At that time of the year, Mars is at low elevation in the morning and Uranus transiting At high elevations in the afternoon: as discussed yesterday this is not optimal to get the best focused observations we need to produce leakage maps at different elevations, but using Mars at low elevations in the morning mitigates this issue. We need at least 3 independent points in each elevation bin to make sure we have a consistent pattern repeating at a given elevation, and use this leakage to correct our data. We suspect we will have to do this as late in the afternoon as possible to have very stable atmosphere, when the source sets from 70 deg down to 20 deg. So these observations will required at least 3 days of excellent weather.

We need simultaneous (same day) observations with XPOL and NIKA2 of strongly polarized sources (not too much affected by leakage variation with El). And the XPOL observations need to be deep enough to achieve high SNR detections at 1mm for comparison with NIKA2-Pol measurements. This will require a couple of days to be carried out in a set of 3-5 quasars with strong polarization (for example 3C286 transiting in the night).

We will go for Crab, OMC1 (transiting at sunset), DR21 (transiting in the morning) to check the results against the data obtained in December 2018 and hence validate the repeatability of NIKA2-Pol. Ideally, we also need to observe fainter/less extended sources such as IRAS4A and B335 whose polarization has also been extensively studied and can be compared to existing data in the literature. Altogether these observations will also require 1.5 days.


*Here below the list of priority QSOs identified from POLAMI at 1mm, and their names in the catalog nika2pol-run42-sources.sou

3C279 (B1253-055)

3C273 (B1226+023)

3C454.3 (B2251+158)

3C286 (B1328+307)

OJ287 (B0851+202)

BLLac (B2200+420)

3C84 (B0316+413)

OT081 (B1749+096)

1156+295 (B1156+295)

1611+343 (B1611+343)

3C 279 had 8% polarization in Jan (I_pol 0.64 Jy) = This is POLAMI B1253-055 and J2000 J1256-0547

3C 273 had 7% polarization in Jan (I_pol 0.36 Jy) = This is POLAMI B1226+023 and J2000 J1229+0203

3C 454.3 had 6% polarization in December 2019 (I_pol 0.3 Jy) but seems not detected in February obs = This is POLAMI B2251+158 and J2000 J2253+1608

3C 286 had 23% polarization in December 2019 (I_pol 60 mJy) = This is POLAMI B1328+308 and J2000 J1331+3030

3C84 had 3% polarization on February 17 (I_pol 0.17 Jy) = This is POLAMI B0316+413 and J2000 J0319+4130

OJ287 had 7% polarization in January 2020 (I_pol 0.2 Jy) = This is POLAMI B0851+202

BL Lac had 8% polarization On Feb 17 (I_pol 0.2 Jy) = This is POLAMI B2200+420

OT081 had 6% polarization On Feb 17 (I_pol 0.13 Jy) = This is POLAMI B1749+096

B1156+295 had 25% polarization in January 2020 (but I_pol 80 mJy)

B1611+343 had 5% polarization on February 2020 (I_pol 30 mJy)


ListOfAstroTargetNika2Run42 (last edited 2020-02-29 10:26:08 by NikaBolometer)