Dataset for article of "Spreading and multi-wavelength emission of an ultra-narrow relativistic jet from GRB 221009A"

This dataset comprises the processed VLBA data of GRB 221009A (projects of BA161 and BL307), obtained using the Python-based VLBI pipeline, which interfaces with the Astronomical Image Processing System (AIPS) software and was executed at the China SKA Regional Centre. The phase-calibrated data can be found in the file folder "calibrated_GRB221009a_data_2026", and the reduction pipeline can be found in the file folder "demo_ba161a__NC_2026". Raw VLBA data can be found in the NRAO Data Archive under project codes BA161 and BL307. To assess the systematic uncertainties of our results, we additionally performed Monte Carlo simulations with antenna gain variations and time-domain resampling tests on the calibrated data. In the gain-variation simulations, each antenna was assigned a random multiplicative gain factor varying within ±10%. In the time-resampling tests, 10% of the visibilities were randomly removed along the time axis. For each epoch and each simulation mode, 2000 independent realizations were performed, and the corresponding output parameter tables are provided. To facilitate reproducibility and independent inspection of the analysis, we also provide the intermediate <code>.uvf</code> files for 100 realizations for both the gain-variation and time-resampling simulations, respectively, which are limited by storage considerations. The tables, data products, and accompanying README files are available in the zipped file “Sim_results_NC_2026”.