Arasi Sathyamurthy | Searcharxiv

arXiv2026

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

Gauribidanur Diamond Array Radio Telescope (GBD-DART) is a new small LPDA antenna array consisting of 64 short dipoles and associated receivers that has been custom developed and deployed at the Gauribidanur observatory (13.604 N, 77.427 E) to study bright Pulsars and Solar transients in the frequency range of 130-350 MHz. The LPDAs are arranged in a checkerboard layout, with opposite pairs combined to enable dual-polarised operation. A diamond-shaped (tilted square) array configuration was chosen to achieve high sidelobe suppression in the East-West and North-South directions. The tile measures 5.9 meters by 5.9 meters, with diagonals along both the North-South and East-West directions, each measuring about 8.4 meters. The LPDA array with one diamond-shaped tile has been fully commissioned and is operating in transit-observing mode, successfully detecting strong pulsars and solar flares over the last seven months. The present digital backend restricts the instantaneous bandwidth for observations to 16 MHz. The array operations are streamlined to facilitate remote operations. Apart from investigating Pulsar and Solar phenomena at low radio frequencies in selected sources, this work aims to provide a training platform for radio astronomy through simple-to-construct, low-cost radio telescopes. In this paper, we present details of the array, including antenna and array response studies, brief descriptions of front-end and backend instrumentation, and illustrative results from observations of both pulsars and solar flares. It will also provide brief details of future upgrade plans, particularly for the tiles and digital backend, to facilitate the observation of additional sources.

astro-ph.IM↗

arXiv2023

Antennas for low-frequency radio telescope of SKA

The low-frequency radio telescope of the Square Kilometre Array (SKA) is being built by the international radio astronomical community to (i) have orders of magnitude higher sensitivity and (ii) be able to map the sky several hundred times faster, than any other existing facilities over the frequency range of 50 - 350 MHz. The sensitivity of a radio telescope array is in general, dependent upon the number of electromagnetic sensors used to receive the sky signal. The total number of them is further constrained by the effects of mutual coupling between the sensor elements, allowable grating lobes in their radiation patterns, etc. The operating frequency band is governed by the desired spatial and spectral responses, acceptable sidelobe and backlobe levels, radiation efficiency, polarization purity and calibratability of sensors' response. This paper presents a brief review of several broadband antennas considered as potential candidates by various engineering groups across the globe, for the low-frequency radio telescope of SKA covering the frequency range of 50 - 350 MHz, on the basis of their suitability for conducting primary scientific objectives.

astro-ph.IM↗