![]() ![]() We construct a toy model to explore this effect: when we first calculate the time it takes for a binary with the Chirp mass to merge,, after entering the detectable window (which we assume to occur at 25 Hz). More massive events, while sampling a larger volume, are likely difficult to detect because they have even shorter merger timescale leading to limited time series data and poorer model fits-and thus lower signal to noise values. It is also the most distant and had the shortest signal detected. The most massive merger observed to date, GW170729, had the lowest signal-to-noise of the sample. In the left-hand panel only the Chirp mass volume factor is included the right-hand panel includes a signal-to-noise ratio adjustment for the most massive Chirp mass events. ![]() Blue lines are the observed O2 GW events from The LIGO Scientific Collaboration & The Virgo Collaboration ( 2019). Black lines show models with the Hobbs kick, red lines models with the Bray kick. This could indicate incorrect assumptions in our models, such as the exact nature of the initial-to-final mass relation for BHs and the assumed mass range when pair-instability supernovae occur.įigure 1. Expected Chirp mass distributions of GW events from: solid lines-binary BH mergers, dashed lines-BH and NS mergers, dotted lines-double NS mergers. However the Bray kick predicts four merger events out of ten with, rather than the lower mass events that have been observed. We also note that the probability of a double NS merger is higher with the Bray kick. We see that models based on the Bray kick are skewed to significantly higher Chirp masses than those with the Hobbs kick. We show these predictions in the left-hand panel of Figure 1. ( 2019) and multiply each Chirp mass bin by, normalizing the total number of expected BH mergers to 10. Events with a higher Chirp mass create stronger GWs and therefore can be detected out to greater distances to estimate the expected observed Chirp mass distribution we take the mass distributions as calculated in Eldridge et al. The distance d to which events can be detected is related to this value such that, thus the effective volume and the relative rate at which events will be detected is given by. Where M 1 and M 2 are the masses of the compact remnants. The likelihood that a GW event is detected is primarily determined by the Chirp mass of the merger, given by ( 2019) we showed how these different kicks can lead to very different GW event rates, here we present a comparison of the expected Chirp mass distribution of GW mergers with simple assumptions taken about the selection effects. ( 2005) kick and the novel Bray & Eldridge ( 2018) kick. We calculate two model sets with different NS kick models, the fiducial Hobbs et al. ![]() 2017 Stanway & Eldridge 2018, for full details). We use our predictions from the latest Binary Population and Spectral Synthesis (BPASS) models, v2.2 (see Eldridge et al. ![]() Upon the release of the latest GW event catalog by The LIGO Scientific Collaboration & The Virgo Collaboration ( 2019) which contains 10 double black hole (BH) mergers and one double neutron-star (NS) merger we believe a brief comparison between this catalog and our model predictions may be of value to the community. ( 2019) we predicted the rates of electromagnetic and gravitational wave (GW) events, including the expected Chirp mass distribution for the latter. ![]()
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