Retrieving the True Masses of Gravitational-wave Sources. (arXiv:1906.11055v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Chen_X/0/1/0/all/0/1">Xian Chen</a> (PKU), <a href="http://arxiv.org/find/astro-ph/1/au:+Shen_Z/0/1/0/all/0/1">Zhe-Feng Shen</a> (PKU)
Gravitational waves (GWs) encode important information about the mass of the
source. For binary black holes (BBHs), the templates that are used to retrieve
the masses normally are developed under the assumption of a vacuum environment.
However, theories suggest that some BBHs form in gas-rich environments. Here we
study the effect of hydrodynamic drag on the chirp signal of a stellar-mass BBH
and the impact on the measurement of the mass. Based on theoretical arguments,
we show that the waveform of a BBH in gas resembles that of a more massive BBH
residing in a vacuum. The effect is important for LISA sources but negligible
for LIGO/Virgo binaries. Furthermore, we carry out a matched-filtering search
of the best fitting parameters. We find that the best-fit chirp mass could be
significantly greater than the real mass if the gas effect is not appropriately
accounted for. Our results have important implications for the future joint
observation of BBHs using both ground- and space-based detectors.
Gravitational waves (GWs) encode important information about the mass of the
source. For binary black holes (BBHs), the templates that are used to retrieve
the masses normally are developed under the assumption of a vacuum environment.
However, theories suggest that some BBHs form in gas-rich environments. Here we
study the effect of hydrodynamic drag on the chirp signal of a stellar-mass BBH
and the impact on the measurement of the mass. Based on theoretical arguments,
we show that the waveform of a BBH in gas resembles that of a more massive BBH
residing in a vacuum. The effect is important for LISA sources but negligible
for LIGO/Virgo binaries. Furthermore, we carry out a matched-filtering search
of the best fitting parameters. We find that the best-fit chirp mass could be
significantly greater than the real mass if the gas effect is not appropriately
accounted for. Our results have important implications for the future joint
observation of BBHs using both ground- and space-based detectors.
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