تقرير
An Unbiased CO Survey toward the Northern Region of the Small Magellanic Cloud with the Atacama Compact Array. I. Overview: CO Cloud Distributions
| العنوان: | An Unbiased CO Survey toward the Northern Region of the Small Magellanic Cloud with the Atacama Compact Array. I. Overview: CO Cloud Distributions |
|---|---|
| المؤلفون: | Kazuki Tokuda, Hiroshi Kondo, Takahiro Ohno, Ayu Konishi, Hidetoshi Sano, Kisetsu Tsuge, Sarolta Zahorecz, Nao Goto, Naslim Neelamkodan, Tony Wong, Marta Sewiło, Hajime Fukushima, Tatsuya Takekoshi, Kazuyuki Muraoka, Akiko Kawamura, Kengo Tachihara, Yasuo Fukui, Toshikazu Onishi |
| المصدر: | The Astrophysical Journal. 922(2) |
| بيانات النشر: | United States: NASA Center for Aerospace Information (CASI), 2021. |
| سنة النشر: | 2021 |
| مصطلحات موضوعية: | Astrophysics, Astronomy |
| الوصف: | We have analyzed the data from a large-scale CO survey toward the northern region of the Small Magellanic Cloud (SMC) obtained with the Atacama Compact Array (ACA) stand-alone mode of ALMA. The primary aim of this study is to comprehensively understand the behavior of CO as an H2 tracer in a low-metallicity environment (Z ∼ 0.2 Zꙩ). The total number of mosaic fields is ∼8000, which results in a field coverage of 0.26 sq.deg (∼2.9 ×10^(5) sq.pc), corresponding to ∼10% of the area of the galaxy. The sensitive ∼2 pc resolution observations reveal the detailed structure of the molecular clouds previously detected in the single-dish NANTEN survey. We have detected a number of compact CO clouds within lower H2 column density (∼10^(20) per sq.cm) regions whose angular scale is similar to the ACA beam size. Most of the clouds in this survey also show peak brightness temperature as low as <1 K, which for optically thick CO emission implies an emission size much smaller than the beam size, leading to beam dilution. The comparison between an available estimation of the total molecular material traced by thermal dust emission and the present CO survey demonstrates that more than ∼90% of H(2) gas cannot be traced by the low-J CO emission. Our processed data cubes and 2D images are publicly available. |
| نوع الوثيقة: | Report |
| اللغة: | English |
| تدمد: | 1538-4357 0004-637X |
| DOI: | 10.3847/1538-4357/ac1ff4 |
| URL الوصول: | https://ntrs.nasa.gov/citations/20220002140 |
| ملاحظات: | 315404 80GSFC21M0002 ALMA #2017.A.00054.S ALMA #2015.1.01296.S JSPS JP18K13582 JSPS JP18H05440 JSPS JP19K14758 JSPS JP19H05075 JSPS 21H00040 JSPS JP21H00049 NSF AST-2009849 NASA 80GSFC21M0002 |
| رقم الأكسشن: | edsnas.20220002140 |
| قاعدة البيانات: | NASA Technical Reports |
| تدمد: | 15384357 0004637X |
|---|---|
| DOI: | 10.3847/1538-4357/ac1ff4 |