev et al., 2003ARep...47..377A 25 = Afanas'ev et al., 2006ARep...50..255A Note (4): The variability index is defined as V=[(Smax-eSmax)-(Smin+eSmin)]/[(Smax-eSmax)+(Smin+eSmin)] where Smax and Smin are the highest and lowest flux densities recorded in the 20 years and e_Smax and e_Smin are the rms errors. Note (5): Spectrum class as follows: 1 = single-component spectrum 2 = two-component stpectrum 3 = spectrum with a dominant extended component 4 = complex spectrum
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 10 A10 --- Name Object name 11 A1 --- n_Name [*] * when no intermediate observations between the minimum and the level assumed to be the flare maximum 13- 14 A2 --- Cl Classification (G1) 16- 20 F5.3 --- z ? Redshift 22- 25 F4.2 --- Vf 7.7-GHz flare variability index 27- 30 I4 mJy DS Flare amplitude (DS=Smax-Smin) 32- 35 F4.2 yr tau Flare timescale 37- 40 F4.2 pc R ? Apparent linear size 42- 47 F6.4 mas theta ? Apparent angular size 48- 54 F7.3 10+12K Tb ? Brightness temperature in the source rest frame 56- 59 F4.2 --- Dvar ? Corresponding Doppler factor, Dvar=(T0b/1012)1/3
Global notes: Note (G1): Classifications as follows: Q = quasar G = galaxy EmG = emission-line galaxy SyG = Seyfert galaxy L = BL Lac object EF = empty field + = identified but not yet classified
History: From electronic version of the journal
(End) Patricia Vannier [CDS] 23-Jun-2008
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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