Superluminous supernova in the context of Supernova

In gamma-ray astronomy, gamma-ray bursts (GRBs) are extremely energetic events occurring in distant galaxies which represent the brightest and most powerful class of explosion in the Universe. These extreme electromagnetic emissions are second only to the Big Bang as the most energetic and luminous phenomena known. Gamma-ray bursts can last from a few milliseconds to several hours. After the initial flash of gamma rays, a longer-lived afterglow is emitted, usually in the longer wavelengths of X-ray, ultraviolet, optical, infrared, microwave or radio frequencies.

The intense radiation of most observed GRBs is thought to be released during a supernova or superluminous supernova as a high-mass star implodes to form a neutron star or a black hole. Short-duration (sGRB) events are a subclass of GRB signals that are now known to originate from the cataclysmic merger of binary neutron stars.

A hypernova is a very energetic supernova which is believed to result from an extreme core collapse scenario. In this case, a massive star (>30 solar masses) collapses to form a rotating black hole emitting twin astrophysical jets and surrounded by an accretion disk. It is a type of stellar explosion that ejects material with an unusually high kinetic energy, an order of magnitude higher than most supernovae, with a luminosity at least 10 times greater. Hypernovae release such intense gamma rays that they often appear similar to a type Ic supernova, but with unusually broad spectral lines indicating an extremely high expansion velocity. Hypernovae are one of the mechanisms for producing long gamma ray bursts (GRBs), which range from 2 seconds to over a minute in duration. They have also been referred to as superluminous supernovae, though that classification also includes other types of extremely luminous stellar explosions that have different origins.

Stellar explosion can refer to:

• Nova
• Kilonova
• Micronova
• Supernova
  • Type Ia supernova
  • Type Ib and Ic supernovae
  • Type II supernova
  • Superluminous supernova
  • Hypernova
  • Pair-instability supernova
• Supernova impostor, stellar explosions that appear similar to supernova, but do not destroy their progenitor stars
  • Failed supernova
• Luminous red nova, an explosion thought to be caused by stellar collision
• Solar flares are a minor type of stellar explosion
• Tidal disruption event, the pulling apart of a star by tidal forces

SN 2005ap was an extremely energetic Type Ic supernova in the galaxy SDSS J130115.12+274327.5. With a peak absolute magnitude of around −22.7, it is the second-brightest superluminous supernova yet recorded, twice as bright as the previous record holder, SN 2006gy, though SN 2005ap was eventually surpassed by ASASSN-15lh. It was initially classified as Type II-L, but later revised to Type Ic. It was discovered on 3 March 2005, on unfiltered optical images taken with the 0.45 m ROTSE-IIIb (Robotic Optical Transient Search Experiment) telescope, which is located at the McDonald Observatory in West Texas, by Robert Quimby, as part of the Texas Supernova Search that also discovered SN 2006gy. Although it was discovered before SN 2006gy, it was not recognized as being brighter until October 2007. As it occurred 4.7 billion light years from Earth, it was not visible to the naked eye.

Although SN 2005ap was twice as bright at its peak than SN 2006gy, it was not as energetic overall, as the former brightened and dimmed in a typical period of a few days whereas the latter remained very bright for many months. SN 2005ap was about 300 times brighter than normal for a Type II supernova. It has been speculated that this hypernova involved the formation of a quark star. Quimby has suggested that the hypernova is of a new type distinct from the standard Type II supernova, and his research group have identified five other supernovae similar to SN 2005ap and SCP 06F6, all of which were extremely bright and lacking in hydrogen.