AT2018lqh: Black Hole Born from a Rotating Star?

Abstract

Recently an intriguing transient AT 2018lqh, with only a day-scale duration and a high luminosity of 7 × 10 42 erg s −1 , has been discovered. While several possibilities are raised on its origin, the nature of this transient is yet to be unveiled. We propose that a black hole (BH) with ∼ 30 M forming from a rotating blue supergiant can generate a transient like AT 2018lqh. We find that this scenario can consistently explain the optical/UV emission and the tentative late-time X-ray detection, as well as the radio upper limits. If super-Eddington accretion onto the nascent BH powers the X-ray emission, continued X-ray observations may be able to test the presence of an accretion disk around the BH.

Radiative diffusion in a time-dependent outflow: a model for fast blue optical transients

“…So we conclude that it is reasonable to have a velocity distribution of the outflow. We assume that the velocity of particles is distributed in the range of (v min , v max ) (Kashiyama & Quataert 2015;Tsuna et al 2021). We describe the physical process briefly and perform analytical calculations.…”