The ALMaQUEST Survey. VIII. What Causes the Discrepancy in the Velocity between the CO and Hα Rotation Curves in Galaxies?
學年 111
學期 1
出版（發表）日期 2022-08-04
作品名稱 The ALMaQUEST Survey. VIII. What Causes the Discrepancy in the Velocity between the CO and Hα Rotation Curves in Galaxies?
作品名稱（其他語言）
著者 Yung-Chau Su; Lihwai Lin; Hsi-An Pan et al.
單位
出版者
著錄名稱、卷期、頁數 The Astrophysical Journal 934(2), p.19
摘要 We compare the CO(1–0) and Hα kinematics in 34 nearby galaxies, selected from the ALMaQUEST and EDGE-CALIFA surveys. We use 3D-Barolo, a 3D tilted-ring model, to derive the CO and Hα rotation curves. Before comparing rotation curves in the 34 nearby galaxies, we found systematics between the MaNGA and CALIFA data using eight MaNGA-CALIFA overlapping galaxies. We assume the rotation curves based on the MaNGA data are accurate and made the corresponding correction to the CALIFA data. Our result shows that ∼56% (19/34) of our galaxies present slower Hα rotation curves compared to the CO rotation curves, with a median value of 6.5 km s−1. The remaining galaxies (15/34) show consistent CO–Hα rotation velocity within uncertainties. As a result, the Hα rotation may underestimate the total dynamical mass by 6% for a circular velocity of 200 km s−1 (the median value in our sample). Furthermore, the difference in the velocity between the CO and Hα rotational velocity is found to correlate with the difference in velocity dispersion between CO and Hα, suggesting that gas pressure plays a role in the discrepancy in velocity. After incorporating the effect of pressure support due to the turbulent gas motion into our sample, the median value of the difference in the velocities decreases to 1.9 km s−1, which in turn reduces the underestimation of the dynamical mass to ∼2%. Finally, we also investigate the role that the extraplanar diffuse ionized gas plays in the discrepancy in the velocity of CO–Hα.
關鍵字 Galaxy kinematics;Galaxy rotation;Interstellar medium;Galaxy dynamics;Molecular gas;Optical astronomy;Radio astronomy
語言 en
ISSN
期刊性質 國外
收錄於 SCI
產學合作
通訊作者
審稿制度 是
國別 USA
公開徵稿
出版型式 ,電子版
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