Searching for a Ringdown Overtone in GW150914. (arXiv:2205.07809v1 [gr-qc])
<a href="http://arxiv.org/find/gr-qc/1/au:+Finch_E/0/1/0/all/0/1">Eliot Finch</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Moore_C/0/1/0/all/0/1">Christopher J. Moore</a>
We reanalyze the GW150914 post-merger data searching for quasinormal modes
beyond the fundamental, quadrupolar mode. There is currently an ongoing
disagreement in the literature about whether, and to what extent, the data
contains evidence for a quasinormal mode overtone. We use a frequency-domain
approach to ringdown data analysis that was recently proposed by the authors.
Our analysis has several advantages compared to other analyses performed mainly
in the time domain; in particular, the source sky position and the ringdown
start time are marginalized over (as opposed to simply being fixed) as part of
a Bayesian ringdown analysis. We find tentative evidence for an overtone in
GW150914, but at a lower significance than reported elsewhere. Our preferred
analysis, marginalizing over the uncertainty in the time of peak strain
amplitude, gives a posterior on the overtone amplitude peaked away from zero at
$sim 1.8sigma$.
We reanalyze the GW150914 post-merger data searching for quasinormal modes
beyond the fundamental, quadrupolar mode. There is currently an ongoing
disagreement in the literature about whether, and to what extent, the data
contains evidence for a quasinormal mode overtone. We use a frequency-domain
approach to ringdown data analysis that was recently proposed by the authors.
Our analysis has several advantages compared to other analyses performed mainly
in the time domain; in particular, the source sky position and the ringdown
start time are marginalized over (as opposed to simply being fixed) as part of
a Bayesian ringdown analysis. We find tentative evidence for an overtone in
GW150914, but at a lower significance than reported elsewhere. Our preferred
analysis, marginalizing over the uncertainty in the time of peak strain
amplitude, gives a posterior on the overtone amplitude peaked away from zero at
$sim 1.8sigma$.
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