Detection of 84 GHz Class I Methanol Maser Emission toward NGC 253
| Autor: | Tiege P. McCarthy, Simon P. Ellingsen, Shari L. Breen, Maxim A. Voronkov, Xi Chen |
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| Rok vydání: | 2018 |
| Předmět: |
010308 nuclear & particles physics
Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) Astrophysics::High Energy Astrophysical Phenomena 0103 physical sciences FOS: Physical sciences Astrophysics::Solar and Stellar Astrophysics Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics - Astrophysics of Galaxies 010303 astronomy & astrophysics 01 natural sciences Astrophysics::Galaxy Astrophysics |
| Zdroj: | The Astrophysical Journal. 867:L4 |
| ISSN: | 2041-8213 |
| DOI: | 10.3847/2041-8213/aae82c |
| Popis: | We have investigated the central region of NGC 253 for the presence of 84.5-GHz ($5_{-1}\rightarrow4_0$E) methanol emission using the Australia Telescope Compact Array. We present the second detection of 84.5-GHz class~I methanol maser emission outside the Milky Way. This maser emission is offset from dynamical centre of NGC 253, in a region with previously detected emission from class~I maser transitions (36.2-GHz $4_{-1}\rightarrow3_0$E and 44.1-GHz $7_{0}\rightarrow6_1$A$^{+}$ methanol lines) . The emission features a narrow linewidth ($\sim$12 km s$^{-1}$) with a luminosity approximately 5 orders of magnitude higher than typical Galactic sources. We determine an integrated line intensity ratio of $1.2\pm0.4$ between the 36.2 GHz and 84.5-GHz class I methanol maser emission, which is similar to the ratio observed towards Galactic sources. The three methanol maser transitions observed toward NGC 253 each show a different distribution, suggesting differing physical conditions between the maser sites and that observations of additional class~I methanol transitions will facilitate investigations of the maser pumping regime. Accepted into ApJL 12 October 2018. 10 pages, 3 Figures and 2 Tables |
| Databáze: | OpenAIRE |
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