Abstract
Long-duration 3-ray bursts (GRBs) accompany the collapse of massive stars and carry information about the central engine. However, no 3D models have been able to follow these jets from their birth via black hole (BH) to the photosphere. We present the first such 3D general-relativity magnetohydrodynamic simulations, which span over six orders of magnitude in space and time. The collapsing stellar envelope forms an accretion disk, which drags inwardly the magnetic flux that accumulates around the BH, becomes dynamically important, and launches bipolar jets. The jets reach the photosphere at 1/41012 cm with an opening angle θ j ∼6° and a Lorentz factor "j 2 30, unbinding 390% of the star. We find that (i) the disk-jet system spontaneously develops misalignment relative to the BH rotational axis. As a result, the jet wobbles with an angle θ t ∼12°, which can naturally explain quiescent times in GRB lightcurves. The effective opening angle for detection θ j + θ t suggests that the intrinsic GRB rate is lower by an order of magnitude than standard estimates. This suggests that successful GRBs are rarer than currently thought and emerge in only 1/40.1% of supernovae Ib/c, implying that jets are either not launched or choked inside most supernova Ib/c progenitors. (ii) The magnetic energy in the jet decreases due to mixing with the star, resulting in jets with a hybrid composition of magnetic and thermal components at the photosphere, where 1/410% of the gas maintains magnetization σ 3 0.1. This indicates that both a photospheric component and reconnection may play a role in the prompt emission.
| Original language | English (US) |
|---|---|
| Article number | L9 |
| Journal | Astrophysical Journal Letters |
| Volume | 933 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jul 1 2022 |
Funding
We thank François Foucart, Daniel Kasen, Brian Metzger, and Ehud Nakar for helpful comments. O.G. is supported by a CIERA Postdoctoral Fellowship. A.T. was supported by NSF grants AST-2107839, AST-1815304, AST-1911080, AST-2031997, and by Fermi Cycle 14 Guest Investigator program 80NSSC22K0031. A.T. and O.B. were partly supported by an NSF-BSF grant 2020747. O.B. acknowledges support by ISF grant 1657/18. D.G. acknowledges support from the Fermi Cycle 14 Guest Investigator Program 80NSSC21K1951, 80NSSC21K1938, and the NSF AST-2107806 grants. An award of computer time was provided by the Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program under award PHY129. This research used resources of the Oak Ridge Leadership Computing Facility, which is a DOE Office of Science User Facility supported under contract DE-AC05-00OR22725. The authors acknowledge the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing HPC and visualization resources that have contributed to the research results reported within this paper via the LRAC allocation AST20011 ( http://www.tacc.utexas.edu ). This research was also enabled in part by support provided by Compute Canada allocation xsp-772 ( http://www.computecanada.ca ).
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science