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H2020

RADIOFOREGROUNDS Report Summary

Project ID: 687312
Funded under: H2020-EU.2.1.6.

Periodic Reporting for period 1 - RADIOFOREGROUNDS (Ultimate modelling of Radio foregrounds: a key ingredient for cosmology)

Reporting period: 2016-01-01 to 2016-12-31

Summary of the context and overall objectives of the project

The aim of this project is to combine two unique datasets, the nine Planck all-sky (30-857 GHz) maps and the four QUIJOTE Northern sky (10-20 GHz) maps, to provide the best possible characterization of the physical properties of polarized emissions in the microwave domain, together with an unprecedentedly thorough description of the intensity signal. This legacy information will be essential for future sub-orbital or satellite experiments.

In particular, the combination of Planck and QUIJOTE will allow us to achieve the following objetives:

-to provide state-of-the-art legacy maps of the synchrotron and AME emissions in the Northern sky;
-to characterize the synchrotron spectral index with high accuracy, fitting for the curvature of the synchrotron spectrum to constrain cosmic-ray electron physics;
-to study the large-scale properties of the Galactic magnetic field using the radio information;
-to model and characterize the level of a possible contribution of polarized anomalous microwave emission (AME);
-to characterize the population of radio sources measured by Planck by adding unique information in the frequency domain of 10-20GHz;
-to provide “added-value” data products for the scientific community;
-to provide specific (open source) software tools for data processing, data visualization and public information.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The QUIJOTE (Q-U-I JOint TEnerife) experiment is a polarimeter with the aim of characterising the polarisation of the Cosmic Microwave Background and other galactic or extragalactic physical processes that emit in microwaves in the frequency range 10-42GHz, and at large angular scales (1-degree resolution). The project consists of two telescopes and three instruments surveying a large sky area from the Teide Observatory to provide high sensitivity maps of the Stokes parameters I, Q and U. The first QUIJOTE instrument, known as Multi-Frequency Instrument (MFI), has been surveying the northern sky in four individual frequencies between 10 and 20 GHz since November 2012. At the end of year 1 on the RADIOFOREGROUNDS project, we have accumulated more than 6700 hrs of observations with the MFI, providing data with an average sensitivity of 50 muK/beam in Stokes Q and U in a region of 20,000 square-degrees. Preliminary maps are internally available within the project, as well as numerical simulations that are being used to test our numerical methods to separate astrophysical components.
Using dedicated QUIJOTE observations around the Galactic region 25º<l<45º, we have confirmed (Génova-Santos et al. 2017) the presence of anomalous microwave emission (AME) towards two molecular complexes, W43 and W47. We also detected at high significance the AME associated with W44, the first clear detection of this emission towards a supernova remnant. The new QUIJOTE polarisation data, in combination with Wilkinson Microwave Anisotropy Probe (WMAP) and PLANCK satellite data are essential to set upper limits on the polarisation fraction of W43 of AME to be less than 0.39 per cent (95 per cent C.L.) from QUIJOTE 17 GHz, and less than 0.22 per cent from WMAP 41 GHz data, which are the most stringent constraints ever obtained on the polarisation fraction of the AME. For typical physical conditions (grain temperature and magnetic field strengths), and in the case of perfect alignment between the grains and the magnetic field, the models of electric or magnetic dipole emissions predict higher polarisation fractions.
We have also developed a code to model the synchrotron and thermal dust emission processes in intensity and polarisation. Various models of the relativistic electron and dust grains 3D density distributions have been implemented. These models are based on parametric representations of the halo and spiral arms of the Galaxy, as well as of possible singular structures (e.g. bubbles).
Concerning the modelling of the radio source emission, we have obtained a refined model of the radio emission in star forming galaxies (Obi et al. 2017), and we have obtained predictions for the expected QUIJOTE source catalogue, with a separation of the contributions of star-forming, radio-quiet and radio-loud objects to the source counts, redshift distribution and luminosity function. From the observational point of view, we have implemented and tested the tools for single and multi-frequency detection of sources in radio maps, and we have started a follow-up programme with the VLA of a complete sample of 51 radio sources selected to have a flux density above 1 Jy in total intensity at 30 GHz in the 2013 all-sky Planck Catalogue of Compact sources, and which are also located inside the QUIJOTE cosmological fields.
Finally, we have defined the data sources and architecture of the final database of the RADIOFOREGROUNDS project, and we have prepared the Data Management Plan.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Using the combination of QUIJOTE data with Planck and WMAP, we have set the most stringent constraints ever obtained on the polarisation fraction of the AME. These limits provide important information to disentangle the physical mechanisms producing this emission.

We also detected at high significance the AME emission associated with the SNR W44, the first clear detection of this emission towards a supernova remnant.

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