Dual-purpose use of the Santa Maria VGOS antenna for geodetic VLBI and methanol maser observations

This paper presents the technical specifications and scientific capabilities of the Santa Maria VGOS antenna, a 13.2-meter radio telescope that is part of the RAEGE (Rede Atlântica de Estações Geodinâmicas e Espaciais) network in the Azores. While primarily designed for geodetic Very Long Baseline Interferometry (VLBI), we demonstrate its potential for astronomical applications in single-dish mode, particularly for observing methanol masers at 6.68 GHz and 12.18 GHz. The technical description includes the broadband cryogenic receiver, backend system, and observing strategy, which enable high-sensitivity and high-resolution observations. We report the detection of methanol maser emission from sources including G009.621 + 0.196, G109.871 + 2.114, G111.542 + 0.777, G133.947 + 1.064, and G134.029 + 1.072, with flux densities comparable to or within the range of previous studies. By comparing these results with those from large interferometric arrays (e.g., VLA, EVN) and single-dish surveys (e.g., MMB, M2O), we highlight the single-dish VGOS antenna’s suitability for long-term maser monitoring. We also discuss system limitations, such as sensitivity and spatial resolution, and propose mitigation strategies. These findings demonstrate the versatility of VGOS systems and provide a framework for leveraging a global VGOS network for cost-effective, flexible, dual-purpose geodetic and astrophysical research.