J/A+A/631/A110 N131 bubble CO (3-2), (2-1) and (1-0) observations (Zhang+, 2019)
Using CO line ratios to trace compressed areas in bubble N131.
Zhang C.-P., Li G.-X., Zhou C., Yuan L., Zhu M.
<Astron. Astrophys. 631, A110 (2019)>
=2019A&A...631A.110Z 2019A&A...631A.110Z (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; Radio sources ; Millimetric/submm sources ;
Carbon monoxide
Keywords: ISM: bubbles - infrared: ISM - stars: formation - molecular data -
ISM: individual objects: N131
Abstract:
N131 is a typical infrared dust bubble showing an expanding ringlike
shell. We study what kinds of CO line ratios can be used to trace the
interaction in the expanding bubble. We carry out new CO (3-2)
observations towards bubble N131 using JCMT 15-m telescope, and derive
line ratios by combining with our previous CO (2-1) and CO (1-0)
data from IRAM 30-m observations. To trace the interaction between the
molecular gas and the ionized gas in the HII region, we use RADEX to
model the dependence of CO line ratios on kinetic temperature and H2
volume density, and examine the abnormal line ratios based on other
simulations. We present CO (3-2), CO (2-1), and CO (1-0)
integrated intensity maps convolved to the same angular resolution
(22.5"). The three different CO transition maps show apparently
similar morphology. The line ratios of WCO(3-2)/WCO(2-1) mostly
range from 0.2 to 1.2 with a median of 0.54±0.12, while the line
ratios of WCO(2-1)/WCO(1-0) range from 0.5 to 1.6 with a median of
0.84±0.15. The high CO line ratios WCO(3-2)/WCO(2-1)>0.8 and
WCO(2-1)/WCO(1-0)>1.2 are beyond the threshold predicted by
numerical simulations based on the assumed density-temperature
structure for the inner rims of ringlike shell, where are the
compressed areas in bubble N131.
These high CO integrated intensity ratios, such as
WCO(3-2)/WCO(2-1)>0.8 and WCO(2-1)/WCO(1-0)>1.2, can be used
as a tracer of gas compressed regions with a relatively high
temperature and density. This further suggests that the non-Gaussian
part of the line-ratio distribution can be used to trace the
interaction between the molecular gas and the hot gas in the bubble.
Description:
We carry out new CO (3-2) observations towards bubble N131 using
JCMT 15-m telescope, and derive line ratios by combining with our
previous CO (2-1) and CO (1-0) data from IRAM 30-m observations.
To trace the interaction between the molecular gas and the ionized gas
in the HII region, we use RADEX to model the dependence of CO line
ratios on kinetic temperature and H_2 volume density, and examine the
abnormal line ratios based on other simulations.
Objects:
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RA (2000) DE Designation(s)
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19 52 21.0 +26 20 54 N131 = [CPA2006] N131
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 112 5 List of fits files
fits/* . 5 Individual fits files
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See also:
J/A+A/585/A117 : N131 bubble CO integrated intensity maps (Zhang+, 2016)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 29 I2 Kibyte size Size of FITS file
31- 46 A16 --- FileName Name of FITS file, in subdirectory fits
48-112 A65 --- Title Title of the FITS file
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Acknowledgements:
Chuan-Peng Zhang, zcp0507(at)gmail.com
(End) Chuan-Peng Zhang [Beijing], Patricia Vannier [CDS] 14-Oct-2019