2013A&A...554A..91H


Query : 2013A&A...554A..91H

2013A&A...554A..91H - Astronomy and Astrophysics, volume 554A, 91-91 (2013/6-1)

Millimeter dust emission compared with other mass estimates in N11 molecular clouds in the LMC.

HERRERA C.N., RUBIO M., BOLATTO A.D., BOULANGER F., ISRAEL F.P. and RANTAKYROE F.T.

Abstract (from CDS):

CO and dust emission at millimeter wavelengths are independent tracers of cold interstellar matter, which have seldom been compared on the scale of giant molecular clouds (GMCs) in other galaxies. In this study, and for the first time for the Large Magellanic Cloud (LMC), we compute the molecular cloud masses from the millimeter emission of the dust and compare them with the masses derived from their CO luminosity and virial theorem. We present CO (J=1-0 and J=2-1) and 1.2 mm continuum observations of the N11 star-forming region in the LMC obtained with the SEST telescope and the SIMBA bolometer, respectively. We use the CO data to identify individual molecular clouds and measure their physical properties (CO luminosity, size, line width, and virial masses). The correlations between the properties of the N11 clouds agree with those found in earlier studies in the LMC that sample a larger set of clouds and a wider range of cloud masses. For the N11 molecular clouds, we compare the masses estimated from the CO luminosity (XCOLCO), the virial theorem (Mvir) and the millimeter dust luminosity (L1.2mm(dust)). The measured ratios LCO/Mvir and L1.2mm(dust)/Mvir constrain the XCO and Kdust (dust emissivity at 1.2mm per unit gas mass) parameters as a function of the virial parameter αvir. The comparison between the different mass estimates yields a XCO-factor of 8.8±3.5x1020cm–2(K.km/s)–1αvir–1 and a Kdust parameter of 1.5±0.5x10–3cm2/gαvir. We compare our N11 results with a similar analysis for molecular clouds in the Gould Belt in the solar neighborhood. We do not find a large discrepancy in N11 between the dust millimeter and virial masses as reported in earlier studies of molecular clouds in the Small Magellanic Cloud. The ratio between L1.2mm and Mvir in N11 is half of what is measured for Gould Belt clouds, which can be accounted for by a factor of two lower gas-to-dust mass ratio, as the difference in gas metallicities. If the two samples have similar αvir values, this result implies that their dust far-IR properties are also similar.

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Journal keyword(s): ISM: clouds - Magellanic Clouds - galaxies: ISM - radio lines: ISM

Nomenclature: Table 2: [HRB2013] NN (Nos 1-19).

Status at CDS : All or part of tables of objects could be ingested in SIMBAD with priority 2.

Simbad objects: 12

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Number of rows : 12
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9944 1
2 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 6044 1
3 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3790 0
4 NGC 1761 As* 04 56 39 -66 29.0     9.94     ~ 97 0
5 LHA 120-N 11 HII 04 56 51.4 -66 24 24           ~ 241 0
6 NGC 1763 As* 04 56 51.5 -66 24 25     9.40     ~ 158 3
7 NGC 1769 As* 04 57 44.5 -66 27 42           ~ 68 2
8 NGC 1773 HII 04 58 12.0 -66 21 36           ~ 50 1
9 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 15596 1
10 NAME Gould Belt PoG ~ ~           ~ 774 1
11 NAME Galactic Molecular Ring PoG ~ ~           ~ 40 0
12 NAME Local Group GrG ~ ~           ~ 7395 0

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2021.10.23-11:23:09

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