NuSTAR and Swift Observations of Swift J1357.2-0933 During an Early Phase of Its 2017 Outburst
Abstract
We present a detailed spectral analysis of Swift and NuSTAR observations of the very faint X-ray transient and black hole system, Swift J1357.2-0933, during an early, low-hard state of its 2017 outburst. Swift J1357.2-0933 was observed at ∼0.02% of the Eddington luminosity (for a distance of 2.3 kpc and a mass of 4 {\text{}}{M}⊙ ). Despite the low luminosity, the broadband X-ray spectrum between 0.3 and 78 keV requires the presence of a disk blackbody component with an inner disk temperature of {T}{in}∼ 0.06 {keV} in addition to a thermal Comptonization component with a photon index of {{Γ }}∼ 1.70. Using a more physical model, which takes strong relativistic effects into account, and assuming a high inclination of 70°, which is motivated by the presence of dips in optical light curves, we find that the accretion disk is truncated within a few {R}{ISCO} from the black hole, independent of the spin.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 2018
- DOI:
- 10.3847/1538-4357/aa9d3e
- arXiv:
- arXiv:1712.02804
- Bibcode:
- 2018ApJ...852...34S
- Keywords:
-
- binaries: close;
- stars: black holes;
- X-rays: binaries;
- X-rays: individual: Swift J1357.2-0933;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 11 pages, 5 figures, accepted for publication in ApJ