论文标题
SIT 45：相互作用，紧凑和星形的孤立星系三重态
SIT 45: An interacting, compact, and star-forming isolated galaxy triplet
论文作者
论文摘要
合并系统位置45（UGC 12589）是一个不寻常的孤立星系三重态，由三个合并的晚期星系组成，其中315个系统中的315个系统（基于SDSS的基于SDSS的孤立三胞胎目录）。这项工作的主要目的是研究其动力学进化和恒星形成历史（SFH），以及其对本地和大规模环境的依赖。为了研究其动态，诸如速度分散（$σ_{v} $），谐波半径（$ r_ {h} $），跨度时间（$ h_0t_c $）和病毒质量（$ m_ {vir} $）等参数，以及以及三分之一的compactness。为了限制SFH，我们使用CIGALE使用从紫外线到红外的多波长数据拟合其观察到的光谱分布。根据其SFH的说法，SIT 45呈现恒星形成，那里的星系也显示了最近的（$ \ sim $ 200 MYR）恒星形成的增加，这表明该活动可能是由相互作用触发的。它的动态配置表明，与SIT相比，该系统是高度发展的。但是，基于紧凑型组的观测值，这对于由星形成晚期星系组成的系统并不预期。我们得出的结论是，SIT 45是一个由三个相互作用的星系组成的系统，它们正在同一暗物质光环中演变，其中其紧凑型配置是持续相互作用的结果，而不是由于长期演变（如其$ H_0T_C $值所暗示的）。我们考虑了三个三胞胎的当前配置的两个方案，其中一个成员是潮汐星系，另一个成员是潮汐星系，则该星系在交互后到达系统。两种情况都需要进一步探索。因此，孤立的三重态SIT 45是研究短时间机制（$ \ sim 10^8 $年）的理想系统，例如由较高红移时更频繁的相互作用触发的starbursts。
The merging system SIT 45 (UGC 12589) is an unusual isolated galaxy triplet, consisting of three merging late-type galaxies, out of 315 systems in the SIT (SDSS-based catalogue of Isolated Triplets). The main aims of this work are to study its dynamical evolution and star formation history (SFH), as well as its dependence on its local and large-scale environment. To study its dynamics, parameters such as the velocity dispersion ($σ_{v}$), the harmonic radius ($R_{H}$), the crossing time ($H_0t_c$), and the virial mass ($M_{vir}$), along with the compactness of the triplet ($S$) were considered. To constrain the SFH, we used CIGALE to fit its observed spectral energy distribution using multi-wavelength data from the ultraviolet to the infrared. According to its SFH, SIT 45 presents star-formation, where the galaxies also present recent ($\sim $200 Myr) star-formation increase, indicating that this activity may have been triggered by the interaction. Its dynamical configuration suggests that the system is highly evolved in comparison to the SIT. However this is not expected for systems composed of star-forming late-type galaxies, based on observations in compact groups. We conclude that SIT 45 is a system of three interacting galaxies that are evolving within the same dark matter halo, where its compact configuration is a consequence of the on-going interaction, rather than due to a long-term evolution (as suggested from its $H_0t_c$ value). We consider two scenarios for the present configuration of the triplet, one where one of the members is a tidal galaxy, and another where this galaxy arrives to the system after the interaction. Both scenarios need further exploration. The isolated triplet SIT 45 is therefore an ideal system to study short timescale mechanisms ($\sim 10^8$ years), such as starbursts triggered by interactions which are more frequent at higher redshift.
