The Origin of Inequality: Isolated Formation of a 30+10 M ⊙ Binary Black Hole Merger
The Origin of Inequality: Isolated Formation of a 30+10 M ⊙ Binary Black Hole Merger
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DOI：
10.3847/2041-8213/abb5b5
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发表时间：
2020-04
期刊：
影响因子：
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通讯作者：
A. Olejak;M. Fishbach;K. Belczynski;D. Holz;J. Lasota;M. Miller;T. Bulik
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文献类型：
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作者：
A. Olejak;M. Fishbach;K. Belczynski;D. Holz;J. Lasota;M. Miller;T. Bulik
LIGO和处女座的合作报告了GW190412的探测，这是迄今为止质量最不相等的黑洞-黑洞(BH-BH)的合并。(LIGO/Virgo最近发表了另一个具有更多不等质量组件的系统：GW190814(m 1=23，m 2=2.6)；然而，尚不清楚它是BH-BH还是BH-NS合并(Abbott等人)。)。)它们分别为m1=24.4-34.7和m2=7.4-10.1，对应的质量比为q=0.21-0.41(90%概率范围)。此外，GW190412‘S的有效自旋估计为χef=0.14-0.34，而初级BH的自旋在a自旋=0.17-0.59的范围内。基于这一点和之前的检测，≳10%的BH-BH合并具有Q≲0.4.主要的BH-BH形成通道(即，密集恒星系统中的动力学、经典孤立的双星演化或化学均质演化)倾向于产生具有类似质量的BH-BH合并(典型的Q≳为0.5)。在这里，我们测试经典的孤立二进制进化通道是否可以产生类似GW190412的合并。我们展示了我们的标准二元进化场景，以及我们过去使用的关于输入物理的典型假设，产生了这样的合并。对于输入物理的这个特定模型，局部宇宙中的整体BH-BH合并率密度(z∼0)是，而对于具有率密度的系统是。我们的标准模型的结果与GW190412中黑洞的质量和自转以及LIGO/Virgo对不等质量的BH-BH合并的比例的估计是一致的。由于GW190412显示了一些微弱的自旋错位证据，我们在我们的模型中提供了进动参数的分布，并得出结论：如果在新的LIGO/VIGO探测中系统进动的证据很强，并且超过10%的BH-BH合并具有较大的面内自旋分量(χp>；0.5)，那么可以排除公共包络孤立的双星BH-BH形成通道作为它们的起源。
The LIGO/Virgo Collaboration has reported the detection of GW190412, a black hole–black hole (BH–BH) merger with the most unequal masses to date. (Another system, with even more unequal-mass components, was recently published by LIGO/Virgo: GW190814 (m 1 = 23 , m 2 = 2.6 ); however, it is not known whether it is a BH–BH or BH–NS merger (Abbott et al. ).) They are m 1 = 24.4–34.7 and m 2 = 7.4–10.1 , corresponding to a mass ratio of q = 0.21–0.41 (90% probability range). Additionally, GW190412's effective spin was estimated to be χ eff = 0.14–0.34, with the spin of the primary BH in the range a spin = 0.17–0.59. Based on this and prior detections, ≳10% of BH–BH mergers have q ≲ 0.4. Major BH–BH formation channels (i.e., dynamics in dense stellar systems, classical isolated binary evolution, or chemically homogeneous evolution) tend to produce BH–BH mergers with comparable masses (typically with q ≳ 0.5). Here we test whether the classical isolated binary evolution channel can produce mergers resembling GW190412. We show that our standard binary evolution scenario, with the typical assumptions on input physics that we have used in the past, produces such mergers. For this particular model of the input physics the overall BH–BH merger rate density in the local universe (z ∼ 0) is , while for systems with the rate density is . The results from our standard model are consistent with the masses and spins of the black holes in GW190412, as well as with the LIGO/Virgo estimate of the fraction of unequal-mass BH–BH mergers. As GW190412 shows some weak evidence for misaligned spins, we provide distribution of the precession parameter in our models and conclude that if among the new LIGO/Virgo detections the evidence of system precession is strong and more than 10% of BH–BH mergers have large in-plane spin components (χ p > 0.5), then the common envelope isolated binary BH–BH formation channel can be excluded as their origin.