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 1603.09341astro-ph.GA
收藏

将来自Milky Way的稠密气体连接到外部整流罩

Linking Dense Gas from the Milky Way to External Galaxies

Ian W. Stephens, James M. Jackson, J. Scott Whitaker, Yanett Contreras, Andrés E. Guzmán, Patricio Sanhueza, Jonathan B. Foster, Jill M. Rathborne

摘要:

在对65个星系的观测中,Gao & Solomon(2004)发现红外光度($L_{\rm{IR}}$,恒星形成速率的替代物)和HCN(1-0)光度($L_{\rm{HCN}}$)之间存在紧密的线性关系。Wu et al.(2005,2010)发现,这种关系从这些星系延伸到亮度低得多的银河系分子高质量恒星形成团块($\sim$ 1 pc尺度),并假设存在一个特征比率$L_{\rm{IR}}$ / $L_{\rm{HCN}}$的高质量恒星形成团块。星系的高-所罗门关系可以解释为大量高质量恒星形成团块的总和,导致星系的$L_{\rm{IR}}$ / $L_{\rm{HCN}}$比率相同。我们使用高密度示踪剂(包括HCN(1-0)、N $_2$ H $^+$(1- 0)、HCO $^+$(1-0)、HNC(1 - 0)、HC $_3$ N(1 - 0 -9)和C $_2$ H(1-0))对毫米天文遗产小组90 GHz(MALT 90)巡天的$\sim$ 300个银河系团块进行了测试,以验证这种解释和高-所罗门关系的其他可能起源。MALT 90数据表明,星系中的Gao-Solomon关系不能用望远镜光束中大量高质量团块的混合来满意地解释。这些团块不仅在$L_{\rm{IR}}$ / $L_{\rm{HCN}}$比率上有很大的散射,而且需要太多的高质量团块才能解释银河系的IR和HCN光度。我们认为,在$L_{\rm{IR}}$ / $L_{\rm{HCN}}$比率的分散收敛到高所罗门关系的分散在一些尺寸尺度$\gtrsim$ 1千秒差距。我们认为高-所罗门关系可能是由一个普遍的大尺度恒星形成效率、初始质量函数、核心质量函数和团块质量函数的结果。

英文摘要:

In a survey of 65 galaxies, Gao & Solomon (2004) found a tight linear relation between the infrared luminosity ($L_{\rm{IR}}$, a proxy for the star formation rate) and the HCN(1-0) luminosity ($L_{\rm{HCN}}$). Wu et al. (2005, 2010) found that this relation extends from these galaxies to the much less luminous Galactic molecular high-mass star-forming clumps ($\sim$1 pc scales), and posited that there exists a characteristic ratio $L_{\rm{IR}}$ /$L_{\rm{HCN}}$ for high-mass star-forming clumps. The Gao-Solomon relation for galaxies could then be explained as a summation of large numbers of high-mass star-forming clumps, resulting in the same $L_{\rm{IR}}$ /$L_{\rm{HCN}}$ ratio for galaxies. We test this explanation and other possible origins of the Gao-Solomon relation using high-density tracers (including HCN(1-0), N$_2$H$^+$(1-0), HCO$^+$(1-0), HNC(1-0), HC$_3$N(10-9), and C$_2$H(1-0)) for $\sim$300 Galactic clumps from the Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey. The MALT90 data show that the Gao-Solomon relation in galaxies cannot be satisfactorily explained by the blending of large numbers of high-mass clumps in the telescope beam. Not only do the clumps have a large scatter in the $L_{\rm{IR}}$/$L_{\rm{HCN}}$ ratio, but also far too many high-mass clumps are required to account for the Galactic IR and HCN luminosities. We suggest that the scatter in the $L_{\rm{IR}}$/$L_{\rm{HCN}}$ ratio converges to the scatter of the Gao-Solomon relation at some size-scale $\gtrsim$1 kpc. We suggest that the Gao-Solomon relation could instead result from of a universal large-scale star formation efficiency, initial mass function, core mass function, and clump mass function.

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。

↑