分类： 天文学 >> 天文学 提交时间： 2023-02-19
Shin-Jeong Kim
Se-Heon Oh
Jing Wang
Lister Staveley-Smith
Bärbel S. Koribalski
Minsu Kim
Hye-Jin Park
Shinna Kim
Kristine Spekkens
Tobias Westmeier
O. Ivy Wong
Gerhardt R. Meurer
Peter Kamphuis.
Barbara Catinella
Kristen B. W. McQuinn
Frank Bigiel
Benne W. Holwerda
Jonghwan Rhee
Karen Lee-Waddell
Nathan Deg
摘要： We examine the HI gas kinematics of galaxy pairs in two clusters and a group using Australian Square Kilometre Array Pathfinder (ASKAP) WALLABY pilot survey observations. We compare the HI properties of galaxy pair candidates in the Hydra I and Norma clusters, and the NGC 4636 group, with those of non-paired control galaxies selected in the same fields. We perform HI profile decomposition of the sample galaxies using a tool, {\sc baygaud} which allows us to de-blend a line-of-sight velocity profile with an optimal number of Gaussian components. We construct HI super-profiles of the sample galaxies via stacking of their line profiles after aligning the central velocities. We fit a double Gaussian model to the super-profiles and classify them as kinematically narrow and broad components with respect to their velocity dispersions. Additionally, we investigate the gravitational instability of HI gas disks of the sample galaxies using Toomre Q parameters and HI morphological disturbances. We investigate the effect of the cluster environment on the HI properties of galaxy pairs by dividing the cluster environment into three subcluster regions (i.e., outskirts, infalling and central regions). We find that the denser cluster environment (i.e., infalling and central regions) is likely to impact the HI gas properties of galaxies in a way of decreasing the amplitude of the kinematically narrow HI gas ($M_{\rm{narrow}}^{\rm{HI}}$/$M_{\rm{total}}^{\rm{HI}}$), and increasing the Toomre Q values of the infalling and central galaxies. This tendency is likely to be more enhanced for galaxy pairs in the cluster environment.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Shun Wang
Jing Wang
Bi-Qing For
Bumhyun Lee
Tristan Reynolds
Xuchen Lin
Lister Staveley-Smith
Li Shao
O. Ivy Wong
Barbara Catinella
Paolo Serra
Lourdes Verdes-Montenegro
Tobias Westmeier
Karen Lee-Waddell
Baerbel S. Koribalski
Chandrashekar Murugeshan
Ahmed Elagali
Dane Kleiner
Jonghwan Rhee
Frank Bigiel
摘要： We study the tidal interaction of galaxies in the Eridanus supergroup, using HI data from the pre-pilot survey of WALLABY (Widefield ASKAP L-band Legacy All-sky Blind surveY). We obtain optical photometric measurements and quantify the strength of tidal perturbation using a tidal parameter $S_{sum}$. For low-mass galaxies of $M_* \lesssim 10^9 M_\odot$, we find a dependence of decreasing HI-to-optical disk size ratio with increasing $S_{sum}$, but no dependence of HI spectral line asymmetry with $S_{sum}$. This is consistent with the behavior expected under tidal stripping. We confirm that the color profile shape and color gradient depend on the stellar mass, but there is additional correlation of low-mass galaxies having their color gradients within $2R_{50}$ increasing with higher $S_{sum}$. For these low-mass galaxies, the dependence of color gradients on $S_{sum}$ is driven by color becoming progressively redder in the inner disk when tidal perturbations are stronger. For high-mass galaxies, there is no dependence of color gradients on $S_{sum}$, and we find a marginal reddening throughout the disks with increasing $S_{sum}$. Our result highlights tidal interaction as an important environmental effect in producing the faint end of the star formation suppressed sequence in galaxy groups.
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