Jiamusi Pulsar Observations: II. Scintillations of 10 Pulsars
Context. Pulsars scintillate. Dynamic spectra show brightness variation of pulsars in the time and frequency domain. Secondary spectra demonstrate the distribution of fluctuation power in the dynamic spectra. Aims. Dynamic spectra strongly depend on observational frequencies, but were often observed at frequencies lower than 1.5 GHz. Scintillation observations at higher frequencies help to constrain the turbulence feature of the interstellar medium over a wide frequency range and can detect the scintillations of more distant pulsars. Methods. Ten pulsars were observed at 2250 MHz (S-band) with the Jiamusi 66 m telescope to study their scintillations. Their dynamic spectra were first obtained, from which the decorrelation bandwidths and time scales of diffractive scintillation were then derived by autocorrelation. Secondary spectra were calculated by forming the Fourier power spectra of the dynamic spectra. Results. Most of the newly obtained dynamic spectra are at the highest frequency or have the longest time span of any published data for these pulsars. For PSRs B0540+23, B2324+60 and B2351+61, these were the first dynamic spectra ever reported. The frequencydependence of scintillation parameters indicates that the intervening medium can rarely be ideally turbulent with a Kolmogorov spectrum. The thin screen model worked well at S-band for the scintillation of PSR B1933+16. Parabolic arcs were detected in the secondary spectra of three pulsars, PSRs B0355+54, B0540+23 and B2154+40, all of which were asymmetrically distributed. The inverted arclets of PSR B0355+54 were seen to evolve along the main parabola within a continuous observing session of 12 hours, from which the angular velocity of the pulsar was estimated that was consistent with the measurement by very long baseline interferometry (VLBI).