SAAO Weekly Colloquium 20 March 2025 by Dr Iniyan Natarajan скачать в хорошем качестве

SAAO Weekly Colloquium 20 March 2025 by Dr Iniyan Natarajan

Title: Calibrating (Sub)mm-wave VLBI Observations Abstract: The Event Horizon Telescope (EHT) is a global VLBI network of (sub)mm-wave radio telescopes that has produced the first resolved images of the supermassive black holes M87* and Sgr A*. The configuration of the EHT has changed each year as new telescopes, instrumentation, and frequency bands are added to the array, with the next-generation upgrade to the EHT (ngEHT) expected to roughly double the number of stations, observe simultaneously at multiple frequencies, and include a mode of routine regular observations with a dedicated VLBI sub-array, presenting new challenges to calibrating EHT data. We present an improved reference calibration pipeline (EHT-HOPS) that supports calibration of multi-campaign data from EHT and similar VLBI arrays, accommodating diverse observing conditions, featuring improved performance, code integration and usability, and supporting hybrid polarization basis data reduction. Planned future developments include complex bandpass and full polarization calibration, simultaneous multi-band processing, and integration with new data formats to generate standardised calibrated data products for (sub)mm VLBI observations.