A Multifrequency Census of 100 Pulsars below 100 MHz with LWA: A Systematic Study of Flux Density, Spectra, Timing, Dispersion, Polarization, and Its Variation from a Decade of Observations

Abstract

We present a census of 100 pulsars, the largest below 100 MHz, including 94 normal pulsars and six millisecond pulsars, with the Long Wavelength Array (LWA). Pulse profiles are detected across a range of frequencies from 26 to 88 MHz, including new narrow-band profiles facilitating profile evolution studies and breaks in pulsar spectra at low frequencies. We report mean flux density, spectral index, curvature, and low-frequency turnover frequency measurements for 97 pulsars, including new measurements for 61 sources. Multi-frequency profile widths are presented for all pulsars, including component spacing for 27 pulsars with two components. Polarized emission is detected from 27 of the sources (the largest sample at these frequencies) in multiple frequency bands, with one new detection. We also provide new timing solutions for five recently-discovered pulsars. Low-frequency observations with the LWA are especially sensitive to propagation effects arising in the interstellar medium. We have made the most sensitive measurements of pulsar dispersion measures (DMs) and rotation measures (RMs), with median uncertainties of 2.9x10^-4 pc cm^-3 and 0.01 rad m^-2, respectively, and can track their variations over almost a decade, along with other frequency-dependent effects. This allows stringent limits on average magnetic fields, with no variations detected above ~20 nG. Finally, the census yields some interesting phenomena in individual sources, including the detection of frequency and time-dependent DM variations in B2217+47, and the detection of highly circularly polarized emission from J0051+0423.

Accepted for publication in ApJ. 22 pages, 11 figures, supplementary figures and tables in appendix

References in corpus (17)

• Polarimetry of 600 pulsars from observations at 1.4 GHz with the Parkes radio telescope
• Low-frequency Faraday rotation measures towards pulsars using LOFAR: probing the 3-D Galactic halo magnetic field
• The LOFAR Tied-Array All-Sky Survey (LOTAAS): Survey overview and initial pulsar discoveries
• Pulsar polarisation below 200 MHz: Average profiles and propagation effects
• The analysis of the largest sample of multi-frequency pulsar scatter time estimates
• The impact of Solar wind variability on pulsar timing
• First detection of frequency-dependent, time-variable dispersion measures
• Faraday rotation measures of northern-hemisphere pulsars using CHIME/Pulsar
• The NANOGrav 12.5-Year Data Set: Polarimetry and Faraday Rotation Measures from Observations of Millisecond Pulsars with the Green Bank Telescope
• Scattering study of Pulsars below 100 MHz using LWA1
• Meterwavelength Single-pulse Polarimetric Emission Survey. V. Flux density, component spectral variation and emission states
• The effect of Pulse profile evolution on Pulsar Dispersion Measure
• Pulsar Observations at Low Frequencies: Applications to Pulsar Timing and Solar Wind Models
• The second decametre pulsar census at UTR-2 radio telescope
• Detection of frequency-dependent dispersion measure toward the millisecond pulsar PSR J2241-5236 from contemporaneous wide-band observations
• Flux Density Stability and Temporal Changes in the Spectra of Millisecond Pulsars using the GMRT
• Detecting Pulsar Polarization below 100 MHz with the Long Wavelength Array

Cited by in corpus (2)

• Design and Commissioning of an LWA Swarm Station: The Long Wavelength Array -- North Arm
• 50-250 MHz Pulsar Census with an SKA-Low prototype station: Spectra and Polarization