• Tremblay, S. E.
• Ord, Stephen
• Straten, W. Van
• Smith, K. R.
• Kudale, Sanjay
• Swainston, Nicholas
• Mcsweeney, S. J.
• Bhat, Ramesh
• Williams, A.
• Walker, M.
• Meyers, B. W.
• Kaplan, D. L.
• Johnston-Hollitt, M.
• Tocknell, J.
• Lange, R.
• Dai, S.

Abstract

<jats:title>Abstract</jats:title><jats:p>We present an overview of the Southern-sky MWA Rapid Two-metre (SMART) pulsar survey that exploits the Murchison Widefield Array’s large field of view and voltage-capture system to survey the sky south of 30<jats:inline-formula><jats:alternatives><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S1323358023000176_inline1.png" /><jats:tex-math> $^$ </jats:tex-math></jats:alternatives></jats:inline-formula> in declination for pulsars and fast transients in the 140–170 MHz band. The survey is enabled by the advent of the Phase II MWA’s compact configuration, which offers an enormous efficiency in beam-forming and processing costs, thereby making an all-sky survey of this magnitude tractable with the MWA. Even with the long dwell times employed for the survey (4800 s), data collection can be completed in <jats:inline-formula><jats:alternatives><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S1323358023000176_inline2.png" /><jats:tex-math> $&lt;$ </jats:tex-math></jats:alternatives></jats:inline-formula>100 h of telescope time, while still retaining the ability to reach a limiting sensitivity of <jats:inline-formula><jats:alternatives><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S1323358023000176_inline3.png" /><jats:tex-math></jats:tex-math></jats:alternatives></jats:inline-formula>2–3 mJy (at 150 MHz, near zenith), which is effectively 3–5 times deeper than the previous-generation low-frequency southern-sky pulsar survey, completed in the 1990s. Each observation is processed to generate <jats:inline-formula><jats:alternatives><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S1323358023000176_inline4.png" /><jats:tex-math></jats:tex-math></jats:alternatives></jats:inline-formula>5000–8000 tied-array beams that tessellate the full <jats:inline-formula><jats:alternatives><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S1323358023000176_inline5.png" /><jats:tex-math> $ 610\, {{deg}^{2}}$ </jats:tex-math></jats:alternatives></jats:inline-formula> field of view (at 155 MHz), which are then processed to search for pulsars. The voltage-capture recording of the survey also allows a multitude of <jats:italic>post hoc</jats:italic> processing options including the reprocessing of data for higher time resolution and even exploring image-based techniques for pulsar candidate identification. Due to the substantial computational cost in pulsar searches at low frequencies, the survey data processing is undertaken in multiple passes: in the first pass, a shallow survey is performed, where 10 min of each observation is processed, reaching about one-third of the full-search sensitivity. Here we present the system overview including details of ongoing processing and initial results. Further details including first pulsar discoveries and a census of low-frequency detections are presented in a companion paper. Future plans include deeper searches to reach the full sensitivity and acceleration searches to target binary and millisecond pulsars. Our simulation analysis forecasts <jats:inline-formula><jats:alternatives><jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" mime-subtype="png" xlink:href="S1323358023000176_inline6.png" /><jats:tex-math></jats:tex-math></jats:alternatives></jats:inline-formula>300 new pulsars upon the completion of full processing. The SMART survey will also generate a complete digital record of the low-frequency sky, which will serve as a valuable reference for future pulsar searches planned with the low-frequency Square Kilometre Array.</jats:p>

Topics

• impedance spectroscopy
• phase
• simulation
• positron annihilation lifetime spectroscopy
• Photoacoustic spectroscopy
• forming