NuSTAR and AstroSat observations of thermonuclear X-ray bursts with short-recurrence times in 4U 1636‑536
Abstract
We report results from the spectro-timing analysis of the atoll source 4U 1636‑536 observed with NuSTAR and AstroSat during its hard spectral state. In three observations of 207 ks total exposure, we identify 31 thermonuclear X-ray bursts including five doublets and a triplet. Recurrence time as short as 3.8 min is seen in one of the doublets. To the best of our knowledge, this is the shortest recurrence time known for this source. Our time-averaged spectroscopy during the bursts indicates the presence of an additional power-law or a blackbody component in a few cases, perhaps due to varying temperatures during bursts or plausible deviation from ideal blackbody behavior; however, it is difficult to probe this using the time-resolved spectroscopy owing to limited statistics. Time-resolved bursts are well fit using an absorbed blackbody model with temperatures varying between 1.7 and 2.2 keV. Burst oscillations around 581 Hz are detected with 3
- Publication:
-
Journal of Astrophysics and Astronomy
- Pub Date:
- December 2022
- DOI:
- arXiv:
- arXiv:2202.07379
- Bibcode:
- 2022JApA...43...45R
- Keywords:
-
- Stars: neutron;
- X-ray: binaries;
- X-ray: bursts;
- X-ray: individual (4U 1636−536);
- X-ray: individual (4U 1636‑536);
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 11 pages, 9 figures, 3 tables. Accepted for publication in the special issue of JAA, "Astrophysical jets and observational facilities: National perspective"