Fast Radio Bursts

Fast Radio Bursts

FRBs are bright millisecond duration radio emissions discovered in 2007 in surveys for radio pulsars, i.e rapidly rotating neutron stars that emit beams of radio emission from the open magnetic field lines at their magnetic poles. The burst was discovered during a search of archival data from a 1.4 GHz survey of the Magellanic Clouds using the multi-beam receiver on the 64 m Parkes radio telescope. It is estimated that the average FRB releases as much energy in a millisecond as the Sun puts out in 3 days. While FRBs appear similar to the individual pulses from pulsars, their large dispersive delays suggest that they originate from far outside the Milky Way and hence are many orders of magnitude more luminous. The total number of FRBs detected till now is above 600.

Some repeating FRBs have also been found, first such identified FRB was the FRB121102 found in 2012 November 02. This meant that follow up observations could be performed on such objects. It also meant that the source of the bursts survived such massive emission of energy and the cataclysmic models of origins of FRBs which meant the destruction of source could be ruled out or modified. Spectroscopic observations of the FRB host galaxy revealed the counterpart to be a low-metallicity, star-forming dwarf galaxy at a redshift of z = 0.193 confirming the extragalactic origin of FRB 121102.

The origins of FRBs are still unknown and at present there are various theories but none conclusive. Nu- merous theoretical models have been proposed to interpret these mysterious events. There have been driven by observations and ground-breaking results from numerous radio observatories: Parkes, Green Bank Telescope, archival data from Arecibo, the Australian Square Kilometer Array Pathfinder (ASKAP), the Canadian Hydro- gen Intensity Mapping Experiment (CHIME), the Five-hundred-meter Aperture Spherical Telescope (FAST), the Survey for Transient Astronomical Radio Emissions 2 (STARE2), to name a few. There are prospects of using FRBs to probe the extreme environments in which they are created as well as other objects in the path. They also have high implied all-sky event rate, there is a detectable FRB occurring every minute.[3] Due to the small field of view of current radio telescopes we have been limited in the number of events detected. Increasingthe field of view implies trading off the sensitivity. We are interested in the highly energetic events, making such trade off possible.

The estimated rate is roughly ≳ 103 FRBs detectable over whole sky every day with large radio facilities. A large radio facility with a wide field of view will maximize the number of detections. We use the Schechter Luminosity function to approximate the number of FRBs that can be detected for a given luminosity and beam pattern of radio telescope.