Binary black holes population and cosmology in new lights: Signature of PISN mass and formation channel in GWTC-3

Abstract

The mass, spin, and merger rate distribution of the binary black holes (BBHs) across cosmic redshifts provide a unique way to shed light on their formation channel. Along with the redshift dependence of the BBH merger rate, the mass distribution of BBHs can also exhibit redshift dependence due to different formation channels and due to its dependence on the metallicity of the parent stars. In this work, we explore the redshift dependence of the BBH mass distribution jointly with the merger rate evolution from the third gravitational wave (GW) catalog GWTC-3 of the LIGO-Virgo-KAGRA collaboration. This analysis sheds light on multiple new aspects of the BBH formation channel and mass distribution. We obtain interesting constraints on the minimum delay time between the formation of stars and mergers of BBHs t min d = 1.95 +0.97 −0.93 Gyrs, along with a hint towards a steeper power-law form of the delay time distribution ((t d ) d ) with an index d < −1.55 at 68% C.L. The mass distribution of the BBHs agrees with a power-law form with a Gaussian peak at µ g = 40.26 +1.04 −2.32 M which agrees with the theoretical prediction of the lower edge of the PISN mass scale and differs from the previous analysis. This analysis sheds light on the lower edge of the PISN mass scale of black holes and provides hints toward the formation channel of the BBH systems that are different from the usual fiducial scenario with a power-law index d = −1. Our results are consistent with the scenarios of varying (or fixed) Hubble constant and also for events with lower matched filtering network signal to noise ratio.

Uncertainty and bias of cosmology and astrophysical population model from statistical dark sirens

“…This could be of astrophysical significance. For example, the location of the mass gap due to pair instability supernovae could be biased by substructures produced by dynamical formation channels or the redshift-dependence in the mass function (Mukherjee 2021;María Ezquiaga & Holz 2022;Karathanasis et al 2022). Our Eq.…”

“…More possibilities with different parametrizations are also considered in, e.g., LIGO Scientific Collaboration et al (2021c); Roulet et al (2021). Furthermore, the mass distribution could contain more complicated features (Tiwari & Fairhurst 2021) and/or be redshift dependent (Mukherjee 2021;Mapelli et al 2022;van Son et al 2022;Karathanasis et al 2022), introducing more features beyond what is captured by the model described in Sec. 3.…”

Uncertainty and Bias of Cosmology and Astrophysical Population Model from Statistical Dark Sirens

“…This could be of astrophysical significance. For example, the location of the mass gap due to pair-instability supernovae could be biased by substructures produced by dynamical formation channels or the redshift dependence in the mass function (Mukherjee 2022;Karathanasis et al 2022;María Ezquiaga & Holz 2022). Our Equation (11) thus provides a simple and analytical way to quantify the bias.…”

“…The gray ellipses are obtained by summing the Fisher information from the marginalized redshift and primary mass distribution together, and the olive ones are from the 3D r(m 1 , m 2 , z) distribution. and/or be redshift-dependent (Mukherjee 2022;Karathanasis et al 2022;Mapelli et al 2022;van Son et al 2022), introducing more features beyond what is captured by the model described in Section 3. Similarly, an error in the redshift model ψ(z) could also bias the inferred cosmology (You et al 2021).…”

Compact Binary Coalescences: Astrophysical Processes and Lessons Learned

“…The BH mass distribution and the inferred BBH merger rate make the current scenario even more complex. The former seems to have statistically significant substructures, that is, it shows up as clumpy, with BHs that tend to accumulate at chirp masses 3 M = 8 , 14 , 27 M , whereas the latter increases with redshift [80, [86][87][88].…”