Physical Properties of H ii Regions in M51 from Spectroscopic Observations
| Autor: | Xu Kong, Peng Wei, Lu Ma, Jiantao Sun, Tuhong Zhong, Hu Zou, Zhimin Zhou, Yewei Mao, Xiang Liu, Ning Hu, Lin Lin, Shu-Guo Ma, Fei Dang, Xinkui Lin, Zesen Lin, Xu Zhou |
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| Rok vydání: | 2020 |
| Předmět: |
Physics
Spiral galaxy 010504 meteorology & atmospheric sciences Stellar population Star formation Metallicity Extinction (astronomy) FOS: Physical sciences Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Astrophysics - Astrophysics of Galaxies 01 natural sciences Galaxy Space and Planetary Science Bulge Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences Galaxy formation and evolution Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics 0105 earth and related environmental sciences |
| Zdroj: | Publications of the Astronomical Society of the Pacific. 132:094101 |
| ISSN: | 1538-3873 |
| DOI: | 10.1088/1538-3873/ab9d92 |
| Popis: | M51 and NGC 5195 is an interacting system that can be explored in great details with ground-based telescopes. The H II regions in M51 were observed using the 2.16 m telescope of the National Astronomical Observatories of the Chinese Academy of Sciences and the 6.5 m Multiple Mirror Telescope with spatial resolution of less than $\sim100$ pc. We obtain a total of 113 spectra across the galaxy and combine the literature data of Croxall et al. to derive a series of physical properties, including the gas-phase extinction, stellar population age, star formation rate (SFR) surface density, and oxygen abundance. The spatial distributions and radial profiles of these properties are investigated in order to study the characteristics of M51 and the clues to the formation and evolution of this galaxy. M51 presents a mild radial extinction gradient. The lower gas-phase extinction in the north spiral arms compared to the south arms are possibly caused by the past encounters with the companion galaxy of NGC 5195. A number of H II regions have the stellar age between 50 and 500 Myr, consistent with the recent interaction history by simulations in the literatures. The SFR surface density presents a mild radial gradient, which is ubiquitous in spiral galaxies. There is a negative metallicity gradient of $-0.08$ dex $R_{e}^{-1}$ in the disk region, which is also commonly found in many spiral galaxies. It is supported by the "inside-out" scenario of galaxy formation. We find a positive abundance gradient of 0.26 dex $R_{e}^{-1}$ in the inner region. There are possible reasons causing the positive gradient, including the freezing of the chemical enrichment due to the star-forming quenching in the bulge and the gas infall and dilution due to the pseudobulge growth and/or galactic interaction. Comment: 20 pages, 8 figures, 1 appendix, Accepted for publication in PASP. Comments and suggestions are welcome |
| Databáze: | OpenAIRE |
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