CMB & Foreground Polarisation

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CMB & Foreground CMB & Foreground Polarisation Polarisation CMB 2003 Workshop, Minneapolis Carlo Baccigalupi, SISSA/ISAS

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CMB & Foreground Polarisation. Carlo Baccigalupi, SISSA/ISAS. CMB 2003 Workshop, Minneapolis. What We Know. What We Guess. Known (Polarisation) Foregrounds Existing Data. Existing Simulations Microwave Frequency Scaling Approaching from Low Frequency. CMB Contamination. CMB Cleaning. - PowerPoint PPT Presentation

Transcript of CMB & Foreground Polarisation

Page 1: CMB & Foreground Polarisation

CMB & CMB & Foreground Foreground PolarisationPolarisation

CMB 2003 Workshop, Minneapolis

Carlo Baccigalupi, SISSA/ISAS

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What We KnowWhat We Know What We GuessWhat We Guess

CMB ContaminationCMB ContaminationCMB CleaningCMB Cleaning

Known (Polarisation) ForegroundsExisting Data

Existing SimulationsMicrowave Frequency ScalingApproaching from Low Frequency

E, B & TEContamination Sky Distribution

Experience The MagicNew SpellsMagic Limitations & Future Arts

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Physics Frequency Angle Relevance

Frequency Scaling

All Sky Data

Patchy Data

Simulations

Synchrotron Synchrotron Synchrotron electrons spinning electrons spinning Galactic magnetic fieldGalactic magnetic field

< 100 GHz1o or more

Not Uniform Not Uniform Electrom Density Electrom Density

Fluctuations, Fluctuations, -2.5 -

3.2

Yes,Yes, 0.50.5 MHzMHz

FWHMFWHM1 deg1 deg

Yes,Yes, 1-3 1-3 GHzGHz

FWHMFWHM5 5 arcminarcmin

All Sky All Sky All All FrequenciesFrequencies

Free-Free BremsstrahluBremsstrahlung ng Galactic electron-ion Galactic electron-ion scatteringscattering

< 100 GHz 1o or more

Not Uniform Not Uniform Electrom Spectral Electrom Spectral

Distribution, Distribution, -2 -2.2

Yes,Yes, Traced Traced by Hby H emission emission

From All From All SkySky

All Sky All Sky All All FrequenciesFrequencies

Thermal Dust

Grey Body Grey Body by by dust grains reprocessing dust grains reprocessing UV star radiation UV star radiation

>100 GHz1o or more

Not UniformNot UniformTemperature Temperature FluctuationsFluctuations

Yes,Yes, 100 100 mm

FWHMFWHM6 6 arcminarcmin

From All From All SkySky

All Sky All Sky All All FrequenciesFrequencies

Non-Thermal Dust

SZ Inverse Inverse Compton Compton of CMB of CMB through thermal, non-through thermal, non-thermal and kinetic thermal and kinetic intracluster gasintracluster gas

Allarcmin

Uniform, Uniform, CMB CMB Rayileigh-Jeans-Wien Rayileigh-Jeans-Wien shift, dependence on shift, dependence on intracluster physicsintracluster physics

All Sky All Sky Thermal, All Thermal, All FrequenciesFrequencies

Radio Sources

See See SynchrotronSynchrotronwith different with different populations: internal populations: internal

structures, ...structures, ...

< 100 GHzarcmin

Not Uniform Not Uniform different populations: different populations:

flat, inverse, ... flat, inverse, ...

Yes,Yes, 1-20 1-20 GHzGHz

FWHMFWHMarcsecarcsec

All Sky All Sky All All FrequenciesFrequencies

Infrared Sources

See Thermal See Thermal DustDustwith different with different populations: elliptical, populations: elliptical, spirals, starburst, ...spirals, starburst, ...

>100 GHzarcmin

Not Uniform Not Uniform different populations, different populations, elliptical, spirals, starburst, cold sources, ...

Yes,Yes,12-100 12-100 mmFWHMFWHM2 2 arcminarcmin

Yes,Yes, 5-200 5-200 mmFWHMFWHM arcsec arcsec

850 850 m, 23 m, 23 arcsecarcsec

All Sky All Sky All All FrequenciesFrequencies

...

Foreground Chart: Total IntensityForeground Chart: Total Intensity

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Physics Frequency Angle Relevance

Frequency Scaling

All Sky Data

Patchy Data

Simulations

Synchrotron Synchrotron Synchrotron electrons spinning electrons spinning Galactic magnetic fieldGalactic magnetic field

< 100 GHzAll Scales

Not Uniform Not Uniform Electrom Density Electrom Density

Fluctuations, Fluctuations, -2.5 -

3.2

Yes,Yes, 0.50.5 MHzMHz

FWHMFWHM1 deg1 deg

Yes,Yes, 1-3 1-3 GHzGHz

FWHMFWHM5 5 arcminarcmin

All Sky All Sky All All FrequenciesFrequencies

Free-Free BremsstrahluBremsstrahlungngGalactic electron-ion Galactic electron-ion scattering; expected scattering; expected vanishing in polarisationvanishing in polarisation

Thermal Dust

Alligned Dust Alligned Dust Grains Grains grain grain magnetic moment magnetic moment alligned with Galactic alligned with Galactic magnetic fieldmagnetic field

Non-Thermal Dust

SZ Inverse Inverse Compton Compton multiple scattering, multiple scattering, intracluster peculiar intracluster peculiar velocitiesvelocities

Allarcmin

Not Uniform, Not Uniform, CMB Rayileigh-Jeans-CMB Rayileigh-Jeans-Wien shift, dependence Wien shift, dependence on intracluster physicson intracluster physics

Radio Sources

See See Synchrotron Synchrotron with different with different populations: internal populations: internal

structures, ...structures, ...

< 100 GHzarcmin

Not Uniform Not Uniform different populations: different populations:

flat, inverse, ... flat, inverse, ...

Yes,Yes, 1-20 1-20 GHzGHz

FWHMFWHMarcsecarcsec

Infrared Sources

See Thermal See Thermal DustDustwith different with different populations, internal populations, internal structures, ...structures, ...

>100 GHzarcmin

Not Uniform Not Uniform different populations, different populations, elliptical, spirals, starburst, cold sources, ...

...

Foreground Chart: PolarisationForeground Chart: Polarisation

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CMB & Radio CMB & Radio Source Source

PolarisationPolarisation

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Radio Sources: RecipeRadio Sources: Recipe

• Study polarised sources from the NVSS catalogue at 1.4 GHz

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Radio Sources: RecipeRadio Sources: Recipe

• Study polarised sources from the NVSS catalogue at 1.4 GHz

• Look for common sources in the GB6 catalogue at 4.85 GHz in total intensity for estimating the spectral index distribution

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Radio Sources: RecipeRadio Sources: Recipe

• Study polarised sources from the NVSS catalogue at 1.4 GHz

• Look for common sources in the GB6 catalogue at 4.85 GHz in total intensity for estimating the spectral index distribution

• Calculate the radio polarisation degree: 1GHz 2 %

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Radio Sources: RecipeRadio Sources: Recipe

• Study polarised sources from the NVSS catalogue at 1.4 GHz

• Look for common sources in the GB6 catalogue at 4.85 GHz in total intensity for estimating the spectral index distribution

• Calculate the radio polarisation degree: 1GHz 2 %

• Check on higher frequencies (up to 10 GHz, Mack et al. 2002) and correct for Faraday depolarisation: 10GHz 31GHz

(steep), 10GHz 1-31GHz (flat spectra)

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Radio Sources: RecipeRadio Sources: Recipe

Tucci et al. 2003, Mesa, Baccigalupi et al. A&A 2002Tucci et al. 2003, Mesa, Baccigalupi et al. A&A 2002

• Study polarised sources from the NVSS catalogue at 1.4 GHz

• Look for common sources in the GB6 catalogue at 4.85 GHz in total intensity for estimating the spectral index distribution

• Calculate the radio polarisation degree: 1GHz 2 %

• Check on higher frequencies (up to 10 GHz, Mack et al. 2002) and correct for Faraday depolarisation: 10GHz 31GHz (steep), 10GHz 1-31GHz (flat spectra)

• Extrapolate the NVSS polarised population to the microwave band using the recipe by Toffolatti (1998) or applying the estimated spectral index distribution and correcting for steepening at 15 GHz (Taylor et al. 2001)

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Radio Sources: CMB ContaminationRadio Sources: CMB Contamination

30 GHz

100 GHz

Tucci et al. 2003, Mesa et al. A&A 2002Tucci et al. 2003, Mesa et al. A&A 2002

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Radio Sources: PerspectsRadio Sources: Perspects

Analyse ATCA Polarised Sources at 18.5 GHz

Ricci et al. in preparation Ricci et al. in preparation

Measure Microwave Sources Polarisation Degree

Check Faraday Depolarisation with Radio Band

Investigate the Physics of the Sources

Improve CMB Contamination Estimate

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CMB & CMB & Synchrotron Synchrotron PolarisationPolarisation

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Synchrotron: Giardino et al. 2002Synchrotron: Giardino et al. 2002

Analyse the Haslam radio Synchrotron template assuming theoretical polarisation emission

Analyse low & medium Galactic latitude data (Duncan 1997, 1999, Uyaniker 1999)Extrapolate Haslam to

small angles and convolve with radio polarisation angle statistics from D97, D99, U99

Extrapolate to MicrowaveBuild Q & U templates assuming random polarisation angle

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Synchrotron: Synchrotron: Tucci et al. 2000, Baccigalupi et al. 2001Tucci et al. 2000, Baccigalupi et al. 2001

Analyse low & medium Galactic latitudes data (Duncan 1997, 1999, Uyaniker 1999)

Extrapolate to Microwave as Giardino (2002) rescaling power to match Baccigalupi (2001)

Take Brouw & Spoelstra (1976) as representative of the degree and sub-degree angular scales

Check depolarisation with known rotation measures and removing bright HII regions on the Galactic plane

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Synchrotron: E & B CMB ContaminationSynchrotron: E & B CMB Contamination

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Synchrotron: TE CMB ContaminationSynchrotron: TE CMB Contamination

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SS, -3.2 < , -3.2 < < –2.5 < –2.5

Synchrotron: Non-Rigid Frequency Scaling Synchrotron: Non-Rigid Frequency Scaling

Giardino et al. 2002Giardino et al. 2002

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Synchrotron: Riddles Synchrotron: Riddles

• Are our predictions reliable?

• What is the structure of the spectral index on degree and sub-degree sngular scales?

• What is the statistics of the polarisation angle?

• Why in Duncan et al. (1997, 1999) and Uyaniker (1999) the signal does not depend on latitude up to b=20o ?

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Component Component Separation Separation PolarisationPolarisation

Non-blind: Tegmark Efstathiou 1996, Bouchet & Gispert 1998, Hobson et al. 1998, Stolyarov et al. 2001

Blind: Baccigalupi et al. 2000, Delabrouille et al. 2002, Maino et al. 2002, Delabrouille, Cardoso, Patanchon 2003

Data: Barreiro et al. 2003, Maino et al. 2003

Polarisation: Baccigalupi et al. 2003

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Pixels or Modes Components

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Experience the MagicExperience the Magic

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Components

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Pixels or Modes

Experience the MagicExperience the Magic

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Fre

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Pixels or Modes

Experience the MagicExperience the Magic

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Fre

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Pixels or Modes

Experience the MagicExperience the Magic

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Experience the MagicExperience the Magic

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217, 353 GHz, dust + 217, 353 GHz, dust + CMBCMB

CMB recoveryCMB recovery

OUT

IN

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OUT

IN

217, 353 GHz, dust + 217, 353 GHz, dust + CMBCMB

dust recoverydust recovery

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Noiseless, 70 & 100 GHz Uniform Synchrotron Spectral Index

Component Separation in Polarisation Component Separation in Polarisation

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Component Separation in Polarisation Component Separation in Polarisation Noiseless, 70 & 100 GHz Non-uniform Synchrotron Spectral Index

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Component Separation in Polarisation Component Separation in Polarisation The effect of non-uniform spectral index The effect of non-uniform spectral index

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Noisy, 70 & 100 GHz, Non-Uniform Synchrotron Spectral Index

S/N=0.5Crash at S/N=0.2

Crash at S/N=0.5 S/N=0.5

Component Separation in Polarisation Component Separation in Polarisation GamesGames

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Component Separation in Polarisation Component Separation in Polarisation Is that so easy?Is that so easy?

•Simulations indicate that Planck is sensitive to T/S=30% in presence of foregrounds

•Systematics: beam asymmetry, noise sky and spectral distribution. (Hu et al. 2003)

•Foreground knowledge still poor

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Conclusions

• CMB Contaminations from Radio Sources: under control

• CMB Contamination to E and TE: under control• CMB Contamination to B: significant on all sky• New data analysis techniques

make at least conceivable to face such a contamination

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