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Dong, Fengqiu

University of British Columbia

The Canadian Hydrogen Mapping Experiment (CHIME) is a radio telescope located in British Columbia, Canada. Initially built to survey the neutral hydrogen in the universe, it has had multiple additional jobs thrust upon its shoulders. One such responsibility is the discovery and continual monitoring of pulsars. With the large sky coverage and daily observing cadence, CHIME lends itself well to the hitherto poorly understood population of sporadic pulsars. The understanding of the population of sporadic pulsars, and in turn, all pulsars, will be informative for many areas of Galactic archaeology and supernova. First, I develop a new way to correct for the selection effects in the brightness distribution and nulling fraction of pulsars using their single pulses. This method, called LuNfit, is unique in that it can be applied to the most extreme examples of sporadic pulsars. Furthermore, it can be used on radio transients that do not have underlying periods, such as repeating fast radio bursts. I demonstrate the effectiveness of LuNfit by applying it to three known rotating radio transients (RRATs). I show that despite being classified as a RRAT through null detections when folding, PSR J0012+54 is may be a persistent emitter. Then, I take LuNfit further and incorporate pulse widths into the process. I conduct a year-long single pulse survey with CHIME/FRB, detecting 424 known and unknown pulsars. I apply LuNfit to a subset of 35 pulsars. This effort lays the groundwork for a larger population level analysis using large field of view single pulse surveys like CHIME/FRB. Finally, I discover a new long period transient, CHIME J0630+25, with a period of 421 s. This marks the fifth object in this new class. Their nature remains unknown, but I speculate that CHIME J0630+25 is likely a white dwarf or a neutron star. I further monitor the object across multiple wavelengths. With Neils Gehrels Swift X-ray telescope observations, I find 2 potential X-ray counterparts. At a distance of 170 pc, CHIME J0630+25 is the closest known long period transient.

Text

2024-10-21

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/89462

Astronomy

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/