J/A+A/469/451 Radio continuum spectra of GPS galaxies (Torniainen+, 2007)
Radio continuum spectra of gigahertz-peaked spectrum galaxies.
Torniainen I., Tornikoski M., Lahteenmaki A., Aller M.F., Aller H.D.,
Mingaliev M.G.
<Astron. Astrophys. 469, 451 (2007)>
=2007A&A...469..451T 2007A&A...469..451T
ADC_Keywords: Galaxies, radio ; QSOs
Keywords: quasars: general ; radio continuum: galaxies
Abstract:
Recent studies have shown that a remarkable share of quasars
classified in the literature as gigahertz-peaked spectrum (GPS)
sources and high frequency peakers (HFPs) are actually flaring
flat-spectrum sources or blazars. Thus, at least among the quasar-type
samples, genuine GPS sources and HFPs seem to be rare.
We have studied variability and the shape of the radio continuum
spectra of a sample of 96 galaxy-type GPS sources and HFPs in order to
find out whether there is a similar contamination in the galaxy-type
samples.
Description:
Radio continuum spectral properties of a sample of 96 galaxy-type
gigahertz-peaked spectrum (GPS) sources are presented. When available,
also the redshifts of the sources are listed.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 58 96 The sample of galaxy-type GPS sources
--------------------------------------------------------------------------------
See also:
J/A+AS/132/341 : ROSAT GPS optical identification (Motch+ 1998)
J/A+AS/135/273 : 408MHz obs. of GPS sources from JVAS survey (Marecki+ 1999)
J/A+A/369/380 : CSS/GPS radio sources VLA observations (Fanti+, 2001)
J/A+A/463/97 : Optical observations of GPS radio sources (Labiano+, 2007)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Source B1950 name of the source
10- 14 F5.3 --- z ? Redshift
15 A1 --- u_z [?] Uncertainty flag for redshift
17- 21 F5.2 GHz FpO Peak frequency in the observers frame
23- 27 F5.2 GHz FpR ? Peak frequency in the rest frame
29- 32 F4.2 --- var The greatest fractional variability index (1)
34- 36 I3 --- o_var Number of observations (2)
38- 43 F6.3 GHz Fvar Center frequency (3)
45- 48 F4.2 --- alpha0 ? Spectral index below the peak frequency (4)
50- 54 F5.2 --- alpha1 ? Spectral index above the peak frequency (4)
56- 58 A3 --- Class Classification proposed in this paper (5)
--------------------------------------------------------------------------------
Note (1): The greatest fractional variability index of the data bins
for the source
Note (2): Number of observations in the data bin with the greatest
fractional variability index
Note (3): Center frequency of the data bin with the greatest fractional
variability index
Note (4): Spectral index α defined so that Flux density
S∝να
Note (5): Classification of the radio continuum spectrum as follows:
gps = genuine GPS source
c = convex
v = variable
f = flat
s = steep
f/s = flat at lower and steep at higher frequencies
n = possible GPS source but not enough data for classification
--------------------------------------------------------------------------------
Acknowledgements:
I. Torniainen, ilo(at)kurp.hut.fi
(End) I. Torniainen [Metsahovi Radio Obs.], Patricia Vannier [CDS] 25-Apr-2007