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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2410.21375 |
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| _version_ | 1866912090656079872 |
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| author | Park, Minjung Conroy, Charlie Johnson, Benjamin D. Leja, Joel Dotter, Aaron Cargile, Phillip A. |
| author_facet | Park, Minjung Conroy, Charlie Johnson, Benjamin D. Leja, Joel Dotter, Aaron Cargile, Phillip A. |
| contents | We present new stellar population models, $α$-MC, self-consistently taking into account non-solar $\rm [α/Fe]$ abundances for both isochrones and stellar spectra. The $α$-MC models are based on $α$-enhanced MIST isochrones and C3K spectral libraries, which are publicly available in FSPS. Our new models cover a wide range of ages ($\rm \log (age/yr) = 5.0 - 10.3$), metallicities ($\rm [Fe/H]=[-2.5,+0.5]$ in steps of 0.25, $\rm [α/Fe]=-0.2,+0.0,+0.2,+0.4,+0.6$), and wavelengths ($0.1-2.5\,\rm μm$). We investigate the separate and combined effects of $α$-enhanced isochrones and stellar spectral libraries on simple stellar populations (SSPs), including their broadband colors, spectral indices, and full spectra. We find that the primary effect of $α$-enhancement in isochrones is to lower the overall continuum levels and redden the continuum shapes, while $α$-enhancement in stellar spectra mainly affects individual spectral lines. At constant $\rm [Fe/H]$, $α$-enhancement has significant impacts on the broadband colors by $\rm \sim 0.1-0.4\,mag$ across all ages ($\rm 0.01 - 10\,Gyr$). The effects of $α$-enhancement on colors at fixed $\rm [Z/H]$ are smaller, by $\rm \sim 0.1-0.2\,mag$. The spectral indices involving $α$-elements, Ca4227 and Mg b, increase with $\rm [α/Fe]$ (both at fixed $\rm [Fe/H]$ and fixed $\rm [Z/H]$) due to enhanced $α$-abundances. At constant $\rm [Fe/H]$, $α$-enhancement weakens most Fe-sensitive and Hydrogen Balmer lines. Our new self-consistent $α$-enhanced models will be essential in deriving accurate physical properties of high-redshift galaxies, where $α$-enhancement is expected to be common. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2410_21375 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | $α$-MC: Self-consistent $α$-enhanced stellar population models covering a wide range of age, metallicity, and wavelength Park, Minjung Conroy, Charlie Johnson, Benjamin D. Leja, Joel Dotter, Aaron Cargile, Phillip A. Astrophysics of Galaxies We present new stellar population models, $α$-MC, self-consistently taking into account non-solar $\rm [α/Fe]$ abundances for both isochrones and stellar spectra. The $α$-MC models are based on $α$-enhanced MIST isochrones and C3K spectral libraries, which are publicly available in FSPS. Our new models cover a wide range of ages ($\rm \log (age/yr) = 5.0 - 10.3$), metallicities ($\rm [Fe/H]=[-2.5,+0.5]$ in steps of 0.25, $\rm [α/Fe]=-0.2,+0.0,+0.2,+0.4,+0.6$), and wavelengths ($0.1-2.5\,\rm μm$). We investigate the separate and combined effects of $α$-enhanced isochrones and stellar spectral libraries on simple stellar populations (SSPs), including their broadband colors, spectral indices, and full spectra. We find that the primary effect of $α$-enhancement in isochrones is to lower the overall continuum levels and redden the continuum shapes, while $α$-enhancement in stellar spectra mainly affects individual spectral lines. At constant $\rm [Fe/H]$, $α$-enhancement has significant impacts on the broadband colors by $\rm \sim 0.1-0.4\,mag$ across all ages ($\rm 0.01 - 10\,Gyr$). The effects of $α$-enhancement on colors at fixed $\rm [Z/H]$ are smaller, by $\rm \sim 0.1-0.2\,mag$. The spectral indices involving $α$-elements, Ca4227 and Mg b, increase with $\rm [α/Fe]$ (both at fixed $\rm [Fe/H]$ and fixed $\rm [Z/H]$) due to enhanced $α$-abundances. At constant $\rm [Fe/H]$, $α$-enhancement weakens most Fe-sensitive and Hydrogen Balmer lines. Our new self-consistent $α$-enhanced models will be essential in deriving accurate physical properties of high-redshift galaxies, where $α$-enhancement is expected to be common. |
| title | $α$-MC: Self-consistent $α$-enhanced stellar population models covering a wide range of age, metallicity, and wavelength |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2410.21375 |