Are stellar–mass binary black hole mergers isotropically distributed?. (arXiv:2003.02919v2 [astro-ph.HE] UPDATED)

Are stellar–mass binary black hole mergers isotropically distributed?. (arXiv:2003.02919v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Stiskalek_R/0/1/0/all/0/1">Richard Stiskalek</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Veitch_J/0/1/0/all/0/1">John Veitch</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Messenger_C/0/1/0/all/0/1">Chris Messenger</a>

The Advanced LIGO and Advanced Virgo gravitational wave detectors have
detected a population of binary black hole mergers in their first two observing
runs. For each of these events we have been able to associate a potential sky
location region represented as a probability distribution on the sky. Thus, at
this point we may begin to ask the question of whether this distribution agrees
with the isotropic model of the Universe, or if there is any evidence of
anisotropy. We perform Bayesian model selection between an isotropic and a
simple anisotropic model, taking into account the anisotropic selection
function caused by the underlying antenna patterns and sensitivity of the
interferometers over the sidereal day. We find an inconclusive Bayes factor of
$1.3:1$, suggesting that the data from the first two observing runs is
insufficient to pick a preferred model. However, the first detections were
mostly poorly localised in the sky (before the Advanced Virgo joined the
network), spanning large portions of the sky and hampering detection of
potential anisotropy. It will be appropriate to repeat this analysis with
events from the recent third LIGO observational run and a more sophisticated
cosmological model.

The Advanced LIGO and Advanced Virgo gravitational wave detectors have
detected a population of binary black hole mergers in their first two observing
runs. For each of these events we have been able to associate a potential sky
location region represented as a probability distribution on the sky. Thus, at
this point we may begin to ask the question of whether this distribution agrees
with the isotropic model of the Universe, or if there is any evidence of
anisotropy. We perform Bayesian model selection between an isotropic and a
simple anisotropic model, taking into account the anisotropic selection
function caused by the underlying antenna patterns and sensitivity of the
interferometers over the sidereal day. We find an inconclusive Bayes factor of
$1.3:1$, suggesting that the data from the first two observing runs is
insufficient to pick a preferred model. However, the first detections were
mostly poorly localised in the sky (before the Advanced Virgo joined the
network), spanning large portions of the sky and hampering detection of
potential anisotropy. It will be appropriate to repeat this analysis with
events from the recent third LIGO observational run and a more sophisticated
cosmological model.

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