J/AJ/115/2587 Einstein IPC database ultrasoft survey (Thompson+ 1998)
Initial results of a comprehensive ultrasoft survey of the Einstein IPC
database: source list and confirmation of the selection procedure.
Thompson R.J., Shelton R.G., Arning C.A.
<Astron. J. 115, 2587 (1998)>
=1998AJ....115.2587T 1998AJ....115.2587T
ADC_Keywords: X-ray sources
Mission_Name: Einstein
Keywords: binaries: close - pulsars: general - surveys - white dwarfs -
X-rays
Abstract:
We have carried out a survey of the entire Einstein IPC database (a
total of 5934 sources) to select objects with strong components of
ultrasoft X-ray emission (i.e., emission below 0.5keV). The selection
criteria are based on ratios of counts within three broad energy bands
(i.e., X-ray "colors"). A total of 516 objects have been selected,
with 202 (39%) having been identified through correlations with other
databases. Of the currently identified objects, 45% are active
galactic nuclei, 28% are stellar objects, 6% are "normal" galaxies and
galaxy clusters, and the remaining 21% are "nonstellar" Galactic
objects such as cataclysmic variables, pulsars, and white dwarfs. We
present a discussion of the survey selection procedure, the list of
selected sources, and discussions of interesting objects from the
aforementioned groups. We discuss the remarkable success of our rather
"low resolution" method of estimating spectral shape and present plans
for follow-up studies of the as yet unidentified sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 90 516 Source information, Part I
table2.dat 86 516 Source information, Part II
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See also:
IX/13 : The 2E Catalogue (Harris+ 1994)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- IPC IPC number
7- 8 I2 --- Source Object source number in the field
10- 11 I2 h RAh Right ascension (J2000.0)
13- 14 I2 min RAm Right ascension (J2000.0)
16- 20 F5.2 s RAs Right ascension (J2000.0)
22 A1 --- DE- Declination sign
23- 24 I2 deg DEd Declination (J2000.0)
26- 27 I2 arcmin DEm Declination (J2000.0)
29- 33 F5.2 arcsec DEs Declination (J2000.0)
35- 40 F6.2 10-3ct/s CountRate Count rate over the 0.2-4keV passband
43- 48 F6.3 10-3ct/s e_CountRate rms uncertainty on CountRate
50- 53 F4.1 --- S/N Signal-to-noise ration
55- 58 I4 --- RECO ? Rib and edge code
60- 90 A31 --- Ident *Identification of optical counterpart
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Note on Ident: one error corrected, see the "History" section below.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- IPC IPC number
7- 8 I2 --- Source Object source number in the field
10- 11 I2 h RAh Right ascension (J2000.0)
13- 14 I2 min RAm Right ascension (J2000.0)
16- 20 F5.2 s RAs Right ascension (J2000.0)
22 A1 --- DE- Declination sign
23- 24 I2 deg DEd Declination (J2000.0)
26- 27 I2 arcmin DEm Declination (J2000.0)
29- 33 F5.2 arcsec DEs Declination (J2000.0)
35- 43 F9.3 ct C1 Counts in the low (0.16-0.56keV) colour band
45- 52 F8.3 ct e_C1 rms uncertainty on C1
54- 61 F8.3 ct C2 Counts in the medium (0.56-1.08keV) colour band
63- 69 F7.3 ct e_C2 rms uncertainty on C2
71- 78 F8.3 ct C3 Counts in the high (1.08-3.5keV) colour band
80- 86 F7.3 ct e_C3 rms uncertainty on C3
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Table 3: Classes of objects
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Class Percentage of
identified sources
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Active galactic nuclei 45
Stellar 28
Normal galaxies and galaxy clusters 6
Cataclysmic variables (AM Herculis stars) 4
PG 1159 objects/planetary nebulae 1
DA white dwarfs 9
X-ray binaries 3
Pulsars 1
T Tauri stars 2
W UMa variables/symbiotic stars 1
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History: From AJ electronic version
* 27-Oct-1999: Corrected SAO number in table1 for source IPC 3727
(is SAO 110135, not SAO 10135)
(End) James Marcout, Patricia Bauer [CDS] 31-Aug-1998