J/A+AS/139/575 RASS AGN sample (Wei+, 1999)
An AGN sample with high X-ray-to-optical flux ratio from RASS. I.
The optical identification.
Wei J.Y., Xu D.W., Dong X.Y., Hu J.Y.
<Astron. Astrophys. Suppl. Ser. 139, 575 (1999)>
=1999A&AS..139..575W 1999A&AS..139..575W
ADC_Keywords: X-ray sources ; Active gal. nuclei ; Magnitudes ; Redshifts
Mission_Name: ROSAT
Keywords: surveys - X-rays: general - X-rays: galaxies - galaxies: active
Abstract:
We present the first results of a program to identify the unknown
bright active galactic nuclei (AGN) in the ROSAT All Sky Survey Bright
Source Catalog (RASS-BSC). We have used logC+0.4R as an alternative
expression for log(fX/fopt), where C is X-ray count rate and R
stands for R magnitude. Then a high X-ray-to-optical flux ratio
criterion has been used to select an AGN sample with 165 unidentified
X-ray sources for optical spectroscopy. Those 165 X-ray sources have
been identified in the following classes: 115 emission line AGN (QSOs
and Seyferts), 2 BL Lac objects and 4 BL Lac candidates, 22 clusters
of galaxies, 12 Galactic stars and 10 objects remain unidentified.
This represent a success rate of about 73% for detecting AGN using our
selection criteria. Plausibility is based upon the optical
classification and X-ray characteristics of the sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 98 184 X-ray identification information
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See also:
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
I/243 : The PMM USNO-A1.0 Catalogue (Monet 1997)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- 1RXSJ ROSAT name
17- 18 I2 h RAh Right ascension (J2000) (1)
20- 21 I2 min RAm Right ascension (J2000)
23- 27 F5.2 s RAs Right ascension (J2000)
29 A1 --- DE- Declination sign (J2000)
30- 31 I2 deg DEd Declination (J2000)
33- 34 I2 arcmin DEm Declination (J2000)
36- 39 F4.1 arcsec DEs Declination (J2000)
41- 42 I2 arcsec PE ? ROSAT X-ray position error (2)
44- 47 F4.1 arcsec Sep Angular separation between the X-ray source
and the proposed optical counterpart
49- 53 F5.3 ct/s CR ? ROSAT total count rate (2)
55- 59 F5.2 --- HR1 ? Hardness ratio 1 (3)
61- 65 F5.2 --- HR2 ? Hardness ratio 2 (3)
67- 69 I3 arcsec Ext ? Extent (2)
71- 74 F4.1 mag Rmag R magnitude (4)
76- 79 F4.1 mag Bmag B magnitude (4)
81- 86 A6 --- ID Classification of the optical counterpart (5)
88- 92 F5.3 --- z ? Average redshift for extragalactic counterpart
94- 98 F5.1 mag BMAG ? Absolute B magnitude
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Note (1): Position of the proposed optical counterpart
Note (2): Value as given in RASS-BSC, Cat. IX/10
Note (3): HR1=(B-A)/(B+A), where A means the count rate in the energy range
0.1-0.4 keV and B in the energy range 0.5-2.0 keV.
HR2=(D-C)/(D+C), where C means the count rate in the energy range
0.5-0.9 keV and D in the energy range 0.9-2.0 keV.
Note (4): Magnitudes obtained from USNO-A1.0 with an accuracy between
0.25 and 0.40 magnitudes depending on the declination (Monet et al.,
1996, Cat. I/243)
Note (5): The abbreviations have the following meanings:
QSO: quasi-stellar object (unresolved or resolved object with
MB < 23 showing a Seyfert 1 spectrum)
Sey: Seyfert galaxy
BL: BL Lac object
BL can: BL Lac candidate
CL: cluster of galaxies
WD: white dwarf
CV: cataclysmic variable star
M: M star
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History: From A&AS electronic version
(End) Patricia Bauer [CDS] 11-Feb-2000