The scatter about the ‘Universal’ dwarf spheroidal mass profile: a kinematic study of the M31 satellites And V and And VI
The scatter about the ‘Universal’ dwarf spheroidal mass profile: a kinematic study of the M31 satellites And V and And VI
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关于“通用”矮球体质量分布的分散：M31 卫星 And V 和 And VI 的运动学研究
DOI：
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
K. Venn
中科院分区：
文献类型：
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作者：
M. Collins;S. Chapman;R. Rich;M. Irwin;J. Peñarrubia;R. Ibata;Nobuo Arimoto;Alyson Brooks;A. Ferguson;G. Lewis;A. McConnachie;K. Venn
虽然银河系的卫星（MW）已经被证明在它们的质量方面大体上是一致的，它们包含在一个半光半径（M_half）内，具有“普遍的”质量剖面，但许多M31卫星被发现与这些关系不一致，并且在它们的中心区域似乎比它们的MW表兄弟在运动上更冷。在这项工作中，我们利用Keck低分辨率成像光谱仪（LRIS）和深度成像多目标光谱仪（DEIMOS）仪器以及斯巴鲁Suprime-Cam成像仪的数据，研究了两个M31矮球体（dSph）和V和VI的新的运动学和更新的结构特性。我们测量到和V和VI的系统速度v_r分别为- 393.1±4.2和- 344.8±2.5 km s^(−1)，σ_v的色散分别为11.5^(+5.3)_（−4.4）和9.4^(+3.2)_(−2.4)km s^(−1)，这意味着这两个天体的σv和r_half的趋势与它们的MW对应体一致。我们还研究了“经典”（即M_V < - 8） MW和M31 dSph的MW dSph质量分布的这种散射性质。当将“经典”MW和M31 dSph与尺寸-速度色散平面上最拟合的质量剖面进行比较时，我们发现这些剖面在正（即更热）和负（即更冷）方向上都有普遍的散射。然而，除了一个例外（CVnI），只有M31 dSph被发现向较冷的区域散射，并且，除了和I dSph，只有MW物体向较热的色散散射。综合总体的散点大于单独测量误差的预期。我们在两个宿主不同的盘晕质量（即恒星和重子占总质量）比的背景下评估了这一差异，并认为dSph的潜在质量分布因星系而异，并且被宿主的重子成分所修改。
While the satellites of the Milky Way (MW) have been shown to be largely consistent in terms of their mass contained within one half-light radius (M_half) with a ‘universal’ mass profile, a number of M31 satellites are found to be inconsistent with these relations, and seem kinematically colder in their central regions than their MW cousins. In this work, we present new kinematic and updated structural properties for two M31 dwarf spheroidals (dSph), And V and And VI, using data from the Keck Low Resolution Imaging Spectrograph (LRIS) and the DEep Imaging Multi-Object Spectrograph (DEIMOS) instruments and the Subaru Suprime-Cam imager. We measure systemic velocities of v_r=−393.1 ± 4.2 and −344.8 ± 2.5 km s^(−1), and dispersions of σ_v= 11.5^(+5.3)_(−4.4) and 9.4^(+3.2)_(−2.4) km s^(−1) for And V and And VI, respectively, meaning these two objects are consistent with the trends in σv and r_half set by their MW counterparts. We also investigate the nature of this scatter about the MW dSph mass profiles for the ‘classical’ (i.e. M_V < −8) MW and M31 dSph. When comparing both the ‘classical’ MW and M31 dSph to the best-fitting mass profiles in the size–velocity dispersion plane, we find general scatter in both the positive (i.e. hotter) and negative (i.e. colder) directions from these profiles. However, barring one exception (CVnI) only the M31 dSph are found to scatter towards a colder regime, and, excepting the And I dSph, only MW objects scatter to hotter dispersions. The scatter for the combined population is greater than expected from measurement errors alone. We assess this divide in the context of the differing disc-to-halo mass (i.e. stars and baryons to total virial mass) ratios of the two hosts and argue that the underlying mass profiles for dSph differ from galaxy to galaxy, and are modified by the baryonic component of the host.
深部大型双筒望远镜观察 Canes Venatici I 矮星系
DOI：
10.1086/525559
发表时间：
2008
期刊：
The Astrophysical Journal Letters
影响因子：
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作者：
Martin;Coleman;De Jong;J. T. A
通讯作者：
J. T. A