arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1103.2199astro-ph.HEastro-ph.GA
收藏

X射线双星对晚型星系演化的贡献:演化粒子数合成模拟

The contribution of X-ray binaries to the evolution of late-type galaxies: Evolutionary population synthesis simulations

Zhao-Yu Zuo, Xiang-Dong Li

摘要:

对正常晚型星系的X射线研究表明,非核X射线发射主要是由X射线双星,并提供了一个有用的恒星形成活动的措施。我们用Hurley等人开发的演化总体合成程序模拟了晚型星系在宇宙历史的$\sim$ 14 Gyr上的X射线演化。我们的计算揭示了X射线光质比$L_{\rm X}/M$随时间的减小,与观测结果一致(图~ 7 $a$)。我们表明,这种减少是恒星和双星的演化和星系中的质量积累过程的自然结果。发现X射线与光学光度之比$L_{\rm X}/L_{\rm B}$相当恒定(约为$\sim 10^{30}$ erg/s $^{-1}$ $L_{\rm B,\odot}^{-1}$,图~ 7 $b$),对星系中的恒星形成历史不敏感。$L_{\rm X}/L_{\rm B}$的几乎恒定值与观察到的$L_{\rm X}/L_{\rm B}$从$z=0$增加至1.4相矛盾。这种差异可能是由于强烈的恒星形成活动导致了X射线和B波段辐射之间的非线性关系。

英文摘要:

X-ray studies of normal late-type galaxies have shown that non-nuclear X-ray emission is typically dominated by X-ray binaries, and provides a useful measure of star formation activity. We have modeled the X-ray evolution of late-type galaxies over the $\sim$ 14 Gyr of cosmic history, with an evolutionary population synthesis code developed by Hurley et al. Our calculations reveal a decrease of the X-ray luminosity-to-mass ratio $L_{\rm X}/M$ with time, in agreement with observations (Fig.~7$a$). We show that this decrease is a natural consequence of stellar and binary evolution and mass accumulating process in galaxies. The X-ray-to-optical luminosity ratio $L_{\rm X}/L_{\rm B}$ is found to be fairly constant (around $\sim 10^{30}$ erg\,s$^{-1}$$L_{\rm B,\odot}^{-1}$, Fig.~7$b$), and insensitive to the star formation history in the galaxies. The nearly constant value of $L_{\rm X}/L_{\rm B}$ is in conflict with the observed increase in $L_{\rm X}/L_{\rm B}$ from $z=0$ to 1.4. The discrepancy may be caused by intense obscured star formation activity that leads to nonlinear relationship between X-ray and B-band emission.

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。

↑