Improved galactic foreground removal for B-mode detection with clustering methods
Artikel i vetenskaplig tidskrift, 2022

Characterizing the sub-mm Galactic emission has become increasingly critical especially in identifying and removing its polarized contribution from the one emitted by the cosmic microwave background (CMB). In this work, we present a parametric foreground removal performed on to sub-patches identified in the celestial sphere by means of spectral clustering. Our approach takes into account efficiently both the geometrical affinity and the similarity induced by the measurements and the accompanying errors. The optimal partition is then used to parametrically separate the Galactic emission encoding thermal dust and synchrotron from the CMB one applied on two nominal observations of forthcoming experiments from the ground and from the space. Moreover, the clustering is performed on tracers that are different from the data used for component separation, e.g. the spectral index maps of dust and synchrotron. Performing the parametric fit singularly on each of the clustering derived regions results in an overall improvement: both controlling the bias and the uncertainties in the CMB B-mode recovered maps. We finally apply this technique using the map of the number of clouds along the line of sight, Nc, as estimated from H I emission data and perform parametric fitting on to patches derived by clustering on this map. We show that adopting the Nc map as a tracer for the patches related to the thermal dust emission, results in reducing the B-mode residuals post-component separation. The code is made publicly available https://github.com/giuspugl/fgcluster.

ISM

cosmological parameters

inflation

cosmic background radiation

diffuse radiation

Astrophysics - Astrophysics of Galaxies

Astrophysics - Cosmology and Nongalactic Astrophysics

ISM: clouds

Författare

G. Puglisi

University of California

Lawrence Berkeley National Laboratory

Gueorgui Mihaylov

King's College London

Georgia Panopoulou

California Institute of Technology (Caltech)

Davide Poletti

Universita' degli Studi di Milano-Bicocca

Josquin Errard

Université Paris Diderot

Paola A. Puglisi

Royal Mail Group

Giacomo Vianello

Cape Analytics

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 511 2 2052-2074

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.1093/mnras/stac069

Mer information

Senast uppdaterat

2023-10-05