J/A+A/589/A28 N66, N88 & N25+N26 emission line maps (Requena-Torres+, 2016)
Carbon gas in SMC low-metallicity star-forming regions.
Requena-Torres M.A., Israel F.P., Okada Y., Guesten R., Stutzki J.,
Risacher C., Simon R., Zinnecker H.
<Astron. Astrophys. 589, A28 (2016)>
=2016A&A...589A..28R 2016A&A...589A..28R (SIMBAD/NED BibCode)
ADC_Keywords: Magellanic Clouds ; Interstellar medium ; Line Profiles
Keywords: Magellanic Clouds - ISM: kinematics and dynamics -
ISM: lines and bands - ISM: individual objects: N66 -
ISM: individual objects: N88 - ISM: individual objects: N25/N26
Abstract:
This paper presents [CII], [CI] and CO emission line maps of the
star-forming regions N66, N25+N26, and N88 in the metal-poor Local
Group dwarf galaxy SMC. The spatial and velocity structure of the
large HII region N66 reveals an expanding ring of shocked molecular
gas centered on the exciting star cluster NGC346, whereas a more
distant dense molecular cloud is being eroded by UV radiation from the
same cluster. In the N25+N26 and N88 maps, diffuse [CII] emission at a
relatively low surface brightness extends well beyond the compact
boundaries of the bright emission associated with the HII regions.
In all regions, the distribution of this bright [CII] emission and the
less prominent [CI] emission closely follows the outline of the CO
complexes, but the intensity of the [CII] and [CI] emission is
generally anticorrelated, which can be understood by the action of
photodissociation and photoionization processes. Notwithstanding the
overall similarity of CO and [CII] maps, the intensity ratio of these
lines varies significantly, mostly due to changes in CO brightness.
[CII] emission line profiles are up to 50% wider in velocity than
corresponding CO profiles. A radiative transfer analysis shows that
the [CII] line is the dominant tracer of (CO-dark) molecular hydrogen
in the SMC. CO emission traces only a minor fraction of the total
amount of gas. The similarity of the spatial distribution and line
profile shape, and the dominance of molecular gas associated with
CII rather than CO emission imply that in the low-metallicity
environment of the SMC the small amount of dense molecular gas traced
by CO is embedded in the much more extended molecular gas traced only
by [CII] emission. The contribution from neutral atomic and ionized
hydrogen zones is negligible in the star-forming regions observed
Description:
Datacubes of molecular and atomic emission for three star forming
regions in the Small Magellanic Cloud galaxy.
Objects:
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RA (ICRS) DE Designation(s)
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00 48 09.12 -73 14 19.1 N25 = LHA 115-N 25
00 59 27.40 -72 10 10.7 N66 = LHA 115-N 66
01 24 08.1 -73 09 04 N88 = LHA 115-N 88
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 155 21 List of fits files
fits/* . 21 Individual fits files
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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- 21 I2 --- Nx Number of pixels along X-axis
23- 26 I4 --- Ny Number of pixels along Y-axis
28- 30 I3 --- Nz ? Number of pixels along Z-axis
32- 38 F7.4 deg bAngleGLS ? Lower value of GLS angle interval
40- 46 F7.4 deg BAngleGLS ? Upper value of GLS angle interval
48- 57 F10.8 deg dAngleGLS ? GLS angle resolution
59- 70 E12.6 km/s bVRAD Lower value of VRAD interval
72- 82 E11.6 km/s BVRAD Upper value of VRAD interval
84- 91 F8.3 km/s dVRAD VRAD interval resolution
93- 96 I4 Kibyte size Size of FITS file
98-112 A15 --- FileName Name of FITS file, in subdirectory fits
114-155 A42 --- Title Title of the FITS file
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Acknowledgements:
Miguel Angel Requena-Torres, mrequena(at)stsci.edu
(End) Miguel A. Requena Torres [STScI, USA], Patricia Vannier [CDS] 14-Mar-2016