CHAOS VIII: Far-Ultraviolet Spectra of M101 and The Impact of Wolf-Rayet Stars
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| Auteurs principaux: | , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866911893911764992 |
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| author | Berg, Danielle A. Skillman, Evan D. Chisholm, John Pogge, Richard W. Gazagnes, Simon Rogers, Noah S. J. Erb, Dawn K. Arellano-Córdova, Karla Z. Leitherer, Claus Appel, Jackie Moustakas, John |
| author_facet | Berg, Danielle A. Skillman, Evan D. Chisholm, John Pogge, Richard W. Gazagnes, Simon Rogers, Noah S. J. Erb, Dawn K. Arellano-Córdova, Karla Z. Leitherer, Claus Appel, Jackie Moustakas, John |
| contents | We investigate the stellar and nebular properties of 9 H II regions in the spiral galaxy M101 with far-ultraviolet (FUV; ~900-2000 Å) and optical (~3200-10000 Å) spectra. We detect significant C III] 1907,1909 nebular emission in 7 regions, but O III] 1666 only in the lowest-metallicity region. We produce new analytic functions of the carbon ICF as a function of metallicity in order to perform a preliminary C/O abundance analysis. The FUV spectra also contain numerous stellar emission and P-Cygni features that we fit with luminosity-weighted combinations of single-burst Starburst99 and BPASS models. We find that the best-fit Starburst99 models closely match the observed very-high-ionization P-Cygni features, requiring very-hot, young (~< 3 Myr), metal-enriched massive stars. The youngest stellar populations are strongly correlated with broad He II emission, nitrogen Wolf-Rayet (WR) FUV and optical spectral features, and enhanced N/O gas abundances. Thus, the short-lived WR phase may be driving excess emission in several N P-Cygni wind features (955 Å, 991 Å, 1720 Å) that bias the stellar continuum fits to higher metallicities relative to the gas-phase metallicities. Accurate characterization of these H II regions requires additional inclusion of WR stars in the stellar population synthesis models. Our FUV spectra demonstrate that the ~900-1200 Å FUV can provide a strong test-bed for future WR atmosphere and evolution models. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2405_19477 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | CHAOS VIII: Far-Ultraviolet Spectra of M101 and The Impact of Wolf-Rayet Stars Berg, Danielle A. Skillman, Evan D. Chisholm, John Pogge, Richard W. Gazagnes, Simon Rogers, Noah S. J. Erb, Dawn K. Arellano-Córdova, Karla Z. Leitherer, Claus Appel, Jackie Moustakas, John Astrophysics of Galaxies We investigate the stellar and nebular properties of 9 H II regions in the spiral galaxy M101 with far-ultraviolet (FUV; ~900-2000 Å) and optical (~3200-10000 Å) spectra. We detect significant C III] 1907,1909 nebular emission in 7 regions, but O III] 1666 only in the lowest-metallicity region. We produce new analytic functions of the carbon ICF as a function of metallicity in order to perform a preliminary C/O abundance analysis. The FUV spectra also contain numerous stellar emission and P-Cygni features that we fit with luminosity-weighted combinations of single-burst Starburst99 and BPASS models. We find that the best-fit Starburst99 models closely match the observed very-high-ionization P-Cygni features, requiring very-hot, young (~< 3 Myr), metal-enriched massive stars. The youngest stellar populations are strongly correlated with broad He II emission, nitrogen Wolf-Rayet (WR) FUV and optical spectral features, and enhanced N/O gas abundances. Thus, the short-lived WR phase may be driving excess emission in several N P-Cygni wind features (955 Å, 991 Å, 1720 Å) that bias the stellar continuum fits to higher metallicities relative to the gas-phase metallicities. Accurate characterization of these H II regions requires additional inclusion of WR stars in the stellar population synthesis models. Our FUV spectra demonstrate that the ~900-1200 Å FUV can provide a strong test-bed for future WR atmosphere and evolution models. |
| title | CHAOS VIII: Far-Ultraviolet Spectra of M101 and The Impact of Wolf-Rayet Stars |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2405.19477 |