Speaker
Description
The Global Millimetre VLBI Array (GMVA) is a high-sensitivity global millimetre VLBI instrument that operates at wavelengths of 3 mm and 7 mm. Recent enhancements, such as the inclusion of phased ALMA and the upgrade of the NOEMA observatory, have significantly improved the array’s sensitivity and imaging capabilities. The GMVA now plays a central role in enabling high-resolution studies of active galactic nuclei, black hole environments and relativistic jet dynamics. In this contribution, we present updates on the array’s scientific achievements, ongoing technical upgrades — including increased bandwidth and improved calibration strategies — and strengthened coordination with other arrays. A significant opportunity in this regard is offered by the implementation and prospects of the single-optical-path frequency-phase-transfer (FPT) technique, which is currently being deployed for the 13 mm/7 mm/3.5 mm option in most European antennas. We also report on the recent successful testing of the long APEX–IRAM 30 m baseline, where dual-frequency VLBI observations at 86 and 258 GHz demonstrated improved coherence and phase stability using FPT (Zhao et al.). Adopting such techniques across mm-VLBI arrays supported by multi-band receiver systems is set to substantially enhance high-frequency sensitivity and operational robustness, paving the way for the next generation of VLBI science.
