J/A+A/454/1047 XMM view of NGC 6231 open cluster (Sana+, 2006)
An XMM-Newton view of the NGC 6231 young open cluster: I. The catalogue.
Sana H., Gosset E., Rauw G., Sung H., Vreux J.-M.
<Astron. Astrophys. 454, 1047 (2006)>
=2006A&A...454.1047S 2006A&A...454.1047S
ADC_Keywords: Clusters, open ; Cross identifications ; Photometry, UBVRI ;
Stars, OB ; Stars, pre-main sequence ; X-ray sources
Keywords: open clusters and associations: individual: NGC 6231 -
X-rays: individuals: NGC 6231 - X-rays: stars - stars: early-type -
catalogues
Abstract:
We present the results of an X-ray campaign towards the young open
cluster NGC 6231. The XMM-Newton observations, of a total duration of
about 180 ks, reveals that NGC 6231 is very rich in the X-ray domain
too. Indeed, 610 X-ray sources are detected in the present field of
view, centered on the cluster core. The limiting sensitivity of our
survey is approximately 610-15erg/s/cm2 but clearly depends on the
location in the field of view and on the source spectrum. Using
different existing catalogues, over 85% of the X-ray sources could be
associated with at least one optical and/or infrared counterpart
within a limited cross-correlation radius of 2.5 or 3-arcsec according
to the optical/IR catalogue used. The surface density distribution of
the X-ray sources presents a slight N-S elongation. Once corrected for
the spatial sensitivity variation of the EPIC instruments, the radial
profile of the source surface density is well described by a King
profile with a central density of about 8 sources per arcmin2 and a
core radius close to 3.1-arcmin. The distribution of the X-ray sources
seems closely related to the optical source distribution. The expected
number of foreground and background sources should represent about 9%
of the detected sources, thus strongly suggesting that most of the
observed X-ray emitters are physically belonging to NGC 6231. Finally,
beside a few bright but soft objects -- corresponding to the
early-type stars of the cluster -- most of the sources are relatively
faint (∼5x10-15erg/s/cm2) with an energy distribution peaked
around 1.0-2.0keV.
Description:
The catalogue of the 610 X-ray sources detected in the 30'-diameter
field of view of XMM-Newton is presented. Table 3 lists the equatorial
coordinates, logarithmic likelihoods and count rates for the three
EPIC instruments and for various energy ranges. Table 6 provides the
cross-identification of the X-ray sources with various
optical/infrared catalogues (2MASS, GSC2.2, USNO B1.0, SSB06) as well
as with commonly used denominations (HD/HDE, CD, CPD, Segg., SBL98,
Braes). Only the closest identification is reported here.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 406 610 X-ray source catalogue in NGC 6231
table6.dat 255 610 Cross-identification of the X-ray catalogue
with different optical/IR catalogues
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
I/271 : The Guide Star Catalog, Version 2.2 (GSC2.2) (STScI, 2001)
I/284 : The USNO-B1.0 Catalog (Monet+ 2003)
J/A+AS/137/233 : UBVI imaging photometry of NGC 6231 (Baume+, 1999)
J/AJ/115/734 : NGC 6231 UBVRI and Hα photometry (Sung+ 1998)
J/A+A/325/167 : Geneva photometry in NGC 6231 (Raboud+ 1997)
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 Internal X-ray source numbering scheme
6- 20 A15 --- XMMUJ Recommended XMM source denomination (G1)
23- 27 F5.2 arcsec e_Pos Error on the source position
30- 37 F8.1 --- L2(pn) ?=- PN: Equivalent likelihood L2
40- 46 F7.3 ct/ks CR(pn) ?=- PN: count-rate in [0.5-10.0 keV]
48- 54 F7.3 ct/ks e_CR(pn) ?=- PN: error on CR [0.5-10.0 keV]
56- 62 F7.3 ct/ks CRs(pn) ?=- PN: count-rate in [0.5-1.0 keV]
64- 70 F7.3 ct/ks e_CRs(pn) ?=- PN: error on CR_s [0.5-1.0 keV]
72- 78 F7.3 ct/ks CRm(pn) ?=- PN: count-rate in [1.0-2.5 keV]
80- 86 F7.3 ct/ks e_CRm(pn) ?=- PN: error on CR_m [1.0-2.5 keV]
88- 94 F7.3 ct/ks CRh(pn) ?=- PN: count-rate in [2.5-10.0 keV]
96-102 F7.3 ct/ks e_CRh(pn) ?=- PN: error on CR_m [2.5-10.0 keV]
104-110 F7.3 --- HR1(pn) ?=- PN: softer hardness ratio (2)
112-118 F7.3 --- e_HR1(pn) ?=- PN: error on HR1
120-126 F7.3 --- HR2(pn) ?=- PN: harder hardness ratio (3)
128-134 F7.3 --- e_HR2(pn) ?=- PN: error on HR2
137-144 F8.1 --- L2(m1) ?=- M1: Equivalent likelihood L2
147-153 F7.3 ct/ks CR(m1) ?=- M1: count-rate in [0.5-10.0 keV]
155-161 F7.3 ct/ks e_CR(m1) ?=- M1: error on CR [0.5-10.0 keV]
163-169 F7.3 ct/ks CRs(m1) ?=- M1: count-rate in [0.5-1.0 keV]
171-177 F7.3 ct/ks e_CRs(m1) ?=- M1: error on CRs [0.5-1.0 keV]
179-185 F7.3 ct/ks CRm(m1) ?=- M1: count-rate in [1.0-2.5 keV]
187-193 F7.3 ct/ks e_CRm(m1) ?=- M1: error on CRm [1.0-2.5 keV]
195-201 F7.3 ct/ks CRh(m1) ?=- M1: count-rate in [2.5-10.0 keV]
203-209 F7.3 ct/ks e_CRh(m1) ?=- M1: error on CRm [2.5-10.0 keV]
211-217 F7.3 --- HR1(m1) ?=- M1: softer hardness ratio (2)
219-225 F7.3 --- e_HR1(m1) ?=- M1: error on HR1
227-233 F7.3 --- HR2(m1) ?=- M1: harder hardness ratio (3)
235-241 F7.3 --- e_HR2(m1) ?=- M1: error on HR2
244-251 F8.1 --- L2(m2) ?=- M2: equivalent likelihood L2
254-260 F7.3 ct/ks CR(m2) ?=- M2: count-rate in [0.5-10.0keV]
262-268 F7.3 ct/ks e_CR(m2) ?=- M2: error on CR [0.5-10.0keV]
270-276 F7.3 ct/ks CRs(m2) ?=- M2: count-rate in [0.5-1.0keV]
278-284 F7.3 ct/ks e_CRs(m2) ?=- M2: error on CRs [0.5-1.0keV]
286-292 F7.3 ct/ks CRm(m2) ?=- M2: count-rate in [1.0-2.5keV]
294-300 F7.3 ct/ks e_CRm(m2) ?=- M2: error on CRm [1.0-2.5keV]
302-308 F7.3 ct/ks CRh(m2) ?=- M2: count-rate in [2.5-10.0keV]
310-316 F7.3 ct/ks e_CRh(m2) ?=- M2: error on CRm [2.5-10.0keV]
318-324 F7.3 --- HR1(m2) ?=- M2: softer hardness ratio (2)
326-332 F7.3 --- e_HR1(m2) ?=- M2: error on HR1
334-340 F7.3 --- HR2(m2) ?=- M2: harder hardness ratio (3)
342-348 F7.3 --- e_HR2(m2) ?=- M2: error on HR2
351-358 F8.1 --- L2(epic) Epic: total equivalent likelihood L2
361-364 A4 --- Instr Used combination of instruments
367-369 A3 --- Ext Extended source flag
372-384 A13 --- Com Comments and warnings
387-388 I2 h RAh X-ray source right ascension (J2000) (4)
389-390 I2 min RAm X-ray source right ascension (J2000) (4)
391-395 F5.2 s RAs X-ray source right ascension (J2000) (4)
398 A1 --- DE- X-ray source declination sign (J2000) (4)
399-400 I2 deg DEd X-ray source declination (J2000) (4)
401-402 I2 arcmin DEm X-ray source declination (J2000) (4)
403-406 F4.1 arcsec DEs X-ray source declination (J2000) (4)
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Note (2): HR1=(CRm-CRs)/(CRm+CRs)
Note (3): HR2=(CRh-CRm)/(CRh+CRm)
Note (4): In order to avoid systematic shifts, the coordinates have been
rounded, not truncated.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Internal X-ray source numbering scheme
6- 20 A15 --- XMMUJ Recommended XMM source denomination (G1)
23- 27 F5.3 arcsec DX2 ? 2MASS: correlation distance
30- 45 A16 --- 2MASS 2MASS (II/246) source name
48- 53 F6.3 mag Jmag ? 2MASS: J magnitude
56- 61 F6.3 mag Hmag ? 2MASS: H magnitude
64- 69 F6.3 mag Kmag ? 2MASS: K magnitude
72- 76 F5.3 arcsec DXG ? GSC2.2: correlation distance
79- 92 A14 --- GSC2.2 GSC2.2 (I/271) source name
95- 99 F5.2 mag Rmag ? GSC2.2: R magnitude
102-106 F5.2 mag Bmag ? GSC2.2: B magnitude
109-113 F5.2 mag Vmag ? GSC2.2: V magnitude
116-120 F5.3 arcsec DXU ? USNO B1.0: correlation distance
123-134 A12 --- USNOB1.0 USNO B1.0 (I/284) source name
137-141 F5.2 mag R1mag ? USNO B1.0: R1 magnitude
144-148 F5.2 mag B1mag ? USNO B1.0: B1 magnitude
151-155 F5.2 mag R2mag ? USNO B1.0: R2 magnitude
158-162 F5.2 mag B2mag ? USNO B1.0: B2 magnitude
165-169 F5.2 mag Imag ? USNO B1.0: I magnitude
172-176 F5.3 arcsec DXS ? SSB06: correlation distance
179 A1 --- f_SSB06 [*] SSB06: flag (2)
180-184 A5 --- SSB06 SSB06 (Sung et al., 2006, in prep.) source name
187-192 F6.3 mag Vmag2 ? SSB06: V magnitude
195-200 F6.3 mag V-I ? SSB06: V-I colour
203-208 F6.3 mag B-V ? SSB06: B-V colour
211-216 F6.3 mag U-B ? SSB06: U-B colour
219-224 I6 --- HD/HDE ? CI: HD/HDE number
227-231 I5 --- CD ? CI: CD number (in format CD-41 NNNNN)
232 A1 --- n_CD [p] Multiplicity index on CD
234-237 I4 --- CPD ? CI: CPD number (in format CPD-41 NNNN)
240-242 I3 --- Segg ? CI: Seggewiss (1968VeBon..79....1S 1968VeBon..79....1S) number
NGC 6231 NNN in Simbad
245-249 I5 --- SBL98 ? CI: Sung et al., 1998, Cat. J/AJ/115/734
number, Cl* NGC 6231 SBL NNN in Simbad
252-255 I4 --- Braes ? CI: Braes number
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Note (2): An asterisk '*' means that the related stars were saturated in the
SSB06 data set. Quoted photometric data are taken from SBL98.
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Global notes:
Note (G1): XMMUJ is the specified format for XMM-Newton source positions.
It corresponds to the J2000 coordinates in format HHMMSS.s+DDMMSS.
Note that the coordinates are truncated, not rounded.
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Acknowledgements: Hugues Sana, hana(at)eso.org
Eric Gosset, gosset(at)astro.ulg.ac.be
Gregor Rauw, rauw(at)astro.ulg.ac.be
Hwankyung Sung, sungh(at)mso.anu.edu.au
Jean-Marie Vreux, vreux(at)astro.ulg.ac.be
(End) Patricia Vannier [CDS] 17-Jul-2006