Scattering study of Pulsars below 100 MHz using LWA1

Abstract

Interstellar scattering causes pulsar profiles to grow asymmetrically, thus affecting the pulsar timing residuals, and is strongest at lower frequencies. Different Interstellar medium models predict different frequency ($\nu$) and dispersion measure (DM) dependencies for the scattering time-scale ${\tau }_{sc}$. For Gaussian inhomogeneity the expected scaling relation is ${\tau }_{sc}\propto {\nu }^{-4}D{M}^2$, while for a Kolmogorov distribution of irregularities, the expected relation is ${\tau }_{sc}\propto {\nu }^{-4.4}D{M}^{2.2}$. Previous scattering studies show a wide range of scattering index across all ranges of DM. A scattering index below 4 is believed to be either due to limitations of the underlying assumptions of the thin screen model or an anisotropic scattering mechanism. We present a study of scattering for seven nearby pulsars (DM $<50$ pc cm${}^{-3}$) observed at low frequencies ($10-88$ MHz), using the first station of the Long Wavelength Array (LWA1). We examine the scattering spectral index and DM variation over a period of about three years. The results yield insights into the small-scale structure of ISM as well as the applicability of the thin screen model for low DM pulsars.

arXiv comment9 Figures, Accepted for publication by ApJ

References in corpus (29)

• A New Electron Density Model for Estimation of Pulsar and FRB Distances
• Gravitational waves from binary supermassive black holes missing in pulsar observations
• NE2001.I. A New Model for the Galactic Distribution of Free Electrons and its Fluctuations
• The NANOGrav 11-year Data Set: Pulsar-timing Constraints On The Stochastic Gravitational-wave Background
• Faint Scattering Around Pulsars: Probing the Interstellar Medium on Solar System Size Scales
• Understanding the radio emission geometry of PSR B0329+54
• The LWA1 Radio Telescope
• The European Pulsar Timing Array: current efforts and a LEAP toward the future
• Anomalous Radio-Wave Scattering from Interstellar Plasma Structures
• Scatter broadening measurements of 124 pulsars at 327 MHz
• Anomalous scattering of highly dispersed pulsars
• Wide-Band, Low-Frequency Pulse Profiles of 100 Radio Pulsars with LOFAR
• Scattering analysis of LOFAR pulsar observations
• Pulsar Observations Using the First Station of the Long Wavelength Array and the LWA Pulsar Data Archive
• Systematic and Stochastic Variations in Pulsar Dispersion Measures
• Dispersion measure variations in a sample of 168 pulsars
• The Frequency Evolution of Interstellar Pulse Broadening from Radio Pulsars
• The analysis of the largest sample of multi-frequency pulsar scatter time estimates
• Scatter broadening of pulsars and implications on the interstellar medium turbulence
• Pulse broadening analysis for several new pulsars and anomalous scattering
• Bistable Profile Illumination in Pulsars B0919+06 & B1859+07
• Understanding the spin-down rate changes of PSR B0919+06
• Multi-frequency scatter broadening evolution of pulsars - I
• Long term monitoring of mode switching for PSR B0329+54
• The frequency dependence of scattering imprints on pulsar observations
• Jiamusi Pulsar Observations: I. Abnormal emission events of PSR B0919+06
• Low-frequency pulse profile variation in PSR B2217+47: evidence for echoes from the interstellar medium
• On The Existence of Planets Around the Pulsar PSR B0329+54
• Scintillation observations of PSR B0823+26

Cited by in corpus (15)

• Pulsar scintillation studies with LOFAR. I. The census
• The NANOGrav 12.5-Year Data Set: Monitoring Interstellar Scattering Delays
• Long-term scintillation studies of EPTA pulsars. I. Observations and basic results
• Status Report on Global Pulsar-Timing-Array Efforts to Detect Gravitational Waves
• Deconvolving Pulsar Signals with Cyclic Spectroscopy: A Systematic Evaluation
• Pulsar Observations at Low Frequencies: Applications to Pulsar Timing and Solar Wind Models
• A VOEvent based automatic trigger system for the Murchison Widefield Array
• Detection of Echoes in PSR B1508+55 at frequencies below 100 MHz using the LWA1
• Pulsar Scintillation Studies with LOFAR: II. Dual-frequency scattering study of PSR J0826+2637 with LOFAR and NenuFAR
• A Cyclic Spectroscopy Scintillation Study of PSR B1937+21 I. Demonstration of Improved Scintillometry
• Scattering Delay Mitigation in High Accuracy Pulsar Timing: Cyclic Spectroscopy Techniques
• 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
• A Simultaneous Dual-Frequency Scintillation Arc Survey of Six Bright Canonical Pulsars Using the Upgraded Giant Metrewave Radio Telescope
• Evaluating Low-Frequency Pulsar Observations to Monitor Dispersion with the Giant Metrewave Radio Telescope
• 50-250 MHz Pulsar Census with an SKA-Low prototype station: Spectra and Polarization