http://arxiv.org/abs/2001.07882
GW190425 is the second neutron star merger event detected by the Advanced LIGO/Virgo detectors. If interpreted as a double neutron star merger, the total gravitational mass is substantially larger than that of the binary systems identified in the Galaxy. In this work we analyze the gravitational wave data within the neutron star$-$black hole merger scenario. For the black hole, we yield a mass of $2.34^{+0.38}{-0.27}M\odot$ and an aligned spin of $0.133^{+0.070}{-0.054}$. As for the neutron star we find a mass of $1.18^{+0.13}{-0.14}M_\odot$ and the dimensionless tidal deformability of $1.7^{+5.5}_{-1.4}\times 10^{3}$. The ranges of these parameters are corresponding to the 90\% credible intervals. The inferred masses of the neutron star and the black hole are not in tension with current observations and we suggest that GW190425 is a viable candidate of a neutron star$-$black hole merger event. Benefited from the continual enhancement of the sensitivity of the advanced gravitational detectors and the increase of the number of the detectors, similar events are anticipated to be much more precisely measured and the presence of black holes below the so-called mass gap will be unambiguously clarified. If confirmed, the mergers of neutron stars with (quickly rotating) low-mass black holes are likely important production sites of the heaviest $r-$process elements.
M. Han, S. Tang, Y. Hu, et. al.
Thu, 23 Jan 20
15/36
Comments: 6 pages, 3 figures