J/A+A/472/699 ROXA: multi-frequency large sample of blazars (Turriziani+, 2007)
ROXA: a new multi-frequency large sample of blazars selected with SDSS and
2dF optical spectroscopy.
Turriziani S., Cavazzuti E., Giommi P.
<Astron. Astrophys. 472, 699 (2007)>
=2007A&A...472..699T 2007A&A...472..699T
ADC_Keywords: Active gal. nuclei ; BL Lac objects ; QSOs
Keywords: galaxies: BL Lacertae objects: general - quasars: general -
methods: statistical - catalogs
Abstract:
Although Blazars are a small fraction of the overall AGN population
they are expected to be the dominant population of extragalactic
sources in the hard X-ray and gamma-ray bands and have been shown to
be the largest contaminant of CMB fluctuation maps. So far the number
of known blazars is of the order of several hundreds, but the
forthcoming AGILE, GLAST and Planck space observatories will detect
several thousand of objects of this type. In preparation for these
missions it is necessary to identify new samples of blazars to study
their multi-frequency characteristics and statistical properties. We
compiled a sample of objects with blazar-like properties via a
cross-correlation between large radio (NVSS, ATCAPMN) and X-ray
surveys (RASS) using the SDSS-DR4 and 2dF survey data to
spectroscopically identify our candidates and test the validity of the
selection method. We present the Radio-Optical-X-ray catalog built
at ASDC (ROXA), a list of 816 objects among which 510 are confirmed
blazars. Only 19% of the candidates turned out to be certainly
non-blazars demonstrating the high efficiency of our selection method.
Our catalog includes 173 new blazar identifications, or about 10% of
all presently known blazars. The relatively high flux threshold in the
X-ray energy band (given by the RASS survey) preferentially selects
objects with high FX/Fr ratio leading to the discovery of new High
Energy Peaked BL Lac (HBLs).Our catalog therefore includes many new
potential targets for GeV-TeV observations.
Description:
A list of 816 objects among which 510 are confirmed blazars. The
selection method consists in three steps: 1) a first cross-correlation
between radio and X-ray surveys (the NRAO VLA Sky Survey, ATCAPMN
(ATCA catalogue of compact PMN sources) and ROSAT All Sky Survey; 2)
for each radio/X-ray match, optical magnitudes were retrieved from the
Guide Star Catalog; 3) for all radio/optical/X-ray matches we
calculated the X-ray to optical (alphaox) and radio to optical
(alpharo) spectral slopes and took only sources with alphaox and
alpharo values within the blazar area. For each object, redshift, B
and G magnitudes, radio flux at 1.4GHz and at 5GHz, X-ray flux, FX/Fr
ratio, X-ray luminosity, radio luminosity, CaH&K break and
classification are given.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 114 816 ROXA catalog of blazars.
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See also:
VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)
IX/29 : ROSAT All-Sky Survey Faint Source Catalog (Voges+ 2000)
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
II/276 : The SDSS Photometric Catalog, Release 5 (Adelman-McCarthy + 2007)
VII/226 : The 2dF Galaxy Redshift Survey 100k Data Release (2dFGRS Team, 2001)
VII/241 : The 2dF QSO Redshift Survey (Croom+ 2004)
ATCAPMN : http://www.atnf.csiro.au/resources/catalogues/pmn_atca
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [ROXA]
5- 22 A18 --- ROXA Source name (JHHMMSS.s+DDMMSS.s)
24- 27 F4.2 --- z Redshift
29- 32 F4.1 mag Bjmag ?=0 Bj magnitude (from 2dF surveys)
34- 37 F4.1 mag g'mag ?=0 g' magnitude (from SDSS survey)
39- 45 F7.1 mJy F1.4GHz ?=0 Radio flux at 1.4GHz (NVSS)
47- 53 F7.1 mJy F5GHz ?=0 Radio flux at 5GHz (North6cm, GB6 and PMN)
55- 62 E8.3 mW/m2 FX X-ray Flux (RASS)
64- 71 E8.3 mW/m2/Jy FX/Fr Ratio between X-ray flux and radio flux
73- 80 E8.3 10-7W LX X-ray Luminosity
82- 89 E8.3 10-7W/Hz Lr Radio Luminosity
91- 94 F4.2 --- CaH+K ? Calcium Break
96-111 A16 --- Class Classification (1)
113-114 A2 --- n_Class [*@z] Note on Class (2)
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Note (1): Classification as follows:
BLRG = broad line radio galaxies
FSRQ = flat spectrum radio quasars
HFSRQ = X-ray strong flat-spectrum radio quasars
NELG = narrow emission line galaxy
QSO RL = radio loud flat-spectrum radio quasar
QSO RQ = radio quiet steep-spectrum radio quasar
SSRQ = radio loud steep-spectrum radio quasar
R.G. FR II = Radio galaxy of FR II type
R.G./BL Lac = Radio Galaxy/BL transition object
R.G./FSRQ = Radio galaxy/Flat spectrum radio quasars
BL Lac/FSRQ = flat spectrum radio quasars/BL transition object
Note (2): We identify new objects with three different labels as follows:
* = new classification for those objects differently classified in
literature
@ = new object (never identified before this work)
z = objects with newly estimated redshifts
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Acknowledgements:
Elisabetta Cavazzuti, elisabetta.cavazzuti(at)asi.it
(End) Patricia Vannier [CDS] 31-May-2007