Quasi-periodic eruptions from galaxy nuclei
Abstract
I consider quasi-periodic eruptions (QPEs) from galaxy nuclei. All the known cases fit naturally into a picture of accretion from white dwarfs (WDs) in highly eccentric orbits about the central black holes which decay through gravitational wave emission. I argue that ESO 243-39 HLX-1 is a QPE source at an earlier stage of this evolution, with a correspondingly longer period, more extreme eccentricity, and a significantly more massive WD donor. I show explicitly that mass transfer in QPE systems is always highly stable, despite recent claims to the contrary in the literature. This stability may explain the alternating long-short eruptions seen in some QPE sources. As the WD orbit decays, the eruptions occupy larger fractions of the orbit and become brighter, making searches for quasi-periodicities in bright low-mass galaxy nuclei potentially fruitful.
- Publication:
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Monthly Notices of the Royal Astronomical Society
- Pub Date:
- September 2022
- DOI:
- 10.1093/mnras/stac1641
- arXiv:
- arXiv:2206.04698
- Bibcode:
- 2022MNRAS.515.4344K
- Keywords:
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- galaxies: active;
- X-rays: galaxies;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted for MNRAS - final version