- evn2024@mpifr.de
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Contribution
Position determination and imaging of bright radio stars by EVN observations using phase-referencing
Content
Abstract: The VLBI and GAIA observations are on the way to improve the accuracy of celestial reference frame (CRF). Accurate astrometric models of radio stars provide important means to evaluate the consistency between the optical and radio CRFs. This research aims to determine and evaluate the astrometric parameters for the radio stars that have not yet had these parameters determined at radio wavelengths. We proposed 5-epoch EVN phase-referencing observations (across one year) for 16 such radio stars at 8 GHz, and they have been carried out successfully. In data calibration, we employ the standard procedure of phase-referencing technique to ensure the highest accuracy in position determination using AIPS, which is validated with the model fitting using Difmap. We will report about the imaging results and the positions of the radio stars from the first epoch of our EVN observations as well as the comparison with the historical data. A data calibration/processing pipeline will be developed based on this first epoch of observations and used for the remaining four epochs, from which the astrometric models can be estimated.