GRB 980425 was a

gamma-ray burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are immensely energetic explosions that have been observed in distant galaxies. They are the most energetic and luminous electromagnetic events since the Big Bang. Bursts can last from ten milli ...

(GRB) that was detected on 25 April 1998 at 21:49 UTC. GRB 980425 occurred at approximately the same time as

SN 1998bw SN 1998bw was a rare broad-lined Type Ic gamma ray burst supernova detected on 26 April 1998 in the ESO 184-G82 spiral galaxy, which some astronomers believe may be an example of a collapsar (hypernova A hypernova (sometimes called a collap ...

, providing the first evidence that gamma-ray bursts and

supernova A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or when ...

e are related, and at a distance of , remains the closest GRB yet observed.

Observations

GRB 980425 was first detected by the Gamma-Ray Burst Monitor onboard

BeppoSAX BeppoSAX was an Italian–Dutch satellite for X-ray astronomy which played a crucial role in resolving the origin of gamma-ray bursts (GRBs), the most energetic events known in the universe. It was the first X-ray mission capable of simultaneous ...

on 25 April 1998 at 21:49 UTC. The burst lasted approximately 30 seconds and had a single peak in its

light curve In astronomy, a light curve is a graph of light intensity of a celestial object or region as a function of time, typically with the magnitude of light received on the y axis and with time on the x axis. The light is usually in a particular frequ ...

. The Narrow Field Instruments (NFIs) onboard BeppoSAX began making observations of the region approximately 10 hours after the burst was detected. The NFIs detected two previously unknown x-ray sources—one at α = , δ = , and the other at α = , δ = . In the days that followed the burst, a

variable Variable may refer to: * Variable (computer science), a symbolic name associated with a value and whose associated value may be changed * Variable (mathematics), a symbol that represents a quantity in a mathematical expression, as used in many ...

object was detected in the original BeppoSAX error box that was not coincident with either of the two X-ray sources. The object's light curve implied that it might be a

Supernova relation

A search for the burst's radio afterglow resulted in one object that was coincident with the previously discovered supernova candidate, giving early credence to the idea that

and GRB 980425 were related. This was the first evidence of a physical relationship between gamma-ray bursts and supernovae. Evidence for this relationship and the details thereof continues to develop in the years since this breakthrough. Analyses of previously discovered bursts, such as

GRB 970228 GRB 970228"GRB" indicates that the event was a gamma-ray burst, and the numbers follow a YYMMDD format corresponding to the date on which the burst occurred: 28 February 1997. was the first gamma-ray burst (GRB) for which an afterglow was observe ...

and GRB 980326, showed that they may have also been affected by supernovae.

Notes

{{reflist 980425 19980425 April 1998 events Telescopium (constellation)