Chandra Monitoring of a Population of Ultraluminous X-ray Sources
Abstract
We report initial results from a Chandra Large Program to monitor the ULX populations of three nearby ULX-rich spiral galaxies over the course of a year. We find that the ULX population is heterogeneous in long-term variability behaviour. A small number of ULXs show completely persistent flux, though the majority of ULXs show moderate levels of variability with a significant relationship between hardness and luminosity consistent with a supercritically accreting source with varying accretion rate. Seven ULXs show very high-amplitude variability that does not appear to be bimodal like that expected for sources undergoing the propeller effect, but may instead indicate the presence of high-amplitude superorbital periods, a feature also demonstrated by most neutron star ULXs, and may indicate that these sources are good candidates for future pulsation searches.
- Publication:
-
American Astronomical Society Meeting Abstracts
- Pub Date:
- January 2023
- Bibcode:
- 2023AAS...24123301E