TY - JOUR
T1 - Simulating the magnetorotational collapse of supermassive stars
T2 - Incorporating gas pressure perturbations and different rotation profiles
AU - Sun, Lunan
AU - Ruiz, Milton
AU - Shapiro, Stuart L.
N1 - Funding Information:
We thank V. Paschalidis for useful discussions, and the Illinois Relativity Group REU team (E. Connelly, J. Simone and I. Sultan) for visualization assistance. This work has been supported in part by National Science Foundation (NSF) Grants No. PHY-1602536 and No. PHY-1662211, and NASA Grant No. 80NSSC17K0070 at the University of Illinois at Urbana-Champaign. This work made use of the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant No. TG-MCA99S008. This research is part of the Blue Waters sustained-petascale computing project, which 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:
© 2018 American Physical Society.
PY - 2018
Y1 - 2018
N2 - Collapsing supermassive stars (SMSs) with masses M104-6M have long been speculated to be the seeds that can grow and become supermassive black holes (SMBHs). We previously performed general relativistic magnetohydrodynamic (GRMHD) simulations of marginally stable Γ=4/3 polytropes uniformly rotating at the mass-shedding limit and endowed initially with a dynamically unimportant dipole magnetic field to model the direct collapse of SMSs. These configurations are supported entirely by thermal radiation pressure and reliably model SMSs with M106M. We found that around 90% of the initial stellar mass forms a spinning black hole (BH) remnant surrounded by a massive, hot, magnetized torus, which eventually launches a magnetically-driven jet. SMSs could be therefore sources of ultra-long gamma-ray bursts (ULGRBs). Here we perform GRMHD simulations of Γ4/3, polytropes to account for the perturbative role of gas pressure in SMSs with M106M. We also consider different initial stellar rotation profiles. The stars are initially seeded with a dynamically weak dipole magnetic field that is either confined to the stellar interior or extended from its interior into the stellar exterior. We calculate the gravitational wave burst signal for the different cases. We find that the mass of the black hole remnant is 90%-99% of the initial stellar mass, depending sharply on Γ-4/3 as well as on the initial stellar rotation profile. After t∼250-550M≈1-2×103(M/106M) s following the appearance of the BH horizon, an incipient jet is launched and it lasts for ∼104-105(M/106M) s, consistent with the duration of long gamma-ray bursts. Our numerical results suggest that the Blandford-Znajek mechanism powers the incipient jet. They are also in rough agreement with our recently proposed universal model that estimates accretion rates and electromagnetic (Poynting) luminosities that characterize magnetized BH-disk remnant systems that launch a jet. This model helps explain why the outgoing electromagnetic luminosities computed for vastly different BH-disk formation scenarios all reside within a narrow range (∼1052±1 erg s-1), roughly independent of M.
AB - Collapsing supermassive stars (SMSs) with masses M104-6M have long been speculated to be the seeds that can grow and become supermassive black holes (SMBHs). We previously performed general relativistic magnetohydrodynamic (GRMHD) simulations of marginally stable Γ=4/3 polytropes uniformly rotating at the mass-shedding limit and endowed initially with a dynamically unimportant dipole magnetic field to model the direct collapse of SMSs. These configurations are supported entirely by thermal radiation pressure and reliably model SMSs with M106M. We found that around 90% of the initial stellar mass forms a spinning black hole (BH) remnant surrounded by a massive, hot, magnetized torus, which eventually launches a magnetically-driven jet. SMSs could be therefore sources of ultra-long gamma-ray bursts (ULGRBs). Here we perform GRMHD simulations of Γ4/3, polytropes to account for the perturbative role of gas pressure in SMSs with M106M. We also consider different initial stellar rotation profiles. The stars are initially seeded with a dynamically weak dipole magnetic field that is either confined to the stellar interior or extended from its interior into the stellar exterior. We calculate the gravitational wave burst signal for the different cases. We find that the mass of the black hole remnant is 90%-99% of the initial stellar mass, depending sharply on Γ-4/3 as well as on the initial stellar rotation profile. After t∼250-550M≈1-2×103(M/106M) s following the appearance of the BH horizon, an incipient jet is launched and it lasts for ∼104-105(M/106M) s, consistent with the duration of long gamma-ray bursts. Our numerical results suggest that the Blandford-Znajek mechanism powers the incipient jet. They are also in rough agreement with our recently proposed universal model that estimates accretion rates and electromagnetic (Poynting) luminosities that characterize magnetized BH-disk remnant systems that launch a jet. This model helps explain why the outgoing electromagnetic luminosities computed for vastly different BH-disk formation scenarios all reside within a narrow range (∼1052±1 erg s-1), roughly independent of M.
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U2 - 10.1103/PhysRevD.98.103008
DO - 10.1103/PhysRevD.98.103008
M3 - Article
AN - SCOPUS:85057870036
SN - 2470-0010
VL - 98
JO - Physical Review D
JF - Physical Review D
IS - 10
M1 - 103008
ER -