arXiv 1511.080872015-11astro-ph.GAgr-qchep-ph

对“来自MOND的DiskMass巡天的盘状星系质量模型“的评论

Critical take on "Mass models of disk galaxies from the DiskMass Survey in MOND"

Mordehai Milgrom

备注：: 9 pages. Added a figure that compares the MOND predictions with scaled up DiskMass velocity dispersions

摘要：

Angus et al.（2015）最近对MOND提出了如下的错误看法：研究了30个盘星系，他们得到了MOND预测的垂直于盘的速度色散分布，$σ_M(r)$，并将其与$σ(r)$进行了比较，$σ(r)$是Mass项目的一部分。这是一种不同于旋转曲线分析的新的MOND检验方法。MOND的一个重要成就--Angus等人没有讨论--是$σ_M$和$σ$的形状非常一致，即，$η(r)\equivσ_M(r)/σ(r)$与$r$无关很好地一致（而$σ$和$σ_M$强烈地依赖于$r$）. MOND发现的错误是$η$系统地大于1（平均值约为1.3）。我曾向安格斯等人提出，错误可能在于质量离散度太低，不适合当前的目的：基于种群整合的谱线轮廓，它们可能被年轻种群过度加权，已知年轻种群的离散度和尺度高度比老年种群小得多，老年种群对光分布的影响更大。我讨论独立的证据，支持这一观点，并显示，此外，如果的CNOMAS分散被低估只有25%，平均而言，MOND预测是完全符合数据，在形状和大小。现在，Aniyan等人（2015）在相同的基础上质疑了Mass $σ$。他们显示了银河系中的太阳柱：“结合（单一）测量到的年轻+年老盘总人口的速度色散......如果在银河系中发现的这种不匹配是典型的，那么对其进行校正将使测量的质量$\sim 2.$与预测的MOND $σ_M(r)$达到惊人的一致。

英文摘要：

Angus et al. (2015) have recently faulted MOND as follows: Studying thirty disc galaxies from the DiskMass survey, they derive the profiles of velocity dispersion perpendicular to the discs as predicted by MOND, $σ_M(r)$, and compare them with $σ(r)$, measured as part of the DiskMass project. This is a new test of MOND, different from rotation-curve analysis. A nontrivial accomplishment of MOND -- not discussed by Angus et al. -- is that the shapes of $σ_M$ and $σ$ agree very well, i.e, $η(r)\equivσ_M(r)/σ(r)$ is well consistent with being $r$-independent (while $σ$ and $σ_M$ are strongly $r$ dependent). The fault found with MOND was that $η$ is systematically above 1 (with an average of about 1.3). I have suggested to Angus et al. that the fault may lie with the DiskMass dispersions, which may well be too low for the purpose at hand: Being based on population-integrated line profiles, they may be overweighed by younger populations, known to have much smaller dispersions, and scale heights, than the older populations, which weigh more heavily on the light distributions. I discuss independent evidence that supports this view, and show, besides, that if the DiskMas dispersions are underestimates by only 25 %, on average, the MOND predictions are in full agreement with the data, in shape and magnitude. Now, Aniyan et al. (2015) have questioned the DiskMass $σ$ on the same basis. They show for the solar column in the Milky Way that: " Combining the (single) measured velocity dispersion of the total young + old disc population... with the scale height estimated for the older population would underestimate the disc surface density by a factor of $\sim 2.$" If this mismatch found for the Milky Way is typical, correcting for it would bring the measured DiskMass $σ(r)$ to a remarkable agreement with the predicted MOND $σ_M(r)$.

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。

摘要：

英文摘要：

相关论文