恒星反馈对星系晕中热气体的影响:Sunyaev-Zel'dovich效应和软X射线发射
The impact of stellar feedback on hot gas in galaxy haloes: the Sunyaev-Zel'dovich effect and soft X-ray emission
摘要:
热Sunyaev-Zel'dovich(SZ)效应和软X射线辐射在大质量星系周围、星系群和星系团中经常被观测到。我们研究了这些星系晕的观测诊断,用于“现实环境中的反馈”项目中的一套宇宙学“放大”模拟,该项目涵盖了晕质量的大范围(10^10-10^13 Msun)。我们探讨了恒星反馈对热气体观测值的影响。我们模拟的群的性质,如重子分数,SZ通量,和X射线光度(L_X),是广泛地与现有的观测,即使反馈的活动星系核是不包括在内。我们预测未来的观测低质量物体的SZ和弥漫X射线测量,发现他们不只是缩小版本的大质量星系,但更强烈的影响由恒星形成驱动的星系风。低质量晕(<~10^11 Msun)保留了少量的重子,这导致了SZ信号的强烈抑制。因此,我们的模拟预测,对于质量小于10^13 Msun的晕,晕质量的标度比自相似更陡。对于质量小于10^12 Msun的晕,L_X是随时间变化的,主要与恒星形成率(SFR)相关。对于这些天体来说,弥漫的X射线发射主要是由星系风提供动力的,而主导X射线发射的气体以接近于晕圈圆速度的径向速度流出。另一方面,对于质量大于~10^13 Msun的晕,L_X的变化要小得多,并且与SFR不相关,因为发射来自准流体静力学的维里化晕气体。
英文摘要:
The thermal Sunyaev-Zel'dovich (SZ) effect and soft X-ray emission are routinely observed around massive galaxies and in galaxy groups and clusters. We study these observational diagnostics of galaxy haloes for a suite of cosmological `zoom-in' simulations from the `Feedback In Realistic Environments' project, which spans a large range in halo mass 10^10-10^13 Msun). We explore the effect of stellar feedback on the hot gas observables. The properties of our simulated groups, such as baryon fractions, SZ flux, and X-ray luminosities (L_X), are broadly consistent with existing observations, even though feedback from active galactic nuclei is not included. We make predictions for future observations of lower-mass objects for both SZ and diffuse X-ray measurements, finding that they are not just scaled-down versions of massive galaxies, but more strongly affected by galactic winds driven by star formation. Low-mass haloes (<~10^11 Msun) retain a low fraction of their baryons, which results in a strong suppression of the SZ signal. Our simulations therefore predict a scaling with halo mass that is steeper than self-similar for haloes less massive than 10^13 Msun. For halo masses <~10^12 Msun, L_X is time-variable and correlated primarily with the star formation rate (SFR). For these objects, the diffuse X-ray emission is powered mostly by galactic winds and the gas dominating the X-ray emission is flowing out with radial velocities close to the halo's circular velocity. For halo masses >~10^13 Msun, on the other hand, L_X is much less variable and not correlated with the SFR, because the emission originates from the quasi-hydrostatic, virialized halo gas.
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。