Alessia Ritacco on behalf of NIKA collaboration 6 CALIBRATION Goals: • Characterisation of instrumental polarisation • Calibration in polarisation angle HOW? • Planets: unpolarised sources • Quasars: polarised radiogalaxies • Extended known sources
Alessia Ritacco on behalf of NIKA collaboration 6
CALIBRATION
Goals: !
• Characterisation of instrumental polarisation !
• Calibration in polarisation angle
HOW?!• Planets: unpolarised sources!
• Quasars: polarised radiogalaxies!
• Extended known sources
Alessia Ritacco on behalf of NIKA collaboration 7
Uranus observations
Template of the I P leakage effect
Uranus @ 2mm!February 11th, 2015 Ideal case
QI UI
-60 -40 -20 0 20 40 60arcsec
-60
-40
-20
0
20
40
60
arcs
ec
I map 2mm channel
-1.72
2.42
6.57
10.71
14.86[Jy/beam]
-60 -40 -20 0 20 40 60arcsec
-60
-40
-20
0
20
40
60
arcs
ec
Q map 2mm channel
-0.20
-0.08
0.05
0.17
0.30[Jy/beam]
-60 -40 -20 0 20 40 60arcsec
-60
-40
-20
0
20
40
60
arcs
ec
U map 2mm channel
-0.20
-0.08
0.05
0.17
0.30[Jy/beam]
Systematic effect
-60 -40 -20 0 20 40 60arcsec
-60
-40
-20
0
20
40
60
arcs
ec
-0.18
3.55
7.27
10.99
14.72[Jy/beam]
I
-60 -40 -20 0 20 40 60arcsec
-60
-40
-20
0
20
40
60
arcs
ec
-0.20
-0.08
0.05
0.17
0.30[Jy/beam]
Q
-60 -40 -20 0 20 40 60arcsec
-60
-40
-20
0
20
40
60
arcs
ec
-0.20
-0.08
0.05
0.17
0.30[Jy/beam]
U
I Q U
Alessia Ritacco on behalf of NIKA collaboration 8
Systematic effect correction: quasar example3C273 @ 2mm!
February 17th, 2015Systematic effect
Q U
IQ U
Good subtraction of the systematic signal
+
I
+
QI U
QI U
I Q
+
U
I
+
Q
+
U-60 -40 -20 0 20 40 60
arcsec
-60
-40
-20
0
20
40
60
arcs
ec
I map 2mm channel
-0.49
1.57
3.63
5.69
7.75[Jy/beam]
-60 -40 -20 0 20 40 60arcsec
-60
-40
-20
0
20
40
60
arcs
ec
Q map 2mm channel
-0.06
5.0E-03
0.07
0.13
0.20[Jy/beam]
-60 -40 -20 0 20 40 60arcsec
-60
-40
-20
0
20
40
60
arcs
ec
U map 2mm channel
-0.30
-0.22
-0.14
-0.05
0.03[Jy/beam]
-60 -40 -20 0 20 40 60arcsec
-60
-40
-20
0
20
40
60
arcs
ec
I map 2mm channel
-0.62
1.45
3.51
5.57
7.64[Jy/beam]
-60 -40 -20 0 20 40 60arcsec
-60
-40
-20
0
20
40
60
arcs
ec
Q map 2mm channel
-0.15
-0.06
0.03
0.11
0.20[Jy/beam]
-60 -40 -20 0 20 40 60arcsec
-60
-40
-20
0
20
40
60
arcs
ec
U map 2mm channel
-0.15
-0.06
0.03
0.11
0.20[Jy/beam]
Maps corrected
I Q U
I Q U
Alessia Ritacco on behalf of NIKA collaboration 9
KNOWN CALIBRATION SOURCE: CRAB NEBULA
Polarised intensity
GOOD AGREEMENT WITH XPOL EXPERIMENT (Aumont et al. (A&A), 514, A70)
150 GHzI
Q
U
Alessia Ritacco on behalf of NIKA collaboration 10
CONCLUSIONS & PERSPECTIVES
Polarisation setup validated with NIKA!
Preliminary analysis shows a good
agreement with other experiments!
Analysis on extended sources in progress!
NIKA2 first polarised light in 2016
NIKA Collaboration
Thanks !
Alessia Ritacco on behalf of NIKA collaboration 12
BACK-UP SLIDES
Alessia Ritacco on behalf of NIKA collaboration 13
NIKA vs XPOL
Ref: Aumont et al. (A&A), 514, A70 (2010)
NIKA XPOL
Alessia Ritacco on behalf of NIKA collaboration 14
Polarisation integrated in NIKA band
Alessia Ritacco on behalf of NIKA collaboration 15
Polarisation with NIKA2
Bands : 1.15 & 2.05 mm!Beam (FWHM) : 12 ‘’ & 17’’!# Detectors : 2x2000 & 1000!Field of view: 6.5 arc-minutes!Sensitivity : 30 & 20 mJy s1/2
DETECTION STRATEGY: HWP @ 300K+ WIRE GRID @ 100 mK
224 & 1322.2 arcminutes
NIKA