The frequency dependence of scattering imprints on pulsar observations

Abstract

Observations of pulsars across the radio spectrum are revealing a dependence of the characteristic scattering time ($\tau$) on frequency, which is more complex than the simple power law with a theoretically predicted power law index. In this paper we investigate these effects using simulated pulsar data at frequencies below 300 MHz. We investigate different scattering mechanisms, namely isotropic and anisotropic scattering, by thin screens along the line of sight, and the particular frequency dependent impact on pulsar profiles and scattering time scales of each. We also consider how the screen shape, location and offset along the line of sight lead to specific observable effects. We evaluate how well forward fitting techniques perform in determining $\tau$. We investigate the systematic errors in $\tau$ associated with the use of an incorrect fitting method and with the determination of an off-pulse baseline. Our simulations provide examples of average pulse profiles at various frequencies. Using these we compute spectra of $\tau$ and mean flux for different scattering setups. We identify setups that lead to deviations from the simple theoretical picture. This work provides a framework for interpretation of upcoming low frequency data, both in terms of modelling the interstellar medium and understanding intrinsic emission properties of pulsars.

18 pages, 22 figures, corrected equations 5 and 6

References in corpus (6)

• An empirical model for the beams of radio pulsars
• Profile morphology and polarization of young pulsars
• The analysis of the largest sample of multi-frequency pulsar scatter time estimates
• Pulsars with gigahertz-peaked spectra
• Turn-over in pulsar spectra around 1 GHz
• Flux density measurements of GPS candidate pulsars at 610 MHz using interferometric imaging technique

Cited by in corpus (17)

• The gravitational-wave background null hypothesis: Characterizing noise in millisecond pulsar arrival times with the Parkes Pulsar Timing Array
• The NANOGrav 12.5-year Data Set: Wideband Timing of 47 Millisecond Pulsars
• Scattering analysis of LOFAR pulsar observations
• Frequency-Dependent Template Profiles for High Precision Pulsar Timing
• The MeerKAT Pulsar Timing Array: The $4.5$-year data release and the noise and stochastic signals of the millisecond pulsar population
• The Thousand-Pulsar-Array programme on MeerKAT -- V. Scattering analysis of single-component pulsars
• Probing the local interstellar medium with scintillometry of the bright pulsar B1133+16
• Gigahertz-peaked spectra pulsars and thermal absorption model
• The LOFAR Tied-Array All-Sky Survey: Timing of 21 pulsars including the first binary pulsar discovered with LOFAR
• Scattering study of Pulsars below 100 MHz using LWA1
• Probing pulsar scattering between 120 and 280 MHz with the MWA
• The Frequency Dependence of Scintillation Arc Thickness in Pulsar B1133+16
• Deconvolving Pulsar Signals with Cyclic Spectroscopy: A Systematic Evaluation
• Scattering features and variability of the Crab pulsar
• Pulsar polarimetry with the Parkes Ultra-Wideband receiver
• Pulsar Scintillation Studies with LOFAR: II. Dual-frequency scattering study of PSR J0826+2637 with LOFAR and NenuFAR
• A direct measurement of the electron density turbulence parameter $C_1$ and implications for the emission size of the magnetar XTE J1810-197