arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1506.07534astro-ph.GA
收藏

潮汐或暗物质次晕:哪一个更有吸引力?

Tides or dark matter sub-halos: Which ones are more attractive?

Sylvia Ploeckinger

摘要:

年轻的潮汐矮星系(TDGs)是在富气体相互作用星系的潮汐碎片中观测到的。与通常认为的孤立矮星系的情况相反,TDG并没有嵌入它们自己的暗物质(DM)子晕中。因此,它们对恒星反馈更敏感,并且可能在短时间内被破坏。详细的数值和观测研究表明,孤立的DM占主导地位的矮星系可以有超过10 Gyr的寿命。对于TDG的发展,在一个潮汐场与压缩加速度等于重力加速度内DM子晕典型的孤立的矮星系,类似的生存时间预计。潮汐加速度分布依赖于宿主星系的维里质量和TDG与宿主星系之间的距离。我们分析比较潮汐压缩的重力加速度,由于无论是尖形或核心DM子晕的各种维里质量。例如,距离主晕10^13 Msol的100 kpc处的潮汐场可以像10^9 Msol的DM次晕一样稳定。通过将潮汐场与DM次晕的等效引力场联系起来,我们可以使用现有的孤立矮星模型来估计TDG的生存能力。我们发现,从一些TDG的观测推断出的意外高动力学质量的一部分可以解释潮汐压缩,因此TDG需要包含较少的不可观测的物质来理解它们的旋转曲线。

英文摘要:

Young tidal dwarf galaxies (TDGs) are observed in the tidal debris of gas-rich interacting galaxies. In contrast to what is generally assumed to be the case for isolated dwarf galaxies, TDGs are not embedded in their own dark matter (DM) sub-halo. Hence, they are more sensitive to stellar feedback and could be disrupted on a short time-scale. Detailed numerical and observational studies demonstrate that isolated DM-dominated dwarf galaxies can have lifetimes of more than 10 Gyr. For TDGs that evolve in a tidal field with compressing accelerations equal to the gravitational acceleration within a DM sub-halo typical of an isolated dwarf galaxy, a similar survival time is expected. The tidal acceleration profile depends on the virial mass of the host galaxy and the distance between the TDG and its host. We analytically compare the tidal compression to the gravitational acceleration due to either cuspy or cored DM sub-halos of various virial masses. For example, the tidal field at a distance of 100 kpc to a host halo of 10^13 Msol can be as stabilizing as a 10^9 Msol DM sub-halo. By linking the tidal field to the equivalent gravitational field of a DM sub-halo, we can use existing models of isolated dwarfs to estimate the survivability of TDGs. We show that part of the unexpectedly high dynamical masses inferred from observations of some TDGs can be explained by tidal compression and hence TDGs require to contain less unobservable matter to understand their rotation curves.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑