Unraveling the Mystery of Fast Radio Bursts

University Of Texas At Austin, Austin TX

Investigators

Abstract

Fast Radio Bursts (FRBs) are very bright, very fleeting astronomical events that typically last for a few milliseconds and have so far only been detected by radio telescopes. Distances to a few FRBs have been measured to be several billion light years away. These are the most powerful bursts of radio emission that we know of in the universe. A research group at the University of Texas will investigate the largely unknown properties of the progenitors of FRBs, what they are and how they are produced. The research will have wide implications for a number of fields in astronomy, such as the study of compact astrophysical objects like pulsars and magnetars, which are highly magnetized neutron stars. The study of FRBs will also be useful to cosmology, as FRBs are potentially an excellent probe of the material between galaxies and of particles in the extended halos of galaxies. The research will make use of data obtained by various ground-based telescopes supported by the NSF. The project will also include an education and public outreach component. The investigators will attempt to build a group environment that significantly increases the number of under-represented students trained in science. The visual products of the research, of great power and beauty, will be used to disseminate the results, inform the general public about science and the universe, and provide raw material for science curricula, documentaries, and astronomy presentations. Future secondary school teachers will learn, in a class taught by the principal investigator, how to conduct scientific research, and will be exposed to new developments in science. The researchers will carry out a two-pronged attack to decipher the origin of these mysterious bursts. One part of the program will start with the known luminosity and duration of FRBs, and cast a wide net over a large class of radiation (maser) processes to access which model provides a consistent description of the known radiative properties of FRBs. The scientists involved have shown that the force associated with induced-Compton (IC) scattering plays a very important role in narrowing down the likely radiation mechanism for FRBs; many well-known models are unable to sustain the activity for a few milliseconds, because the plasma in the source region is dispersed by the enormous force associated with IC scatterings and the process is shut off in less than one msec. The research work will explore this issue in depth. The group will also attack the problem from the opposite end. They will consider a disturbance at the surface of a neutron star (or a stellar black hole) and determine the conditions under which the disturbance can lead to a few msec-long intense pulse of coherent radio waves. If the object that produces these powerful radio bursts is a neutron star with very strong magnetic fields (magnetar), as is widely believed, the question of why some of these objects produce FRBs and others X- ray and gamma-ray bursts will also be investigated. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.