J/A+A/521/A45 X-ray detections in the σ Ori cluster (Caballero+, 2010)
HRC-I/Chandra X-ray observations towards σ Orionis.
Caballero J.A., Albacete-colombo J.F., Lopez-Santiago J.
<Astron. Astrophys., 521, A45-45 (2010)>
=2010A&A...521A..45C 2010A&A...521A..45C
ADC_Keywords: Clusters, open ; Stars, early-type ; X-ray sources
Keywords: brown dwarfs - stars: early-type - stars: flare -
stars: variables: T Tauri, Herbig Ae/Be - X-rays: stars -
open clusters and associations: individual: σ Orionis
Abstract:
We investigated the X-ray emission from young stars and brown dwarfs
in the σ Orionis cluster (τ≃3Ma, d≃385pc) and its relation
to mass, the presence of circumstellar discs, and separation to the
cluster centre by taking advantage of the superb spatial resolution
of the Chandra X-ray Observatory.
Description:
We used public HRC-I/Chandra data from a 97.6ks pointing towards
the cluster centre and complemented them with X-ray data from
IPC/Einstein, HRI/ROSAT, EPIC/XMM-Newton, and ACIS-S/Chandra together
with optical and infrared photometry and spectroscopy from the
literature and public catalogues. On our HRC-I/Chandra data, we
measured count rates, estimated X-ray fluxes, and searched for
short-term variability. We also looked for long-term variability
by comparing with previous X-ray observations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablec1.dat 72 107 HRC-I/Chandra X-ray detections with significance
over 5.1.
tablec2.dat 87 90 Optical/near-infrared counterparts of X-ray
sources in Table C1
tablec3.dat 99 63 A reappraisal to the X-ray sources near
σ Ori in Wolk (1996, Ph.D. Thesis)
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See also:
J/AN/325/705 : RIJHKs of low-mass stars in σ Ori (Bejar+, 2004)
J/A+A/419/249 : RJHKs photometry of σ Ori low-mass stars (Scholz+, 2004)
J/A+A/446/501 : XMM observations of σ Ori cluster (Franciosini+, 2006)
J/A+A/493/931 : MAD observations of σ Ori (Bouy+, 2009)
J/ApJ/688/362 : Disks around brown dwarfs in σ Ori (Luhman+ 2008)
J/ApJS/191/389 : Photometric monitoring in σ Ori cluster (Cody+, 2010)
J/MNRAS/356/89 : σ Ori low-mass stars (Kenyon+, 2005)
B/chandra : The Chandra Archive Log (CXC, 1999-)
Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/107] Sequential number
5- 6 I2 h RAh Right ascension (J2000)
8- 9 I2 min RAm Right ascension (J2000)
11- 15 F5.2 s RAs Right ascension (J2000)
17 A1 --- DE- Declination sign (J2000)
18- 19 I2 deg DEd Declination (J2000)
21- 22 I2 arcmin DEm Declination (J2000)
24- 27 F4.1 arcsec DEs Declination (J2000)
29- 32 F4.2 arcsec e_Pos Position error
34- 39 F6.2 --- Signi Significance of detection
41- 45 F5.2 arcmin Offaxis Angular separation to the centre of field
of view
47- 52 F6.2 ct/ks CR Count rate
54- 57 F4.2 ct/ks e_CR rms uncertainty on CR
59- 64 F6.2 10-17W/m2 Flux Apparent X-ray flux (10-14erg/cm2/s)
66- 68 I3 --- NX ?=- Source number in Franciosini et al,
2006, Cat. J/A+A/446/501,
<[FPS2006] NX NNN> in Simbad
69 A1 --- n_NX [)<] Uncertain or non-detection (1)
71- 72 I2 --- CXO ?=- Source number in Skinner et al.
2008ApJ...683..796S 2008ApJ...683..796S,
<[SSC2008] NN> in Simbad
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Note (1): Note as follows:
) = uncertainty identification
< = sources not detected by Franciosini et al. (2006, Cat. J/A+A/446/501)
for which the authors provided EPIC count-rate upper levels
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Byte-by-byte Description of file: tablec2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/107] Sequential number
5- 20 A16 --- 2MASS 2MASS name (HHMMSSss+DDMMSSs)
22- 40 A19 --- Name Name
43- 65 A23 --- AName Alternative name
68- 87 A20 --- Class Classification (2)
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Note (2): classes are: Young brown dwarf ; Young star; Young star candidate ;
Field star ; Possible field star ; Galaxy
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Byte-by-byte Description of file: tablec3.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Source Source name (1)
14- 15 I2 h RAh Wolk 1996 Right ascension (J2000)
17- 18 I2 min RAm Wolk 1996 Right ascension (J2000)
20- 23 F4.1 s RAs Wolk 1996 Right ascension (J2000)
25 A1 --- DE- Wolk 1996 Declination sign (J2000)
26- 27 I2 deg DEd Wolk 1996 Declination (J2000)
29- 30 I2 arcmin DEm Wolk 1996 Declination (J2000)
32- 33 I2 arcsec DEs Wolk 1996 Declination (J2000)
35- 40 F6.2 ct/ks CR Count rate
42- 45 F4.2 ct/ks e_CR rms uncertainty on CR
47- 50 A4 --- SpT MK spectral type
51 A1 --- n_SpT [x] when star spectroscopically investigated
by Wolk (1996 PhD thesis) but spectral
type not given
53- 54 I2 h RA2h ? 2MASS Right ascension (J2000)
56- 57 I2 min RA2m ? 2MASS Right ascension (J2000)
59- 63 F5.2 s RA2s ? 2MASS Right ascension (J2000)
65 A1 --- DE2- 2MASS Declination sign (J2000)
66- 67 I2 deg DE2d ? 2MASS Declination (J2000)
69- 70 I2 arcmin DE2m ? 2MASS Declination (J2000)
72- 75 F4.1 arcsec DE2s ? 2MASS Declination (J2000)
77- 78 I2 --- NX ? Source number in Franciosini et al,
2006, Cat. J/A+A/446/501,
<[FPS2006] NX NNN> in Simbad
80- 99 A20 --- Name Alternate name
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Note (1): RHHMMSS-DDMM identified as <[W96] rJHHMMSS-DDMM> in Simbad
NNNN NNNN identified as <[W96] NNNN-NNNN> in Simbad
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 03-Feb-2011