Solar Full Polarization ALMA Test Data Scheduled for Release in November 2023

ALMA will be releasing Solar Full Polarization ALMA test data acquired as part of the Extension and Optimization of Capabilities effort (EOC). The data were used to test, implement, and determine the accuracy of the solar full-polarization observing mode of ALMA. The data consist of:

(1) 45-pointing MOSAIC full-polarization observations with the 12-m Array in Band 3 (LO1: 100 GHz) performed to cover the primary beam's core region on 13 October 2022. The pointing spacing of the MOSAIC pattern is 7 arcsec. The approximate angular resolution of the data is 1.8 arcsec. The RMS of the image is 0.14, 0.14, and 0.17 Jy/beam for Stokes Q, U, and V, respectively. The target region was the following sunspot of NOAA 13119. The released dataset does not include the data accumulated with the 7-m antennas. 

(2) A full-Sun map obtained with the TP Array for the feathering process. The TP Array observations were performed with the interferometric observation simultaneously. The TP Array observations are dual-polarization observations while the 12-m Array observations (1) are full-polarization observations.

Note: Although the 12-m Array observations were done with the MOSAIC function, the images in the SV data are not synthesized with the MOSAIC mode because the solar MOSAIC observations with full-polarization are not verified yet. Instead, the synthesized image of each field will be provided.

The raw data, along with the calibrated measurement sets, reference images, and reduction scripts will be released in early November 2023.