Abstract
We present a comprehensive study of 29 short gamma-ray bursts (SGRBs) observed ≈0.8−60 days postburst using Chandra and XMM-Newton. We provide the inferred distributions of the SGRB jet opening angles and true event rates to compare against neutron star merger rates. We perform a uniform analysis and modeling of their afterglows, obtaining 10 opening angle measurements and 19 lower limits. We report on two new opening angle measurements (SGRBs 050724A and 200411A) and eight updated values, obtaining a median value of 〈θ j〉 ≈ 6.°1 [−3.°2, +9.°3] (68% confidence on the full distribution) from jet measurements alone. For the remaining events, we infer θ j ≳ 0.°5-26°. We uncover a population of SGRBs with wider jets of θ j ≳ 10° (including two measurements of θ j ≳ 15°), representing ∼28% of our sample. Coupled with multiwavelength afterglow information, we derive a total true energy of 〈E true,tot〉 ≈ 1049-1050 erg, which is consistent with magnetohydrodynamic jet launching mechanisms. Furthermore, we determine a range for the beaming-corrected event rate of R true ≈ 360 − 1800 Gpc−3 yr−1, set by the inclusion of a population of wide jets on the low end, and the jet measurements alone on the high end. From a comparison with the latest merger rates, our results are consistent with the majority of SGRBs originating from binary neutron star mergers. However, our inferred rates are well above the latest neutron star-black hole merger rates, consistent with at most a small fraction of SGRBs originating from such mergers.
| Original language | English (US) |
|---|---|
| Article number | 13 |
| Journal | Astrophysical Journal |
| Volume | 959 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 1 2023 |
Funding
The authors acknowledge Phil Evans for the extensive and constructive discussion on how to obtain the full set of unabsorbed X-ray flux light curves for the GRB afterglows from the UK Swift Science Data Centre. The authors also thank Amy Lien for her valuable exchange of ideas on calculating the isotropic γ-ray energies of the events. Support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Numbers GO0-21041X, GO0-21042X, and GO1-22043X issued by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060. The scientific results reported in this article are based to a significant degree on observations made by the Chandra X-ray Observatory, and data obtained from the Chandra Data Archive. In addition, this research has made use of software provided by the Chandra X-ray Center (CXC) in the application package CIAO . This work is based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester. The Fong Group at Northwestern acknowledges support by the National Science Foundation under grant Nos. AST-1814782, AST-1909358, and CAREER grant No. AST-2047919. W.F. gratefully acknowledges support by the David and Lucile Packard Foundation, the Alfred P. Sloan Foundation, and the Research Corporation for Science Advancement through Cottrell Scholar Award #28284. The Berger Time Domain Group at Harvard is supported by NSF and NASA grants. T.L. acknowledges support from the Radboud Excellence Initiative. R.M. acknowledges support from the NSF (grant Nos. AST-2224255 and AST-2221789). B.D.M. acknowledges support from the NSF (grant No. AST-2002577).
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science