We report the results of (a) extensive follow-up observations of the gamma-ray pulsar J1732−3131 that has been recently detected at decameter wavelengths, and (b) deep searches for counterparts of 9 other radio-quiet gamma-ray pulsars at 34 MHz, using the Gauribidanur radio telescope. No periodic signal from J1732−3131 could be detected above a detection threshold of 8σ, even with an effective integration time of more than 40 hours. However, the average profile obtained by combining data from several epochs, at a dispersion measure of 15.44 pc cm −3 , is found to be consistent with that from the earlier detection of this pulsar at a confidence level of 99.2%. We present this consistency between the two profiles as an evidence that J1732−3131 is a faint radio pulsar with an average flux density of 200-400 mJy at 34 MHz. Detection sensitivity of our deep searches, despite the extremely bright sky background at such low frequencies, is generally comparable to that of higher frequency searches for these pulsars, when scaled using reasonable assumptions about the underlying pulsar spectrum. We provide details of our deep searches, and put stringent upper limits on the decameter wavelength flux densities of several radio-quiet gamma-ray pulsars.

We report our search for and a possible detection of periodic radio pulses at 34.5 MHz from the Fermi Large Area Telescope pulsar J1732−3131. The candidate detection has been possible in only one of the many sessions of observations made with the low‐frequency array at Gauribidanur, India, when the otherwise radio weak pulsar may have apparently brightened many folds. The candidate dispersion measure along the sight line, based on the broad periodic profiles from ∼20 min of data, is estimated to be 15.44 ± 0.32 pc cc−1. We present the details of our periodic and single‐pulse search, and discuss the results and their implications relevant to both, the pulsar and the intervening medium.

We report the design and development of a self-contained multi-band receiver (MBR) system, intended for use with a single large aperture to facilitate sensitive & high time-resolution observations simultaneously in 10 discrete frequency bands sampling a wide spectral span (100-1500 MHz) in a nearly log-periodic fashion. The development of this system was primarily motivated by need for tomographic studies of pulsar polar emission regions. Although the system design is optimized for the primary goal, it is also suited for several other interesting astronomical investigations. The system consists of a dual-polarization multi-band feed (with discrete responses corresponding to the 10 bands pre-selected as relatively RFI-free), a common wide-band RF front-end, and independent back-end receiver chains for the 10 individual sub-bands. The raw voltage time-sequences corresponding to 16 MHz bandwidth each for the two linear polarization channels -2and the 10 bands, are recorded at the Nyquist rate simultaneously. We present the preliminary results from the tests and pulsar observations carried out with the Green Bank Telescope using this receiver. The system performance implied by these results, and possible improvements are also briefly discussed.