7C

J/A+A/363/887    High frequency peakers. I. The bright sample (Dallacasa+, 2000) 
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High frequency peakers. I. The bright sample. 
     Dallacasa D., Stanghellini C., Centonza M., Fanti R. 
     
    =2000A&A...363..887D 
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ADC_Keywords: Galaxies, radio ; QSOs ; Radio lines 
Keywords: galaxies: active - radio continuum: galaxies - 
          galaxies: quasars: general 
 
Abstract: 
    Here we present a sample of sources with convex radio spectra peaking 
    at frequencies above a few GHz. We call these radio sources High 
    Frequency Peakers (HFPs). This sample extends to higher turnover 
    frequencies than the samples of Compact Steep Spectrum (CSS) and GHz 
    Peaked Spectrum (GPS) radio sources. HFPs are rare due to the strong 
    bias against them caused by their turnover occurring at frequencies 
    about one order of magnitude higher than in CSS-GPS samples. he sample 
    has been selected by a comparison between the Green Bank survey (87GB) 
    at 4.9 GHz and the NRAO VLA Sky Survey (NVSS) at 1.4 GHz. Then the 
    candidates have been observed with the VLA at 1.365, 1.665, 4.535, 
    4.985, 8.085, 8.485, 14.96 and 22.46 GHz in order to derive a 
    simultaneous radio spectrum, and remove variable sources from the 
    sample. The final list of genuine HFP sources consists of 55 objects 
    with flux density exceeding 300 mJy at 4.9 GHz at the time of the 87GB 
    observation. Optical identifications are available for 29 of them; 
    24 are high redshift quasars, 3 are galaxies (one of them has indeed 
    broad lines in the optical spectrum) and 2 are BL Lac objects. The 
    remaining sources are mostly empty fields (17) on the digitised POSS 
    or have uncertain classification (9). 
 
File Summary: 
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 FileName      Lrecl  Records   Explanations 
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ReadMe            80        .   This file 
table1.dat        94      102   Candidates observed with the VLA 
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See also: 
   VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998) 
   VIII/40 : GB6 catalog of radio sources (Gregory+ 1996) 
   VIII/60 : Interferometer phase calibration sources (Patnaik+ 1998) 
 
Byte-by-byte Description of file: table1.dat 
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   Bytes Format Units   Label     Explanations 
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   1-  9  A9    ---     Name      Name based on J2000 coordinates (HHMM+DDMM) 
  11- 12  I2    h       RAh       Right ascension (J2000) 
  14- 15  I2    min     RAm       Right ascension (J2000) 
  17- 21  F5.2  s       RAs       Right ascension (J2000) 
      23  A1    ---     DE-       Declination sign (J2000) 
  24- 25  I2    deg     DEd       Declination (J2000) 
  27- 28  I2    arcmin  DEm       Declination (J2000) 
  30- 33  F4.1  arcsec  DEs       Declination (J2000) 
  35- 40  F6.1  mJy     NVSS      NVSS (Cat. ) flux density at 1.4GHz 
  42- 46  I5    mJy     87GB      87GB (Cat. ) flux density at 4.85GHz 
  48- 51  I4    mJy     JVAS      ? JVAS (Cat. ) flux density at 8.4GHz 
  53- 57  F5.2  ---     Sp-Index  Spectral index between the NVSS and the 87GB 
                                   (S{prop.to}{nu}^-{alpha}^) 
  59- 66  A8    ---     Sample    Source in other relevant samples (1) 
  68- 70  A3    ---     ID        Optical identification (2) 
  72- 75  F4.1  mag     mag       ? Magnitude from NED database (not all 
                                     in the same band) 
      76  A1    ---   u_mag       [?] Uncertainty flag on mag 
  78- 84  F7.5  ---     z         ? Redshift from NED database 
      85  A1    ---   u_z         [?] Uncertainty flag on z 
  87- 95  A9    ---     B1950     B1950 name 
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Note (1): Other relevant samples: 
       m: sources in common with the new GPS candidate starting list in 
           Marecki et al. (1999, Cat. ) 
      st: objects in the `bright' GPS sample from Stanghellini et al. 
           (1998, Cat. ) 
      sn: sources in the `faint' GPS sample from Snellen et al. 
           (1998A&AS..131..435S) 
       K: compact extragalactic objects in Kovalev et al. 
           (1999, Cat. ) 
 pr, cj1, cj2: HFP candidates in the Caltech-Jodrell Bank flat-spectrum sample 
           (Taylor et al. (1996ApJS..107...37T) and references therein) 
       k: HFP candidates in the  Kellermann et al. (1998AJ....115.1295K) 
           LBA survey at 15 GHz 
 
Note (2): Optical identification (capitals) are from the NED database, 
    when available. We also report our optical ID on the digitised red 
    plates of the Palomar Observatory Sky Survey (POSS) (small `g' and `s' 
    for extended or stellar) when no other optical information is 
    available; a `?' following the optical identification means that the 
    classification is uncertain. 
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History: 
    Prepared via OCR at CDS. 
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(End)                         James Marcout, Patricia Bauer [CDS]    03-May-2001