论文标题
在宇宙学距离处移动引力波源：对哈勃常数测量的影响
Moving gravitational wave sources at cosmological distances: Impact on the measurement of the Hubble constant
论文作者
论文摘要
标准警报器 - 具有EM对应物的GW来源 - 可用于直接测量H_0，这应该有助于缓解现有的哈勃张力。但是，如果由于哈勃流的流动，源在运动的基础上具有相对的速度，则相对论的红移会影响EM对应物的红移和GW源的明显距离，因此需要校正以获得准确的测量结果。我们研究了这种相对速度对扩展宇宙中源的GWS的影响，这表明波的总红移等于相对论红移和宇宙学红移的乘积。此外，我们发现源的相对速度与宇宙红移的线性因子相比，将其明显距离通过一个因子（1+Z_REL）^2改变。我们讨论相对论红移的附加因素是GWS速度依赖性振幅的结果。我们考虑相对速度对chirp质量的影响以及观察者在忽略此速度时会推断出的源距离的表观距离。我们发现，对于不同的天体物理场景，CHIRP质量的误差可能在0.1％至7％之间，而明显距离的误差可能在0.25％至15％之间。此外，我们考虑使用标准警报器在两种情况下使用标准警报器在H_0中引入的误差：（i）当速度对EM对应物的红移的影响被考虑，但不对从GWS获得的明显距离和（ii）当完全忽略了相对速度的效果时。我们发现，在第一种情况下，由于其主机银河系的特殊速度，源移动的误差可能达到1％，在第二种情况下，在GW150914距离源的源具有相同速度时，误差可能超过5％。
Standard sirens - GW sources with an EM counterpart - can be used to measure H_0 directly which should help to ease the existing Hubble tension. However, if the source has a relative velocity to the expanding universe on top of its motion due to the Hubble flow, a relativistic redshift affects the redshift of the EM counterpart and the apparent distance of the GW source, and thus it needs to be corrected to obtain accurate measurements. We study the effect of such a relative velocity on GWs for a source in an expanding universe showing that the total redshift of the wave is equal to the product of the relativistic redshift and the cosmological redshift. We, further, find that a relative velocity of the source changes its apparent distance by a factor (1+z_rel)^2 in contrast to a linear factor for the cosmological redshift. We discuss that the additional factor for the relativistic redshift is a consequence of a velocity-dependent amplitude for GWs. We consider the effect of the relative velocity on the chirp mass and the apparent distance of the source an observer would infer when ignoring this velocity. We find that for different astrophysical scenarios the error can range between 0.1 % and 7 % for the chirp mass while the error in the apparent distance can be between 0.25 % and 15 %. Furthermore, we consider the error introduced in the measurement of H_0 using standard sirens for two cases: (i) when the effect of velocity on the redshift of the EM counterpart is considered but not on the apparent distance obtained from GWs and (ii) when the effect of the relative velocity is ignored completely. We find that in the first case the error can reach 1 % for a source moving due to the peculiar velocity of its host galaxy and that in the second case the error can be more than 5 % for a source at the distance of GW150914 with the same velocity.
