RT info:eu-repo/semantics/doctoralThesis
T1 The Quijote-mfi northern sky survey at 10–20 ghz construction and study of the maps, and characterization of the microwave haze
A1 Guidi, Federica
A2 Programa de Doctorado en Astrofísica
K1 Cosmología
K1 Cosmogonía
K1 Astrofísica
AB Primordial gravitational waves generated during inflation are expected to imprint a peculiar footprint in the large angular scale polarization of the CosmicMicrowave Background (CMB), the so-called B-modes, which however are stillundetected. Characterizing Galactic foregrounds such as polarized dust andsynchrotron emission, as well as having very precise control of instrumental effects, is extremely important to target a clean detection of the CMB B-modes.This thesis is set in this context, and presents an analysis of the data ofthe MFI instrument of the QUIJOTE experiment. QUIJOTE-MFI has beeninstalled at the Teide Observatory since 2012, with the aim to observe the intensity and linear polarization of the microwave sky at four frequencies in therange 10–20 GHz. The purpose of QUIJOTE-MFI is to measure the low frequency Galactic foregrounds such as anomalous microwave emission (AME) andpolarized synchrotron, which need to be precisely characterized to complementthe study of the CMB polarization anisotropies.An important part of this thesis is dedicated to the development of the PICASSO map-making code, which is based on the destriping technique (e.g., Keihänen et al., 2010), and which is used to construct the intensity and linear polarization (Stokes Q and U ) maps for the QUIJOTE experiment. PICASSOallows a precise reconstruction of the signal at large angular scales, which is keyfor B-modes searches. A first version of the code was initially implemented ina previous thesis by Pelaez Santos (2019), and it was further developed duringthis thesis by including the use of priors for the 1/f noise, and a technique forthe fitting of templates in the time domain to the data, during the map-makingstep. PICASSO was validated with realistic simulations of QUIJOTE-MFI data,showing that the reconstruction of the sky signal is precise at the 0.001% leveland for multipoles 20 ∼< ` ∼< 200. In addition, the study of the transfer functionof the code showed that 100% of the sky signal is recovered at scales ` ∼> 10,with only ∼ 2% power loss at 2 ∼< ` ∼< 8 for EE and BB. This work will soon be published in Guidi et al., (submitted).Afterwards, this thesis describes the application of this code for the construction, validation, and study of the QUIJOTE-MFI wide-survey maps, which areobtained from approximately one year of effective observations of the full northern sky, at 10–20 GHz, taken in the period 2012–2018. The wide-survey mapsare presented, analyzed and characterized, in conjunction with their angularpower spectra. The angular power spectra of the polarization maps (which aresynchrotron dominated) can be modeled, at 11 GHz, with a power law C` ∝ `α,with α = −3.00±0.16 for EE and α = −3.09±0.41 for BB, at Galactic latitudes|b| > 5◦ and declinations 6◦ < δ < 70◦, in the multipole range 30 < ` < 300.The relative amplitude of the power of the E and B-modes at ` = 80 is measuredto be ABB/AEE = 0.34±0.10 within the aforementioned sky area, it being lowerthan the BB/EE ratio measured for dust emission by Planck (ABB/AEE = 0.5;Planck Collaboration et al., 2018c). The TB and EB spectra of the maps aremeasured to be compatible with zero within the uncertainties, and the TEspectrum is marginally detected at low multipoles. In addition, a complete setof validation tests, including the analyses of null-tests for the characterizationof the noise in the maps, and cross-correlation analysis for the validation ofthe calibration of the data are presented. These results will be published inRubiño-Martín et al. (in prep.), which will also be accompanied by a set ofpapers focused on the scientific exploitation of the QUIJOTE-MFI wide-surveydata. The maps will be made publicly available.Finally, new data taken in the region surrounding the Galactic center wereanalyzed in combination with the wide-survey data, with the aim of studyingthe so-called microwave Haze. The Haze is a diffuse emission with uncertainand interesting origin, since it could be attributed to dark matter annihilationin the Galactic bulge, or to nuclear activity in the Galactic center. It extendsfrom the Galactic center up to high Galactic latitudes (|b| < 35◦), with spatialcorrespondence to the Fermi bubbles observed in γ-rays, and to the polarizedradio plumes observed by the S-PASS survey at 2.3 GHz. The Haze area isstudied in intensity and in polarization, using the new data provided by theQUIJOTE experiment. An excess of diffuse signal that could be attributed tothe Haze is detected in intensity with ∼ 9σ confidence level. The intensityspectrum of this emission was modeled using a power-law spectrum, leading toa spectral index βH = −2.79 ± 0.08, in the range 11–60 GHz. This result is inslight tension with previous measurements (e.g., Planck Collaboration et al.,2013) that estimated βH = −2.56 ± 0.05. However, in agreement with previousworks, it can be observed that the spectrum of the the Haze is flatter thanthat of the total synchrotron in the same area and frequency range, which has a spectral index βs = −3.00 ± 0.03. In addition, we observed a differencebetween the intensity spectral index of the North and South Haze bubbles, at∼ 6σ confidence level. Finally, a study of the polarized spurs and plumes thatare possibly associated with the Haze is presented, where a clear steepening ofthe spectrum between 11 GHz and 23 GHz can be observed, in agreement withprevious works (Carretti et al., 2013). These results will be published in Guidiet al. (in prep.).
YR 2021
FD 2021
LK http://riull.ull.es/xmlui/handle/915/27330
UL http://riull.ull.es/xmlui/handle/915/27330
LA en
DS Repositorio institucional de la Universidad de La Laguna
RD 28-jun-2024