arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1902.04872astro-ph.GA
收藏

是什么决定了局部(z<0.1)红外星系光度函数的形状?

What determines the shape of the local (z<0.1) infrared galaxy luminosity function?

Myrto Symeonidis, Mat Page

摘要:

通过与活动星系核的红外光度函数的比较,我们研究了是什么形成了星系核的红外光度函数。前者对应于由恒星和活动星系核加热的尘埃的辐射,而后者只包括由活动星系核加热的尘埃的辐射。结果表明,活动星系核的红外辐射在亮红外星系(LIRG)区开始混合到星系光度函数中,在超亮红外星系(ULIRG)区变得显著,超过该光度,局部ULIRG成为活动星系核主导的光度在log(LIR/Lsun)~12.2-12.7范围内。我们认为,由于活动星系核的贡献,红外星系光度函数比紫外/光学星系光度函数具有更平坦的高光度斜率。此外,我们注意到,作为LIR的函数,AGN的贡献增加反映在本地星系的平均尘埃温度(Tdust),并可能负责本地LIR-Tdust关系。然而,虽然我们的研究结果表明,活动星系核发挥了核心作用,在定义本地ULIRG的属性,我们发现,占主导地位的电源在本地ULIRG人口是恒星形成。

英文摘要:

We investigate what shapes the infrared luminosity function of local galaxies by comparing it to the local infrared AGN luminosity function. The former corresponds to emission from dust heated by stars and AGN, whereas the latter includes emission from AGN-heated dust only. Our results show that infrared emission from AGN starts mixing into the galaxy luminosity function in the luminous infrared galaxy (LIRG) regime and becomes significant in the ultraluminous infrared galaxy (ULIRG) regime, with the luminosity above which local ULIRGs become AGN-dominated being in the log(LIR/Lsun)~12.2-12.7 range. We propose that as a result of the AGN contribution, the infrared galaxy luminosity function has a flatter high luminosity slope than UV/optical galaxy luminosity functions. Furthermore, we note that the increased AGN contribution as a function of LIR is reflected in the average dust temperature (Tdust) of local galaxies, and may be responsible for the local LIR-Tdust relation. However, although our results show that AGN play a central role in defining the properties of local ULIRGs, we find that the dominant power source in the local ULIRG population is star-formation.

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。

↑