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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2026
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| Online Access: | https://arxiv.org/abs/2601.04322 |
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| _version_ | 1866914239446253568 |
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| author | Kerkeser, Nazende Ipek Melso, Nicole Schiminovich, David Hamden, Erika Sitaram, Meghna Cevallos-Aleman, Ignacio |
| author_facet | Kerkeser, Nazende Ipek Melso, Nicole Schiminovich, David Hamden, Erika Sitaram, Meghna Cevallos-Aleman, Ignacio |
| contents | We investigate the ionized gas kinematics of HII regions in the disk of NGC 7331 using integral field unit data collected with the Circumgalactic H$α$ Spectrograph (CH$α$S). NGC 7331 is a well-studied nearby galaxy with HII regions resolved by seeing-limited observations, making it ideally suited for this work. The galaxy disk features vigorous star formation, especially in the central ring of starburst activity. We present a catalog of 136 HII regions detected in the SIRTF Nearby Galaxies Survey (SINGS) H$α$ image. Using this refined catalog, we perform aperture photometry on the SINGS narrowband H$α$ images of NGC 7331, extracting the H$α$ luminosity L(H$α$) of these regions. We present corresponding measurements of the average line-of-sight ionized gas velocity dispersion $σ$ in these HII regions with CH$α$S. High-resolution velocity and dispersion maps of the galactic disk are produced from the CH$α$S spectral imaging, selecting spaxels with high signal to noise in order to measure velocity dispersions as low as 12 km s$^{-1}$. Our measurements of the L(H$α$), $\rm Σ_{SFR}$ and $σ$ in NGC 7331 are consistent with spatially resolved observations of HII regions in large surveys of nearby galaxies. We explore the L(H$α$)$- σ$ relationship, identifying turbulent HII regions with nonthermal dispersions likely driven by stellar feedback. The dispersion is correlated with the star formation rate surface density, and using the relation $\rm σ\propto εΣ_{SFR}^α$, HII regions in NGC 7331 are best fit by $ε= 80$ , $α=0.285$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2601_04322 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Investigating HII Regions in the Disk of NGC 7331 with the Circumgalactic H$α$ Spectrograph Kerkeser, Nazende Ipek Melso, Nicole Schiminovich, David Hamden, Erika Sitaram, Meghna Cevallos-Aleman, Ignacio Astrophysics of Galaxies We investigate the ionized gas kinematics of HII regions in the disk of NGC 7331 using integral field unit data collected with the Circumgalactic H$α$ Spectrograph (CH$α$S). NGC 7331 is a well-studied nearby galaxy with HII regions resolved by seeing-limited observations, making it ideally suited for this work. The galaxy disk features vigorous star formation, especially in the central ring of starburst activity. We present a catalog of 136 HII regions detected in the SIRTF Nearby Galaxies Survey (SINGS) H$α$ image. Using this refined catalog, we perform aperture photometry on the SINGS narrowband H$α$ images of NGC 7331, extracting the H$α$ luminosity L(H$α$) of these regions. We present corresponding measurements of the average line-of-sight ionized gas velocity dispersion $σ$ in these HII regions with CH$α$S. High-resolution velocity and dispersion maps of the galactic disk are produced from the CH$α$S spectral imaging, selecting spaxels with high signal to noise in order to measure velocity dispersions as low as 12 km s$^{-1}$. Our measurements of the L(H$α$), $\rm Σ_{SFR}$ and $σ$ in NGC 7331 are consistent with spatially resolved observations of HII regions in large surveys of nearby galaxies. We explore the L(H$α$)$- σ$ relationship, identifying turbulent HII regions with nonthermal dispersions likely driven by stellar feedback. The dispersion is correlated with the star formation rate surface density, and using the relation $\rm σ\propto εΣ_{SFR}^α$, HII regions in NGC 7331 are best fit by $ε= 80$ , $α=0.285$. |
| title | Investigating HII Regions in the Disk of NGC 7331 with the Circumgalactic H$α$ Spectrograph |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2601.04322 |