| Description: | The radio transient sky remains relatively unexplored in the sub-second timescale. Known forms of these transients include single pulses from pulsars, Rotating Radio Transients (RRATs) and Fast Radio Bursts (FRBs). Most of these pulses have been discovered by large single dish telescopes, which cannot provide precise localizations due to their limited angular resolutions. The European VLBI Network (EVN), combining large collecting elements and superior angular resolution, is well-suited for searches and localizations of these pulses. In particular, searching for and localizing Fast Radio Bursts will enable us to identify their locations within their hosts and thereby unveiling their currently unknown origin.
In this summer project, we develop techniques to search for and localize single pulses with the European VLBI Network (EVN) data and apply them to repeating sources (a pulsar and a RRAT) to understand the limitations and uncertainties of these techniques. Shown in A) is a dispersed, astrophysical signal alongside the 80Hz calibration signal at Effelsberg. These calibration signals, resembling pulses, should be removed to allow for searches for truly astrophysical pulses. B) is a sample output of the source detection program we developed, showing the source at the center of the 2 arcmin x 2arcmin map with 0.5 milliarcsec resolution (i.e. a huge map). C) is the "dirty image" around where the source is detected in B); the pulse is clearly visible as the most prominent peak. In this fashion we obtain a position for each pulse. D) shows a histogram of all our measurements from a repeating source, PSR B0525+21; it demonstrates that localizations with milliarcsecond precision is attainable with the EVN. |
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