The LOFAR Tied-Array all-sky survey: Timing of 21 pulsars including the first binary pulsar discovered with LOFAR

Abstract

We report on the multi-frequency timing observations of 21 pulsars discovered in the LOFAR Tied-Array All-Sky Survey (LOTAAS). The timing data were taken at central frequencies of 149 MHz (LOFAR) as well as 334 and 1532 MHz (Lovell Telecope). The sample of pulsars includes 20 isolated pulsars and the first binary pulsar discovered by the survey, PSR J1658+3630. We modelled the timing properties of the pulsars, which showed that they have, on average, larger characteristic ages. We present the pulse profiles of the pulsars across the three observing bands, where PSR J1643+1338 showed profile evolution that appears not to be well-described by the radius-to-frequencymapping model. Furthermore, we modelled the spectra of the pulsars across the same observing bands, using a simple power law, and found an average spectral index of −1.9 ± 0.5. Amongst the pulsars studied here, PSR J1657+3304 showed large flux density variations of a factor of 10 over 300 days, as well as mode changing and nulling on timescales of a few minutes. We modelled the rotational and orbital properties of PSR J1658+3630, which has a spin period of 33 ms in a binary orbit of 3.0 days with a companion of minimum mass of 0.87M , likely a Carbon-Oxygen or Oxygen-Neon-Magnesium type white dwarf. PSR J1658+3630 has a dispersion measure of 3.0 pc cm −3 , making it possibly one of the closest binary pulsars known.

High-cadence Timing of Binary Pulsars with CHIME

“…No sources are detected within 5″ of PSR J2023+2853 in the Two Micron All Sky Survey (Skrutskie et al 2006) or the Gaia mission (Gaia Collaboration et al 2016. The nondetection of the white dwarf companion is expected, as it should have an r-magnitude of 25 in SDSS, smaller than the detection threshold of the surveys above, based on the r-magnitude of the detection made on a similar white dwarf in another pulsar binary system, PSR J1658 +3630 (Tan et al 2020).…”

Search for periodic emission of five gamma-ray pulsars at the frequency of 111 MHz

“…1 shows an example of visualization when processing observations of the well-known pulsar J1638+4005 at an interval of 3 years for the summed power spectrum and at an interval of 5.5 years for the summed periodograms. Pulsar J1638+4005, having P=0.76772 s and DM=33.4 pc/cm 3 (Tan, 2020), was detected in observations at the LPA LPI (Tyulbashev, 2017) in the summed power spectra, and was noted in the original work as a weak pulsar. The average pulsar profile given in the article, obtained in one observation session lasting 3.5 minutes, shows S/N=6.…”

“…The average pulsar profile given in the article, obtained in one observation session lasting 3.5 minutes, shows S/N=6. In Tan (2020), estimates of the integral flux density of this pulsar are given from observations at LOFAR and on the 76-meter Jodrel-Bank telescope: 128 MHz (S=3.1 mJy), 167 MHz (S=1.7 mJy), 334 MHz (S=0.34 mJy), 1532 MHz (S<0.06 mJy). Based on the estimate of the spectral index given in the paper ( = 2.3, ∼ − ), it is possible to estimate the expected integral flux density of this pulsar at the central frequency of the antenna of the LPA LPI ( 110.3 = 5.7 mJy).…”

Radio pulsar beam geometry down to the 100-MHz band: 76 additional sources within the Arecibo Sky

“…The largest overlap is in Paper I and Rankin (2021) but we note several here and in a subsequent paper (Wahl et al, 2021) also. Most of the detections so far have been of "B" pulsars, but fully half of the recent Kharkiv survey are of pulsars discovered with LO-FAR Sanidas et al (2019); Tan et al (2020) and not yet well studied at higher frequencies.…”