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arXiv 1909.01360astro-ph.GAastro-ph.CO
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大质量星系和类星体的高红移隐藏卫星

The hidden satellites of massive galaxies and quasars at high-redshift

Tiago Costa, Joakim Rosdahl, Taysun Kimm

摘要:

使用宇宙学,辐射流体动力学模拟针对一个罕见的$\approx \, 2 \times 10^{12} \, \rm M_\odot$晕在$z \, = \, 6$,我们表明,大量的晕内的卫星星系的数量计数和内部属性的灵敏度调节相结合的本地恒星辐射反馈和强大的潮汐力。在第一次超新星爆发之前,辐射反馈就开始起作用,并导致星系的束缚不那么紧密。因此,当它们附着在主要的祖先上时,更容易受到潮汐剥离的影响,并且在明显较短的时间尺度上被潮汐破坏。因此,在母系统的维里半径内具有$M_{\rm \star} > 10^{7} \, \rm M_\odot$的卫星的数量相对于在没有恒星辐射反馈的情况下执行的相同模拟下降了多达$60 \%$。辐射反馈也会影响中央星系,其有效半径增加了一个因素$\lesssim 3$由于存在一个更广泛和扩散的恒星成分。我们认为,在大质量高红移星系附近的卫星的数量是恒星辐射反馈的强度的一个指标,并可以在极端的宇宙环境中的高红移类星体低得惊人。

英文摘要:

Using cosmological, radiation-hydrodynamic simulations targeting a rare $\approx \, 2 \times 10^{12} \, \rm M_\odot$ halo at $z \, = \, 6$, we show that the number counts and internal properties of satellite galaxies within the massive halo are sensitively regulated by a combination of local stellar radiative feedback and strong tidal forces. Radiative feedback operates before the first supernova explosions erupt and results in less tightly-bound galaxies. Satellites are therefore more vulnerable to tidal stripping when they accrete onto the main progenitor and are tidally disrupted on a significantly shorter timescale. Consequently, the number of satellites with $M_{\rm \star} > 10^{7} \, \rm M_\odot$ within the parent system's virial radius drops by up to $60 \%$ with respect to an identical simulation performed without stellar radiative feedback. Radiative feedback also impacts the central galaxy, whose effective radius increases by a factor $\lesssim 3$ due to the presence of a more extended and diffuse stellar component. We suggest that the number of satellites in the vicinity of massive high-redshift galaxies is an indication of the strength of stellar radiative feedback and and can be anomalously low in the extreme cosmic environments of high-redshift quasars.

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