arXiv 2202.104692022-02-21astro-ph.GA

SAMI星系巡天：电离气体和恒星速度色散之间的差异

The SAMI Galaxy Survey: the difference between ionised gas and stellar velocity dispersions

Sree Oh, Matthew Colless, Francesco D'Eugenio, Scott M. Croom, Luca Cortese, Brent Groves, Lisa J. Kewley, Jesse van de Sande, Henry Zovaro, Mathew R. Varidel, … 展开作者

Sree Oh, Matthew Colless, Francesco D'Eugenio, Scott M. Croom, Luca Cortese, Brent Groves, Lisa J. Kewley, Jesse van de Sande, Henry Zovaro, Mathew R. Varidel, Stefania Barsanti, Sarah Brough, Julia J. Bryant, Sarah Casura, Jon S. Lawrence, Nuria P. F. Lorente, Anne M. Medling, Matt S. Owers, Sukyoung K. Yi

备注：: 18 pages, 13 figures
DOI：: 10.1093/mnras/stac509

阅读 PDF

arXiv 页面 ↗HTML 原文 ↗

摘要：

我们调查的平均本地测量的电离气体（$σ_{\rm gas}$）和恒星（$σ_*$）的1090星系的恒星质量$\log\,(M_*/M_{\odot}) \geq 9.5$从SAMI星系巡天的速度色散。对于恒星形成的星系，$σ_*$往往大于$σ_{\rm gas}$，这表明恒星通常比电离气体更热（不对称漂移）。$σ_{\rm gas}$和$σ_*$（$Δσ$）之间的差异与各种星系性质有关。我们建立了最强的相关性的$Δσ$是与光束涂抹，膨胀$σ_{\rm gas}$超过$σ_*$，介绍了依赖于$Δσ$的有效半径相对于点扩散函数和速度梯度。第二强的相关性是与活动星系核（AGN）（或演化的恒星）的电离气体排放的贡献，这意味着气体的速度色散强烈影响的电源。相比之下，使用从积分谱（$σ_{\rm aper}$）测量的速度分散导致基于孔径的$Δσ$（$Δσ_{\rm aper}$）和电源之间的较小相关性。这表明活动星系核（或老恒星）动态地加热气体，而不会导致明显偏离动态平衡。虽然$Δσ_{\rm aper}$的变化比$Δσ$小得多，但仍然检测到$Δσ_{\rm aper}$和气体速度梯度之间的相关性，这意味着由恒星和电离气体速度色散导出的动力学质量存在小的偏差。

英文摘要：

We investigate the mean locally-measured velocity dispersions of ionised gas ($σ_{\rm gas}$) and stars ($σ_*$) for 1090 galaxies with stellar masses $\log\,(M_*/M_{\odot}) \geq 9.5$ from the SAMI Galaxy Survey. For star-forming galaxies, $σ_*$ tends to be larger than $σ_{\rm gas}$, suggesting that stars are in general dynamically hotter than the ionised gas (asymmetric drift). The difference between $σ_{\rm gas}$ and $σ_*$ ($Δσ$) correlates with various galaxy properties. We establish that the strongest correlation of $Δσ$ is with beam smearing, which inflates $σ_{\rm gas}$ 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 ionised gas emission, implying the gas velocity dispersion is strongly affected by the power source. In contrast, using the velocity dispersion measured from integrated spectra ($σ_{\rm aper}$) results in less correlation between the aperture-based $Δσ$ ($Δσ_{\rm aper}$) 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 $Δσ_{\rm aper}$ is much smaller than that of $Δσ$, a correlation between $Δσ_{\rm aper}$ and gas velocity gradient is still detected, implying there is a small bias in dynamical masses derived from stellar and ionised gas velocity dispersions.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

摘要：

英文摘要：

相关论文