GBD-DART-I: Pulsars and transient source observation between 130 and 350 MHz at Gauribidanur

Abstract

Gauribidanur Diamond Array Radio Telescope (GBD-DART) is a new, low-frequency radio antenna array with 64 log-periodic dipole array (LPDA) and associated receivers, developed and deployed at the Gauribidanur observatory (13.604 N, 77.427 E). It studies bright pulsars and solar transients in the frequency range of 130–350 MHz. The LPDAs are arranged in a checkerboard pattern. The orthogonal polarisation feeds are formed using pairs of opposite LPDAs. A diamond-shaped (tilted square) array configuration was chosen for high sidelobe suppression in the East-West and North-South directions. The tile measures 5.9 by 5.9 m, with diagonals along North-South and East-West directions, each about 8.3 m. The tile operates as a phased array in transit-observing mode and has been successfully detecting strong pulsars and solar flares for eleven months. The current instantaneous observation bandwidth is 16 MHz, limited by the present digital backend. Array operations are streamlined for remote use. In addition to its scientific role, the system serves as a training platform for radio astronomy using a simple, low-cost telescope. This paper presents details of the array and antenna studies, brief descriptions of the front-end and backend instrumentation, and illustrative results from pulsar and solar flare observations. It also briefly discusses future upgrade plans, focusing on tile sensitivity and backend bandwidth, to extend observation capabilities.