Astronomers discover new class of cosmic explosions

Using a range of telescopes operating at different wavelengths, astronomers have found three separate objects that constitute a new class of cosmic explosions, in papers published in the Astrophysical Journal and the Astrophysical Journal Letters.

The astronomers followed up on these objects first discovered using optical telescopes by observing them with two SKA pathfinders: the NSF’s Very Large Array in the US and NCRA’s Giant Metrewave Radio Telescope in India, as well as NASA’s Chandra X-ray space telescope.

These so-called Fast Blue Optical Transients (FBOTs) probably begin the same way as certain supernovae and gamma-ray bursts – when a star much more massive than the Sun explodes at the end of its “normal” atomic fusion-powered life.

However, FBOTs seem to be enshrouded by thick material that was probably shed by the star just before it exploded. When the thick material is struck by the blast wave of the explosion, it causes a bright visible-light burst. And as the blast wave collides with the material around the star as it travels outwards, it produces radio emission.

The astronomers also found that all three objects are located in small, dwarf galaxies, which leads them to believe that the dwarf galaxy properties might allow some very rare evolutionary paths of stars that lead to these distinctive explosions. To better understand this new class of cosmic explosions, they hope to observe more FBOTs and their environments using telescopes covering a wide range of wavelengths.

Artist’s conception illustrates the phenomena that make up the new class of cosmic explosions called Fast Blue Optical Transients. Credit: Bill Saxton, NRAO/AUI/NSF

The artist’s conception illustrates the differences in phenomena resulting from an “ordinary” core-collapse supernova explosion, an explosion creating a gamma-ray burst, and one creating a Fast Blue Optical Transient. Credit: Bill Saxton, NRAO/AUI/NSF

SOURCE: NRAO