Chandra high-resolution imaging of a new transient ultraluminous X-ray source in M81
Abstract
We propose a Chandra DDT observation of a newly discovered X-ray source in the nearby (3.7 Mpc) spiral galaxy M81. The source seems to be a new ultraluminous X-ray source (ULX) that has recently appeared, never before detected, despite numerous X-ray observations of the galaxy. This source is one of a handful of transient ULXs we have discovered recently while searching through Swift/XRT observations. These new ULXs appear to lie among an older stellar population, where models imply neutron star accretors are dominant. Unlike the previous sources identified, M81 has ample HST coverage allowing a search for an optical counterpart, and to age the stellar population of its environment. There are also candidate optical transients from ZTF in the Swift localization region. A 10-ks Chandra observation will provide the accurate X-ray position to identify the counterpart.
- Publication:
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Chandra Proposal
- Pub Date:
- May 2021
- Bibcode:
- 2021cxo..prop.6269B
- Keywords:
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- Chandra Proposal ID #23408846