pilot cospar2018 aumont 2018-07-20graca/cospar-talks/s2_3_pilot_cospar2018_aumont... · jonathan...

PILOTA far-infrared balloon-borne polarization experiment

Jonathan AumontIRAP — Toulouse, France

J.-Ph. Bernard (PI), A. Mangilli, A. Hughes, G. Foënard, I. Ristorcelli, G. De Gasperis, H. Roussel,on behalf of the PILOT Collaboration

COSPAR-18 - Pasadena - July 20th 2018

1.2 THz far-infrared polarization experiment★Reveal the structure of the magnetic field

in our Galaxy and nearby galaxies

★Characterize the geometric and magnetic properties of the dust grains

★Understand polarized foregrounds

★Complete the Planck observations at a higher frequency where the dust polarization has never been observed over large sky regions

PILOT

Planck Collaboration: The Planck mission

Fig. 15. Maximum posterior amplitude polarization maps derived from the Planck observations between 30 and 353 GHz(Planck Collaboration X 2015). The left and right columns show the Stokes Q and U parameters, respectively. Rows show, from topto bottom: CMB; synchrotron polarization at 30 GHz; and thermal dust polarization at 353 GHz. The CMB map has been highpass-filtered with a cosine-apodized filter between ` = 20 and 40, and the Galactic plane (defined by the 17 % CPM83 mask) has beenreplaced with a constrained Gaussian realization (Planck Collaboration IX 2015).

10 30 100 300 1000

Frequency (GHz)

10

-110

010

110

2

RM

S b

rig

htn

ess

tem

per

atu

re (

µK

)

CMB

Thermal dust

Free-freeSynchrotron

30 44 70 100 143 217 353 545 857

Spinning dust

CO 1-0

Sum fg

10 30 100 300 1000

Frequency (GHz)

10

-110

010

110

2

RM

S b

rig

htn

ess

tem

per

atu

re (

µK

)

CMB

Thermal dust

Synchrotron

30 44 70 100 143 217 353

Sum fg

Fig. 16. Brightness temperature rms as a function of frequency and astrophysical component for temperature (left) and polarization(right). For temperature, each component is smoothed to an angular resolution of 1� FWHM, and the lower and upper edges of eachline are defined by masks covering 81 and 93 % of the sky, respectively. For polarization, the corresponding smoothing scale is 400,and the sky fractions are 73 and 93 %.

10. Planck 2015 cosmology results

Since their discovery, anisotropies in the CMB have contributedsignificantly to defining our cosmological model and measuringits key parameters. The standard model of cosmology is basedupon a spatially flat, expanding Universe whose dynamics aregoverned by General Relativity and dominated by cold dark mat-ter and a cosmological constant (⇤). The seeds of structure haveGaussian statistics and form an almost scale-invariant spectrumof adiabatic fluctuations. The 2015 Planck data remain in excel-

lent agreement with this paradigm, and continue to tighten theconstraints on deviations and reduce the uncertainty on the keycosmological parameters.

The major methodological changes in the steps goingfrom sky maps to cosmological parameters are discussedin Planck Collaboration XII (2015); Planck Collaboration XIII(2015). These include the use of Planck polarization data in-stead of WMAP, changes to the foreground masks to includemore sky and dramatically reduce the number of point source“holes,” minor changes to the foreground models, improve-

23

PIL

OT

Planck

PILOT - Instrument

M1

M2

M3

ICS

SteppedHWP

Lens

45°polarizer

Detectorarrays

4

SteppedHWP

PolariserREFLEX (-)

TRANS (+)

83 7

6 25 1

1024 (485) bolometers

1024 (750) bolometers

★Multiplexed bolometer arrays with a total of 2048 detectors at 240 !m (1249 GHz), 2’ resolution

★Observations at more than 2 HWP angles to reconstruct the Stokes parameters I, Q, U

★Detectors cooled down to 0.3 K through closed-cycle 3He fridge

★NEP ★Control of systematics and detector response at 1% level

∼ 4 × 10−16 W/Hz1/2

[The

PIL

OT C

olla

bora

tion

, Ber

nard

et a

l. 20

16]

Lens

1st flightTimmins, Canada

24 h

2015

PILOT


24 h

2015

2nd flightAlice Springs, Australia

33 h

2017

PILOT


24 h

2015

3rd flightTimmins, Canada

2019?


33 h

2017

PILOT


24 h

2015

3rd flightTimmins, Canada

2019?


33 h

2017

Toulouse, FrancePILOT DPC

PILOT

PILOT - 2nd flight

Galactic plane, 1.7 h, 7.1 %Star forming regions, 9.9 h, 41.6 %

Galaxies, 6.1 h, 25.6 %Diffuse field, 4.8 h, 20.2 %

Planets, 0.8 h, 3.5 %Calibrations in all these scenes, 1.2 h, 5%

Total: 23.8 h

April 16th, 2017 from Alice Springs, Australia★ Total flight time: 33.5 h★ Scientific data: 23.8 h★ Ceiling altitude: 32-40 Km

BICEP30x12°

Note: most of these sources are not observable in balloon from South Pole (e.g. BLASTPol, SPIDER)

PILOT - 2nd flight

LMC4x2°

Orion5x10°

Musca2x3°

L02x5°

L305x5°

rho-Oph9x4°

Planck 353 GHz Imap

PILOT - Scanning strategy

HWP rotation

Slew

Elevation and azimuth adjustments

ScanICS calibration sequence

Focal plane footprint on the sky

Target region

Azimuth

Elev

atio

n

[The PILOT Collaboration, Foënard et al. 2018]

★ In-flight good optical quality and nominal resolution

PILOT - In-flight performances Jupiter

2.3’ FWHM



★ In-flight background has a similar shape but is a factor ~2 stronger than ground measurements. Polarized at 4-10 % level

★Variation of the detector responses due to polarized background & atmosphere variations. Modelled and corrected to better than 2 %

PILOT - In-flight performances

29 h

ICS

resp

onse

(AD

U) measured

model

Jupiter

2.3’ FWHM





★Pointing offset varies during flight. Pointing model constructed from elevation + temperatures and Herschel comparison, better than 1’

★Spurious polarization measured on Jupiter of ~ 3 %


29 h

ICS

resp

onse

(AD

U) measured

model

Jupiter

2.3’ FWHM

Orioncontour = Herschel





★Pointing offset varies during flight. Pointing model constructed from elevation + temperatures and Herschel comparison, better than 1’

★Spurious polarization measured on Jupiter of ~ 3 %

★ In-flight white noise levels as expected; noise stability over the whole flight

+ Significant improvements in ongoing analyses


29 h

ICS

resp

onse

(AD

U) measured

model

Jupiter

2.3’ FWHM

Orioncontour = Herschel

29 h

Time-frequency noise power spectra for matrix 6

0 Hz

0.1 Hz

1 Hz

10 Hz

PILOT - Preliminary I maps

L0

Orion

L30

𝛒-OphiuchiGalactic longitude Galactic longitude

Gal

actic

latit

ude

Gal

actic

latit

ude

0° 359°1°

-148°-150°-152°-154°

29°30°31°32°

353°354°355°356°

18°

17°

16°

15°

-20°

-19°

-18°

-17°

-16°

-1°3

0’-1

°00’

-0°3

0’0°

00’

0°30

’1°

00’

1°30

’

-1°0

0’-0

°30’

0°00

’-0

°30’

PILOT - Preliminary polarization mapsG

alac

tic la

titud

e0°

+2°

-2°

-4°

Galactic longitude0° 359° 358°1°2°



Preliminary polarization results PILOT data in L0 field

Total Intensity polar Q polar U

maps shown in EQU-IAU convention at pixel size 1.7’ (Nside=2048)







[The PILOT Collaboration, Mangilli et al. 2018 in prep.]

UQI

★Stokes parameters I, Q and U in the L0 Galactic plane region★Strong signal but low polarization fraction

PILOT - Comparison to Planck

ψ =12

⋅ atan ( UQ )


Prel

imin

ary


ψ =12

⋅ atan ( UQ )


PILOT

353 GHz

217 GHz

143 GHz

Planck 2015data release

Prel

imin

ary


ψ =12

⋅ atan ( UQ )


PILOT353 GHz

217 GHz

143 GHz

Prel

imin

ary

Planck 2018data release

Preliminary

0�0000000 359�300 359�0000�3001�000

Longitude

0�00

0 000

0�

300

�1�

000

300

1�00

0La

titud

eG

alac

tic la

titud

e

Galactic longitude

0°00

’00’

’30

’1°

00-3

0’-1

°00’

0°00’00’’ 359°30’ 359°0030’1°00’

PILOT - Direction of the magnetic field


PILOT - “BICEP” region

PBSA/IDS

SPT3G

SPTPolBICEP2

PILOT

α = 0°30°

60°

90°

120°

150°

180°

-150°

-120°

-90°

-60°

-30°

δ = 0°

-30°

-60°


log 1

0(N

hits)

4.3

3.2

α = 0°

30°

60°

90°

150°

180°

-150°

-120°

-90°

-60°

-30°δ = 0°

-30°

-60°

PILOT

120°

inN s

ide

=51

2pi

xels

★ 4.8 h of data during flight2

★BICEP field observed with 4 tiles, each of them being observed at least twice with 2 different HWP positions

★Goal signal to noise ratio of ~20 on thepolarized intensity integrated over the whole field

★Unique data for constraining the SED or for correlation analyses in CMB observations

PILOT - Legacy

coPILOT

IDS

EBEX

2013

SPICA-Pol

★ coPILOT: modification of PILOT will allow very accurate measurements of C+ (158 µm) total intensity. Dark molecular gas distribution in solar neighborhood, nearby galaxies. Submitted to CNES

★ IDS (Inflation and Dust Surveyor): CMB B-modes + dust, proposed to NASA 2018. Contribution to provide PILOT attitude control + internal calibration source

★SPICA-Pol: polarized instrument on SPICA. Design and science case strongly inspired from PILOT. Accepted in pre-phaseA/0.

★BOOST proposal (IRAP) to lower detector temperature to 150 mK. Increase in sensitivity by 2.7 for PILOT, up to 14 for CoPilot

PILOT - Summary

★Operational and instrumental success of the PILOT two flights

★Unique experiment: observation of the dust polarization at 1.2 THz over large regions of the sky relevant for cosmology

★PILOT legacy for future instruments

★Data analysis in progress. No showstopper for the moment but we are a small team!

- Backup -

PILOT - Improvements after 1st flight

+ arrays #1 and #3 were repaired★ ground tests: array #3 ok, arrays #1 and #5 not working★ in flight: arrays #1, #3 and #5 not working: -17%

+ autonomy tests at 300 mK accomplished ★ detectors were operated 20 mK lower than flight#1 (305 mK): +26%★ in-flight autonomy was longer than the long flight (>33.5 hr)

+ Field stop size increased to avoid edge effects in polarization★ polarization now ok everywhere: gain of 0.6 arrays: +10%

+ Longer flight (flight#1: 14.8hr, flight#2: 23.8 hr): +60%

+ Front baffle thermal insulation was re-designed★ no deterioration observed in flight. No sign of external straylight.

+ More efficient observing strategy implemented★ scans at varying elevation (better control of response variations + de-stripping)★ region of interest mapping (saves 20% of of target time)

= Total: +100%★ important qualitative improvements: less straylight, more scan directions more

HWP positions, more strong pointing sources


log10(Nhits)2.0 3.2

0°

-30°

-60°

-30°

-60°

-90°

-120°

-150°

30°

60°

90°

120°

150°180°

pilot cospar2018 aumont 2018-07-20graca/cospar-talks/s2_3_pilot_cospar2018_aumont... · jonathan...

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