1. Revealing the Spectral State Transition of the Clocked Burster, GS 1826-238, with NuSTAR StrayCats
- Author
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S. B. Yun, B. W. Grefenstette, R. M. Ludlam, M. C. Brumback, D. J. K. Buisson, G Mastroserio, and S. N. Pike
- Subjects
Neutron stars ,Compact objects ,Low-mass x-ray binary stars ,X-ray astronomy ,Astrophysics ,QB460-466 - 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.
- Published
- 2023
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