“The Astrophysics of Fast Radio Bursts”
Fast Radio Bursts (FRB) are luminous ~GHz radio pulses with ~millisecond duration of an unknown, but likely astrophysical, origin. The large dispersion measures of the bursts, which greatly exceed that accumulated through the ISM of the Galaxy or its halo, point to them being extragalactic events. Though most FRBs have been detected only once, the source FRB 121102 was observed to repeat hundreds of times. This property enabled the burster to be localized to a small dwarf galaxy at a redshift of z = 0.19, leading to detailed study of its environment (including its co-location with a star-forming region and persistent synchrotron source). Additional clues come from the polarization, rotation measure, scattering broadening, and narrow spectral energy distribution of the bursts.
Although only ~30 FRB sources are currently published, this sample is poised to expand rapidly over the next few years, thanks to the new surveys, such as SUPERB, ASKAP, and CHIME (Canadian Hydrogen Intensity Mapping Experiment). CHIME began its science run last fall and expects to detect between 2 and 50 FRBs every day once fully operational. CHIME already announced the discovery of several new repeating FRBs, as well as the lowest frequency ~400 MHz burst yet detected, and additional discoveries are slated to be announced this summer. Interferometers such as ASKAP and the VLA can localize the bursts and potentially identify their host galaxies and environments, even at relatively high redshift (z ~ 1).
In parallel with these observational developments, theorists are actively developing models of FRBs. These efforts range from identifying potential central engines (e.g. accreting black hole, flaring magnetars, annihilating dark matter, collapsing neutron stars) to determining the radio emission mechanism (e.g. antenna mechanism, synchrotron maser emission, etc). Several models attempt to connect FRBs to other phenomenon in high energy astrophysics (e.g. magnetars, gamma-ray bursts, superluminous supernovae), making important connections across wavelength band and research communities. Regardless of their origin, the observed dispersion and rotation measures of FRBs may provide novel new probes of baryons and magnetic fields in the intergalactic medium.
Despite growing interest in FRBs by the physics and astrophysics communities, the number of researchers is still modest and (on the observational side) largely focused in Canada and Australia. Given the rapid development of observations, and expertise/interest concentrated in the US, a Flatiron workshop bringing together theorists and observational astronomers, would be particularly timely and impactful. In addition to FRB scientists (which mainly originate from the pulsar community), we will plan to invite researchers with relevant overlapping knowledge, particularly to plasma physics, time-domain astronomy, and compact objects.
For a detailed agenda go here.