J/A+A/646/A103 YSO candidates in S169 (Duronea+, 2021)
Physical characterization of S169: a prototypical IR bubble associated with the
massive star-forming region IRAS 12326-6245.
Duronea N.U., Cichowolski S., Bronfman L., Mendoza E., Finger R.,
Suad L.A., Corti M., Reynoso E.M.
<Astron. Astrophys., 646, A103 (2021)>
=2021A&A...646A.103D 2021A&A...646A.103D (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; YSOs ; Photometry, infrared
Keywords: ISM: bubbles - HII regions - ISM: molecules -
ISM: kinematics and dynamics
Abstract:
With the aim of studying the physical properties of Galactic IR
bubbles and to explore their impact in massive star formation, we
present a study of the IR bubble S169, associated with the massive
star forming region IRAS 12326-6245.
We used CO (2-1),13CO (2-1), C18O (2-1), HCN (3-2), and HCO+
(3-2) line data obtained with the APEX telescope using the on-the-fly
full sampling technique to study the properties of the molecular gas
in the nebula and the IRAS source. To analyze the properties and
distribution of the dust, we made use of images obtained from the
IRAC-GLIMPSE, Herschel, and ATLASGAL archives. The properties of the
ionized gas in the nebula were studied using radio continuum and
Hα images obtained from the SUMSS survey and SuperCOSMOS
database, respectively. In our search for stellar and protostellar
objects in the region, we used point source calalogs obtained from the
MSX, WISE, GLIMPSE, 2MASS, AAVSO, ASCC-2.5V3, and GAIA databases.
The new APEX observations allowed us to identify three molecular
components, each one associated with different regions of the nebula,
namely: at -39km/s (component A), -25km/s (component B), and -17km/s
(component C). Component A is shown to be the most dense and clumpy.
Six molecular condensations (MC1 to MC6) were identified in this
component, with MC3 (the densest and more massive one) being the
molecular counterpart of IRAS 12326-6245. For this source, we
estimated an H2 column density up to 8x1023cm-2. An LTE analysis
of the high density tracer lines HCO+ (3-2) and HCN (3-2) on this
source, assuming 50 and 150K, respectively, indicates column densities
of N(HCO+)=(5.2±0.1)x1013cm-2 and
N(HCN)=(1.9±0.5)x1014cm-2. To explain the morphology and
velocity of components A, B, and C, we propose a simple model
consisting of a partially complete semisphere-like structure expanding
at ∼12km/s. The introduction of this model has led to a discussion
about the distance to both S169 and IRAS 12326-6245, which was
estimated to be ∼2kpc. Several candidate YSOs were identified,
projected mostly onto the molecular condensations MC3, MC4, and MC5,
which indicates that the star-formation process is very active at the
borders of the nebula. A comparison between observable and modeled
parameters was not enough to discern whether the collect-and-collapse
mechanism is acting at the edge of S169. However, other processes such
as radiative-driven implosion or even a combination of both
mechanisms, namely, collect-and-collapse and radiative-driven
implosion, could be acting simultaneously in the region.
Description:
As part of a broader project aimed at characterizing and studying the
physical properties of Galactic IR bubbles and their surroundings, we
present a multiwavelength analysis of the southern IR dust bubble S169
associated with the massive star forming core IRAS 12326-6245.
Table A1 list YSO candidates obtained from MSX, WISE, and Spitzer
catalogs.
Objects:
----------------------------------------------------------
RA (2000) DE Designation(s)
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12 35 31.9 -62 58 16 S169 = [CPA2006] S169
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File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1m.dat 102 2 YSO candidates obtained from MSX catalog
tablea1w.dat 117 48 YSO candidates obtained from WISE catalogs
tablea1s.dat 114 24 YSO candidates obtained from Spitzer catalog
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See also:
V/114 : MSX6C Infrared Point Source Catalog (Egan+ 2003)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
II/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)
Byte-by-byte Description of file: tablea1m.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Origin [MSX ] Source origin
9- 10 I2 --- Seq [1/2] Sequential number
12- 30 A19 --- Name Source name, GLLL.llll+BB.bbbb,
MSX6C GLLL.llll+BB.bbbb in Simbad
32- 33 I2 h RAh Right ascension (J2000)
35- 36 I2 min RAm Right ascension (J2000)
38- 41 F4.1 s RAs Right ascension (J2000)
43 A1 --- DE- Declination sign (J2000)
44- 45 I2 deg DEd Declination (J2000)
47- 48 I2 arcmin DEm Declination (J2000)
50- 53 F4.1 arcsec DEs Declination (J2000)
55- 60 F6.3 Jy F8 MSX6C 8.28um flux density
62- 67 F6.3 Jy F12 MSX6C 12.13um flux density
69- 74 F6.3 Jy F14 MSX6C 14.65um flux density
76- 82 F7.3 Jy F21 MSX6C 21.34um flux density
84-102 A19 --- Note Notes (class, match with other YSO and
with 13CO/CO or IR structure)
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Byte-by-byte Description of file: tablea1w.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Origin [WISE ] Source origin
9- 10 I2 --- Seq [3/50] Sequential number
12- 30 A19 --- Name Source name, JHHMMSS.ss+DDMMSS.s,
WISE JHHMMSS.ss+DDMMSS.s
32- 33 I2 h RAh Right ascension (J2000)
35- 36 I2 min RAm Right ascension (J2000)
38- 41 F4.1 s RAs Right ascension (J2000)
43 A1 --- DE- Declination sign (J2000)
44- 45 I2 deg DEd Declination (J2000)
47- 48 I2 arcmin DEm Declination (J2000)
50- 53 F4.1 arcsec DEs Declination (J2000)
55- 60 F6.3 mag W1 WISE W1 magnitude
62- 67 F6.3 mag W2 WISE W2 magnitude
69- 74 F6.3 mag W3 WISE W3 magnitude
76- 82 F7.3 mag W4 WISE W4 magnitude
84-117 A34 --- Note Notes (class, match with other YSO and
with 13CO/CO or IR structure)
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Byte-by-byte Description of file: tablea1s.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Origin [Spitzer] Source origin
9- 10 I2 --- Seq [51/74] Sequential number
12- 30 A19 --- Name Source name, GLLL.llll+BB.bbbb,
GLIMPSE GLLL.llll+BB.bbbb
32- 33 I2 h RAh Right ascension (J2000)
35- 36 I2 min RAm Right ascension (J2000)
38- 41 F4.1 s RAs Right ascension (J2000)
43 A1 --- DE- Declination sign (J2000)
44- 45 I2 deg DEd Declination (J2000)
47- 48 I2 arcmin DEm Declination (J2000)
50- 53 F4.1 arcsec DEs Declination (J2000)
55- 60 F6.3 mag [3.6] Spitzer/IRAC 3.6um magnitude
62- 67 F6.3 mag [4.5] Spitzer/IRAC 4.5um magnitude
69- 74 F6.3 mag [5.8] Spitzer/IRAC 5.8um magnitude
76- 82 F7.3 mag [8.0] Spitzer/IRAC 8.0um magnitude
84-114 A31 --- Note Notes (class, match with other YSO and
with 13CO/CO or IR structure)
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 22-Apr-2021