J/MNRAS/437/606 IR observations of RCW 121 (IRAS 17149-3916) (Tapia+, 2014)
Herschel, Spitzer and Magellan infrared observations of the star forming
region RCW 121 (IRAS 17149-3916).
Tapia M., Persi P., Roth M., Elia D., Molinari S., Saldano H.P., Gomez, M.
<Mon. Not. R. Astron. Soc. 437, 606 (2014)>
=2014MNRAS.437..606T 2014MNRAS.437..606T
ADC_Keywords: Clusters, open ; Photometry, infrared
Keywords: circumstellar matter - stars: formation - infrared: ISM
Abstract:
We present new deep near-infrared broad- and narrow-band imaging and
low-resolution spectroscopy of the star formation region RCW 121
(IRAS17149-3916) which we analyse in combination with Herschel (70,
160, 250, 350 and 500 microns) and Spitzer (3.6, 4.5, 5.8 and
8 microns) images. The near-infrared photometry reveals the presence
of a stellar cluster of approximate size of 92" which is composed of
at least 264 members, approximately 25 per cent of these showing
excess emission at wavelengths >2.0 microns, indicative of
circumstellar discs. Isochrones corresponding to ages 0.5 to 1.0Myr
and AV=7.8 fit well the position of a large fraction of likely
cluster members in the Ks versus H-Ks diagram. We find three massive
star-forming cores located in the boundaries of an expanding HII
region ionized by a central O-type star. From their far-infrared
spectral energy distributions (SEDs) we derive masses and temperatures
of the dense cores. When these young stellar objects (YSOs) have warm
emission components, the 1.2 to 500 microns SEDs are fitted with
Robitaille et al.'s (2006ApJS..167..256R 2006ApJS..167..256R, 2007ApJS..169..328R 2007ApJS..169..328R)
star-disc-envelope model to obtain their physical parameters. The
masses of the three YSOs are between 8 and 10M☉. The youngest
site (core I) is undetected at wavelengths <100 microns and is at the
earliest evolutionary stage that can currently be detected. The other
two cores (II and III) contain YSOs of similar masses and have
near-infrared counterparts, which imply a more advanced evolutionary
stage. The YSO at core II has been found to have associated a jet,
with strong molecular hydrogen line emission, coexisting with a water
maser source. RCW 121 is another example of multiple star formation
being triggered by the expansion of a single HII region.
Description:
JHKs individual photometric measurements for all sources in the
observed field. Near-IR images were collected on the night of 2009
June 11 and 12 using the Perssons Auxiliary Nasmyth Infrared Camera
(PANIC) attached to the Magellan Baade 6.5-m telescope at Las Campanas
Observatory (Chile).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
jhkphot.dat 61 1602 Individual JHKs photometry
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See also:
J/AJ/131/951 : JHK photometry in the direction of RCW 121 (Roman-Lopes+, 2006)
Byte-by-byte Description of file: jhkphot.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Right ascension (J2000.0)
4- 5 I2 min RAm Right ascension (J2000.0)
7- 11 F5.2 s RAs Right ascension (J2000.0)
13 A1 --- DE- Declination sign (J2000.0)
14- 15 I2 deg DEd Declination (J2000.0)
17- 18 I2 arcmin DEm Declination (J2000.0)
20- 23 F4.1 arcsec DEs Declination (J2000.0)
25- 29 F5.2 mag Jmag ? J magnitude
31- 34 F4.2 mag e_Jmag ? Uncertainty of J magnitude
36- 40 F5.2 mag Hmag H magnitude
42- 45 F4.2 mag e_Hmag Uncertainty of H magnitude
47- 51 F5.2 mag Ksmag Ks magnitude
53- 56 F4.2 mag e_Ksmag Uncertainty of Ks magnitude
58- 61 I4 --- Id [3/4012] Identification number
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Acknowledgements:
Mauricio Tapia, mt(at)astrosen.unam.mx
(End) Mauricio Tapia [IA-UNAM], Patricia Vannier [CDS] 17-Dec-2013