MEASURING THE POLARIZATION OF THE CMB WITH THE QUIJOTE EXPERIMENT Federica Guidi PhD student at IAC CMB: Intensity and Polarization

Radio foregrounds emission OVERVIEW The QUIJOTE experiment

The Map-making process

6/08/2018 Padova, ICYAA 2018 THE COSMIC MICROWAVE BACKGROUND (CMB) History of the Universe in the Big Bang model: • Exponential expansion (Inflation) • Hot , dense and high pressure plasma of particles • Dark matter decouples and start building structures • Recombination: electrons and protons form atoms • Photons becomes free to propagate: Last scattering surface • Structure formation • …

• The CMB is the light coming from the Last Scattering Surface: z=1100 age=380 000y T=3000k • The Universe continues to expand and cool down: T=3000 K To=3K • We cannot look deeper than the surface of the sun as we cannot go farther than the last scattering surface. The CMB is the oldest light we can observe!

6/08/2018 Padova, ICYAA 2018 1964: A.A. Penzias and R. W. THE COSMIC MICROWAVE BACKGROUND (CMB) Wilson measured a uniform radiation at T=3.5K

: uniform emission from any 1992: COBE(FIRAS) measured direction of sky, Black Body spectrum the spectrum of the CMB peaked at 푇0 = 2.725 퐾.

2ℎν3푐2 퐵ν= ℎν 퐾푇0 : due to the relative motion 푒 − 1 of the Sun respect to the last scattering surface 풗 푣2 1− 푐2 ∆푇 = 푇 푣 ~3.3푚퐾 0 1− cos 휃 푐

at smaller angular scales (푙 > 2). The characteristic angular dimension of the anisotropies corresponds to the dimension of the horizon at the last scattering surface: ϑ~1°. ∆푇 ≈ 10−5 K 푇 6/08/2018 Padova, ICYAA 2018 ANGULAR POWER SPECTRA OF THE INTENSITY ANISOTROPIES ∞ 푙 푇 Harmonic decomposition: T 푛ො = σ푙=0 σ푚=−푙 푎푙푚푌푙푚( 푛ො)

Angular power spectrum of anisotropies 퐶푙 : 푇 푇∗ 푇푇 푎푙푚푎푙′푚′ = 훿푙푙′훿푚푚′퐶푙

휃퐻 ≈ 1° 푙H ≈ 200 Collaboration, Planck 2015 results. XIII. Cosmological parameters, A&A 594, A13 (2016)

Constraint on the Cosmological Parameters: ΛCDM: {100 ∙ 휔푏, 휔푐푑푚, 푛푠, 퐴푠, ℎ, 휏푟푒𝑖표}

6/08/2018 Padova, ICYAA 2018 • Stokes parameters: (퐼, 푄, 푈, 푉 = 0)

• Linear polarization invariant under rotation as a spin-2 quantity: CMB POLARIZATION 푄′ ± 𝑖푈′ = 푒±2𝑖휓 푄 ± 𝑖푈

• Spin-2 harmonic decomposition on the sky CMB light is linearly polarized ∞ +푙 ∞ +푙 ±2 푄 ± 𝑖푈 푛 = ෍ ෍ 푎푙푚 ±2푌푙푚 푛 = ෍ ෍ (푎퐸,푙푚 ± 𝑖푎퐵,푙푚)±2푌푙푚 푛 푙=2 푚=−푙 푙=2 푚=−푙 • at recombination: Unpolarized photons are scattered by perturbations perturbations electrons on the last scattering surface. If the incoming light has a quadrupole momentum then the outgoing light is linearly polarized.

• Primordial gravitational waves: 1 +2 −2 −𝑖 +2 −2 푎퐸,푙푚 = (푎푙푚 + 푎푙푚) 푎 = (푎 − 푎 ) 2 퐵,푙푚 2 푙푚 푙푚 Quantum fluctuations in the primordial phase Invariant under Not invariant under induces isotropic and anisotropic stretching. parity transformation Parity transformation The anisotropic stretch is the seed of primordial linear polarization. The Inflation The polarization is a local measurement in the sky. From the harmonic enlarges it to macroscopic scales. decomposition of the polarization map we can identify E and B modes.

6/08/2018 Padova, ICYAA 2018 ANGULAR POWER SPECTRA OF POLARIZATION ANISOTROPIES

Angular power spectra for polarization: 퐸 퐸∗ 퐸퐸 푎푙푚푎푙′푚′ = 훿푙푙′훿푚푚′퐶푙 푇 퐸∗ 푇퐸 푎푙푚푎푙′푚′ = 훿푙푙′훿푚푚′퐶푙 퐵 퐵∗ 퐵퐵 푎푙푚푎푙′푚′ = 훿푙푙′훿푚푚′퐶푙

Planck Collaboration, Planck 2015 results. XIII. Cosmological parameters, A&A 594, A13 (2016)

6/08/2018 Padova, ICYAA 2018 FOREGROUNDS The cosmological emission is strongly hidden by the .

6/08/2018 Padova, ICYAA 2018 Planck 2015 Results. I. Overview of products and scientific results. Planck Collaboration FOREGROUND: SYNCHROTRON

• Cosmic ray electron (푁(퐸) ∝ 퐸−푝) emits photons spiralizing around the galactic magnetic field (B). 훾

퐵

훾 • The spectrum of synchrotron emission is 푝+3 푇 ∝ 퐵(푝+1)/2휈훽 훽 = − ~ − 2.5 휈 2 • Dominates in the lower frequency range.

• Synchrotron radiation is polarized perpendicular to the magnetic fields lines. Polarization degree up to Π=40%. 6/08/2018 Padova, ICYAA 2018 Planck 2015 Results. I. Overview of products and scientific results. Planck Collaboration FOREGROUND: FREE-FREE

• Electron-ion scattering in the interstellar plasma (thermal bremmstrahlung)

• The correspondent brightness temperature depends on the frequency with a spectral index ~2

• The net free-free emission is almost unpolarized for a distribution of electrons.

6/08/2018 Padova, ICYAA 2018 Planck 2015 Results. I. Overview of products and scientific results. Planck Collaboration FOREGROUND: THERMAL DUST

• Interstellar dust grains absorb the interstellar radiation and are heated up. In the cooling process it emits radiation.

• The spectrum is a modified black-body at 푇~14 − 15 퐾 표푢푡푒푟 푔푎푙푎푐푡𝑖푐 푟푒푔𝑖표푛 푇~19 퐾 (𝑖푛푛푒푟 푔푎푙푎푐푡𝑖푔 푟푒푔𝑖표푛):

훽푑 퐼휈~휈 퐵휈(푇) 훽~1.8 • Dominates at frequencies 휈 > 70GHz.

• The grains emit (and absorb) photons most efficiently along the longest axis, while with the alignment mechanism grains tend to align the longer axis perpendicular to the local magnetic field. In dust emission region we will mainly measure polarization perpendicular to the magnetic field. In dust absorption region we will measure polarization parallel to the background field.

• Dust polarization can produce a B mode contamination.

6/08/2018 Padova, ICYAA 2018 Planck 2015 Results. I. Overview of products and scientific results. Planck Collaboration FOREGROUND: ANOMALOUS MICROWAVE EMISSION (AME) • Radiation produced by spinning small dust grains with an electric dipole moment.

• AME is spatially correlated with thermal dust emission.

Poidevin et et al.2018

• Low polarization is expected (in W43 best upper limit on AME polarization up to date: П<0.39% at 17 GHz (QUIJOTE), П<0.22% at 41 GHz (WMAP) ) 6/08/2018 Padova, ICYAA 2018 QUIJOTE : Q-U-I JOint TEnerife CMB Experiment

➢ Site: (altitude 2400 m, 28,3° N, 16.5° W) ➢ Sky coverage: -32° < Dec < 88° (fsky=0.65)

6/08/2018 Padova, ICYAA 2018 QUIJOTE CMB EXPERIMENT

QT1 & MFI (Multi Frequency Instrument) QT2 & TFGI • 4 Horns, 32 channels, 4 (Thirty and Forty GHz frequency bands: Instrument) ( , , , ) GHz • 14 pixels at GHz, • Angular resolution: 15 pixels at GHz 0.92°-0.63° • Angular resolution: • Sensitivity: 0.32°-0.26° 휇퐾 ∙ 푠−1/2 • Sensitivity: 500-600 −1/2 • Stepping polar 85-71 휇퐾 ∙ 푠 modulator (HWP) for • Operative soon (June polarization 2018) • Operative since Nov 2012 6/08/2018 Padova, ICYAA 2018 OBSERVATIONS WITH QUIJOTE : 20.000 푑푒푔2 of the sky covered, more that 21.000 hours휇퐾 of observation, sensitivity of 30 . 1° 푏푒푎푚 Nominal observation: 8h azimuth scans at fixed elevation (30°, 35°, 40°, 50°, 60°, 65°, 70°, 75°, 80°) 3.000 푑푒푔2 : in휇퐾 three separed fields. Expected sensitivity 10 1° 푏푒푎푚 after 1 year휇퐾 with the MFI (@ 11, 13, 17, 19 GHz) and 1 after 1 year with TFGI (@ 30, 40 GHz).1° 푏푒푎푚 : reach 푟~0.05 in three years of operation of the TFGI. 푑푒푔2 covering휇퐾 few hundred sensitivity 30-40 . : 1° 푏푒푎푚 • Perseus molecular complex (Génova-Santos et al. (2015)) : radio foregrounds characterization in those • W44 supernova remnant, W43 and W47 molecular complexes regions. (Génova-Santos et al. (2017)) Raster observation: scans in a azimuth interval and • Taurus molecular cloud (Poidevin et al. submitted) fixed elevation.

6/08/2018 Padova, ICYAA 2018 MAPMAKING

• The science with microwave observations is mostly done using maps. The map-making has an important role for CMB.

• Map-making consists of properly combine the data to produce an image of the sky: o Project the Data from the Time Order domain (TOD) to the corresponding position on the sky (Healpix pixel). o Minimize the instrumental and atmospheric noise.

푚 = 푚1 , 푚2 , 푚3 , … 퐻푒푎푙푝𝑖푥 푎푟푟푎푦: 푝𝑖푥푒푙 표푛 푡ℎ푒 푠푘푦

TOD

t 6/08/2018 Padova, ICYAA 2018 THE ATMOSPHERE The atmospheric emission at mm wavelengths is a big source of disturbance in ground base experiments. It is mainly due by the Precipitable Water Vapor (PWV). Time and space variations of PWV enter in the

data as a 1/f noise component.

퐺퐻푧 22

6/08/2018 Padova, ICYAA 2018 THE NOISE

: random gaussian signal (uncorrelated), with zero mean and standard deviation 휎푤. 푇푠푦푠 휎푤 = (Radiometer formula) ∆휈 ∙ 휏푠 2 휎푤 푃푤 휈 = (Power spectral density) 푓푠 : correlated noise component, with power spectral density depending on the inverse of the frequency^훾. It is due to drifts on the gain of the instrument or atmospheric variations. 2 훾 휎푤 휈푘 푃1/푓 휈 = 푓푠 휈

6/08/2018 Padova, ICYAA 2018

)

푚퐾 ( THE NOISE 푇

: random gaussian signal (uncorrelated), with zero mean and standard deviation 휎푤. 푇푠푦푠 휎푤 = (Radiometer formula) ∆휈 ∙ 휏푠 2 휎푤 푃푤 휈 = (Power spectral density) 푓푠 #푠푎푚푝푙푒 : correlated noise component, with power spectral density depending on the inverse of the frequency^훾. It is due to drifts on the gain of the instrument or atmospheric variations. 2 훾 휎푤 휈푘 푃1/푓 휈 = 푓푠 휈

Clean the data removing offsets with a determined time length: BASELINES.

푚퐾 6/08/2018 Padova, ICYAA 2018 THE DESTRIPER METHOD Example: Total noise 8 data in a tod 4 pixel map 2 baselines

Maximum likelihood estimation for the map 푚푠푘푦 and the baselines 푎.

(neglecting polarization)

6/08/2018 Padova, ICYAA 2018 QUIJOTE WIDE SURVEY MAP: INTENSITY

6/08/2018 Padova, ICYAA 2018 QUIJOTE WIDE SURVEY MAP: POLARIZATION Q

6/08/2018 Padova, ICYAA 2018 WMAP MAP: POLARIZATION Q

6/08/2018 Padova, ICYAA 2018 QUIJOTE WIDE SURVEY MAP: POLARIZATION U

6/08/2018 Padova, ICYAA 2018 WMAP MAP: POLARIZATION U

6/08/2018 Padova, ICYAA 2018 FITTING A FUNCTION WITH THE DESTRIPER METHOD

1 푓Ԧ= A = T sin(푒푙) atm Ԧ Linear dependence 푓 = ∆푇푑𝑖푝표푙푒 푔푙, 푔푏 퐴 = 1 of the data from a known function 푓Ԧ

6/08/2018 Padova, ICYAA 2018 FITTING A FUNCTION WITH THE DESTRIPER METHOD: ATMOSPHERE Ԧ 1 • An imperfect inclination of the zenithal axis of the 푓= Tatm ∙ telescope leads to variations of the atmospheric sin(푒푙) emission, as a function of 1/ sin(푒푙). Fitting this function we can obtain an estimation of the < 푇푎푡푚 > ~3퐾 temperature of the atmosphere. Depending on the frequency

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6/08/2018 Padova, ICYAA 2018 FITTING A FUNCTION WITH THE DESTRIPER METHOD: DIPOLE OF THE CMB 푣2 1 − 2 • Scanning the sky we are measuring the dipole 푐 ∆푇푑𝑖푝표푙푒(푔푙, 푔푏) = 푇0 푣 ~3.3푚퐾 pattern of the CMB in many different positions 1 − 푐 cos 휃(푔푙, 푔푏) of the sky. We know theoretically the dipole Ԧ emission low depending on the line of sight. We 푓 = 퐴 ∙ ∆푇푑𝑖푝표푙푒(푔푙, 푔푏) can fit for this function from the TOD. < 퐴 > = 1 if the voltage-temperature calibration is correct

6/08/2018 Padova, ICYAA 2018 • Polarization measurements are the actual challenge of Cosmology with CMB, in order to detect CMB B modes imprinted by Inflation.

• Radio foregrounds characterization is fundamental to: o Understand the different emission components of our Galaxy; o Study the Anomalous Microwave Emission (AME); o Clean the galactic emission to observe the CMB.

• QUIJOTE is providing IQU maps at low frequencies, covering up to the 65% of the sky, to: o Characterize the synchrotron and AME emission; o Reach 푟~0.05 for B modes detection at large angular scales.

6/08/2018 Padova, ICYAA 2018 6/08/2018 Padova, ICYAA 2018