AT 2021lwx

It was first identified in imagery obtained on 13 April 2021 by the Zwicky Transient Facility (ZTF) astronomical survey[3] and is believed to be due to the accretion of matter into a super massive black hole (SMBH) heavier than one hundred million solar masses (M☉).

[2][1] Forced photometry of earlier ZTF imagery showed AT 2021lwx had already begun brightening by 16 June 2020, as ZTF20abrbeie.

[2][1] Subrayan et al. originally interpreted it to be a tidal disruption event between an SMBH (~108 M☉) and a massive star (~14 M☉).

[2] Wiseman et al. disfavor this interpretation, and instead believe the most likely scenario is "the sudden accretion of a large amount of gas, potentially a giant molecular cloud"[1] (~1,000 M☉),[6] onto an SMBH (>108 M☉).

However, the theoretical limit for an accreting super massive black hole is 1 hundred million solar masses.

(Upper) Light curve of AT2021lwx. (Lower left) Pan-STARRS upper limits up to 750 d (rest frame) before the first detection of AT2021lwx. (Lower right) Comparison to similar transients. [ 1 ]
Rest-frame UV and optical spectra of AT2021lwx and similar objects. [ 1 ]