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NIKA2 run #53 (Jul 9, 2021)

Goals of the run, schedule and staff

NIKA2 tests in a technical time (T07) slot for (i) checking noise traces of array 2 and (ii) test its behaviour on the sky after correlated noise issues of past weeks. Observing in remote mode. Times referred to LT.

Observing report and results

17h00m - 21h00; Ángel: Opacity (tau[225 GHz]) above 0.7 at the beginning, going down to ~0.4 at the end of the shift. Unstable in general. First pointing and focus on Mars. Broad/distorted beams (>21" at 2mm) until ~19h. More decent focus corrections and even a bit broadened beams widths after that. Several pointing/bright sources of NIKA2 Pool catalogues observed in previous semesters under opacity conditions quite similar to the predicted ones for that date were chosen, in order to compare rms statistics. In particular, PCCS2G208.07 and M82 fields observed in W2020 and S2019, respectively, were observed during this technical time slot. PCCS2G208.07 is a Planck compact source of the newIRAM_NIKA2_1mm catalogue prepared by Bilal long ago, addressed to densify the pointing (and possibly, flux calibration) source catalogue for the instrument Users community. It’s an AGN classified as a blazar, with reported variability at least since 2016 (it can be noticed in the comparison frames too). The second one is a known nearby starburst galaxy. The rms estimation given at the top of the plots below was obtained from the statistics on a pseudo-annular background polygon limited by 60% and 80% KIDs coverage isocontours in each case, for comparison purposes. For a given source, exposure time and map geometry are the same for each epoch. It seems clear that array 2 is in good shape (as with maps at 1.15 mm):

Just at the end of this observing shift, we obtained some timelines and noise traces for each array with the window open and after close it. As shown below, traces seem to be again as expected: