J/A+A/363/887 High frequency peakers. I. The bright sample (Dallacasa+, 2000)
High frequency peakers. I. The bright sample. Dallacasa D., Stanghellini C., Centonza M., Fanti R. <Astron. Astrophys. 363, 887 (2000)> =2000A&A...363..887D
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:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 95 102 Candidates observed with the VLA
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
Bytes Format Units Label Explanations
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. VIII/65) flux density at 1.4GHz 42- 46 I5 mJy 87GB 87GB (Cat. VIII/40) flux density at 4.85GHz 48- 51 I4 mJy JVAS ? JVAS (Cat. VIII/60) flux density at 8.4GHz 53- 57 F5.2 --- Sp-Index Spectral index between the NVSS and the 87GB (S∝ν-α) 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
Note (1): Other relevant samples: m: sources in common with the new GPS candidate starting list in Marecki et al. (1999, Cat. J/A+AS/135/273) st: objects in the `bright' GPS sample from Stanghellini et al. (1998, Cat. J/A+AS/131/303) 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. J/A+AS/139/545) 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.
History: Prepared via OCR at CDS.
(End) James Marcout, Patricia Bauer [CDS] 03-May-2001
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