TY - JOUR
T1 - Black hole-neutron star coalescence
T2 - Effects of the neutron star spin on jet launching and dynamical ejecta mass
AU - Ruiz, Milton
AU - Paschalidis, Vasileios
AU - Tsokaros, Antonios
AU - Shapiro, Stuart L.
N1 - Funding Information:
We thank the Illinois Relativity group REU team (K. Nelli, M. N. T. Nguyen, and S. Qunell) for assistance with some of the visualizations. This work was supported by NSF Grants No. PHY-1662211 and No. PHY-2006066, and NASA Grant No. 80NSSC17K0070 to the University of Illinois at Urbana-Champaign, and NSF Grant No. PHY-1912619 to the University of Arizona. This work made use of the Extreme Science and Engineering Discovery Environment, which is supported by National Science Foundation Grant No. TG-MCA99S008. This research is also part of the Frontera computing project at the Texas Advanced Computing Center. Frontera is made possible by National Science Foundation Grant No. OAC-1818253. Resources supporting this work were also provided by the NASA High-End Computing Program through the NASA Advanced Supercomputing Division at Ames Research Center.
Publisher Copyright:
© 2020 American Physical Society.
PY - 2020/12/30
Y1 - 2020/12/30
N2 - Black hole-neutron star (BHNS) mergers are thought to be sources of gravitational waves (GWs) with coincident electromagnetic (EM) counterparts. To further probe whether these systems are viable progenitors of short gamma-ray bursts (SGRBs) and kilonovas, and how one may use (the lack of) EM counterparts associated with LIGO/Virgo candidate BHNS GW events to sharpen parameter estimation, we study the impact of neutron star spin in BHNS mergers. Using dynamical spacetime magnetohydrodynamic simulations of BHNSs initially on a quasicircular orbit, we survey configurations that differ in the BH spin (aBH/MBH=0 and 0.75), the NS spin (aNS/MNS=-0.17, 0, 0.23, and 0.33), and the binary mass ratio (qMBH:MNS=31 and 51). The general trend we find is that increasing the NS prograde spin increases both the rest mass of the accretion disk onto the remnant black hole, and the rest mass of dynamically ejected matter. By a time Δt∼3500-5500M∼88-138(MNS/1.4 M) ms after the peak gravitational-wave amplitude, a magnetically driven jet is launched only for q=31 regardless of the initial NS spin. The lifetime of the jets [Δt∼0.5-0.8(MNS/1.4 M) s] and their outgoing Poynting luminosity [LPoyn∼1051.5±0.5 erg/s] are consistent with typical SGRBs' luminosities and expectations from the Blandford-Znajek mechanism. By the time we terminate our simulations, we do not observe either an outflow or a large-scale magnetic-field collimation for the other systems we consider. The mass range of dynamically ejected matter is 10-4.5-10-2(MNS/1.4 M) M, which can power kilonovas with peak bolometric luminosities Lknova∼1040-1041.4 erg/s with rise times 6.5 h and potentially detectable by the LSST.
AB - Black hole-neutron star (BHNS) mergers are thought to be sources of gravitational waves (GWs) with coincident electromagnetic (EM) counterparts. To further probe whether these systems are viable progenitors of short gamma-ray bursts (SGRBs) and kilonovas, and how one may use (the lack of) EM counterparts associated with LIGO/Virgo candidate BHNS GW events to sharpen parameter estimation, we study the impact of neutron star spin in BHNS mergers. Using dynamical spacetime magnetohydrodynamic simulations of BHNSs initially on a quasicircular orbit, we survey configurations that differ in the BH spin (aBH/MBH=0 and 0.75), the NS spin (aNS/MNS=-0.17, 0, 0.23, and 0.33), and the binary mass ratio (qMBH:MNS=31 and 51). The general trend we find is that increasing the NS prograde spin increases both the rest mass of the accretion disk onto the remnant black hole, and the rest mass of dynamically ejected matter. By a time Δt∼3500-5500M∼88-138(MNS/1.4 M) ms after the peak gravitational-wave amplitude, a magnetically driven jet is launched only for q=31 regardless of the initial NS spin. The lifetime of the jets [Δt∼0.5-0.8(MNS/1.4 M) s] and their outgoing Poynting luminosity [LPoyn∼1051.5±0.5 erg/s] are consistent with typical SGRBs' luminosities and expectations from the Blandford-Znajek mechanism. By the time we terminate our simulations, we do not observe either an outflow or a large-scale magnetic-field collimation for the other systems we consider. The mass range of dynamically ejected matter is 10-4.5-10-2(MNS/1.4 M) M, which can power kilonovas with peak bolometric luminosities Lknova∼1040-1041.4 erg/s with rise times 6.5 h and potentially detectable by the LSST.
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U2 - 10.1103/PhysRevD.102.124077
DO - 10.1103/PhysRevD.102.124077
M3 - Article
AN - SCOPUS:85099145995
SN - 2470-0010
VL - 102
JO - Physical Review D
JF - Physical Review D
IS - 12
M1 - 124077
ER -