J/A+A/575/A42 Optical counterparts of ROSAT X-ray in 2 fields (Greiner+, 2015)
Optical counterparts of ROSAT X-ray sources in two selected fields at
low vs. high Galactic latitudes.
Greiner J., Richter G.A.
<Astron. Astrophys. 575, A42 (2015)>
=2015A&A...575A..42G 2015A&A...575A..42G
ADC_Keywords: X-ray sources ; Stars, variable ; Cross identifications
Keywords: surveys - X-rays: general - stars: variables: general
Abstract:
The optical identification of large number of X-ray sources such as
those from the ROSAT All-Sky Survey is challenging with conventional
spectroscopic follow-up observations.
We investigate two ROSAT All-Sky Survey fields of size 10°x10°
each, one at galactic latitude b=83° (26 Com), the other at
b=-5° (gamma Sge), in order to optically identify the majority of
sources.
We used optical variability, among other more standard methods, as a
means of identifying a large number of ROSAT All- Sky Survey sources.
All objects fainter than about 12mag and brighter than about 17mag,
in or near the error circle of the ROSAT positions, were tested for
optical variability on hundreds of archival plates of the Sonneberg
field patrol.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 101 238 Main X-ray data of the ROSAT sources in 26 Com
table2.dat 96 132 Main X-ray data of the ROSAT sources in γ Sge
table8.dat 118 327 Optical objects inside or near the error circles
of the ROSAT positions in 26 Com
table9.dat 118 415 Optical objects inside or near the error circles
of the ROSAT positions in γ Sge
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See also:
B/xmm : XMM-Newton Observation Log (XMM-Newton Science Operation Center, 2014)
IX/37 : XMM-Newton Serendipitous Source Catalogue (1XMM) (XMM-SSC, 2003)
IX/41 : XMM-Newton Serendipitous Source Catalogue 2XMMi-DR3 (XMM-SSC, 2010)
Byte-by-byte Description of file: table1.dat table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Xseq Running number of the X-ray source
6- 7 I2 h RAh Right Ascension (J2000)
9- 10 I2 min RAm Right Ascension (J2000)
12- 15 F4.1 s RAs Right Ascension (J2000)
17 A1 --- DE- Declination sign (J2000)
18- 19 I2 deg DEd Declination (J2000)
21- 22 I2 arcmin DEm Declination (J2000)
24- 25 I2 arcsec DEs Declination sign (J2000)
29- 43 A15 --- 1RXS ROSAT All-sky Survey Name (IX/10, IX/29)
47- 48 I2 arcsec ePos ?=- 90% confidence error circle
51- 55 F5.3 ct/s CR [0.008/5.7] ROSAT PSPC count rate
58- 62 F5.2 --- HR1 [-1/1] Hardness ratio 1 (1)
65- 68 F4.2 --- e_HR1 Hardness ratio 1 error
72- 76 F5.2 --- HR2 [-1/1] Hardness ratio 2 (1)
79- 82 F4.2 --- e_HR2 Hardness ratio 2 error
85- 90 F6.2 10-16W/m2 Flux X-ray flux (in 10-13erg/cm2/s)
93 A1 --- ID [a-h] Reference to counterpart in
tables 8 and 9 (2)
94-101 A8 --- Comm Comments for reference to counterpart in
tables 8 and 9 (2)
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Note (1): The hardness ratio HR1 is defined as the normalized count difference
(N50-200-N10-40)/(N10-40+N50-200), where Na-b denotes the number of
counts in the PSPC between channels a and b.
Similarly, the hardness ratio HR2 is defined as
(N91-200-N50-90)/N50-200.
HR1 is sensitive to the Galactic foreground absorbing column.
Note (2): The symbol is that of the corresponding object in column 1 of
tables 8, 9, except for the Sge "sources" 87-91, 93-94 which are detections
of flux enhancements of an extended supernova remnant (SNR).
A dash means that no optical identification can be proposed, and
a question mark after the symbol denotes some doubts due to inconclusive
data or other alternatives. "Cluster" denotes cases where the X-ray emission
is more likely associated with the galaxy cluster gas emission rather than
individual galaxies in that cluster.
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Byte-by-byte Description of file: table8.dat table9.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Xseq Running number of the X-ray source
5 A1 --- m_Xseq [a-j] ID for multiple optical objects
10- 11 I2 h RAh ? Right Ascension (J2000) (1)
13- 14 I2 min RAm ? Right Ascension (J2000) (1)
16- 19 F4.1 s RAs ? Right Ascension (J2000) (1)
21 A1 --- DE- Declination sign (J2000) (1)
22- 23 I2 deg DEd ? Declination (J2000) (1)
25- 26 I2 arcmin DEm ? Declination (J2000) (1)
28- 29 I2 arcsec DEs ? Declination (J2000) (1)
32- 33 I2 arcsec Sep ? Distance between X-ray centroid and object
35- 49 A15 --- Name Bright star name
51- 63 A13 --- Var C if constant or GCVS Name if variable (2)
65- 74 A10 --- Type Source type (3)
75- 83 A9 --- SpType Spectral Type from Simbad (4)
85- 88 F4.1 mag Bmag ? USNO B magnitude
90- 93 F4.1 mag Vmag ? USNO V magnitude
95- 98 F4.1 mag Rmag ? USNO R magnitude
101-112 A12 --- Ampl Amplitude of optical variability
114-118 F5.2 [-] X/opt ? log of X-ray to optical flux ratio (5)
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Note (1): No values means that no object visible on our plates (with some
exceptions) is within the error circle of the ROSAT source.
Note (2): If the object is variable: Name from the General Catalogue of
Variable Stars and its supplements (GCVS, Moscow).
If not named, the preliminary designation of newly discovered Sonneberg
variables is given by the usual S-number (some prominent cases among the of
order 70 new variables discovered in this work have already been published
by us separately, and already received an IAU variable star name).
In few cases, the number in the New Catalogue of Suspected Variable Stars
(NSV catalogue, Moscow 1982) is given.
If the object was found to be constant on all plates, a "C" is given while
a "C?" means that there could be small amplitude variations which are
marginal in our data. A void place means that the object was not tested for
variability, for example bright stars (mostly HD stars), and very faint stars
below the plate limit.
Note (3): Type of object and type of variability corresponding to the
nomenclature of the GCVS.
G = galaxy
GCl = cluster of galaxies
AGN = active galactic nucleus
AGN? = supposed AGN only by reason of its blue colour, though in single
cases it may be a white dwarf or a cataclysmic variable.
QSO = quasistellar object
BLL = BL Lacertae object
SY = Seyfert galaxy
ULX = ultra-luminous X-ray source
CV = cataclysmic variable
UGSU = SU UMa type
AM = AM Her type
NC = very slow nova
E = eclipsing variable
EA = Algol type
EB = Beta Lyrae type
CA = chromospherically active star.
RS = RS CVn
BY = BY Dra
UV = UV Cet type
LB = slowly irregular variable of late spectral type
SRB = semi-regular variable of late spectral type
PN = planetary nebula
Note (4): FG means F or G star according to the objective prism spectra taken
with the Hamburg Schmidt telescope on Calar Alto (Bade et al.,
1998A&AS..127..145B 1998A&AS..127..145B, Cat. J/A+AS/127/145).
Note (5): This ratio is arbitrary for variable sources, since the catalogued V
(or (B) band value is taken which is not contemporaneous to the X-ray
observation.
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Acknowledgements:
Jochen Greiner, jcg(at)mpe.mpg.de
(End) Patricia Vannier [CDS] 05-Sep-2014