Search and detection of northern pulsars in the side lobes of the murchison wide-field array

Abstract

New pulsar searching methods can significantly enhance the discovery of new pulsars and observations of single pulsars. This paper searches for pulsars among the observations centered at 185 MHz collected by the Murchison Wide-field Array (MWA). The declinations of two high-latitude northern sky pulsars, identified as J0332+5434 and J2219+4754, exceeded the commonly considered detection limit of MWA (declination≤30°), and appeared in the side lobes of MWA’s incoherent beams. Although the sensitivity is substantially lower in the side lobes than in the main lobe, pulsars are generally very bright at low frequencies, so are observable in the side lobes of low-frequency, wide field of view telescopes. This article describes the search for pulsars with the MWA, and discusses the possibility of further searching and observing the northern sky pulsars in the MWA side lobes. In a simulation study, the MWA detection sensitivity was evaluated at several flux densities of known radio pulsars. We estimated that approximately 30 known northern sky pulsars can be detected in the MWA side lobes. This work promises future pulsar searching by the Square Kilometer Array at low frequencies.