Testing interferometer response of Brazilian Decimetric Array - BDA by analog techniques

• Grant number: 10/18698-6
• Support Opportunities: Research Grants - Visiting Researcher Grant - International
• Start date: June 12, 2011
• End date: June 11, 2012
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Astronomical Instrumentation
• Principal Investigator: Hanumant Shankar Sawant
• Grantee: Hanumant Shankar Sawant
• Visiting researcher: Koovapady Ramachandra Subramanian
• Visiting researcher institution: Pessoa Física - Índia, India
• Host Institution: Instituto Nacional de Pesquisas Espaciais (INPE). Ministério da Ciência, Tecnologia e Inovação (Brasil). São José dos Campos , SP, Brazil
• Associated research grant: 06/55883-0 - Development of Brazilian Decimetric Array (phase II), AP.TEM

Abstract

A team of Brazilian scientists are developing a multi-element interferometer system called Brazilian Decimetric Array (BDA) at Cachoeira Paulista for imaging primarily the Sun and radio sources both galactic and extragalactic. I have contributed to develop the proposal of the BDA project during my visit to INPE in 1997-98, I have also contributed to develop the digital part of the project and proposed the development of the correlator system at Indian Institute of Astrophysics. In due course a MOU was signed between INPE and IIA. During 2003, I tested the receiver system for the prototype BDA (PBDA) at INPE and integrated them with the digital system. I obtained interferometer fringes on Sun with the PBDA for the first time. In this proposed project, all the sub system - Feeders, receivers of 26 antennas will be tested in transit and tracking mode at different elevations by using Sun and strong radio sources. Interferometer fringes along the East -West baselines and skewed baselines from antennas in South array with antennas in East West array will be obtained for the first time. This will determine the baseline lengths with an accuracy of fraction of the wavelength, phases and amplitudes of 325 baselines. All the subsystem will be tested in analog mode and will be kept ready for interfacing digital part of the system. The scientists and engineers will be trained during this process. Details of these are given below. (AU)