On detection of FRBs and pulsars in relativistic binary systems

Barak Zackay (IAS)

Fast radio bursts (FRB's) are an exciting, recently discovered, astrophysical transients which their origins are unknown. Currently, these bursts are believed to be coming from cosmological distances, allowing us to probe the electron content on cosmological length scales. Even though their precise localization is crucial for the determination of their origin, radio interferometers were not extensively employed in searching for them due to computational limitations. I will briefly present the Fast Dispersion Measure Transform (FDMT) algorithm, that allows to reduce the operation count in blind incoherent dedispersion by 2-3 orders of magnitude. In addition, FDMT enables to probe the unexplored domain of sub-microsecond astrophysical pulses.

In addition, I will provide a preview to a novel algorithm that enables the detection of pulsars in relativistic binary systems using observation times longer than an orbital period. Current pulsar search programs limit their searches for integration times shorter than a few percents of the orbital period. Until now, searching for pulsars in binary systems using observation times longer than an orbital period was considered impossible as one has to blindly enumerate all options for the Keplerian parameters, the pulsar rotation period, and the unknown DM.

Using the current state of the art pulsar search techniques and all computers on the earth, such an enumeration would take longer than a Hubble time. I will demonstrate that using the new algorithm, it is possible to conduct such an enumeration on a laptop using real data of the double pulsar PSR J0737-3039. Among the other applications of this algorithm are:
1) Searching for all pulsars on all sky positions in gamma ray observations of the Fermi LAT satellite.
2) Blind searching for continuous gravitational wave sources emitted by pulsars with non-axis-symmetric matter distribution. Previous attempts to conduct all of the above searches contained substantial compromises reducing their sensitivity by more than an order of magnitude.

Thursday, November 9, 2017