X-Raying the Birth of Binary Neutron Stars and Neutron Star-Black Hole Binaries
Abstract
We consider fallback accretion after an ultrastripped supernova (USSN) that accompanies formation of a binary neutron star (BNS) or a neutron star-black hole binary (NS-BH). The fallback matter initially accretes directly to the nascent NS, while it starts to accrete to the circumbinary disk, typically 0.1-1 day after the onset of the USSN explosion. The circumbinary disk mass further accretes, forming mini disks around each compact object, with a super-Eddington rate up to a few years. We show that such a system constitutes a binary ultraluminous X-ray source, and a fraction of the X-rays can emerge through the USSN ejecta. We encourage follow-up observations of USSNe within ≲100 Mpc and ~100-1000 days after the explosion using Chandra, XMM Newton, and NuSTAR, which could detect the X-ray counterpart with time variations representing the properties of the nascent compact binary, e.g., the orbital motion of the binary, the spin of the NS, and/or the quasiperiodic oscillation of the mini disks.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 2022
- DOI:
- 10.3847/1538-4357/ac7ff7
- arXiv:
- arXiv:2204.08851
- Bibcode:
- 2022ApJ...935...86K
- Keywords:
-
- Neutron stars;
- Black holes;
- Compact binary stars;
- Supernovae;
- X-ray binary stars;
- 1108;
- 162;
- 283;
- 1668;
- 1811;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 12 pages, 5 figures