Post Mass-Transfer Binaries

The search for dormant black holes in binaries with stellar companions has yielded many systems actually containing two bright objects, so-called "impostors". Frequently, these impostors are binaries where one star has donated its mass to the other, and the other star is hot and rapidly rotating. Due to the high luminosity and low mass of the donor, the accretor is often not immediately detectable, but spectral disentangling can frequently reveal its presence. In this paper, we present the comprehensive analysis of a sample of 6 systems with high binary mass functions and an undetected secondary, potential dormant black hole candidates. Proposed by El-Badry & Rix (2022) to be potential impostors, we perform spectroscopic follow-up and disentangle the spectra to identify the components of the binary, constraining their formation histories and stellar parameters.

Further interesting imposter systems that my disentanling code has been applied to are presented in El-Badry et al (2022), Müller-Horn et al (2025), and El-Badry et al (2025).