Characterization of Extragalactic Point-Sources on E- and B-mode Maps of the CMB Polarization

Abstract

Although interesting in themselves, extragalactic sources emitting in the microwave range (mainly radio-loud active galactic nuclei and dusty galaxies) are also considered a contaminant from the point of view of Cosmic Microwave Background (CMB) experiments. These sources appear as unresolved point-like objects in CMB measurements because of the limited resolution of CMB experiments. Amongst other issues, point-like sources are known to obstruct the reconstruction of the lensing potential, and can hinder the detection of the Primordial Gravitational Wave Background for low values of $r$. Therefore, extragalactic point-source detection and subtraction is a fundamental part of the component separation process necessary to achieve some of the science goals set for the next generation of CMB experiments. As a previous step to their removal, in this work we present a new filter based on steerable wavelets that allows the characterization of the emission of these extragalactic sources. Instead of the usual approach of working in polarization maps of the Stokes' $Q$ and $U$ parameters, the proposed filter operates on E- and B-mode polarization maps. In this way, it benefits from the lower intensity that, both, the CMB, and the galactic foreground emission, present in B-modes to improve its performance. To demonstrate its potential, we have applied the filter to simulations of the future PICO satellite, and we predict that, for the regions of fainter galactic foreground emission in the 30 GHz and 155 GHz bands of PICO, our filter will be able to characterize sources down to a minimum polarization intensity of, respectively, 125 pK and 14 pK. Adopting a $\Pi =0.02$ polarization degree, these values correspond to 169 mJy and 288 mJy intensities.

23 pages, 8 figures, accepted by JCAP

References in corpus (15)

• Massive neutrinos and cosmology
• CMB-S4 Science Case, Reference Design, and Project Plan
• Planck intermediate results. LVII. Joint Planck LFI and HFI data processing
• Planck constraints on the tensor-to-scalar ratio
• A Measurement of Gravitational Lensing of the Cosmic Microwave Background by Galaxy Clusters Using Data from the South Pole Telescope
• PICO: Probe of Inflation and Cosmic Origins
• Lower bias, lower noise CMB lensing with foreground-hardened estimators
• Demonstration of cosmic microwave background delensing using the cosmic infrared background
• Measuring cluster masses with CMB lensing: a statistical approach
• Theory of Cosmic Microwave Background Polarization
• Comparison of delensing methodologies and assessment of the delensing capabilities of future experiments
• Bias to CMB lensing from lensed foregrounds
• Extragalactic sources in Cosmic Microwave Background maps
• Delensing Degree-Scale $B$-Mode Polarization with High-Redshift Line Intensity Mapping
• The polarimetric multi-frequency radio sources properties

Cited by in corpus (4)

• QUIJOTE scientific results -- IV. A northern sky survey in intensity and polarization at 10-20GHz with the Multi-Frequency Instrument
• A Bayesian method for point source polarization estimation
• Constraining the polarisation flux density and angle of point sources by training a convolutional neural network
• Mitigating point-source contamination in CMB polarization: a Generalized Point Spread Function fitting approach