Foreground & component separation section for B-Pol: from the first proposal to the new submission

Carlo Burigana

INAF-IASF Bologna, burigana@iasfbo.inaf.it

B-Pol Workshop

Institut d'Astrophysique de Paris

28 - 30 July 2010

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep.1

Foreground “subsection”

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep.2

• Galactic studies

– brief review of existing all (or large coverage) sky surveys @ deg resolution:

– WMAP, radio 1.4 GHz, Archeops

– Galactic components of polarized microwave sky

– Some comments on Galaxy modelling

• Extragalactic sources

– Poisson (& clustering) flucts. by polarized extragalactic sources

• radio sources (various classes)

• far-IR sources (various classes)

• APS of the various astrophysical signals vs CMB vs noise

• Mention to perspectives from future (for that time) “observations”:

OCRA (30 GHz), Planck, S-PASS, PGMS, C-BASS, GEM, PILOT, SPT, SCUBA2, ALMA, POLKA, HERTZ, IRAM, …

Comparison between CMB & foreground & noise APS

(from first B-Pol proposal)

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep.3

Legenda of APS figure

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep.4

Component separation “subsection”

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep.5

• Brief review of available (or “in construction”) methods

– Diffuse components: non-blind, blind methods

• template fitting methods, Wiener filtering & maximum entropy

• ICA, FastICA, SMICA, CCA, PolEMICA

• phase methods

– B-Pol 1 deg: relevant for Galactic diffuse component studies

– Sources

• wavelet & bandpass filters, matched filter, Mexican-hat wavelet family

– B-Pol 1deg: essentialy no new sources but studies down to 100 mJy level of sources already detected

Updates/Improvements?

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep.6

• Updates on existing / in progress / foreseen surveys/data (see e.g. talks by Simona, Ettore)

• Improvements in modelling astrophysical signals (see e.g. talks by Lauranne, Richard, Jean-Philippe & notes here by Gianfranco & Anna)

• Comp. sep. methods: updates in description of existing methods, but in particular:– concrete applications to B-Pol of few selected methods for representative

experimental set-up?– concrete applications to B-Pol to define optimal frequencies? (… optimal for

what? …)– N.B.: now the state-of-the-art is much more mature than only few years ago but …

at B-Pol sensitivity level?– see e.g. talks by Jacques, Sara/Anna, Clive

• Extension to higher multipoles?• Is observational strategy an issue?• Link with data analysis in general both for CMB & foreground statistical characterization

Link with CMB-Foreground APS estimation

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep.7

• We predict APS for CMB & foregrounds• Extracting CMB BB APS is the main cosmological goal of B-

Pol• But, how much robust is our APS estimation?• Also, component separation methods (both aimed at CMB

&/or at foregrounds) are interfaced with APS estimators possibly both for CS methods intrinsic needs & as final common goal

• APS estimation is fundamental not only for CMB but also for foreground statistical studies, linked with physical modelling (turbolence/Kolmogorov spectrum, etc.)

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep.8

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep.9

Better definition of astrophysical goals?

• Largely relies on our view of B-Pol, in particular of angular resolution

• FWHM > deg main goals only cosmological, room only for limited astrophysical studies

• FWHM of 10 arcmin additional cosmology, astrophysics-cosmology

(see yesterday talks) & wide astrophysics:– Extragalactic sources (see also yesterday Richard’s talk)– Studies of Galactic sources/structures/features not only of

vey diffuse emissions (see also today Jean-Philippe’s talk)

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep.10

Integral counts of extragalactic sources in polarization

contribution by G. de Zotti & A. Bonaldi (INAF-OAPd)• Radio source counts based on the De Zotti et al.

(2005) model, assuming a mean polarization degree of 3%.

Counts are dominated by blazars.• Counts of far-IR galaxies based on the Negrello

et al. (2007) model, assuming a mean polarization degree of 1%.

The bright tail is dominated by normal spiral galaxies, with a significant contribution from starburst galaxies.

At 350 GHz, strongly lensed proto-spheroidal galaxies may start to show-up in polarization at the mJy level.

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep. – Contr. by G. de Zotti & A. Bonaldi 11

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep. – Contr. by G. de Zotti & A. Bonaldi 12

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep. – Contr. by G. de Zotti & A. Bonaldi 13

Summary on extragalactic sources

• Since Planck will probably detect at ≥5σ only a few tens of extragalactic sources in polarization (López-Caniego et al. 2009) an accurate totally unbiased (blind) determination of the polarization properties of extragalactic sources will remain to be done and is clearly essential to put on a firm basis estimates of extragalactic source contributions to small scale polarization fluctuations. • Of course, polarization data are also of great importance per se, as the prime means to study the roles of magnetic fields in astrophysics. • Blind polarization surveys of large areas at (sub)-mm wavelengths are not feasible from the ground.

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep. – Contr. by G. de Zotti & A. Bonaldi 14

C. Burigana, Paris, 28-30 July 2010, B-Pol: Foregrounds & Comp. Sep.15