J/A+A/312/818 NGC 2516 X-ray sources (Dachs+, 1996)
ROSAT survey of stellar X-ray sources in the young open cluster NGC 2516
Dachs J., Hummel W.
<Astron. Astrophys. 312, 818 (1996)>
=1996A&A...312..818D 1996A&A...312..818D (SIMBAD/NED BibCode)
ADC_Keywords: X-ray sources ; Clusters, open
Mission_Name: ROSAT
Keywords: X-rays: stars - stars: chemically peculiar - stars: emission-line -
open clusters: NGC 2516 - stars: coronae
Description:
The ROSAT PSPC detector was used to obtain a deep pointing with its
center on the young open cluster NGC 2516 and total integration time
of 9284 sec. Altogether 64 X-ray sources were detected showing strong
concentration towards the optical cluster centre. This suggests that
most of the sources are actually associated with NGC 2516. 42 of these
sources could be identified with optical stars in the field of the
cluster; after correction for a mean offset between optical and
nominal ROSAT positions of about 13", optical star and X-ray source
positions are found to agree, on the average, within about 9", while
maximum observed positional differences amount to 27". X-ray sources
identified with optical cluster stars include HR 3147 (=HD 66194;
B2.5IVe), the visually brightest B star in the cluster, three close
visual late B-type binaries (h 4027 A,B, h 4031 A,B, and I 1104 A,B)
with projected separations ranging between about 4x1016cm and
6x1016cm, as well as several (six) chemically peculiar Bp/Ap(Si) and
Ap(SrCrEu) stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2 69 64 X-ray sources detected in NGC 2516
table2.tex 107 158 LaTeX version of table2
table3 89 46 Stars in the field of NGC 2516 identified with
ROSAT X-ray sources
table3.tex 121 151 LaTeX version of table3
table6 100 45 Properties of X-ray sources identified with
optical stars of known (or assumed) distance
table6.tex 123 138 LaTeX version of table6
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Byte-by-byte Description of file: table2
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Bytes Format Units Label Explanations
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1- 2 I2 --- No [1/64] Running number (increasing with α)
4- 5 I2 --- Seq ? X-ray source number, as detected with EXSAS
reduction package (increasing with -δ)
6 A1 --- m_Seq Multiplicity index on Seq
8- 9 I2 h RAh Right ascension (J2000.0) (1)
11- 12 I2 min RAm Right ascension (J2000.0) (1)
14- 18 F5.2 s RAs Right ascension (J2000.0) (1)
20 A1 --- DE- Declination sign
21- 22 I2 deg DEd Declination (J2000.0) (1)
24- 25 I2 arcmin DEm Declination (J2000.0) (1)
27- 30 F4.1 arcsec DEs Declination (J2000.0) (1)
32- 35 F4.1 arcsec Dr 90% confidence source radius
36 A1 --- u_Dr Undertainty flag on Dr
38- 42 F5.1 ct/s CtRate Count rate corrected for vignetting and for
the life-time factor (=0.978)
44- 46 F3.1 ct/s e_CtRate rms uncertainty on Count rate
48- 52 F5.2 --- HR1 Hardness ratio HR1
53 A1 --- u_HR1 Uncertainty flag on HR1
54- 57 F4.2 --- e_HR1 ? rms uncertainty on HR1
59- 63 F5.2 --- HR2 Hardness ration HR2
64 A1 --- u_HR2 Uncertainty flag on HR2
66- 69 F4.2 --- e_HR2 ? rms uncertainty on HR2
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Note (1): The coordinates are corrected for pointing offset of (+1.6s, 4.7")
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Byte-by-byte Description of file: table3
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Bytes Format Units Label Explanations
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2- 3 I2 --- No ? Running number from table2
4 A1 --- m_No [)] A ')' indicates the second component of a
binary
6- 15 A10 --- Name Identification HD, CPD or CD
18 A1 --- n_Name [bc] b = HR 3138; c = HR 3147
21- 23 I3 --- DK ? Running number in the photometric study of
Dachs and Kabus (1989), hereafter DK
24 A1 --- m_DK Multiplicity index on DK
26- 35 A10 --- Sp Spectral type
37 A1 --- n_Sp [g] A 'g' indicates new spectral type
40- 41 I2 h RAh Right ascension J2000.0 (optical source)
43- 44 I2 min RAm Right ascension J2000.0 (optical source)
46- 50 F5.2 s RAs Right ascension J2000.0 (optical source)
52 A1 --- n_RA [def] (1)
54 A1 --- DE- Declination sign
55- 56 I2 deg DEd Declination J2000.0 (optical source)
58- 59 I2 arcmin DEm Declination J2000.0 (optical source)
61- 64 F4.1 arcsec DEs Declination J2000.0 (optical source)
66 A1 --- n_DE [def] (1)
68- 72 F5.2 s DRA Position difference ROSAT minus optical in RA (2)
73 A1 --- n_DRA [d] (1)
75- 80 F6.2 arcsec DDE Position difference ROSAT minus optical in DE (2)
81 A1 --- n_DDE [d] (1)
83- 86 F4.1 arcsec Dr Angular distance between optical and X-ray
positions
88- 89 A2 --- Memb Cluster membership of star,
M=member, NM=non-member
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Note (1): d) corrected for proper motion between 1992 and 2000
e) PPM position
f) CPC position
Note (2): Position difference corrected for pointing offset (+1.6s, -4.7")
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Byte-by-byte Description of file: table6
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Bytes Format Units Label Explanations
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3- 4 I2 --- No Running number of table2
5 A1 --- m_No [)] A ')' indicates the second component
of a binary
7- 18 A12 --- Name Identification from table3 HD, CPD, CD or
DK
20- 30 A11 --- Sp Spectral type (from DK or this paper)
32- 36 F5.2 mag Vmag V magnitude (from DK)
37 A1 --- u_Vmag Uncertainty flag on Vmag
38- 42 F5.2 mag B-V ? B-V color index (from DK)
45- 47 I3 pc d Adopted distance
48 A1 --- u_d Uncertainty flag on distance
50- 54 F5.2 mag Mv Inferred absolute visual magnitude
55 A1 --- u_Mv Uncertainty flag on Mv
57- 61 F5.2 solLum Lbol Bolometric luminosity
62 A1 --- u_Lbol Uncertainty flag on Lbol
64- 68 F5.1 10-14mW/m2 Fx ? ROSAT X-ray flux (10-14erg/cm2/s) (1)
69 A1 --- u_Fx Uncertainty flag on Fx
72- 74 F3.1 10-14mW/m2 e_Fx ? rms uncertainty on Fx
77- 84 E8.2 10-7W Lx ? X-ray luminosity (0.16-2.5keV)
86- 93 E8.2 10-7W e_Lx ? Rms uncertainty on Lx
94 A1 --- u_Lx Uncertainty flag on Lx
96- 99 F4.2 --- -log(Lx/Lbol) ? -log(X-ray/bolometric luminosities)
100 A1 --- u_-log(Lx/Lbol) Uncertainty flag on -log(Lx/Lbol)
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Note (1): Adopted flux conversion factor CF for NGC 2516 cluster stars showing
HR1~+1.0: CF∼1.4x10-11erg/cm2/s (counts/s)-1
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Courtesy: Wolfgang Hummel
References:
Dachs J. and Kabus H., 1989, A&AS 78, 25 =1989A&AS...78...25D 1989A&AS...78...25D
(End) Patricia Bauer [CDS] 16-Apr-1996