Discovery of a steep-spectrum low-luminosity pulsar with the Murchison Widefield Array

Abstract

We report the discovery of the first new pulsar with the Murchison Widefield Array (MWA), PSR J0036$-$1033, a long-period (0.9 s) nonrecycled pulsar with a dispersion measure (DM) of 23.1 $\mathrm{pc}\mathrm{c}{\mathrm{m}}^{-3}$. It was found after processing only a small fraction ($\sim$1%) of data from an ongoing all-sky pulsar survey. Follow-up observations have been made with the MWA, the upgraded Giant Metrewave Radio Telescope (uGMRT), and the Parkes 64 m telescopes, spanning a frequency range from $\sim$150 MHz to 4 GHz. The pulsar is faint, with an estimated flux density ($S$) of $\sim$1 mJy at 400 MHz and a spectrum $S(\nu )\propto {\nu }^{-2.0\pm 0.2}$, where $\nu$ is frequency. The DM-derived distance implies that it is also a low-luminosity source ($\sim$ 0.1 $\mathrm{mJy}\mathrm{kp}{\mathrm{c}}^2$ at 1400 MHz). The analysis of archival MWA observations reveals that the pulsar's mean flux density varies by up to a factor of $\sim$5-6 on timescales of several weeks to months. By combining MWA and uGMRT data, the pulsar position was determined to arcsecond precision. We also report on polarization properties detected in the MWA and Parkes bands. The pulsar's nondetection in previous pulsar and continuum imaging surveys, the observed high variability, and its detection in a small fraction of the survey data searched to date, all hint at a larger population of pulsars that await discovery in the southern hemisphere, with the MWA and the future low-frequency Square Kilometre Array.

12 pages, 6 figures, 2 tables, Accepted for publication in The ApJ Letters

References in corpus (15)

• A New Electron Density Model for Estimation of Pulsar and FRB Distances
• PSRCHIVE and PSRFITS An Open Approach to Radio Pulsar Data Storage and Analysis
• The Parkes multibeam pulsar survey: VI. Discovery and timing of 142 pulsars and a Galactic population analysis
• GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue
• The Green Bank Northern Celestial Cap Pulsar Survey - I: Survey Description, Data Analysis, and Initial Results
• The detection of an extremely bright fast radio burst in a phased array feed survey
• The LOFAR Tied-Array All-Sky Survey (LOTAAS): Survey overview and initial pulsar discoveries
• LOFAR discovery of the fastest-spinning millisecond pulsar in the Galactic field
• Wideband polarized radio emission from the newly revived magnetar XTE J1810$-$197
• The High Time and Frequency Resolution Capabilities of the Murchison Widefield Array
• Low Frequency Observations of the Subpulse Drifter PSR J0034-0721 with the Murchison Widefield Array
• The LOFAR Tied-Array All-Sky Survey: Timing of 21 pulsars including the first binary pulsar discovered with LOFAR
• A Census of Southern Pulsars at 185 MHz
• Hunting for radio emission from the intermittent pulsar J1107-5907 at low frequencies
• MWA tied-array processing III: Microsecond time resolution via a polyphase synthesis filter

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• pulsar_spectra: A pulsar flux density catalogue and spectrum fitting repository
• The Southern-sky MWA Rapid Two-metre (SMART) pulsar survey -- I. Survey design and processing pipeline
• The Southern-sky MWA Rapid Two-metre (SMART) pulsar survey -- II. Survey status, pulsar census, and first pulsar discoveries
• Spectral analysis of 22 radio pulsars using SKA-Low precursor stations
• Multi-messenger observations of double neutron stars in Galactic disk with gravitational and radio waves
• MWA Tied-Array Processing IV: A Multi-Pixel Beamformer for Pulsar Surveys and Ionospheric Corrected Localisation
• A targeted search for repeating fast radio bursts with the MWA