J/A+A/460/133 Chandra X-ray sources in NGC 2362 (Damiani+, 2006)
The young star cluster NGC 2362: low-mass population and initial mass
function from a Chandra X-ray observation.
Damiani F., Micela G., Sciortino S., Huelamo N., Moitinho A.,
Harnden F.R.Jr., Murray S.S.
<Astron. Astrophys. 460, 133 (2006)>
=2006A&A...460..133D 2006A&A...460..133D
ADC_Keywords: Clusters, open ; X-ray sources
Keywords: open clusters and associations: individual (NGC 2362) -
stars: coronae - stars: pre-main-sequence - stars: mass function -
X-rays: stars
Description:
We observed the young cluster NGC 2362 in X-rays with Chandra ACIS-I,
and detected 387 point X-ray sources, most of which are shown to be
cluster members. We report here the list of all detected X-ray sources
and their basic X-ray properties, and report separately their
identifications with optical stars, using data from Moitinho et al.
(2001ApJ...563L..73M 2001ApJ...563L..73M; UBVRI photometry) and Dahm (2005, Cat.
J/AJ/130/1805; Hα data). We include in the second table a
classification of optically-identified X-ray sources, based on
position in the HR diagram, which helps to separate rather clearly
cluster members from field objects.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 71 387 Detected X-ray sources in NGC 2362
table3.dat 39 320 Optical identifications of X-ray sources
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See also:
J/AJ/130/1805 : Hα emission stars in NGC 2362 (Dahm+, 2005)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq X-ray source number
5 I1 h RAh Right ascension (J2000)
7- 8 I2 min RAm Right ascension (J2000)
10- 14 F5.2 s RAs Right ascension (J2000)
16 A1 --- DE- Declination sign
17- 18 I2 deg DEd Declination (J2000)
20- 21 I2 arcmin DEm Declination (J2000)
23- 26 F4.1 arcsec DEs Declination (J2000)
28- 31 F4.2 arcsec e_Pos Positional Error
33- 37 F5.2 ct/ks CR X-ray Count Rate
39- 42 F4.2 ct/ks e_CR Error on X-ray Count Rate
44- 47 F4.1 % P(K-S) Probability of no Variability
49- 53 F5.2 --- HR1 Hardness ratio 1 (1)
55- 59 F5.2 --- HR2 Hardness ratio 2 (1)
61- 65 F5.2 [10-7W] LX X-ray Luminosity (band 0.2-4.0keV)
67- 71 F5.2 [10-7W] LXQ ? Quiescent X-ray Luminosity (2)
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Note (1): X-ray Hardness Ratios are defined with reference to the X-ray
counts collected in three energy bands S, M, H (respectively
soft: [0.3-1.2]keV; medium: [1.2-2.2]keV; hard: [2.2-8.0]keV),
as HR1=(M-S)/(M+S), HR2=(H-M)/(H+M)
Note (2): A Quiescent X-ray Luminosity is defined for sources showing X-ray
flares, trying to model and subtract the flare contribution, leaving
only the non-variable component of the emission.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq X-ray source number
5- 9 I5 --- Moi Star number from Moitinho et al.
(2001ApJ...563L..73M 2001ApJ...563L..73M)
11- 14 F4.2 arcsec Offset Offset between X-ray and optical positions
16- 21 F6.3 mag Vmag V-band magnitude from Moitinho et al.
(2001ApJ...563L..73M 2001ApJ...563L..73M)
23- 27 F5.3 mag V-I V-I color from Moitinho+ (2001ApJ...563L..73M 2001ApJ...563L..73M)
29- 31 I3 --- D ? Star number from Dahm (2005, J/AJ/130/1805)
Cl* NGC 2362 D NNN in Simbad
33- 37 F5.2 0.1nm EW(Ha) ? Hα equivalent width, from
Dahm (2005, Cat. J/AJ/130/1805)
39 I1 --- Group Classification (1)
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Note (1): Optical counterparts of X-ray sources are grouped according to
their position in the HR diagram: group 1 and 2 stars are (candidate)
high- and intermediate-mass main-sequence cluster members; group 3
stars fall in a narrow pre-main-sequence locus and are best candidates
as low-mass PMS members; groups 4 and 5 are stars falling slightly
above this locus (possible binaries) or slightly below it. Group 6
stars fall elsewhere in the diagram and are not members.
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Acknowledgements:
Francesco Damiani, damiani (at)astropa.unipa.it
(End) Patricia Vannier [CDS] 21-Nov-2006