J/MNRAS/435/2003 G305 star-forming complex in 13CO (Hindson+, 2013)
The G305 star-forming complex: radio continuum and molecular line observations.
Hindson L., Thompson M.A., Urquhart J.S., Faimali A., Johnston-Hollitt M.,
Clark J.S., Davies B.
<Mon. Not. R. Astron. Soc., 435, 2003-2022 (2013)>
=2013MNRAS.435.2003H 2013MNRAS.435.2003H
ADC_Keywords: H II regions ; Morphology ; Radio lines
Keywords: stars: formation - ISM: clouds - HII regions
Abstract:
We present 109-115GHz (3mm) wide-field spectral line observations of
12CO, 13CO and C18O J=1-0 molecular emission and 5.5 and 8.8GHz
(6 and 3cm) radio continuum emission towards the high-mass
star-forming complex known as G305. The morphology of G305 is
dominated by a large evacuated cavity at the centre of the complex
driven by clusters of O stars surrounded by molecular gas. Our goals
are to determine the physical properties of the molecular environment
and reveal the relationship between the molecular and ionized gas and
star formation in G305. This is in an effort to characterize the
star-forming environment and constrain the star formation history in
an attempt to evaluate the impact of high-mass stars on the evolution
of the G305 complex. Analysis of CO emission in G305 reveals 156
molecular clumps with the following physical characteristics;
excitation temperatures ranging from 7 to 25K, optical depths of
0.2-0.9, H2) column densities of 0.1-4.0x1022cm-2, clump masses
ranging from 102 to 104M☉ and a total molecular mass of
>3.5x105M☉. The 5.5 and 8.8GHz radio continuum emission
reveals an extended low surface brightness ionized environment within
which we identify 15 large-scale features with a further eight smaller
sources projected within these features. By comparing to mid-infrared
emission and archival data, we identify nine HII regions, seven
compact HII regions, one UC HII region and four extended regions. The
total integrated flux of the radio continuum emission at 5.5GHz is ∼
180Jy corresponding to a Lyman continuum output of
2.4x1050photons/s. We compare the ionized and molecular environment
with optically identified high-mass stars and ongoing star formation,
identified from the literature. Analysis of this data set reveals a
star formation rate of 0.008-0.016M☉/yr and efficiency of 7-12%,
allows us to probe the star formation history of the region and
discuss the impact of high-mass stars on the evolution of G305.
Description:
The CO observations of the G305 complex were obtained during two
observing runs in September of 2010 and 2011 using the 3mm receiver
on the Mopra 22m millimetre-wave telescope operated by the
Australia Telescope National Facility (ATNF).
Objects:
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RA (ICRS) DE Designation(s)
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13 10 17.5 -62 38 34 GAL 305.10+00.14 = GAL 305.10+00.14
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 65 156 Observed properties of the 156 detected 13CO
clumps reported by CLUMPFIND
table4.dat 92 156 Physical properties of the 156 13CO clumps
detected within G305
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/156] Clump sequential number
<[HTU2013] NNN> in Simbad
5- 16 A12 --- Name Clump Name (GLLL.ll+B.bb)
18- 23 F6.2 deg GLON Peak Galactic longitude
25- 29 F5.2 deg GLAT Peak Galactic latitude
31- 35 F5.1 km/s Vlsr [-48/-17] LSR clump velocity
37- 42 F6.2 arcsec dGlon [38/170] Dimension along galactic longitude (1)
44- 49 F6.2 arcsec dGlat [37/240] Dimension along galactic latitude (1)
51- 54 F4.2 pc Reff Effective radius
56- 59 F4.2 km/s dVlsr [0.9/5.7] Dimension along LSR velocity (1)
61- 65 F5.2 K Tb [1.9/15.4] Peak brightness temperature
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Note (1): CLUMPFIND position-position-velocity (PPV) dimension.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [1/156] Clump sequential number
<[HTU2013] NNN> in Simbad
5- 16 A12 --- Name Clump Name (GLLL.ll+B.bb)
18- 21 F4.2 --- tau [0.18/0.86] 13CO optical depth
23- 26 F4.2 --- e_tau [0.01/2.08] rms uncertainty on tau
28- 32 F5.2 K Tex [7/25] Excitation temperature
34- 37 F4.2 K e_Tex [0.09/0.28] rms uncertainty on Tex
39- 42 F4.2 10+22cm-2 NH2 [0.1/4.1] H2 clump density
44- 47 F4.2 10+22cm-2 e_NH2 [0.02/0.2] rms uncertainty on NH2
49- 51 F3.1 10+3cm-3 nH2 [0.3/4.5] H2 density number
53- 55 F3.1 10+3cm-3 e_nH2 [0.2/2.2] rms uncertainty on nH2
57- 59 F3.1 10+2Msun/pc2 Sc [0.3/9.1] Surface mass density Σc
61- 63 F3.1 10+2Msun/pc2 e_Sc [0.1/2.9] rms uncertainty on Sc
65- 68 F4.1 10+3Msun M [0.1/23] Clump mass
70- 72 F3.1 10+3Msun e_M [0.1/1.1] rms uncertainty on M
74- 77 F4.1 10+3Msun Mvir [0.2/19] Virial mass Mvir
79- 81 F3.1 10+3Msun e_Mvir [0.1/9.5] rms uncertainty on Mvir
83- 87 F5.2 --- avir [0.2/11.7] Ratio αvir of the
internal supporting energy to the
gravitational energy (Mvir/M)
89- 92 F4.2 --- e_avir [0.1/6.2] rms uncertainty on alphavir
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 26-Sep-2014