2E61

2E61 is a gamma-ray burst (GRB) observed on July 19, 2005, by the Swift Gamma-Ray Burst Mission. It was detected at 14:21:34 UTC in the constellation of Draco, at a redshift of 0.808, indicating a distance of approximately 9.75 billion light years.

The burst was classified as a long-duration gamma-ray burst, characterized by an initial X-ray and gamma-ray peak, followed by a prolonged X-ray plateau and a steep decay phase. The peak luminosity of 2E61 was measured to be approximately 1.4 x 10^51 erg/s, a relatively high value for a long-duration GRB.

Further observations by the X-ray Telescope (XRT) and Ultra-Violet and Optical Telescope (UVOT) on the Swift spacecraft revealed a soft X-ray spectrum with a slope of 2.05, indicating a possible highly scattered or transparent environment. The GRB afterglow was observed to brighten by a factor of 14 in the course of nearly 100 seconds.

The study of GRBs has led to a wide range of research areas, including cosmology, astrophysics and high-energy physics. Gamma-ray bursts are thought to be responsible for enriching the universe with heavy elements such as iron and nickel, synthesized at the core of massive stellar explosions. The classification and study of these events has shed light into some of the mechanisms that govern the behavior of collapsing massive stars, as well as yielding significant insights into the basic laws of physics governing the fabric of spacetime.