تقرير
First detection of [13CII] in the Large Magellanic Cloud
| العنوان: | First detection of [13CII] in the Large Magellanic Cloud |
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| المؤلفون: | Okada, Yoko, Higgins, Ronan, Ossenkopf-Okada, Volker, Guevara, Cristian, Stutzki, Jürgen, Mertens, Marc |
| المصدر: | A&A 631, L12 (2019) |
| سنة النشر: | 2019 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Astrophysics of Galaxies |
| الوصف: | [13CII] observations in several Galactic sources show that the fine-structure [12CII] emission is often optically thick (the optical depths around 1 to a few). The aim of our study is to test whether this also affects the [12CII] emission from nearby galaxies like the Large Magellanic Cloud (LMC). We observed three star-forming regions in the LMC with upGREAT on board SOFIA at the frequency of the [CII] line. The 4GHz band width covers all three hyperfine lines of [13CII] simultaneously. For the analysis, we combined the [13CII] F=1-0 and F=1-1 hyperfine components, as they do not overlap with the [12CII] line in velocity. Three positions in N159 and N160 show an enhancement of [13CII] compared to the abundance-ratio-scaled [12CII] profile. This is likely due to the [12CII] line being optically thick, supported by the fact that the [13CII] line profile is narrower than [12CII], the enhancement varies with velocity, and the peak velocity of [13CII] matches the [OI] 63um self-absorption. The [12CII] line profile is broader than expected from a simple optical depth broadening of the [13CII] line, supporting the scenario of several PDR components in one beam having varying [12CII] optical depths. The derived [12CII] optical depth at three positions (beam size of 14arcsec, corresponding to 3.4pc) is 1--3, which is similar to values observed in several Galactic sources shown in previous studies. If this also applies to distant galaxies, the [CII] intensity will be underestimated by a factor of approximately 2. Comment: 5 pages with 3 figures plus one page appendix with 4 figures, accepted for publication in A&A Letter |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1051/0004-6361/201936685 |
| URL الوصول: | http://arxiv.org/abs/1910.12693 |
| رقم الأكسشن: | edsarx.1910.12693 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1051/0004-6361/201936685 |
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