Diffractive and refractive timescales at 4.8 GHz in PSR B0329+54

Abstract

Aims. We present the results of flux density monitoring of PSR B0329+54 at the frequency of 4.8 GHz using the 32-m TCfA radiotelescope. The observations were conducted between 2002 and 2005. The main goal of the project was to find interstellar scintillation (ISS) parameters for the pulsar at the frequency at which it was never studied in detail. To achieve this, the 20 observing sessions consisted of 3-min integrations, which on average lasted 24 h. This gave us sufficient sensitivity to all types of flux density variations over a wide range of timescales. The character of the observations makes our project unique amongst other ISS oriented observing programs, at least at high frequency. Methods. Flux density time series obtained for each session were analysed using structure functions. For some of the individual sessions as well as for the general average structure function we were able to identify two distinctive timescales present, the timescales of diffractive and refractive scintillations. To the best of our knowledge, this is the first case when both scintillation timescales, t DISS = 42.7 min and t RISS = 305 min, were observed simultaneously in a uniform data set and estimated using the same method. Results. The obtained values of the ISS parameters combined with the data found in the literature allowed us to study the frequency dependence of these parameters over a wide range of observing frequencies, which is crucial for understanding the ISM turbulence. We found that the Kolmogorov spectrum is not best suited for describing the density fluctuations of the ISM, and a power-law spectrum with β = 4 seems to fit better with our results. We were also able to estimate the transition frequency (transition from strong to weak scintillation regimes) as ν c = 10.1 GHz, much higher than was previously predicted. We were also able to estimate the strength of scattering parameter u = 2.67 and the Fresnel scale as r F = 6.7 × 10 8 m.

Multifrequency Study on the Mode Switching of PSR J0614+2229

“…A factor that needs to be checked is whether refractive and diffractive interstellar scintillation may affect the flux and spectral estimates. It is known that refractive scintillation (Gupta et al 1994) has a timescale of the order of days and diffractive scintillation (Lewandowski et al 2011) can be of the order of minutes. RSL+16 has excluded the effect of both kinds of scintillation on their flux estimates by comparing with the scintillation timescales with the total integration time.…”

The analysis of the largest sample of multifrequency pulsar scatter time estimates

“…To create the new version of the plot in addition to the data used by L04 and all the references therein (see the figure caption for a full reference list) we used our data presented in Paper 1 (these are shown as open red circles) and the results of our current research (full blue circles). We also added two α estimations from our scintillation studies of PSR B0329+54 (α = 3.86 ± 0.24, Lewandowski et al 2011) and PSR B0823+26 (α = 3.94 ± 0.36, Daszuta, Lewandowski & Kijak 2013); these are shown in Figure 2 by diamonds. The current version of the α versus DM plot looks significantly different from the one showed by L04, and not only because we increased the number of measurements (by the factor of 2.25).…”

Pulse-to-pulse flux density modulation from pulsars at 8.35 GHz

“…This behaviour is clearly due to the strong interstellar scintillation and makes flux measurements of this source uncertain. According to the work of Lewandowski et al (2011), the pulsar B0329+54 has a transition frequency between 8 and 10 GHz, which suggests that it may have undergone occasional …”