Gamma-ray bursts are among the most energetic and explosive events in the universe. They are also short-lived, lasting from a few milliseconds to about a minute, making it tough for astronomers to observe a gamma-ray burst in detail. Using a wide array of ground- and space-based telescope observations, an international team constructed one of the most detailed descriptions of a gamma-ray burst to date.
NASA’s Fermi Gamma-ray Space Telescope has identified the farthest gamma-ray blazars, a type of galaxy whose intense emissions are powered by supersized black holes. Light from the most distant object began its journey to us when the universe was 1.4 billion years old, or nearly 10 percent of its present age.
Fast radio bursts (FRBs) were first discovered in 2007, and in the years since radio astronomers have detected a few dozen of these events. Researchers have found that these mysterious “cosmic whistles” can release a billion times more energy in gamma-rays than they do in radio waves, rivalling supernovae in their explosive power.
Using data from NASA’s Fermi Gamma-ray Space Telescope and other facilities, an international team has found the first gamma-ray binary in another galaxy and the most luminous one ever seen. The dual-star system, dubbed LMC P3, contains a massive star and a crushed stellar core that interact to produce a cyclic flood of gamma rays.
Atoms or their constituents account for a mere 4.9 percent of the universe. The rest is dark matter, so understanding this ubiquitous yet mysterious substance is a prime goal of modern astrophysics. By studying the spatial distribution of gamma-ray emission in the Milky Way, astronomers believe they have now identified a signature of dark matter annihilation.
In April 2015, after travelling for about half the age of the universe, a flood of powerful gamma rays from a distant galaxy slammed into Earth’s atmosphere. Observations of PKS 1441+25, a rare type of galaxy called a blazar, provide a look into the environment near a supermassive black hole at the galaxy’s centre and offer a glimpse into the state of the cosmos 7 billion years ago.
On 15 June 2015, a long-time acquaintance of X-ray and gamma ray astronomers made its comeback to the cosmic stage: V404 Cygni, a system comprising a black hole and a star orbiting one another. It is located in our Milky Way galaxy, almost 8,000 light-years away in the constellation Cygnus, the Swan.