Eighteen new pulsars discovered with Arecibo data analysis

Astronomers from West Virginia University and elsewhere report the detection of 18 new pulsars using the Arecibo Observatory (AO) as part of the AO 327-MHz Drift Survey. The findings were detailed in a research paper published Feb. 6 on the arXiv pre-print server.

Pulsars are highly magnetized, rotating neutron stars emitting a beam of electromagnetic radiation. They are usually detected in the form of short bursts of radio emission; however, some of them are also observed via optical, X-ray and gamma-ray telescopes.

AO327 is a drift survey for pulsars with the Arecibo telescope at 327 MHz, which began in 2010 and ended in December 2020. Its aim was to search the entire Arecibo sky (declinations between −1 and 38 degrees) for pulsars and radio transients.

By analyzing the data from AO327, a team of astronomers led by Timothy E. E. Olszański has discovered 18 new pulsars. This increases the total number of pulsars found by this survey to 95.

“In total, 95 pulsars have been discovered in the AO327 survey. These are the last of the AO327 discoveries which can be followed up with the Arecibo Observatory,” the researchers wrote in the paper.

Based on the data from AO327, Olszański’s team identified 49 pulsars, out of which 18 had not been previously reported. Afterward, they obtained phase-connected timing solutions for all these pulsars.

It turned out that besides one partially recycled pulsar, designated PSR J0916+0658, all the identified sources are non-recycled pulsars. They all have spin periods ranging from 40 milliseconds to 5.05 seconds, and their dispersion measures are between 17.8 and 133.2 pc/cm³.

According to the paper, 29 out of the whole sample of pulsars reported in the study show some form of amplitude modulation alone, while one source was found to showcase subpulse drift alone, and 13 of them show evidence of both.

Moreover, the study found that one pulsar, designated PSR J1942+0147, exhibits the rare effect of bi-drifting, and another one, known as PSR J0225+1727, possesses an interpulse (which is offset by 164 degrees from the main pulse). Bi-drifting is a rare type of subpulse drift in which the drift slopes have different signs for different components.

The astronomers note that future studies of the pulsars reported in the paper will further explore their emission features and will investigate their polarization properties. They expect many more pulsar discoveries from the AO327 survey.

“Currently, less than 2% of survey search observations remain to be processed and more than 60% of search candidates remain to be inspected. We expect at least another 100 pulsars to be discovered,” the authors of the paper conclude.

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