J/MNRAS/437/1561 DR 21 Chandra source catalogue (Rivilla+, 2014)
The role of low-mass star clusters in forming the massive stars in DR 21.
Rivilla V.M., Jimenez-serra I., Martin-pintado J., Sanz-forcada J.
<Mon. Not. R. Astron. Soc., 437, 1561-1575 (2014)>
=2014MNRAS.437.1561R 2014MNRAS.437.1561R
ADC_Keywords: Associations, stellar ; X-ray sources ; Stars, pre-main sequence
Keywords: stars: formation - stars: low-mass - stars: massive -
stars: pre-main-sequence - galaxies: star clusters: general -
X-rays: stars
Abstract:
We have studied the young low-mass pre-main sequence (PMS) stellar
population associated with the massive star-forming region DR 21 by
using archival X-ray Chandra observations and by complementing them
with existing optical and infrared (IR) surveys. The Chandra
observations have revealed for the first time a new highly extincted
population of PMS low-mass stars previously missed in observations at
other wavelengths. The X-ray population exhibits three main stellar
density peaks, coincident with the massive star-forming regions, being
the DR 21 core the main peak. The cross-correlated X-ray/IR sample
exhibits a radial 'Spokes-like' stellar filamentary structure that
extends from the DR 21 core towards the northeast. The near-IR data
reveal a centrally peaked structure for the extinction, which exhibits
its maximum in the DR 21 core and gradually decreases with the
distance to the N-S cloud axis and to the cluster centre. We find
evidence of a global mass segregation in the full low-mass stellar
cluster, and of a stellar age segregation, with the youngest stars
still embedded in the N-S cloud, and more evolved stars more spatially
distributed. The results are consistent with the scenario where an
elongated overall potential well created by the full low-mass stellar
cluster funnels gas through filaments feeding stellar formation.
Besides the full gravitational well, smaller scale local potential
wells created by dense stellar sub-clusters of low-mass stars are
privileged in the competition for the gas of the common reservoir,
allowing the formation of massive stars. We also discuss the
possibility that a stellar collision in the very dense stellar cluster
revealed by Chandra in the DR 21 core is the origin of the large-scale
and highly energetic outflow arising from this region.
Description:
In our analysis, we used archival stellar catalogues in X-rays,
optical and IR wavelengths. We also made use of the Spitzer 4.6um
and 8um images (Cygnus-X Legacy Project), and the Submillimetre
Common-User Bolometer Array (SCUBA) 850um data (Matthews et al.
2009ApJS..182..143M 2009ApJS..182..143M, Cat. J/ApJS/182/143).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 97 281 DR 21 Chandra source catalogue, with SDSS, UKIDSS
and Spitzer counterparts
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See also:
J/ApJS/182/143 : SCUPOL Legacy polarimetry of SCUBA (Matthews+, 2009)
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 [1/281] DR21 X 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- 31 I3 ct Counts [2/320] X-ray counts
33- 37 F5.2 [10-7W] logLX ?=0 X-ray luminosity
(not corrected from extinction)
39- 57 A19 --- SDSS SDSS counterpart name (JHHMMSS.ss+DDMMSS.s)
59- 77 A19 --- UKIDSS UKIDSS counterpart name (JHHMMSS.ss+DDMMSS.s)
79- 97 A19 --- SSTCYGX Spitzer-SSTCYGX counterpart name
(JHHMMSS.ss+DDMMSS.s)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 19-Nov-2014