arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节（Veterans Day），12 日无更新
arXiv 1508.06017astro-ph.GA
收藏

是什么促使M*- SFR关系在高质量时翻转？凸起的作用

What drives the M*-SFR relation turning over at high masses? The role of bulges

Zhizheng Pan, Xianzhong Zheng, Weipeng Lin, Jinrong Li, Jing Wang, Lulu Fan, Xu Kong

备注：
this paper has been refused by ApJL
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

目前还不清楚凸起的增长是否是导致恒星形成主序（MS）在高质量端变平的原因。为了研究隆起在塑造MS中的作用，我们比较了NUV $-r$颜色之间的中央（$r<R_{50}$）和外部区域的6401个本地恒星形成星系的样本。NUV $-r$的颜色是一个很好的恒星形成率指标。我们发现，在$M_{\ast}<10^{10.2}M_{\sun}$，中心NUV $-r$平均仅比外部NUV $-r$红$\sim$ 0.25等。在$M_{\ast}=10^{10.2}M_{\sun}$之上，对于更大质量的星系，中央NUV $-r$系统地变得比外部NUV $-r$红得多，这表明中央隆起在大质量端更加演化。当根据星系的Sérsic指数$n$对星系进行划分时，我们发现即使在固定的B/T和$M_{\ast}$下，$n$ >2.0的星系在中央NUV $-r$颜色上也比$n$ <2.0的星系红。这表明，恒星在球丘中的形成更强烈地依赖于$n$（或中心质量密度），而不是B/T。最后，我们发现在$M_{\ast}>10^{10.2}M_{\sun}$处，随着$M_{\ast}$的增加，$n$ >2.0的星系比例迅速增加，这与在相同的跃迁质量下MS的翻转是一致的.我们的结论是，低sSFR密集的隆起在$M_{\ast}>10^{10.2}M_{\sun}$星系的比例增加，而不是增加B/T，是负责平坦的斜率的$M_{\ast}$ $-$ SFR关系在高质量。

英文摘要：

It is unclear whether bulge growth is responsible for the flattening of the star formation main sequence (MS) at the high mass end. To investigate the role of bulges in shaping the MS, we compare the NUV$-r$ color between the central ($r<R_{50}$) and outer regions for a sample of 6401 local star-forming galaxies. The NUV$-r$ color is a good specific star formation rate indicator. We find that at $M_{\ast}<10^{10.2}M_{\sun}$, the central NUV$-r$ is on average only $\sim$ 0.25 mag redder than the outer NUV$-r$. Above $M_{\ast}=10^{10.2}M_{\sun}$, the central NUV$-r$ becomes systematically much redder than the outer NUV$-r$ for more massive galaxies, indicating that the central bulge is more evolved at the massive end. When dividing the galaxies according to their Sérsic index $n$, we find that galaxies with $n$>2.0 tend to be redder in the central NUV$-r$ color than those with $n$<2.0, even at fixed B/T and $M_{\ast}$. This suggests that star formation in bulges is more strongly dependent on $n$ (or central mass density) than on B/T. Finally, we find that the fraction of galaxies with $n$>2.0 rapidly increases with $M_{\ast}$ at $M_{\ast}>10^{10.2}M_{\sun}$, which is consistent with the turning over of the MS at the same transition mass. We conclude that the increasing fraction of low-sSFR dense bulges in $M_{\ast}>10^{10.2}M_{\sun}$ galaxies, rather than increasing B/T, is responsible for the flattened slope of the $M_{\ast}$$-$SFR relation at high masses.

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。

↑