Mapping has begun at UTMOST, not just for its own sake but as a means of verifying our correlator — and is an important milestone on the way to coherence of the astronomical signal across the array, and the search for FRBs.
Our first images are shown below, using only 88 modules, corresponding to about 1/4 of the telescope surface area. The rest of the telescope modules will be accessible after the GPU correlator is upgraded to its final capacity in mid-2015.
Our first image taken with UTMOST, a 6 hr track of a radio galaxy J2359-6054. The phase calibrator J2341-5816 was observed for for 10 minutes for every 1 hour track of the galaxy. Natural weighting and uvrange of (0.1,5) kilolambda was used. This is the clean map and the RMS is ~3 mJy/beam. Credit: Shivani Bhandari.
An image of the supernova remnant of SN1987A in the LMC, made from 6 hours of data, split by ~40 hours. A calibrator was observed every hour. Image noise ~ 22 mJy, and contour levels are at -110, 110, 220, 330 … mJy. This very early image is one of the first made with the new GPU-based correlator system, and utilises only a fraction of the final system sensitivity. Credit: Shivani Bhandari, Vikram Ravi, Chris Flynn.
This is our best image to date in the mapping program. Nine hours were spent tracking the source. We observed a nearby phase calibrator every two hours. The image noise ~ 5 mJy, and contour levels are shown at levels of -25, 25, 50, 75 … mJy in the image. Only 1/4 of the array was used (the remaining 3/4 to become accessible with the installation of the second half of our GPU correlator). Credit: Vikram Ravi, Chris Flynn, Matthew Bailes.