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Foreground & component separation section for B-Pol: from the first proposal to the new submission. Carlo Burigana INAF-IASF Bologna, [email protected]. B-Pol Workshop Institut d'Astrophysique de Paris 28 - 30 July 2010. - PowerPoint PPT Presentation
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Foreground & component separation section for B-Pol: from the first proposal to the new submission
Carlo Burigana
INAF-IASF Bologna, [email protected]
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