arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0801.3606astro-ph
收藏

极低质量Galerkin的重子Tully-Fisher关系

Baryonic Tully-Fisher Relation for Extremely Low Mass Galaxies

Ayesha Begum, Jayaram N. Chengalur, I. D. Karachentsev, M. E. Sharina

备注：
7 pages, 7 figures. Accepted for publication in MNRAS
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

我们研究了一个由极暗（M_B > -14.0）星系和亮（即L_*）星系组成的样本的Tully-Fisher关系。精确（~ 10%）的距离，I波段测光，和B-V颜色是已知的大多数星系在我们的样本。暗星系是从暗不规则星系GMRT巡天（FIGGS）中提取的，我们得到了它们的HI自转速度。对于微弱的星系，我们发现，即使中位数HI和恒星质量是可比的，HI质量的相关性显着更好的圆速度指标比恒星质量。我们还发现W $_{20}$与质量的相关性比旋转速度更好，尽管差异在统计学上不显著。暗星系系统地低于由亮星系定义的I波段TF关系，并且也显示出明显更多的内禀散射。这意味着这些星系中的恒星形成过程比大型星系的效率更低，也更不受监管。我们发现，虽然暗端偏差大大减少重子塔利-费舍尔（BTF）的关系，在暗端的BTF的存在一个突破是受系统学，如假设的恒星质量与光的比例。如果我们假设存在一个内禀BTF，并试图通过寻找导致最紧BTF的处方来确定重子质量，我们发现，缩放HI质量比缩放恒星质光比导致更显著的收紧。然而，我们发现的最显著的收紧是，如果我们缩放了暗淡（但不是明亮）星系的整个重子质量。这样的一种情况将与矮星系（但不是大的）有很大一部分黑暗或“失踪”重子的模型相一致。

英文摘要：

We study Tully-Fisher relations for a sample that combines extremely faint (M_B > -14.0) galaxies along with bright (i.e. L_*) galaxies. Accurate (~ 10%) distances, I band photometry, and B-V colors are known for the majority of the galaxies in our sample. The faint galaxies are drawn from the Faint Irregular Galaxy GMRT survey (FIGGS), and we have HI rotation velocities derived from aperture synthesis observations for all of them. For the faint galaxies, we find that even though the median HI and stellar masses are comparable, the HI mass correlates significantly better with the circular velocity indicators than the stellar mass. We also find that W$_{20}$ correlates better with mass than the rotation velocity, although the difference is not statistically significant. The faint galaxies lie systematically below the I band TF relation defined by bright galaxies, and also show significantly more intrinsic scatter. This implies that the integrated star formation in these galaxies has been both less efficient and also less regulated than in large galaxies. We find that while the faint end deviation is greatly reduced in Baryonic Tully-Fisher (BTF) relations, the existence of a break at the faint end of the BTF is subject to systematics such as the assumed stellar mass to light ratio. If we assume that there is an intrinsic BTF and try to determine the baryonic mass by searching for prescriptions that lead to the tightest BTF, we find that scaling the HI mass leads to a much more significant tightening than scaling the stellar mass to light ratio. The most significant tightening that we find however, is if we scale the entire baryonic mass of the faint (but not the bright) galaxies. Such a scenario would be consistent with models where dwarf (but not large) galaxies have a large fraction of dark or ``missing'' baryons (Slightly abridged)

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。

↑