ASTE observations in the 345 GHz window towards the HII region N113 of the Large Magellanic Cloud

Paron, S.; Ortega, M. E.; Cunningham, M. R.; Jones, P. A.; Rubio, M.; Fariña, C.; Komugi, Shinya

doi:10.1051/0004-6361/201424534

Cited by 15 publications

(17 citation statements)

References 37 publications

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“…Herrera et al (2013), using the 12 CO J=2-1, obtained similar relations between M vir and M LTE for most of their catalogued clumps in N11. Our results, obtained with the 13 CO, an optically thinner tracer, show that even deeper parts of the molecular clumps are not gravitationally bounded and may be supported by external pressure, as found in molecular clouds around Galactic Hii regions (Rathborne et al 2002;Massi et al 1997), and in the LMC, in N113 (Paron et al 2014) and Cloud B of Complex No.37 (Garay et al 2002).…”

Section: Discussionsupporting

confidence: 56%

¹²CO and ¹³CO J = 3–2 observations toward N11 in the Large Magellanic Cloud

Peña

Paron

Rubio

et al. 2019

A&A

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Aims. After 30 Doradus, N11 is the second largest and brightest nebula in the Large Magellanic Cloud (LMC). This large nebula has several OB associations with bright nebulae at its surroundings. N11 was previously mapped at the lowest rotational transitions of 12 CO (J=1-0 and 2-1), and in some particular regions pointings of the 13 CO J=1-0 and 2-1 lines were also performed. Observations of higher CO rotational transitions are needed to map gas with higher critical densities, useful to study in a more accurate way the physical conditions of the gas component and its relation with the UV radiation. Methods. Using the Atacama Submillimeter Telescope Experiment we mapped the whole extension of the N11 nebula in the 12 CO J=3-2 line, and three sub-regions in the 13 CO J=3-2 line. The regions mapped in the 13 CO J=3-2 were selected based on that they may be exposed to the radiation at different ways: a region lying over the nebula related to the OB association LH10 (N11B), another one that it is associated with the southern part of the nebula related to the OB association LH13 (N11D), and finally a farther area at the southwest without any embedded OB association (N11I). Results. We found that the morphology of the molecular clouds lying in each region shows some signatures that could be explained by the expansion of the nebulae and the action of the radiation. Fragmentation generated in a molecular shell due to the expansion of the N11 nebula is suggested. The integrated line ratios 12 CO/ 13 CO show evidences of selective photodissociation of the 13 CO, and probably other mechanisms such as chemical fractionation. The values found for the integrated line ratios 12 CO J=3-2/1-0 are in agreement with values that were assumed in previous works, and the CO contribution to the continuum at 870 µm was directly derived. The distribution of the integrated line ratios 12 CO J=3-2/2-1 show hints of stellar feedback in N11B and N11D. The ratio between the virial and LTE mass (M vir /M LTE ) is higher than unity in all analyzed molecular clumps, which suggests that the clumps are not gravitationally bounded and may be supported by external pressure. A non-LTE analysis suggests that we are mapping gas with densities about a few 10 3 cm −3 . The molecular clump at N11B, the unique molecular feature with direct evidence of ongoing star formation, is the densest one among the analyzed clumps. Key words. galaxies: ISM -Magellanic Clouds -HII regions -ISM: individual objects: N11 12 CO(1-0) 12 CO(2-1) CO(3-2) 12 2B 12 CO(1-0) CO(2-1) 12 CO(3-2) 12 1D CO(1-0) 12 CO(2-1) 12 CO(3-2) 12 1I CO(3-2) 13 CO(3-2) 13 CO(3-2) 13 Fig. 10. 12 CO J=1-0. 2-1, and 3-2, and 13 CO J=3-2 spectra toward the peak of clump 2B, 1D, and 2I. The red curves are the Gaussian fits. The rms noise of each spectrum is (from top to bottom): 178.0, 95.2 and 31.2 mK (clump 2B), 140.0, 62.9 and 25.6 mK (clump 1D), and 142.0, 55.7 and 35.6 mK (clump 2I). The 12 CO J=2-1 and 3-2, and 13 CO J=3-2 spectra were convolved with the 45 ′′ resolution of the J=1-0 line.

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Section: Discussionsupporting

confidence: 56%

¹²CO and ¹³CO J = 3–2 observations toward N11 in the Large Magellanic Cloud

Peña

Paron

Rubio

et al. 2019

A&A

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“…Early studies by the SEST 15 m telescope conducted multiline observations toward H II regions in the LMC and detected molecular species as large as CH 3 OH, C 3 H 2 , and SO 2 (Johansson et al 1994;Chin et al 1997;Heikkilä et al 1999;Wang et al 2009). Submillimeter observations of relatively dense molecular gas in star-forming regions in the LMC are also reported (Paron et al 2014(Paron et al , 2016. Nishimura et al (2016) recently conducted deep and unbiased spectral line surveys in the 3 mm window toward a number of molecular clouds in the LMC using the Mopra telescope.…”

Section: Introductionmentioning

confidence: 99%

The Detection of a Hot Molecular Core in the Large Magellanic Cloud With Alma

Shimonishi

Onaka

Kawamura

et al. 2016

ApJ

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We report the first detection of a hot molecular core outside our Galaxy based on radio observations with ALMA toward a high-mass young stellar object (YSO) in a nearby low metallicity galaxy, the Large Magellanic Cloud (LMC). are detected from a compact region (∼0.1 pc) associated with a high-mass YSO, ST11. The temperature of molecular gas is estimated to be higher than 100 K based on rotation diagram analysis of SO 2 and 34 SO 2 lines. The compact source size, warm gas temperature, high density, and rich molecular lines around a high-mass protostar suggest that ST11 is associated with a hot molecular core. We find that the molecular abundances of the LMC hot core are significantly different from those of Galactic hot cores. The abundances of CH 3 OH, H 2 CO, and HNCO are remarkably lower compared to Galactic hot cores by at least 1-3 orders of magnitude. We suggest that these abundances are characterized by the deficiency of molecules whose formation requires the hydrogenation of CO on grain surfaces. In contrast, NO shows a high abundance in ST11 despite the notably low abundance of nitrogen in the LMC. A multitude of SO 2 and its isotopologue line detections in ST11 imply that SO 2 can be a key molecular tracer of hot core chemistry in metal-poor environments. Furthermore, we find molecular outflows around the hot core, which is the second detection of an extragalactic protostellar outflow. In this paper, we discuss the physical and chemical characteristics of a hot molecular core in the low metallicity environment.

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“…With the idea of carry out a comparative study of the physical conditions of the molecular gas in Hii regions in the LMC using molecular lines in the 345 GHz windows, we have made observations with the Atacama Submillimetre Figure 1. Main area of the LMC in which the location of the Hii regions studied in this paper (N159, N132, and N166) and N133 from Paron et al (2014) are indicated. As reference, 30 Dor and the location of the LMC molecular ridge are also showed.…”

Section: Introductionmentioning

confidence: 99%

A view of Large Magellanic Cloud H ii regions N159, N132, and N166 through the 345-GHz window

Paron

Ortega

Fariña

et al. 2015

Mon. Not. R. Astron. Soc.

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We present results obtained towards the Hii regions N159, N166, and N132 from the emission of several molecular lines in the 345 GHz window. Using ASTE we mapped a 2.′ 4 × 2. ′ 4 region towards the molecular cloud N159-W in the 13 CO J=3-2 line and observed several molecular lines at an IR peak very close to a massive young stellar object.12 CO and 13 CO J=3-2 were observed towards two positions in N166 and one position in N132. The 13 CO J=3-2 map of the N159-W cloud shows that the molecular peak is shifted southwest compared to the peak of the IR emission. Towards the IR peak we detected emission from HCN, HNC, HCO + , C 2 H J=4-3, CS J=7-6, and tentatively C 18 O J=3-2. This is the first reported detection of these molecular lines in N159-W. The analysis of the C 2 H line yields more evidence supporting that the chemistry involving this molecular species in compact and/or UCHii regions in the LMC should be similar to that in Galactic ones. A non-LTE study of the CO emission suggests the presence of both cool and warm gas in the analysed region. The same analysis for the CS, HCO + , HCN, and HNC shows that it is very likely that their emissions arise mainly from warm gas with a density between 5×10 5 to some 10 6 cm −3 . The obtained HCN HNC abundance ratio greater than 1 is compatible with warm gas and with an star-forming scenario. From the analysis of the molecular lines observed towards N132 and N166 we propose that both regions should have similar physical conditions, with densities of about 10 3 cm −3 .

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ASTE observations in the 345 GHz window towards the HII region N113 of the Large Magellanic Cloud

Cited by 15 publications

References 37 publications

¹²CO and ¹³CO J = 3–2 observations toward N11 in the Large Magellanic Cloud

¹²CO and ¹³CO J = 3–2 observations toward N11 in the Large Magellanic Cloud

The Detection of a Hot Molecular Core in the Large Magellanic Cloud With Alma

A view of Large Magellanic Cloud H ii regions N159, N132, and N166 through the 345-GHz window

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ASTE observations in the 345 GHz window towards the HII region N113 of the Large Magellanic Cloud

Cited by 15 publications

References 37 publications

12CO and 13CO J = 3–2 observations toward N11 in the Large Magellanic Cloud

12CO and 13CO J = 3–2 observations toward N11 in the Large Magellanic Cloud

The Detection of a Hot Molecular Core in the Large Magellanic Cloud With Alma

A view of Large Magellanic Cloud H ii regions N159, N132, and N166 through the 345-GHz window

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¹²CO and ¹³CO J = 3–2 observations toward N11 in the Large Magellanic Cloud

¹²CO and ¹³CO J = 3–2 observations toward N11 in the Large Magellanic Cloud