J/A+A/482/483 GHz-peaked spectrum (GPS) sources (Torniainen+, 2008)
Cluster analyses of gigahertz-peaked spectrum sources with self-organising maps.
Torniainen I., Tornikoski M., Turunen M., Lainela M., Lahteenmaki A.,
Hovatta T., Mingaliev M.G., Aller M.F., Aller H.D.
<Astron. Astrophys. 482, 483 (2008)>
=2008A&A...482..483T 2008A&A...482..483T
ADC_Keywords: QSOs ; Radio sources ; Photometry ; Polarization
Keywords: galaxies: active - galaxies: quasars: general -
radio continuum: galaxies
Abstract:
Gigahertz-peaked spectrum (GPS) sources and high frequency peakers
(HFPs) are among the smallest of active galactic nuclei currently
believed to represent the earliest phases in the evolution of
extragalactic radio sources. Recently there has been evidence of
contamination by other types of radio sources among the GPS and HFP
samples, but the confirmed GPS sources or HFPs also seem to form a
very heterogeneous population.
We study the statistical clustering of the GPS sources and the HFPs by
taking as many source parameters as possible to find homogeneous
groups among the sources. We expect the clustering to give us insight
into the physical parameters that play a role in different source
populations.
We have collected a sample of 206 GPS sources and HFPs from the
literature and gathered a massive database of various source
properties, such as the redshift, the size, the polarization, the
magnitudes, and the properties of the radio continuum. To visualize
and to cluster these multidimensional data we used self-organising
maps (SOM), which are neural networks trained by an unsupervised
algorithm. We have classified the sources with an auxiliary
classification to trace the locations of different types of radio
continuum spectra on the map.
Description:
Various properties of a sample of 206 gigahertz-peaked spectrum
sources are presented together with their literature references.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 368 206 Data for each source
refs.dat 74 64 References
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Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- SRC Source name (HHMM+DDd/d)
12- 17 A6 --- ID Optical ID (1)
19- 25 A7 --- r_ID Reference for optical ID
26 A1 --- u_ID [)] Uncertainty flag on r_ID
27- 31 A5 --- OClass Original classification, as GPS or HFP (High-
Frequency Peaker)
33- 39 A7 --- r_OClass Reference for original classification
41- 45 A5 --- Class Auxiliary classification (3)
47- 50 F4.2 --- z ?=9.99 Redshift
52- 57 A6 --- r_z Reference for redshift
58 A1 --- f_z [*] * for photometric redshift
60- 64 F5.2 kpc Szkpc ?=99.99 Size of the source
66- 71 A6 --- r_Szkpc Reference for size
72 A1 --- f_Szkpc [*] * for recalculated size (2)
74- 78 F5.2 [W/Hz] P5GHz ?=99.99 log(10) of source power at 5GHz (5)
80- 83 A4 --- r_P5GHz [calc] Reference for P5GHz
85- 89 F5.2 % polOpt ?=99.99 Optical polarization
91- 98 A8 --- r_polOpt Reference for optical polarization
100-104 F5.2 % polRad ?=99.99 Radio polarization
106-112 A7 --- r_polRad Reference for radio polarization
113 A1 --- f_polRad [*] * for zuk99 and step95 reference
114-119 A6 --- n_polRad Note on polRad
121-125 F5.2 mag Bmag ?=99.99 B magnitude
127-131 A5 --- r_Bmag Reference for B magnitude
133-137 F5.2 mag Vmag ?=99.99 V magnitude
139-144 A6 --- r_Vmag Reference for V magnitude
146-150 F5.2 mag Rmag ?=99.99 R magnitude
152-158 A7 --- r_Rmag Reference for R magnitude
159 A1 --- f_Rmag [*] * when calculated from r magnitude
161-165 F5.2 mag Imag ?=99.99 I magnitude
167-172 A6 --- r_Imag Reference for I magnitude
173 A1 --- f_Imag [*] * when calculated from i magnitude
175-179 F5.2 mag V-R ?=99.99 V-R colour index
181-185 A5 --- r_V-R Reference for V-R colour
187-191 F5.2 mag B-V ?=99.99 B-V colour index
193-196 A4 --- r_B-V Reference for B-V colour
198-202 F5.2 mag U-B ?=99.99 U-B colour index
204-207 A4 --- r_U-B [vv03] Reference for U-B colour
209-212 F4.2 mag R-I ?=9.99 R-I colour index
214-219 A6 --- r_R-I Reference for R-I colour
221-225 F5.2 GHz Freq ?=99.99 Rest-frame frequency of the turnover
of the spectrum
227-231 F5.2 --- ab ?=99.99 Spectral index below the turnover
233-238 F6.2 --- aa ?=999.99 Spectral index above the turnover
240-245 F6.2 --- symm ?=999.99 Symmetry of the spectrum
247-251 F5.2 --- curv ?=99.99 Curvature of the spectrum
253-257 F5.2 --- FWHM ?=99.99 Full width at half maximum of the
spectrum
259-264 F6.2 --- Mid ?=999.99 Mid-frequency of the bin used in
calculations
266-270 F5.2 --- VI ?=99.99 Variability index
272-275 I4 --- o_VI ?=9999 Number of data points used for VI
277-283 F7.2 10+22cm-2 NHX ?=9999.99 Hydrogen column density in X-rays
285-289 A5 --- r_NHX Reference for NHX
291-294 F4.2 --- Gamma ?=9.99 Power-law slope in X-rays
296-300 A5 --- r_Gamma Reference for power-law slope in X-rays
302-306 F5.2 10+20cm-2 NH21 ?=99.99 Neutral hydrogen column density
308-313 A6 --- r_NH21 Reference for NH21
315-319 F5.2 mag Emag ?=99.99 E (photographic red) magnitude
321-327 A7 --- r_Emag reference for E magnitude
329-333 F5.2 mag Omag ?=99.99 O (photographic blue) magnitude
335-341 A7 --- r_Omag Reference for O magnitude
343-347 F5.2 mag O-E ?=99.99 O-E colour index
349-355 A7 --- r_O-E Reference for O-E colour
357-361 A5 --- Morph VLBI morphology (4)
363-368 A6 --- r_Morph Reference for VLBI morphology
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Note (1): Optical identification as follows:
BLO = BL Lac object
BLO/G = BL Lac object/galaxy
EF = empty field
GAL = galaxy
GA/QS = galaxy/QSO
HPQ = high polarization quasar
LPQ = low polarization quasar
LPQ&bl = low polarization quasar and bl
S = stellar
QSO = quasar
Note (2): Unless otherwise stated * means that the linear size has
been recalculated from the angular size with H0=71km/s/Mpc,
OmegaM=0.27, Omegavac=0.73 with Edward L. Wright's Cosmology
Calculator (http://www.astro.ucla.edu/~wright/CosmoCalc.html).
Note (3): Auxiliary classification as follows:
n = not enough data for GPS identification
s = steep spectrum
f = flat spectrum
f/s = flat at low frequencies, steep at high frequencies
c = convex spectrum
idb = inverted during bursts
v = variability of Var_DeltaS>3
gps = gigahertz peaked spectrum
Note (4): VLBI morphology as follows:
cd = compact double
cj = core-jet object
cj/cd = core-jet object/compact double
cso = compact symmetric object
ct = compact triple
cx = complex
gl = gravitational lens
ln = linear
s = stellar
unres = unresolved
mr = marginally resolved
p = point-like
Note (5): Unit [W/Hz] was not specified in the paper.
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Ref Reference code
9- 27 A19 --- BibCode BibCode
29- 50 A22 --- Aut Author's name
52- 74 A23 --- Com Comments
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Acknowledgements:
I. Torniainen, ilo(at)kurp.hut.fi
(End) I. Torniainen [Metsahovi Radio Obs.], Patricia Vannier [CDS] 28-Feb-2008