Monitoring of the radio emission of the Crab Nebula pulsar at low frequencies

A strong correlation between scattering and dispersion measure variations was observed during the long-term monitoring of giant radio pulses from the Crab Nebula pulsar (PSR B0531+21) at low frequencies (44, 63, and 111 MHz). Three distinct increases in scattering were recorded between 2002 and 2010, with the scattering index γ deviating from expected values (γ = 4.0 for Gaussian and γ = 4.4 for Kolmogorov distributions) during these periods. This anomaly suggests the presence of dense plasma structures with developed Langmuir turbulence along the pulsar’s line of sight. The magnetic field in the Crab Nebula was estimated at 100 µG using rotation measure measurements. Observations were conducted using the LPA and DKR-1000 radio telescopes, with data analyzed via specialized software modeling pulse propagation.

Kuz’min, A. D., Belyatsky, Yu. A., Dumsky, D. V., Izvekova, V. A., Lapaev, K. A., Logvinenko, S. V., Losovsky, B. Ya., & Pugachev, V. D. (2011). Monitoring of the radio emission of the Crab Nebula pulsar at low frequencies. Astronomy Reports, 55(5), 416–424. https://doi.org/10.1134/s1063772911040032