Discrepancy in tidal deformability of GW170817 between the Advanced LIGO twins. (arXiv:1812.06100v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Narikawa_T/0/1/0/all/0/1">Tatsuya Narikawa</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Uchikata_N/0/1/0/all/0/1">Nami Uchikata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kawaguchi_K/0/1/0/all/0/1">Kyohei Kawaguchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kiuchi_K/0/1/0/all/0/1">Kenta Kiuchi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kyutoku_K/0/1/0/all/0/1">Koutarou Kyutoku</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Shibata_M/0/1/0/all/0/1">Masaru Shibata</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tagoshi_H/0/1/0/all/0/1">Hideyuki Tagoshi</a>

We find that the Hanford and Livingston detectors of Advanced LIGO derive
distinct posterior probability distribution of binary tidal deformability
tilde{Lambda} of the first binary-neutron-star merger GW170817. Analyzing
public data of GW170817 with a nested-sampling engine and the default TaylorF2
waveform provided by the LALInference package, we obtain significantly
multimodal distribution characterized by a disconnected
highest-posterior-density 90% credible interval from the Livingston detector.
Furthermore, the distribution derived by the Livingston detector changes
irregularly when we vary the maximum frequency of the data used in the
analysis. These features are not observed for the Hanford detector. By imposing
the flat prior on tidal deformability of individual stars, symmetric 90%
credible intervals of tilde{Lambda} are estimated to be 234^{+960}_{-172} with
the Hanford detector, 1639^{+578}_{-1193} with the Livingston detector, and
183^{+993}_{-130} with the LIGO-Virgo detector network. While they are all
consistent, the discrepancy and irregular behavior suggest that an in-depth
study of noise properties might improve our understanding of GW170817 and
future events.

We find that the Hanford and Livingston detectors of Advanced LIGO derive
distinct posterior probability distribution of binary tidal deformability
tilde{Lambda} of the first binary-neutron-star merger GW170817. Analyzing
public data of GW170817 with a nested-sampling engine and the default TaylorF2
waveform provided by the LALInference package, we obtain significantly
multimodal distribution characterized by a disconnected
highest-posterior-density 90% credible interval from the Livingston detector.
Furthermore, the distribution derived by the Livingston detector changes
irregularly when we vary the maximum frequency of the data used in the
analysis. These features are not observed for the Hanford detector. By imposing
the flat prior on tidal deformability of individual stars, symmetric 90%
credible intervals of tilde{Lambda} are estimated to be 234^{+960}_{-172} with
the Hanford detector, 1639^{+578}_{-1193} with the Livingston detector, and
183^{+993}_{-130} with the LIGO-Virgo detector network. While they are all
consistent, the discrepancy and irregular behavior suggest that an in-depth
study of noise properties might improve our understanding of GW170817 and
future events.

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