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arXiv 1708.02587astro-ph.GA
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孤立的矮星系合并中的一个广泛的、杂乱的星暴dm1647 +21

A Widespread, Clumpy Starburst in the Isolated Ongoing Dwarf Galaxy Merger dm1647+21

G. C. Privon, S. Stierwalt, D. R. Patton, G. Besla, S. Pearson, M. Putman, K. E. Johnson, N. Kallivayalil, S. Liss

摘要:

孤立的矮星系对之间的相互作用提供了一个关键的窗口,低质量等级,气体占主导地位的星系组装和恒星质量的积累在低金属系统。我们提出了第一个VLT/MUSE光学IFU的相互作用的矮对dm 1647 +21,从TiNy泰坦调查选择的意见。H $α$辐射分布广泛,对应的总无遮蔽恒星形成率(SFR)为0.44 M $_{\odot}$/年$^{-1}$,比SDSS数据推断的SFR高2.7倍。暗示特定的SFR(sSFR)的系统被提升超过一个数量级以上的非相互作用的矮星在相同的质量范围。这种增加主要是由低质量星系,其中有一个$>$ 50的sSFR增强。检查经典的光学线诊断的空间分辨地图,我们发现ISM激发可以完全解释恒星形成。电离气体的速度场与简单转动不一致。动力学模拟表明,不规则的速度场和恒星结构是一致的,该系统作为一个正在进行的两个矮星系之间的相互作用的识别。在这个系统中,恒星形成的广泛的,clusively增强指出了合并对矮星系的影响的重要差异,与大质量星系相比:而不是气体到核的漏斗并引起核星暴,低质量星系合并中的星暴可能是由大规模的ISM压缩触发的,因此更加分散。

英文摘要:

Interactions between pairs of isolated dwarf galaxies provide a critical window into low-mass hierarchical, gas-dominated galaxy assembly and the buildup of stellar mass in low-metallicity systems. We present the first VLT/MUSE optical IFU observations of the interacting dwarf pair dm1647+21, selected from the TiNy Titans survey. The H$α$ emission is widespread and corresponds to a total unobscured star formation rate (SFR) of 0.44 M$_{\odot}$ yr$^{-1}$, 2.7 times higher than the SFR inferred from SDSS data. The implied specific SFR (sSFR) for the system is elevated by more than an order of magnitude above non-interacting dwarfs in the same mass range. This increase is dominated by the lower-mass galaxy, which has a sSFR enhancement of $>$ 50. Examining the spatially-resolved maps of classic optical line diagnostics, we find the ISM excitation can be fully explained by star formation. The velocity field of the ionized gas is not consistent with simple rotation. Dynamical simulations indicate that the irregular velocity field and the stellar structure is consistent with the identification of this system as an ongoing interaction between two dwarf galaxies. The widespread, clumpy enhancements in star formation in this system point to important differences in the effect of mergers on dwarf galaxies, compared to massive galaxies: rather than the funneling of gas to the nucleus and giving rise to a nuclear starburst, starbursts in low-mass galaxy mergers may be triggered by large-scale ISM compression, and thus be more distributed.

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