J/AJ/127/2659 CHANDRA observations of NGC 2264 (Ramirez+, 2004)
CHANDRA X-ray observations of young clusters. I. NGC 2264 data.
Ramirez S.V., Rebull L., Stauffer J., Hearty T., Hillenbrand L., Jones B.,
Makidon R., Pravdo S., Strom S., Werner M.
<Astron. J., 127, 2659-2673 (2004)>
=2004AJ....127.2659R 2004AJ....127.2659R
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; X-ray sources ;
Photometry, UBVRI ; Photometry, infrared
Keywords: stars: activity - stars: pre-main-sequence - X-rays: stars
Abstract:
We present results of a Chandra observation of a field in NGC 2264.
The observations were taken with the ACIS-I camera with an exposure
time of 48.1ks. We present a catalog of 263 sources, which includes
X-ray luminosity, optical and infrared photometry, and X-ray
variability information. We found 41 variable sources, 14 of which
have a flarelike light curve, and two of which have a pattern of a
steady increase or decrease over a 10-hr period. The optical and
infrared photometry for the stars identified as X-ray sources are
consistent with most of these objects being premain-sequence stars
with ages younger than 3Myr.
Description:
NGC 2264 was observed with the Advanced CCD Imaging Spectrometer
(ACIS) detector on board the Chandra X-Ray Observatory on 2002
February 9.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 104 263 The catalog of X-Ray Sources
table4.dat 115 213 Optical/infrared sources with X-ray counterparts
table5.dat 89 213 Cross identification of sources with
optical/infrared counterparts
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/AJ/123/1528 : UBV(RI)C and JHK photometry in NGC 2264 (Rebull+, 2002)
J/A+A/345/521 : BVRI photometry of NGC 2264 (Flaccomio+, 1999)
J/A+A/355/651 : HRI observations of PMS stars in NGC 2264 (Flaccomio+, 2000)
J/A+A/417/557 : Rotation + variability of PMS Stars in NGC 2264 (Lamm, 2004)
J/AJ/127/2228 : VRI photometry of PMS stars in NGC 2264 OB (Makidon+, 2004)
J/AJ/127/1117 : Halpha emission-line stars in NGC 2264 (Reipurth+, 2004)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [RRS2004] Chandra source identification number,
[RRS2004] NGC 2264 NNN in Simbad
5- 10 A6 --- --- [CXORRS]
12- 27 A16 --- CXORRS Chandra source name (JHHMMSS.s+DDMMSS)
29 I1 h RAh Hour of right ascension (J2000)
31- 32 I2 min RAm Minute of right ascension (J2000)
34- 38 F5.2 s RAs Second of right ascension (J2000)
39 A1 --- DE- Sign of declination (J2000)
40 I1 deg DEd Degree of declination (J2000)
42- 43 I2 arcmin DEm Arcminute of declination (J2000)
45- 50 F6.3 arcsec DEs Arcsecond of declination (J2000)
52- 56 F5.2 arcmin phi Off-axis angle
58- 62 F5.2 arcsec RExt Count extraction radius
64- 67 F4.2 --- fPSF Fraction of the PSF enclosed
69- 72 F4.1 ks ExpTime Effective exposure time
74- 79 F6.2 ct/ks CR Count rate (1)
81- 89 E9.3 mW/m2 FX X-ray flux in units of ergs/cm2/s (2)
91- 95 F5.2 [10-7W] logLX Logarithm of the X-ray luminosity in units
of ergs/s (3)
97- 99 I3 % Prob Constant-source probability (4)
101-103 A3 --- Com Additional comments (5)
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Note (1): CR = NC/fPSF * ExpTime, where NC is the net counts. See text.
Note (2): Computed using the derived conversion factor.
Note (3): Assuming a distance to NGC 2264 of 760pc
(Sung et al., 1997AJ....114.2644S 1997AJ....114.2644S).
Note (4): As derived from the chi-square value comparing the data with a
constant light curve. See text.
Note (5): Additional comments as follows:
v = Variable star
f = Flarelike light curve
p = Possible flare in the light curve
s = Steady increase or decrease in the light curve
g = Galaxy
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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- 23 A23 --- Name Previously published name (1)
25 I1 h RAh Hour of right ascension (J2000)
27- 28 I2 min RAm Minute of right ascension (J2000)
30- 34 F5.2 s RAs Second of right ascension (J2000)
36 I1 deg DEd Degree of declination (J2000)
38- 39 I2 arcmin DEm Arcminute of declination (J2000)
41- 45 F5.2 arcsec DEs Arcsecond of declination (J2000)
47- 49 I3 --- [RRS2004] Chandra source identification number,
[RRS2004] NGC 2264 NNN in Simbad
51- 55 F5.2 mag Umag ? The U-band magnitude
57 A1 --- f_Umag [c] Flag on Umag (2)
59- 63 F5.2 mag Bmag ? The B-band magnitude
65 A1 --- f_Bmag [c] Flag on Bmag (2)
67- 71 F5.2 mag Vmag ? The V-band magnitude
73 A1 --- f_Vmag [c] Flag on Vmag (2)
75- 79 F5.2 mag Rcmag ? The Cousins R-band magnitude
81 A1 --- f_Rcmag [c] Flag on Rcmag (2)
83- 87 F5.2 mag Icmag ? The Cousins I band magnitude
89 A1 --- f_Icmag [c] Flag on Icmag (2)
91- 95 F5.2 mag Jmag ? 2MASS (II/246) or Rebull et al. (2002,
Cat. J/AJ/123/1528) J-band magnitude
97 A1 --- f_Jmag [abc] Flag on Jmag (2)
99-103 F5.2 mag Hmag ? 2MASS (II/246) or Rebull et al. (2002,
Cat. J/AJ/123/1528) H-band magnitude
105 A1 --- f_Hmag [ac] Flag on Hmag (2)
107-111 F5.2 mag Kmag ? 2MASS (II/246) or Rebull et al. (2002,
Cat. J/AJ/123/1528) K-band magnitude
113 A1 --- f_Kmag [ac] Flag on Kmag (2)
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Note (1): We constructed the catalog by combining our original UBV(RI)c
survey from Rebull et al. (2002, Cat. J/AJ/123/1528) ("R" names)
with other published catalogs. If optical photometry and/or spectral
types were not available in Rebull et al. (2002, Cat. J/AJ/123/1528),
we took photometry from Park et al. (2000AJ....120..894P 2000AJ....120..894P), Flaccomio
et al. (1999, Cat. J/A+A/345/521), or Sung et al. (1997AJ....114.2644S 1997AJ....114.2644S)
in that order, augmented by 15 spectral types from the SIMBAD database.
Nomenclature in Simbad:
- Walker 143 = NGC 2264 143 in Simbad
- R NNNN = CL* NGC 2264 RMS NNNN in Simbad
- Sung NNNN not yet in Simbad (from 1997AJ....114.2644S 1997AJ....114.2644S)
Note (2): Flags on magnitudes have the following meaning:
a = Photometry from 2MASS (VII/233) Extended Source Catalog
b = Photometry contaminated by a diffraction spike
c = Photometry contaminated by a saturated column
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [RRS2004] Chandra source identification number,
[RRS2004] NGC 2264 NNN in Simbad
5 A1 --- --- [R]
7- 10 I4 --- RMS ? The Rebull et al. (2002, Cat. J/AJ/123/1528)
name, CL* NGC 2264 RMS NNNN in Simbad
12- 15 A4 --- --- [Sung]
17- 20 A4 --- SBL The Sung et al. (1997AJ....114.2644S 1997AJ....114.2644S) name,
Cl* NGC 2264 SBL NNNN in Simbad
22- 26 A5 --- --- [2MASS]
28- 44 A17 --- 2MASS The 2MASS (II/246) name
46- 88 A43 --- OName Other names (1)
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Note (1): Other names:
Ogura = Ogura, 1984PASJ...36..139O 1984PASJ...36..139O, KHA NNN in Simbad
Walker = Walker, 1956ApJS....2..365W 1956ApJS....2..365W, NGC 2264 NNN
VSB = Vasilevskis et al., 1965AJ.....70..797V 1965AJ.....70..797V, Cl* NGC 2264 Vas NNN
FX = Flaccomio et al., 2000, cat. J/A+A/355/651, [FMS2000] XNNN
HBC = Herbig & Bell, 1988, Cat. V/73, HBC NNN
Herbig = Herbig, 1954ApJ...119..483H 1954ApJ...119..483H, Em* LkHA NN
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 08-Jul-2004