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arXiv 0710.3795astro-phgr-qc
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用引力波定域合并的大质量黑洞双星

Localizing coalescing massive black hole binaries with gravitational waves

Ryan N. Lang, Scott A. Hughes

摘要:

大质量黑洞双星合并是空间引力波观测站(如{ \it LISA})的主要目标。GW测量可以将合并双星在天空中的位置定位为椭圆,其长轴为几十角分到几度,取决于源红移,短轴为小$2 - 4$倍。如果忽略弱的引力透镜,GWs还可以确定源的光度距离,对于近距离源的精确度超过10%,对于更远的源则降低到百分之几。事实上,弱透镜效应不能被忽略,并且预计会限制距离固定的精度,误差不小于百分之几。假设一个测量良好的宇宙学,源的红移可以以类似的精度推断出来。因此,全球变暖本身就可以将二进制精确定位为三维“像素”,这可以帮助指导对这些事件的主机的搜索。我们研究这个像素的时间演变,研究它在合并和合并前的几个间隔。在合并前一天,误差椭圆的长轴通常比其最终值大$\sim 1.5-6$倍。短轴大一个$\sim 2-9$的因子,并且忽略透镜作用,光度距离的误差大一个$\sim 1.5-7$的因子。这种短时间内的巨大变化是由于自旋引起的岁差,这在合并前的最后几天最强。随着时间的推移,进化的速度越来越慢。对于$z = 1$,我们发现GWS会在合并前一个月将合并双星定位到$\sim 10\ \mathrm{deg}^2$内,并确定距离(因此红移)为百分之几。

英文摘要:

Massive black hole binary coalescences are prime targets for space-based gravitational wave (GW) observatories such as {\it LISA}. GW measurements can localize the position of a coalescing binary on the sky to an ellipse with a major axis of a few tens of arcminutes to a few degrees, depending on source redshift, and a minor axis which is $2 - 4$ times smaller. Neglecting weak gravitational lensing, the GWs would also determine the source's luminosity distance to better than percent accuracy for close sources, degrading to several percent for more distant sources. Weak lensing cannot, in fact, be neglected and is expected to limit the accuracy with which distances can be fixed to errors no less than a few percent. Assuming a well-measured cosmology, the source's redshift could be inferred with similar accuracy. GWs alone can thus pinpoint a binary to a three-dimensional ``pixel'' which can help guide searches for the hosts of these events. We examine the time evolution of this pixel, studying it at merger and at several intervals before merger. One day before merger, the major axis of the error ellipse is typically larger than its final value by a factor of $\sim 1.5-6$. The minor axis is larger by a factor of $\sim 2-9$, and, neglecting lensing, the error in the luminosity distance is larger by a factor of $\sim 1.5-7$. This large change over a short period of time is due to spin-induced precession, which is strongest in the final days before merger. The evolution is slower as we go back further in time. For $z = 1$, we find that GWs will localize a coalescing binary to within $\sim 10\ \mathrm{deg}^2$ as early as a month prior to merger and determine distance (and hence redshift) to several percent.

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。

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