Revealing the Spectral State Transition of the Clocked Burster, GS 1826-238, with NuSTAR StrayCats
Abstract
We present the long-term analysis of GS 1826-238, a neutron star X-ray binary known as the Clocked Burster, using data from NuSTAR StrayCats. StrayCats, a catalog of NuSTAR stray light data, contains data from bright, off-axis X-ray sources that have not been focused by the NuSTAR optics. We obtained stray light observations of the source from 2014-2021, reduced and analyzed the data using nustar-gen-utils Python tools, demonstrating the transition of the source from the island atoll state to a banana branch. We also present the light-curve analysis of Type I X-ray bursts from the Clocked Burster and show that the bursts from the banana/soft state are systematically shorter in duration than those from the island/hard state and have a higher burst fluence. From our analysis, we note an increase in the mass accretion rate of the source, and a decrease in burst frequency with the transition.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2023
- DOI:
- 10.3847/1538-4357/acb689
- arXiv:
- arXiv:2212.05243
- Bibcode:
- 2023ApJ...947...81Y
- Keywords:
-
- Neutron stars;
- Compact objects;
- Low-mass x-ray binary stars;
- X-ray astronomy;
- 1108;
- 288;
- 939;
- 1810;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- doi:10.3847/1538-4357/acb689