Observational Inference on the Delay Time Distribution of Short Gamma-Ray Bursts
Observational Inference on the Delay Time Distribution of Short Gamma-Ray Bursts
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DOI：
10.3847/2041-8213/ac91cd
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发表时间：
2022-06
期刊：
影响因子：
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通讯作者：
M. Zevin;A. Nugent;S. Adhikari;W. Fong;D. Holz;L. Kelley
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作者：
M. Zevin;A. Nugent;S. Adhikari;W. Fong;D. Holz;L. Kelley
中子星星合并的延迟时间分布提供了关键的洞察二进制演化过程和合并率的紧凑型物体二进制的演变。然而，目前的观测限制，这种延迟时间分布依赖于小样本的银河系双中子星（不确定的选择效果），一个单一的多信使引力波事件，和间接证据的中子星星合并的基础上r-过程富集。我们使用一个样本的68个宿主星系的短伽玛射线暴的延迟时间分布上放置新的约束，并利用这一结果来推断合并率演化的紧凑型物体双星包含中子星。我们得到的幂律斜率为α=−1.83−0.39+0.35（中位数和90%可信区间），α为7200万年，可信度为99%，最大延迟时间限制为tmax>7.95Gyr。我们发现这些约束与理论预期大体上是一致的，尽管我们恢复的幂律斜率比传统的α = −1的值要陡得多，而且我们的最小延迟时间也比通常假设的1000万年大。将这个宇宙学探测器与银河系双中子星人口的命运紧密的对象二进制系统将是至关重要的理解这两个人口的独特的选择效应。除了探测一个显着更大的红移制度的中子星星合并比可能与目前的引力波探测器，补充我们的结果与未来的多信使引力波事件也将有助于确定短伽玛射线暴是否普遍导致紧凑的对象二进制合并。
The delay time distribution of neutron star mergers provides critical insights into binary evolution processes and the merger rate evolution of compact object binaries. However, current observational constraints on this delay time distribution rely on the small sample of Galactic double neutron stars (with uncertain selection effects), a single multimessenger gravitational wave event, and indirect evidence of neutron star mergers based on r-process enrichment. We use a sample of 68 host galaxies of short gamma-ray bursts to place novel constraints on the delay time distribution and leverage this result to infer the merger rate evolution of compact object binaries containing neutron stars. We recover a power-law slope of α=−1.83−0.39+0.35 (median and 90% credible interval) with α 72Myr at 99% credibility, and a maximum delay time constrained to tmax>7.95Gyr at 99% credibility. We find these constraints to be broadly consistent with theoretical expectations, although our recovered power-law slope is substantially steeper than the conventional value of α = −1, and our minimum delay time is larger than the typically assumed value of 10 Myr. Pairing this cosmological probe of the fate of compact object binary systems with the Galactic population of double neutron stars will be crucial for understanding the unique selection effects governing both of these populations. In addition to probing a significantly larger redshift regime of neutron star mergers than possible with current gravitational wave detectors, complementing our results with future multimessenger gravitational wave events will also help determine if short gamma-ray bursts ubiquitously result from compact object binary mergers.