Reprocessing of the Parkes 70-cm Survey and Discovery of a New Radio Pulsar in the Large Magellanic Cloud

TL;DR

Reprocessing the Parkes 70-cm survey data with expanded search parameters led to the detection of additional known pulsars, discovery of a new pulsar in the LMC, and insights into survey limitations and data archival issues.

Contribution

This study reprocessed archival survey data with enhanced search techniques, resulting in new pulsar detections and the discovery of a previously unknown pulsar in the Large Magellanic Cloud.

Findings

Detected 94 additional known pulsars not found in original survey.

Discovered a new pulsar PSR J0540-69 in the LMC.

Identified limitations due to missing data and candidate sifting methods.

Abstract

We have reprocessed the data archived from the Parkes 70-cm pulsar (PKS70) survey with an expanded DM search range and an acceleration search. Our goal was to detect pulsars that might have been missed in the original survey processing. Of the original 43842 pointings, 34869 pointings were archived, along with 440 additional pointings for confirmation or timing. We processed all of these archived data and detected 359 known pulsars: 265 of these were detected in the original survey, while an additional 94 currently known pulsars were detected in our reprocessing. A few among those 94 pulsars are highly accelerated binary pulsars. Furthermore, we detected 5 more pulsars with DMs higher than the original survey thresholds, as well as 6 more pulsars below the nominal survey sensitivity threshold (from the original survey beams with longer integrations). We missed detection of 33 (of the 298) pulsars detected in the original survey, in part because portions of the survey data were missing in the archive and our early stage candidate sifting method. We discovered one new pulsar in the re-analysis, PSR J0540$-$69 which has a spin period of 0.909 s and resides in the Large Magellanic Cloud (LMC). This new pulsar appeared in three PKS70 beams and one additional L-band observation that targeted the LMC pulsar PSR B0540$-$69. The numerous pulsar detections found in our re-analysis and the discovery of a new pulsar in the LMC highlight the value of conducting multiple searches through pulsar datasets.