The SAMI Galaxy Survey: the difference between ionized gas and stellar velocity dispersions
ABSTRACT We investigate the mean locally measured velocity dispersions of ionized gas (σgas) and stars (σ*) for 1090 galaxies with stellar masses $\log \, (M_{\!\ast }/M_{\odot }) \ge 9.5$ from the SAMI Galaxy Survey. For star-forming galaxies, σ* tends to be larger than σgas, suggesting that stars...
Published in: | Monthly Notices of the Royal Astronomical Society |
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Oxford University Press (OUP)
2022
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Online Access: | http://dx.doi.org/10.1093/mnras/stac509 https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stac509/42619377/stac509.pdf https://academic.oup.com/mnras/article-pdf/512/2/1765/42993295/stac509.pdf |
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croxfordunivpr:10.1093/mnras/stac509 2024-04-28T08:37:20+00:00 The SAMI Galaxy Survey: the difference between ionized gas and stellar velocity dispersions Oh, Sree Colless, Matthew D’Eugenio, Francesco Croom, Scott M Cortese, Luca Groves, Brent Kewley, Lisa J van de Sande, Jesse Zovaro, Henry Varidel, Mathew R Barsanti, Stefania Bland-Hawthorn, Joss Brough, Sarah Bryant, Julia J Casura, Sarah Lawrence, Jon S Lorente, Nuria P F Medling, Anne M Owers, Matt S Yi, Sukyoung K Australian Research Council Centre of Excellence for All Sky Astrophysics University of Sydney Australian Astronomical Observatory ERC Australian Research Council National Science Foundation National Research Foundation of Korea 2022 http://dx.doi.org/10.1093/mnras/stac509 https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stac509/42619377/stac509.pdf https://academic.oup.com/mnras/article-pdf/512/2/1765/42993295/stac509.pdf en eng Oxford University Press (OUP) https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model Monthly Notices of the Royal Astronomical Society volume 512, issue 2, page 1765-1780 ISSN 0035-8711 1365-2966 Space and Planetary Science Astronomy and Astrophysics journal-article 2022 croxfordunivpr https://doi.org/10.1093/mnras/stac509 2024-04-09T07:54:47Z ABSTRACT We investigate the mean locally measured velocity dispersions of ionized gas (σgas) and stars (σ*) for 1090 galaxies with stellar masses $\log \, (M_{\!\ast }/M_{\odot }) \ge 9.5$ from the SAMI Galaxy Survey. For star-forming galaxies, σ* tends to be larger than σgas, suggesting that stars are in general dynamically hotter than the ionized gas (asymmetric drift). The difference between σgas and σ* (Δσ) correlates with various galaxy properties. We establish that the strongest correlation of Δσ is with beam smearing, which inflates σgas more than σ*, introducing a dependence of Δσ on both the effective radius relative to the point spread function and velocity gradients. The second strongest correlation is with the contribution of active galactic nuclei (AGN) (or evolved stars) to the ionized gas emission, implying that the gas velocity dispersion is strongly affected by the power source. In contrast, using the velocity dispersion measured from integrated spectra (σap) results in less correlation between the aperture-based Δσ (Δσap) and the power source. This suggests that the AGN (or old stars) dynamically heat the gas without causing significant deviations from dynamical equilibrium. Although the variation of Δσap is much smaller than that of Δσ, a correlation between Δσap and gas velocity gradient is still detected, implying that there is a small bias in dynamical masses derived from stellar and ionized gas velocity dispersions. Article in Journal/Newspaper sami Oxford University Press Monthly Notices of the Royal Astronomical Society 512 2 1765 1780 |
institution |
Open Polar |
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Oxford University Press |
op_collection_id |
croxfordunivpr |
language |
English |
topic |
Space and Planetary Science Astronomy and Astrophysics |
spellingShingle |
Space and Planetary Science Astronomy and Astrophysics Oh, Sree Colless, Matthew D’Eugenio, Francesco Croom, Scott M Cortese, Luca Groves, Brent Kewley, Lisa J van de Sande, Jesse Zovaro, Henry Varidel, Mathew R Barsanti, Stefania Bland-Hawthorn, Joss Brough, Sarah Bryant, Julia J Casura, Sarah Lawrence, Jon S Lorente, Nuria P F Medling, Anne M Owers, Matt S Yi, Sukyoung K The SAMI Galaxy Survey: the difference between ionized gas and stellar velocity dispersions |
topic_facet |
Space and Planetary Science Astronomy and Astrophysics |
description |
ABSTRACT We investigate the mean locally measured velocity dispersions of ionized gas (σgas) and stars (σ*) for 1090 galaxies with stellar masses $\log \, (M_{\!\ast }/M_{\odot }) \ge 9.5$ from the SAMI Galaxy Survey. For star-forming galaxies, σ* tends to be larger than σgas, suggesting that stars are in general dynamically hotter than the ionized gas (asymmetric drift). The difference between σgas and σ* (Δσ) correlates with various galaxy properties. We establish that the strongest correlation of Δσ is with beam smearing, which inflates σgas more than σ*, introducing a dependence of Δσ on both the effective radius relative to the point spread function and velocity gradients. The second strongest correlation is with the contribution of active galactic nuclei (AGN) (or evolved stars) to the ionized gas emission, implying that the gas velocity dispersion is strongly affected by the power source. In contrast, using the velocity dispersion measured from integrated spectra (σap) results in less correlation between the aperture-based Δσ (Δσap) and the power source. This suggests that the AGN (or old stars) dynamically heat the gas without causing significant deviations from dynamical equilibrium. Although the variation of Δσap is much smaller than that of Δσ, a correlation between Δσap and gas velocity gradient is still detected, implying that there is a small bias in dynamical masses derived from stellar and ionized gas velocity dispersions. |
author2 |
Australian Research Council Centre of Excellence for All Sky Astrophysics University of Sydney Australian Astronomical Observatory ERC Australian Research Council National Science Foundation National Research Foundation of Korea |
format |
Article in Journal/Newspaper |
author |
Oh, Sree Colless, Matthew D’Eugenio, Francesco Croom, Scott M Cortese, Luca Groves, Brent Kewley, Lisa J van de Sande, Jesse Zovaro, Henry Varidel, Mathew R Barsanti, Stefania Bland-Hawthorn, Joss Brough, Sarah Bryant, Julia J Casura, Sarah Lawrence, Jon S Lorente, Nuria P F Medling, Anne M Owers, Matt S Yi, Sukyoung K |
author_facet |
Oh, Sree Colless, Matthew D’Eugenio, Francesco Croom, Scott M Cortese, Luca Groves, Brent Kewley, Lisa J van de Sande, Jesse Zovaro, Henry Varidel, Mathew R Barsanti, Stefania Bland-Hawthorn, Joss Brough, Sarah Bryant, Julia J Casura, Sarah Lawrence, Jon S Lorente, Nuria P F Medling, Anne M Owers, Matt S Yi, Sukyoung K |
author_sort |
Oh, Sree |
title |
The SAMI Galaxy Survey: the difference between ionized gas and stellar velocity dispersions |
title_short |
The SAMI Galaxy Survey: the difference between ionized gas and stellar velocity dispersions |
title_full |
The SAMI Galaxy Survey: the difference between ionized gas and stellar velocity dispersions |
title_fullStr |
The SAMI Galaxy Survey: the difference between ionized gas and stellar velocity dispersions |
title_full_unstemmed |
The SAMI Galaxy Survey: the difference between ionized gas and stellar velocity dispersions |
title_sort |
sami galaxy survey: the difference between ionized gas and stellar velocity dispersions |
publisher |
Oxford University Press (OUP) |
publishDate |
2022 |
url |
http://dx.doi.org/10.1093/mnras/stac509 https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stac509/42619377/stac509.pdf https://academic.oup.com/mnras/article-pdf/512/2/1765/42993295/stac509.pdf |
genre |
sami |
genre_facet |
sami |
op_source |
Monthly Notices of the Royal Astronomical Society volume 512, issue 2, page 1765-1780 ISSN 0035-8711 1365-2966 |
op_rights |
https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model |
op_doi |
https://doi.org/10.1093/mnras/stac509 |
container_title |
Monthly Notices of the Royal Astronomical Society |
container_volume |
512 |
container_issue |
2 |
container_start_page |
1765 |
op_container_end_page |
1780 |
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1797568786734252032 |