分类： 天文学 >> 天文学 提交时间： 2023-02-19
摘要： We present a study of the bulge-to-total ratio (B/T) of a Ks-band-selected sample of 88 close major-merger pairs of galaxies (H-KPAIR) based on 2-D decomposition of SDSS r-band images with \textsc{galfit}. We investigate the dependence of the interaction-induced specific star formation rate enhancement ($\rm sSFR_{enh}$) on the B/T ratio, and the effects of this dependence on the differences between star-forming galaxies (SFGs) in spiral+spiral (S+S) and spiral+elliptical (S+E) pairs. Of all 132 spiral galaxies in H-KPAIR, the 44 in S+E pairs show higher B/T than those in the 44 S+S pairs, with means of $\rm B/T = 0.35 \pm 0.05$ and $\rm B/T = 0.26 \pm 0.03$, respectively. There is a strong negative dependence of $\rm sSFR_{enh}$ on the B/T ratio and only paired SFGs with $\rm B/T5\sigma$) enhancement. Paired SFGs in S+S pairs show a similar trend, and many disky SFGs ($\rm B/T 0.7$~dex). For SFGs in S+E, the sSFR has no clear B/T dependence, nor any significant enhancement in any B/T bin. Disky SFGs in S+S show significant ($>4\sigma$) enhancement in the molecular gas content ($\rm M_{H_2}/M_{star}$), while SFGs in S+E have no such enhancement in any B/T bin. No significant enhancement on total gas content ($\rm M_{gas}/M_{star}$) is found in any B/T bin for paired galaxies. The star formation efficiency of either the total gas ($\rm SFE_{gas} = SFR/M_{gas}$) or the molecular gas ($\rm SFE_{H_2} = SFR/M_{H_2}$) does not depend on the B/T ratio. The only significant ($>4\sigma$) SFE enhancement found for paired SFGs is the $\rm SFE_{gas}$ for disky SFGs in S+S pairs.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Qingyang Li
Xiaohu Yang
Chengze Liu
Yipeng Jing
Min He
Jiasheng Huang
Y. Sophia Dai
Marcin Sawicki
Stephane Arnouts
Stephen Gwyn
Thibaud Moutard
H. J. Mo
Kai Wang
Antonios Katsianis
Weiguang Cui
Jiaxin Han
I-Non Chiu
Yizhou Gu
Haojie Xu
摘要： Using the extended halo-based group finder developed by Yang et al. (2021), which is able to deal with galaxies via spectroscopic and photometric redshifts simultaneously, we construct galaxy group and candidate protocluster catalogs in a wide redshift range ($0 2.0$. By checking the galaxy number distributions within a $5-7\ h^{-1}\mathrm{Mpc}$ projected separation and a redshift difference $\Delta z \le 0.1$ around those richest groups at redshift $z>2$, we identified a list of 761, 343 and 43 protocluster candidates in the redshift bins $2\leq z<3$, $3\leq z<4$ and $z \geq 4$, respectively. In general, these catalogs of galaxy groups and protocluster candidates will provide useful environmental information in probing galaxy evolution along the cosmic time.
点击量
待评议
点击量
下载量
评论
