TY - JOUR
T1 - Dynamical stability of quasitoroidal differentially rotating neutron stars
AU - Espino, Pedro L.
AU - Paschalidis, Vasileios
AU - Baumgarte, Thomas W.
AU - Shapiro, Stuart L.
N1 - Funding Information:
P. E. and V. P. thank KITP for hospitality during the GRAVAST19 program, where part of this work was completed. This research was supported in part by National Science Foundation (NSF) Grant No. PHY-1912619 at the University of Arizona, NSF Grant No. PHY-1662211, and NASA Grant No. 80NSSC17K0070 at the University of Illinois at Urbana-Champaign, NSF Grant No. PHY-1707526 to Bowdoin College, and through sabbatical support from the Simons Foundation (Grant No. 561147 to T. W. B.). The simulations presented in this work were carried out in part on the Ocelote and ElGato clusters at the University of Arizona, the Blue Waters supercomputer at NCSA, and the Stampede2 cluster at TACC under XSEDE allocation PHY180044. Research at KITP. is supported in part by the National Science Foundation under Grant No. NSF PHY-1748958. The Blue Waters sustained-petascale computing project is supported by the National Science Foundation (Grants No. OCI-0725070 and No. ACI-1238993) and the State of Illinois. Blue Waters is a joint effort of the University of Illinois at Urbana-Champaign and its National Center for Supercomputing Applications.
Publisher Copyright:
© 2019 American Physical Society.
PY - 2019/8/16
Y1 - 2019/8/16
N2 - We investigate the dynamical stability of relativistic, differentially rotating, quasitoroidal models of neutron stars through hydrodynamical simulations in full general relativity. We find that all quasitoroidal configurations studied in this work are dynamically unstable against the growth of nonaxisymmetric modes. Both one-arm and bar mode instabilities grow during their evolution. We find that very high rest mass configurations collapse to form black holes. Our calculations suggest that configurations whose rest mass is less than the binary neutron star threshold mass for prompt collapse to black hole transition dynamically to spheroidal, differentially rotating stars that are dynamically stable, but secularly unstable. Our study shows that the existence of extreme quasitoroidal neutron star equilibrium solutions does not imply that long-lived binary neutron star merger remnants can be much more massive than previously found. Finally, we find models that are initially supra-Kerr (J/M2>1) and undergo catastrophic collapse on a dynamical timescale, in contrast to what was found in earlier works. However, cosmic censorship is respected in all of our cases. Our work explicitly demonstrates that exceeding the Kerr bound in rotating neutron star models does not imply dynamical stability.
AB - We investigate the dynamical stability of relativistic, differentially rotating, quasitoroidal models of neutron stars through hydrodynamical simulations in full general relativity. We find that all quasitoroidal configurations studied in this work are dynamically unstable against the growth of nonaxisymmetric modes. Both one-arm and bar mode instabilities grow during their evolution. We find that very high rest mass configurations collapse to form black holes. Our calculations suggest that configurations whose rest mass is less than the binary neutron star threshold mass for prompt collapse to black hole transition dynamically to spheroidal, differentially rotating stars that are dynamically stable, but secularly unstable. Our study shows that the existence of extreme quasitoroidal neutron star equilibrium solutions does not imply that long-lived binary neutron star merger remnants can be much more massive than previously found. Finally, we find models that are initially supra-Kerr (J/M2>1) and undergo catastrophic collapse on a dynamical timescale, in contrast to what was found in earlier works. However, cosmic censorship is respected in all of our cases. Our work explicitly demonstrates that exceeding the Kerr bound in rotating neutron star models does not imply dynamical stability.
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U2 - 10.1103/PhysRevD.100.043014
DO - 10.1103/PhysRevD.100.043014
M3 - Article
AN - SCOPUS:85072169254
SN - 2470-0010
VL - 100
JO - Physical Review D
JF - Physical Review D
IS - 4
M1 - 043014
ER -