Gamma Ray Bursts


Just before 2000 UTC on 14 January, the Fermi and Swift satellites detected a spike of gamma rays from the constellation Fornax. The missions alerted the astronomical community to the location of the burst, dubbed GRB 190114C. Ground-based facilities detected radiation with up to a trillion times the energy of visible light from the gamma-ray burst.

The illustration above shows the set-up for the most common type of GRB. The core of a massive star (left) has collapsed and formed a black hole. This “engine” drives a jet of particles that moves through the collapsing star and out into space at nearly the speed of light. The so-called prompt emission, which typically lasts a minute or less, may arise from the jet’s interaction with gas near the newborn black hole and from collisions between shells of fast-moving internal shockwaves within the jet itself. The afterglow emission occurs as the leading edge of the jet sweeps through the surroundings creating an external shock wave, and emitting radiation across a broad spectrum. That may continue for months to years in the case of radio and visible light and for hours at the highest gamma-ray energies yet observed.

Image Credit: NASA

Note: My principal contribution to the Swift satellite was the design and testing of the power regulation system for the X-ray detectors in Burst Alert Telescope.

GRB 080916C


Gamma ray bursts are the brightest explosions we see in the Universe. The farthest known GRB occurred 12.2 billion light-years away in the constellation Carina. The explosion that created GRB 080916C contained the power of 9,000 supernovae. This very short movie shows Fermi Large Area Telescope observations of GRB 080916C. About 8 minutes of data are compressed into 6 seconds. The colored dots represent gamma rays of different energies. The blue dots represent lower-energy gamma rays; green, moderate energies; and red, the highest energies.

Video Credit: NASA / DOE / Fermi LAT Collaboration

Gamma Ray Burst


When a massive star collapses to form a black hole, a burst of gamma rays results as particles are blasted outward at nearly the speed of light. This animation shows the most common type of gamma-ray burst. An end-on view of a jet greatly boosts its apparent brightness. One especially bright burst (GRB 130427A) was detected in 2013 by the Fermi and Swift satellites. A Fermi image of that burst ends the animation sequence.

Video Credit: NASA

Swift’s Gamma Ray Burst Number 1,000


grb151027b_uvot_xrt_labeled_2160GRB 151027B, Swift‘s 1,000th burst, is in the center of this composite X-ray, ultraviolet, and optical image. X-rays were captured by Swift‘s X-Ray Telescope within minutes after the Burst Alert Telescope detected the blast. Swift‘s Ultraviolet/Optical Telescope (UVOT) began observations a few seconds later and faintly detected the burst in visible light. The image includes X-rays with energies from 300 to 6,000 eV, mostly from the burst, and lower-energy light seen through the UVOT’s visible, blue and ultraviolet filters (color shifted, respectively, to red, green and blue).

Image Credit: NASA