吉他星系Arp 105尾巴和桥中潮汐矮星系的结构与动力学性质
Structural and dynamical properties of Tidal dwarf galaxies in the tails and bridge of the Guitar galaxy Arp 105
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中文总结 AI 辅助
研究阿贝尔1185星系团中Arp 105系统内潮汐矮星系及潮汐桥，通过多波长分析其恒星形成、金属度等性质，利用光谱能量分布建模得恒星质量，还估计动力学质量比，发现暗物质不足，后续观测或增进对潮汐矮星系形成的理解。
中文摘要 AI 辅助
我们对阿贝尔1185星系团中红移z = 0.029的相互作用系统Arp 105中的两个潮汐矮星系候选体和一个潮汐桥进行了多波长（远紫外到红外）分析。用AstroSat上的紫外成像望远镜获得的远紫外观测揭示了潮汐星系Arp~105N和Arp~105S有强烈的FUV发射，表明近期有恒星形成。在Arp~105N中，强星云发射线和大的等效宽度意味着在瞬时爆发假设下主导星暴年龄约为6 - 10 Myr，而FUV发射表明过去约100 - 200 Myr有持续恒星形成。相对较高的金属度与潮汐矮星系由宿主星系继承物质形成的预期一致，表明Arp~105N有由宿主星系剥离的老年恒星和原位形成的年轻恒星组成的复合恒星群体。光谱能量分布建模得出Arp~105N、Arp~105S和潮汐桥的恒星质量分别为5.75×10⁹、0.8×10⁹和6.8×10⁹ M☉。基于VLA HI测量的Arp~105N动力学质量估计和基于CFHT Hα运动学的A105S动力学质量估计，它们的动力学与重子质量比分别约为1.95和1.30，表明暗物质不足。进一步观测，特别是积分场光谱学和高分辨率21 cm观测，可能更好地限制运动学并增进对潮汐矮星系形成的理解。
英文摘要
We present a multi-wavelength (far-ultraviolet to infrared) analysis of two tidal dwarf galaxy (TDG) candidates and a tidal bridge in the interacting system Arp 105 at $z = 0.029$ in the Abell 1185 cluster. Far-ultraviolet observations obtained with the Ultraviolet Imaging Telescope onboard AstroSat reveal strong FUV emission from the tidal galaxies Arp~105N and Arp~105S, indicating recent star formation. In Arp~105N, strong nebular emission lines and large equivalent widths $EW(Hα)=77.6\pm1.3$ $\overset{\circ}{\mathrm {A}}$ and $EW(Hβ)=15.8\pm1.7$ $\overset{\circ}{\mathrm {A}}$ imply a dominant starburst age of $\sim$6 - 10~Myr under an instantaneous-burst assumption, while the FUV emission suggests star formation sustained over the past $\sim100 - 200$~Myr. The relatively high metallicity, $\sim2/3,Z_\odot$ (based on the strong-line method), is consistent with expectations for a tidal dwarf galaxy formed from material inherited from the host galaxy. Together, these results suggest that Arp~105N hosts a composite stellar population, consisting of older stars stripped from the host galaxy and younger stars formed in situ. Spectral energy distribution modeling yields stellar masses of $5.75\times10^{9}$, $0.8\times10^{9}$, and $6.8\times10^{9},\rm M_\odot$ for Arp~105N, Arp~105S, and the tidal bridge, respectively. Based on the dynamical mass estimate from VLA HI measurements for Arp~105N and based on CFHT H$α$ kinematics for A105S, they have a dynamical-to-baryonic mass ratio of $\sim1.95$ and $\sim1.30$, respectively, indicating a deficiency of dark matter. Further observations, particularly integral field spectroscopy and high-resolution 21~cm observations, may provide better constraints into the kinematics and improve understanding of TDG formation.
