My understanding of the abstract is (I'm not an astronomer): TON 618 is an active SMBH ("hyperluminous, broad-absorption-line, radio-loud quasar" [0]). The SM

My understanding of the abstract is (I'm not an astronomer): TON 618 is an active SMBH ("hyperluminous, broad-absorption-line, radio-loud quasar" [0]). The SMBH they found has a smaller mass [2], but it is passive (= much darker). From the abstract: "Outside the local Universe, measurements of MBH are usually only possible for SMBHs in an active state: limiting sample size and introducing selection biases. Gravitational lensing makes it possible to measure the mass of non-active SMBHs." [1] [0] https://en.wikipedia.org/wiki/TON_618 https://en.wikipedia.org/wiki/TON_618 [1] https://academic.oup.com/mnras/article-abstract/521/3/3298/7085506 https://academic.oup.com/mnras/article-abstract/521/3/3298/7... [2] "it could be a supermassive black hole equivalent to 13 billion suns: 1.3±0.6)×10^10 M" https://en.wikipedia.org/wiki/Abell_1201_BCG https://en.wikipedia.org/wiki/Abell_1201_BCG