تقرير
The detection of a hot molecular core in the extreme outer Galaxy
| العنوان: | The detection of a hot molecular core in the extreme outer Galaxy |
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| المؤلفون: | Shimonishi, Takashi, Izumi, Natsuko, Furuya, Kenji, Yasui, Chikako |
| سنة النشر: | 2021 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Astrophysics of Galaxies, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics |
| الوصف: | Interstellar chemistry in low metallicity environments is crucial to understand chemical processes in the past metal-poor universe. Recent studies of interstellar molecules in nearby low-metallicity galaxies have suggested that the metallicity has a significant effect on chemistry of star-forming cores. Here we report the first detection of a hot molecular core in the extreme outer Galaxy, which is an excellent laboratory to study star formation and interstellar medium in a Galactic low-metallicity environment. The target star-forming region, WB89-789, is located at the galactocentric distance of 19 kpc. Our ALMA observations in 241-246, 256-261, 337-341, and 349-353 GHz have detected a variety of carbon-, oxygen-, nitrogen-, sulfur-, and silicon-bearing species, including complex organic molecules (COMs) containing up to nine atoms, towards a warm (>100 K) and compact (<0.03 pc) region associated with a protostar (~8x10^3 L_sun). Deuterated species such as HDO, HDCO, D2CO, and CH2DOH are also detected. A comparison of fractional abundances of COMs relative to CH3OH between the outer Galactic hot core and an inner Galactic counterpart shows a remarkable similarity. On the other hand, the molecular abundances in the present source do not resemble those of low-metallicity hot cores in the Large Magellanic Cloud. The results suggest that a great molecular complexity exists even in a primordial environment of the extreme outer Galaxy. The detection of another embedded protostar associated with high-velocity SiO outflows is also reported. Comment: Accepted for publication in ApJ, 44 pages, 24 figures, 13 tables |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.3847/1538-4357/ac289b |
| الوصول الحر: | http://arxiv.org/abs/2109.11123Test |
| رقم الانضمام: | edsarx.2109.11123 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.3847/1538-4357/ac289b |
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