Hidden Explosions
The 2010 Astronomy and Astrophysics Decadal Survey highlighted time domain astronomy as an area with excellent discovery potential. As at other wavelengths, the radio sky is dynamic, exhibiting variability on timescales from milliseconds to years. Such radio transients often signal explosive events, in some cases probing the highest energy particle populations in the Universe. These diverse phenomena include astrophysical blast waves, catastrophic collapses, compact object mergers accompanied by gravitational waves, magnetic acceleration of relativistic charged particles, shocks in high energy particle jets and magnetized diffuse interstellar plasma, flaring reconnection events in low mass star atmospheres, and the cosmic beacons of rotating neutron stars, white dwarfs, and black hole accretion disks.
While the detection of such events has relied on the synoptic survey capability of wide-field optical, X-ray and gamma-ray observatories, VLASS now also offers the potential to systematically characterize the dynamic sky at radio frequencies, targeting Galactic and extragalactic transient populations. The most numerous radio transients, with the greatest potential impact, belong to populations that are hidden from view at other wavebands, and in some cases are detectable only at radio wavelengths.
