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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 (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:
FileName Lrecl Records Explanations
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
Byte-by-byte Description of file: table2
Bytes Format Units Label Explanations
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
Note (1): The coordinates are corrected for pointing offset of (+1.6s, 4.7")
Byte-by-byte Description of file: table3
Bytes Format Units Label Explanations
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
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")
Byte-by-byte Description of file: table6
Bytes Format Units Label Explanations
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^-14^erg/cm^2^/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)
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
Courtesy: Wolfgang Hummel References: Dachs J. and Kabus H., 1989, A&AS 78, 25 =1989A&AS...78...25D
(End) Patricia Bauer [CDS] 16-Apr-1996
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