Daily Image
28-08-2018
VLBI fringes with MeerKAT
| Submitter: | Harro Verkouter |
| Description: | In February 2018, the recently inaugurated MeerKAT array co-observed with one of the European VLBI Network's (EVN) Network Monitoring Experiments (NME) 'N18L1'. Beamformer spectra and single dish voltage time series were captured from the MeerKAT system by SARAO (South African Radio Astronomy Observatory) staff. As MeerKAT's sampling rate and data formats are not yet VLBI compatible, software was developed by JIVE staff(*) to extract and resample 2 x 32 MHz, overlapping with the 8 x 8 MHz bands observed by the EVN stations, and reformat it to the VLBI Data Interchange Format (VDIF). Shown are fringes between one MeerKAT (Me) dish, m011v, and the EVN stations Effelsberg, Germany (Ef) and Hartebeesthoek, South Africa (Hh) in all eight EVN bands. They appear in LR and RR polarization because the MeerKAT receivers are linear whilst VLBI telescopes observe in circular. Finding VLBI fringes using a single 13.5 m MeerKAT dish on an 8000+ km baseline clearly demonstrates the excellent quality of the dish and receiver system. Fringes were also found using the beamformed output, using the same signal processing chain. These, however, are still under investigation. This result, while modest, is an important first step(**) towards including the phased-up MeerKAT in global VLBI observations, and, eventually the SKA. These fringes are the result of a close cooperation between staff at the SKA-SA/SARAO office and JIVE. This project was made possible by NWO and NRF through DOME-SA: KAT7 commissioning for the AVN/EVN (nr. 629.003.903) (*) Entirely in python, with help from the numpy and SciPy modules (**) It takes over an hour to extract ten seconds worth of data from the single dish time series. Converting the complex spectra from the beamformer takes an order of magnitude longer. |
| Copyright: | SARAO/JIVE |
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