Massive Black Hole Binaries from the TNG50-3 Simulation. I. Coalescence and LISA Detection Rates
Massive Black Hole Binaries from the TNG50-3 Simulation. I. Coalescence and LISA Detection Rates
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DOI：
10.3847/1538-4357/ac74b5
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发表时间：
2022-01
期刊：
影响因子：
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通讯作者：
Kunyang Li;Tamara Bogdanovi'c;D. Ballantyne;M. Bonetti
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文献类型：
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作者：
Kunyang Li;Tamara Bogdanovi'c;D. Ballantyne;M. Bonetti
我们评估了引力波激光干涉仪空间天线(LISA)瞄准的大质量黑洞(MBH)双星的宇宙学会聚和探测率。我们的计算从来自TNG50-3宇宙学模拟的一组引力未束缚的MBH对开始，并使用我们先前工作中建立的半解析模型跟踪它们从千帕秒尺度到合并的轨道演化。我们发现，对于大多数在哈勃时间内合并的MBH对来说，动力摩擦是决定其合并速率的最重要的机制。我们的模型预测了MBH合并速率≲0.45yr−1和LISA探测速率≲0.34yr−1。大多数LISA探测应该起源于富气星系中红移为1.6⊙z≤2.4的106到106.8 M≤MBH，并且具有特征的信噪比S/N∼100。然而，我们发现，如果考虑MBH吸积的辐射反馈的影响，聚合率和探测率以及平均S/N值都会显著降低。在这种情况下，LISA的合并率降低了78%(至≲0.1年−1)，LISA探测率降低了94%(至0.02年−1)，而平均S/N为∼10。我们强调，由于TNG50-3中有限的MBH质量范围，我们的模型提供了对LISA探测率的保守估计，这与文献中从宇宙学模拟中提取其MBH对的其他工作是一致的。
We evaluate the cosmological coalescence and detection rates for massive black hole (MBH) binaries targeted by the gravitational wave observatory Laser Interferometer Space Antenna (LISA). Our calculation starts with a population of gravitationally unbound MBH pairs, drawn from the TNG50-3 cosmological simulation, and follows their orbital evolution from kiloparsec scales all the way to coalescence using a semi-analytic model developed in our previous work. We find that for the majority of MBH pairs that coalesce within a Hubble time dynamical friction is the most important mechanism that determines their coalescence rate. Our model predicts an MBH coalescence rate ≲0.45 yr−1 and a LISA detection rate ≲0.34 yr−1. Most LISA detections should originate from 106 to 106.8 M ⊙ MBHs in gas-rich galaxies at redshifts 1.6 ≤ z ≤ 2.4 and have a characteristic signal-to-noise ratio S/N ∼100. We however find a dramatic reduction in the coalescence and detection rates, as well as the average S/N, if the effects of radiative feedback from accreting MBHs are taken into account. In this case, the MBH coalescence rate is reduced by 78% (to ≲0.1 yr−1), and the LISA detection rate is reduced by 94% (to 0.02 yr−1), whereas the average S/N is ∼10. We emphasize that our model provides a conservative estimate of the LISA detection rates, due to the limited MBH mass range in TNG50-3, consistent with other works in the literature that draw their MBH pairs from cosmological simulations.