ASASSN-15lh
ASASSN-15lh (supernova designation SN 2015L) is an extremely luminous astronomical transient event discovered by the All Sky Automated Survey for SuperNovae (ASAS-SN), with the appearance of a superluminous supernova event. It was first detected on June 14, 2015, located within a faint galaxy in the southern constellation Indus, and was the most luminous supernova-like object ever observed. At its peak, ASASSN-15lh was 570 billion times brighter than the Sun, and 20 times brighter than the combined light emitted by the Milky Way Galaxy. The emitted energy was exceeded by PS1-10adi.
A visual band light curve for ASASSN-15lh, plotted from data published by Godoy-Rivera et al. (2017). The purple line shows the brightness of the host galaxy. | |
| SLSNe (Type Ic), SNSLSN-I | |
| Right ascension | 22h 2m 15.45s |
|---|---|
| Declination | −61° 39′ 34.64″ |
| Distance | 1,171 megaparsecs 3.82 gigalight-years |
| Redshift | 0.2326 |
| Host | APMUKS(BJ) B215839.70−615403.9 |
| Peak apparent magnitude | 16.9 |
| Other designations | SN 2015L |
The nature of ASASSN-15lh is disputed. The most popular explanations are that it is the most luminous type I supernova (hypernova) ever observed, or a tidal disruption event around a supermassive black hole. Other hypotheses include: gravitational lensing; a quark nova inside a Wolf–Rayet star; or a rapid magnetar spindown.