The High Time Resolution Universe Pulsar Survey – XVI. Discovery and timing of 40 pulsars from the southern Galactic plane

Abstract

We present the results of processing an additional 44 % of the High Time Resolution Universe South Low Latitude (HTRU-S LowLat) pulsar survey, the most sensitive blind pulsar survey of the southern Galactic plane to date. Our partially-coherent segmented acceleration search pipeline is designed to enable the discovery of pulsars in short, highly-accelerated orbits, while our 72-min integration lengths will allow us to discover pulsars at the lower end of the pulsar luminosity distribution. We report the discovery of 40 pulsars, including three millisecond pulsar-white dwarf binary systems (PSRs J1537−5312, J1547−5709 and J1618−4624), a black-widow binary system (PSR J1745−23) and a candidate black-widow binary system (PSR J1727−2951), a glitching pulsar (PSR J1706−4434), an eclipsing binary pulsar with a 1.5-yr orbital period (PSR J1653−45), and a pair of long spin-period binary pulsars which display either nulling or intermittent behaviour (PSRs J1812−15 and J1831−04). We show that the total population of 100 pulsars discovered in the HTRU-S LowLat survey to date represents both an older and lower-luminosity population, and indicates that we have yet to reach the bottom of the luminosity distribution function. We present evaluations of the performance of our search technique and of the overall yield of the survey, considering the 94 % of the survey which we have processed to date. We show that our pulsar yield falls below earlier predictions by approximately 25 % (especially in the case of millisecond pulsars), and discuss explanations for this discrepancy as well as future adaptations in RFI mitigation and searching techniques which may address these shortfalls.

News and views regarding PSR J1757-1854, a highly-relativistic binary pulsar

“…This is also shown in Figure 2. However, we note that these DM-distance estimates typically come with large uncertainties 13 , making a definitive determination difficult. Additionally, the McMillan Galactic potential model 10 we have used in our analysis has known shortcomings at distances of approximately 7-9 kpc in the central regions of the Galaxy near PSR J1757-1854's position, further complicating this assessment.…”

The High Time Resolution Universe Pulsar Survey -- XVII. PSR J1325-6253, a low eccentricity double neutron star system from an ultra-stripped supernova

“…After folding, an optimized S/N of 14.3 was obtained, well above the false alarm threshold, S/N thresh = 9 of our search. The non-detection of PSR J1325−6253 in previous processing of the survey conducted by Ng et al (2015) and Cameron et al (2020) was due to the segmented nature of their pipeline. In those searches, the 72-min full-length observations were only searched for accelerations, |𝑎| ≤ 1 m s −2 and higher acceleration searches were only performed on segmented observations where the sensitivity of a pulsar signal is degraded by a factor of √ 𝑁, where 𝑁 in the number of segments of the full integration observation.…”

“…Their orbits therefore closely resemble that of the immediate post-SN state and can be used to constrain the mass-loss and kicks NSs receive at birth in such systems. In this paper we present the discovery and timing analysis of the binary pulsar PSR J1325−6253 which was discovered in a reprocessing of the High Time Resolution Universe South Low Latitude (HTRU-S LowLat) pulsar survey (Keith et al 2010;Ng et al 2015;Cameron et al 2020). PSR J1325−6253 is the second DNS system discovered in the survey after PSR J1757−1854, which remains the most accelerated known pulsar in a Galactic DNS system (Cameron et al 2018).…”

Two Extreme Steep-Spectrum, Polarized Radio Sources Towards the Galactic Bulge

“…We searched for single pulses up to the DM of 3000 pc-cm −3 with pulse widths ranging from 0.3 to 77 ms. We were able to constrain the presence of isolated 1 ms wide single pulses with a 6σ sensitivity of 25 mJy. Additionally, a 72-min integration at 1.5 GHz was re-processed from the High Time Resolution Universe South Low Latitude (HTRU-S LowLat) pulsar survey (Cameron et al 2020) in a line of sight near C1709−3918, but no pulsations were found (Vishnu Balakrishnan and Rahul Sengar, private communication).…”