J/A+A/355/651 HRI observations of PMS stars in NGC 2264 (Flaccomio+, 2000)
HRI observations of PMS stars in NGC 2264.
Flaccomio E., Micela G., Sciortino S., Damiani F., Favata F.,
Harnden F.R.Jr, Schachter J.
<Astron. Astrophys. 355, 651 (2000)>
=2000A&A...355..651F 2000A&A...355..651F
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; X-ray sources
Keywords: stars: coronae - stars: formation -
stars: luminosity function, mass function - stars: pre-main sequence -
Galaxy: open clusters and associations: individual: NGC 2264 - X-rays
Abstract:
We analyze six ROSAT HRI observations pointed toward the Star Forming
Region (SFR) NGC 2264. Three are pointed to the southern star
formation core, the other three about 20' to the north. We detect 169
X-ray sources, ∼95% of which are likely to be Pre Main Sequence
(PMS) stars, significantly enlarging the known population of the SFR
in the area covered by the observations. Using published BVRI
photometry we place the X-ray sources with well defined optical
counterparts on the HRI diagram and estimate their masses and ages.
Our comparison of the mass function and age distribution of the X-ray
sources with results previously obtained for NGC 2264, demonstrates
that deep X-ray observations provide, at least in this case, a very
efficient method of selecting SFR members and does not introduce
stronger biases than other methods.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 134 169 List of detected X-ray sources
table4.dat 45 124 Counterparts of uniquely identified X-ray sources
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See also:
IX/28 : ROSAT HRI Pointed Observations (1RXH) (ROSAT Team, 2000)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [FMS2000] Source name ([FMS2000] XNNN in Simbad)
4 A1 --- n_[FMS2000] [*] *: denotes unique counterparts
6 I1 h RAh Right ascension (J2000)
8- 9 I2 min RAm Right ascension (J2000)
11- 14 F4.1 s RAs Right ascension (J2000)
16 A1 --- DE- Declination sign (J2000)
17 I1 deg DEd Declination (J2000)
19- 20 I2 arcmin DEm Declination (J2000)
22- 25 F4.1 arcsec DEs Declination (J2000)
27- 31 F5.2 ct/ks CRMax Maximum count rate
33- 35 F3.1 ct/ks e_CRMax rms uncertainty on CRMax
37 A1 --- l_CRMin Limit flag on CRMin
38- 42 F5.2 ct/ks CRMin Minimum count rate
44- 46 F3.1 ct/ks e_CRMin ? rms uncertainty on CRMin
48 A1 --- l_<logLX> Limit flag on <logLX>
49- 53 F5.2 [10-7W] <logLX> Maximum likelihood X-ray luminosity
55- 59 F5.1 --- SNR Signifiance of source detection
61- 62 I2 --- Pvar ? Probability of the source being variable
64-134 A71 ---- Ident Suggested optical counterparts (1)
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Note (1): We attempted identifications using stars from the following works:
WNNN = Walker, 1956ApJS....2..365W 1956ApJS....2..365W (NGC 2264 NNN)
VNNN = Vasilevskis et al., 1965AJ.....70..797V 1965AJ.....70..797V (Cl* NGC 2264 Vas NNN)
HNN = Herbig, 1954ApJ...119..483H 1954ApJ...119..483H (Em* LkHA NN)
MNNN = Marcy, 1980AJ.....85..230M 1980AJ.....85..230M (Em* LkHA NNN)
ONNN = Ogura, 1984PASJ...36..139O 1984PASJ...36..139O (KHA NNN)
SNNN = Sung et al., 1997AJ....114.2644S 1997AJ....114.2644S (Cl* NGC 2264 SBL NNN)
FNNN = Flaccomio et al., 1999, Cat. J/A+A/345/521 (Cl* NGC 2264 FMS NNN)
MXNNN = Young (private communication)
Notes following the object number are:
b = part of a visual double system, unresolved by the other authors
m = denotes that the counterpart is reported as a NGC 2264 member
in the cited paper
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [FMS2000] Source name ([FMS2000] XNNN in Simbad)
5- 9 F5.2 mag Vmag ? V magnitude
10 A1 --- n_Vmag [ab] V magnitude origin if not that
specified in Ref (1)
12- 16 F5.2 mag B-V ? B-V colour index
17 A1 --- n_B-V [ab] B-V colour origin if not that
specified in Ref (1)
19- 23 F5.2 mag V-I ? V-I colour index
24 A1 --- n_V-I [bc] V-I colour origin if not that
specified in Ref (1)
26- 31 A6 --- SpType MK spectral type
32 A1 --- n_SpType [b] Spectral type origin if not that
specified in Ref (1)
34- 37 F4.2 [K] logTeff ? Effective temperature
39- 43 F5.2 [solLum] log(Lbol) ? Bolometric luminosity
45 A1 --- Ref [SF] Reference for reported photometry (1)
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Note (1): References as follows:
a = Data from Sagar & Joshi (1983MNRAS.205..747S 1983MNRAS.205..747S)
b = Data from Perez (1987PASP...99.1050P 1987PASP...99.1050P)
c = Data from Cousin (1980, South African Astronomical Observatory
Circular 1, 234)
S = Sung et al., 1997AJ....114.2644S 1997AJ....114.2644S
F = Flaccomio et al., 1999, Cat. J/A+A/345/521
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History:
Prepared via OCR at CDS.
(End) James Marcout, Patricia Bauer [CDS] 07-Jan-2002