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تسجيل مستخدم جديدComment on the article Anisotropies in the astrophysical gravitational-wave background: The impact of black hole distributions by A.C. Jenkins et al. [arXiv:1810.13435]
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We investigate the discrepancy pointed out by Jenkins et al. in Ref. [1] between the predictions of anisotropies of the astrophysical gravitational wave (GW) background, derived using different methods in Cusin et al. [2] and in Jenkins et al. [3]. We show that this discrepancy is not due to our treatment of galaxy clustering, contrary to the claim made in Ref. [1] and we show that our modeling of clustering gives results in very good agreement with observations. Furthermore we show that the power law spectrum used in Refs. [1] and [3] to describe galaxy clustering is incorrect on large scales and leads to a different scaling of the multipoles $C_ell$. Moreover, we also explain that the analytic derivation of the gravitational wave background correlation function in Refs. [1] and [3] is mathematically ill-defined and predicts an amplitude of the angular power spectrum which depends on the (arbitrary) choice of a non-physical cut-off.
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We use population inference to explore the impact that uncertainties in the distribution of binary black holes (BBH) have on the astrophysical gravitational-wave background (AGWB). Our results show that the AGWB monopole is sensitive to the nature of
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We offer a brief response to the criticisms put forward by Cusin et al in arXiv:1811.03582 about our work arXiv:1810.13435 and arXiv:1806.01718, emphasising that none of these criticisms are relevant to our main results.
In the literature different approaches have been proposed to compute the anisotropies of the astrophysical gravitational wave background. The different expressions derived, although starting from our work Cusin, Pitrou, Uzan, Phys.Rev.D96, 103019 (20
17) [1], seem to differ. This article compares the various theoretical expressions proposed so far and provides a separate derivation based on a Boltzmann approach. We show that all the theoretical formula in the literature are equivalent and boil down to the one of Ref. [1] when a proper matching of terms and integration by parts are performed. The difference between the various predictions presented for anisotropies in a cosmological context can only lie in the astrophysical modeling of sources, and neither in the theory nor in the cosmological description of the large scale structures. Finally we comment on the gauge invariance of expressions.
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