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Full-Text Articles in Physical Sciences and Mathematics
Fast Radio Bursts From Interacting Binary Neutron Star Systems, Bing Zhang
Fast Radio Bursts From Interacting Binary Neutron Star Systems, Bing Zhang
Physics & Astronomy Faculty Research
Recent observations of repeating fast radio bursts (FRBs) suggest that some FRBs reside in an environment consistent with that of binary neutron star (BNS) mergers. The bursting rate for repeaters could be very high and the emission site is likely from a magnetosphere. We discuss a hypothesis of producing abundant repeating FRBs in BNS systems. Decades to centuries before a BNS system coalesces, the magnetospheres of the two neutron stars start to interact relentlessly. Abrupt magnetic reconnection accelerates particles, which emit coherent radio waves in bunches via curvature radiation. FRBs are detected as these bright radiation beams point toward Earth. …
Relation Between Gravitational Mass And Baryonic Mass For Non-Rotating And Rapidly Rotating Neutron Stars, He Gao, Shun-Ke Ai, Zhou-Jian Cao, Bing Zhang, Zhen-Yu Zhu, Ang Li, Nai-Bo Zhang, Andreas Bauswein
Relation Between Gravitational Mass And Baryonic Mass For Non-Rotating And Rapidly Rotating Neutron Stars, He Gao, Shun-Ke Ai, Zhou-Jian Cao, Bing Zhang, Zhen-Yu Zhu, Ang Li, Nai-Bo Zhang, Andreas Bauswein
Physics & Astronomy Faculty Research
With a selected sample of neutron star (NS) equations of state (EOSs) that are consistent with the current observations and have a range of maximum masses, we investigate the relations between NS gravitational mass Mg and baryonic mass Mb, and the relations between the maximum NS mass supported through uniform rotation (Mmax) and that of nonrotating NSs (MTOV). We find that for an EOS-independent quadratic, universal transformation formula (Mb=Mg+A×M2g)(Mb=Mg+A×Mg2), the best-fit A value is 0.080 for non-rotating NSs, 0.064 for maximally rotating NSs, and 0.073 when NSs with arbitrary rotation are considered. The residual error of the transformation is ∼ …
The Delay Time Of Gravitational Wave — Gamma-Ray Burst Associations, Bing Zhang
The Delay Time Of Gravitational Wave — Gamma-Ray Burst Associations, Bing Zhang
Physics & Astronomy Faculty Research
The first gravitational wave (GW) — gamma-ray burst (GRB) association, GW170817/GRB 170817A, had an offset in time, with the GRB trigger time delayed by ∼1.7 s with respect to the merger time of the GW signal. We generally discuss the astrophysical origin of the delay time, Δt, of GW-GRB associations within the context of compact binary coalescence (CBC) — short GRB (sGRB) associations and GW burst — long GRB (lGRB) associations. In general, the delay time should include three terms, the time to launch a clean (relativistic) jet, Δtjet; the time for the jet to break out from the surrounding …
Charged Compact Binary Coalescence Signal And Electromagnetic Counterpart Of Plunging Black Hole–Neutron Star Mergers, Bing Zhang
Physics & Astronomy Faculty Research
If at least one of the members of a compact binary coalescence is charged, the inspiral of the two members would generate a Poynting flux with an increasing power, giving rise to a brief electromagnetic counterpart temporally associated with the chirp signal of the merger (with possibly a small temporal offset), which we term as the charged compact binary coalescence (cCBC) signal. We develop a general theory of cCBC for any mass and amount of charge for each member. Neutron stars (NSs), as spinning magnets, are guaranteed to be charged, so the cCBC signal should accompany all NS mergers. The …
A Long-Lived Neutron Star Merger Remnant In Gw170817: Constraints And Clues From X-Ray Observations, L Piro, E Troja, Bing Zhang, G Ryan, H Van Eerten, R Ricci, M H. Wieringa, A Tiengo, N R. Butler, S B. Cenko, O D. Fox, H G. Khandrika, G Novara, A Rossi, T Sakamoto
A Long-Lived Neutron Star Merger Remnant In Gw170817: Constraints And Clues From X-Ray Observations, L Piro, E Troja, Bing Zhang, G Ryan, H Van Eerten, R Ricci, M H. Wieringa, A Tiengo, N R. Butler, S B. Cenko, O D. Fox, H G. Khandrika, G Novara, A Rossi, T Sakamoto
Physics & Astronomy Faculty Research
Multimessenger observations of GW170817 have not conclusively established whether the merger remnant is a black hole (BH) or a neutron star (NS). We show that a long-lived magnetized NS with a poloidal field B ≈ 1012 G is fully consistent with the electromagnetic dataset, when spin-down losses are dominated by gravitational wave (GW) emission. ... See full text for complete abstract.
Circumbinary Discs Around Merging Stellar-Mass Black Holes, Rebecca G. Martin, Chris Nixon, Fu-Guo Xie, Andrew King
Circumbinary Discs Around Merging Stellar-Mass Black Holes, Rebecca G. Martin, Chris Nixon, Fu-Guo Xie, Andrew King
Physics & Astronomy Faculty Research
A circumbinary disc around a pair of merging stellar-mass black holes may be shocked and heated during the recoil of the merged hole, causing a near-simultaneous electromagnetic counterpart to the gravitational wave event. The shocks occur around the recoil radius, where the disc orbital velocity is equal to the recoil velocity. The amount of mass present near this radius at the time of the merger is critical in determining how much radiation is released. We explore the evolution of a circumbinary disc in two limits. First, we consider an accretion disc that feels no torque from the binary. The disc …
The Origin Of The Prompt Emission For Short Grb 170817a: Photosphere Emission Or Synchrotron Emission?, Yan-Zhi Meng, Jin-Jun Geng, Bin-Bin Zhang, Jun-Jie Wei, Di Xiao, Liang-Duan Liu, He Gao, Xue-Feng Wu, En-Wei Liang, Yong-Feng Huang, Zi-Gao Dai, Bing Zhang
The Origin Of The Prompt Emission For Short Grb 170817a: Photosphere Emission Or Synchrotron Emission?, Yan-Zhi Meng, Jin-Jun Geng, Bin-Bin Zhang, Jun-Jie Wei, Di Xiao, Liang-Duan Liu, He Gao, Xue-Feng Wu, En-Wei Liang, Yong-Feng Huang, Zi-Gao Dai, Bing Zhang
Physics & Astronomy Faculty Research
The first gravitational-wave event from the merger of a binary neutron star system (GW170817) was detected recently. The associated short gamma-ray burst (GRB 170817A) has a low isotropic luminosity (~1047 erg s−1) and a peak energy E p ~ 145 keV during the initial main emission between −0.3 and 0.4 s. The origin of this short GRB is still under debate, but a plausible interpretation is that it is due to the off-axis emission from a structured jet. We consider two possibilities. First, since the best-fit spectral model for the main pulse of GRB 170817A is a cutoff power law …
The Allowed Parameter Space Of A Long-Lived Neutron Star As The Merger Remnant Of Gw170817, Shunke Ai, He Gao, Zi-Gao Dai, Xue-Feng Wu, Ang Li, Bing Zhang, Mu-Zi Li
The Allowed Parameter Space Of A Long-Lived Neutron Star As The Merger Remnant Of Gw170817, Shunke Ai, He Gao, Zi-Gao Dai, Xue-Feng Wu, Ang Li, Bing Zhang, Mu-Zi Li
Physics & Astronomy Faculty Research
Due to the limited sensitivity of the current gravitational wave (GW) detectors, the central remnant of the binary neutron star (NS) merger associated with GW170817 remains an open question. In view of the relatively large total mass, it is generally proposed that the merger of GW170817 would lead to a short-lived hypermassive NS or directly produce a black hole (BH). There is no clear evidence to support or rule out a long-lived NS as the merger remnant. Here, we utilize the GW and electromagnetic (EM) signals to comprehensively investigate the parameter space that allows a long-lived NS to survive as …