This PhD thesis is focus on the LSPE/Strip instrument observations. It is the ground-based, low-frequency counterpart of the whole experiment LSPE (Large Scale Polarization Explorer), leads by Italian Cosmology consortium. It is a radio frequency telescope that sensitives at the microwave frequencies (43GHz and 95Ghz). It will be deployed at the Teide Observatory (Tenerife - Canary Islands) for observing the curly part of the polarization of the Cosmic Microwave Background - CMB. The angular correlation pattern of the curly part of the CMB polarization is called B-modes and is predicted by inflation theory. Today, this kind of polarization pattern has not been observed yet, but if will been observed it represents the smoking gun for inflation theory of the early Universe opening the possibility to understand the exotic processes happened where the Universe was at the very beginning. The CMB polarization signal is at (or below) one part of a million. It represents a very challenging target for current instrumentation technology. Moreover, every ground-based telescope has to deal with the atmospheric spurious signal. The absorption-emission mechanism of the water vapor mixed in the atmosphere is particularly strong in the microwave bandwidth, increasing the total balance of the white noise of the instrument. The water vapor is not well mixed in the atmosphere producing a quasi-spin-synchronous signal extremely difficult to separate from the scientific data. This spurious signal is a $1/f$-like noise and is not a totally spin-sync signal because the water vapor structures are blown by the wind and the final signal is the convolution of the telescope scanning strategy and the displacement of water vapor structures along the line of sight of the telescope. IIn this work I just develop a model for assessing the the atmospheric brightness temperature with a statistical approach and I didn't go thought the problem of how to get rid of these fluctuations from the scientific signal. For cleaning the data from the spurious correlated signal of the atmosphere, a new model of mapmaking has to be developed focusing on that specific signal. From initial simulations made by colleagues from Lawrence Berkeley National Laboratory seems that the more promising approach is to use the atmospheric signal and using it as a signal template (prior) for a modified mapmaking algorithm. Unfortunately it is a very challenging problem and the studies on it are still ongoing.

ATMOSPHERIC CHARACTERIZATION FOR LSPE/Strip OBSERVATIONS / S. Mandelli ; SUPERVISOR: A. MENNELLA ; PHD COORDINATOR: A. MENNELLA. - Dipartimento di Fisica Aldo Pontremoli - Universita' degli Studi di Milano. Dipartimento di Fisica Aldo Pontremoli, 2024 Sep 23. 34. ciclo

MICROWAVE BACKGROUND GROUND-BASED OBSERVATIONS

S. Mandelli
2024

Abstract

This PhD thesis is focus on the LSPE/Strip instrument observations. It is the ground-based, low-frequency counterpart of the whole experiment LSPE (Large Scale Polarization Explorer), leads by Italian Cosmology consortium. It is a radio frequency telescope that sensitives at the microwave frequencies (43GHz and 95Ghz). It will be deployed at the Teide Observatory (Tenerife - Canary Islands) for observing the curly part of the polarization of the Cosmic Microwave Background - CMB. The angular correlation pattern of the curly part of the CMB polarization is called B-modes and is predicted by inflation theory. Today, this kind of polarization pattern has not been observed yet, but if will been observed it represents the smoking gun for inflation theory of the early Universe opening the possibility to understand the exotic processes happened where the Universe was at the very beginning. The CMB polarization signal is at (or below) one part of a million. It represents a very challenging target for current instrumentation technology. Moreover, every ground-based telescope has to deal with the atmospheric spurious signal. The absorption-emission mechanism of the water vapor mixed in the atmosphere is particularly strong in the microwave bandwidth, increasing the total balance of the white noise of the instrument. The water vapor is not well mixed in the atmosphere producing a quasi-spin-synchronous signal extremely difficult to separate from the scientific data. This spurious signal is a $1/f$-like noise and is not a totally spin-sync signal because the water vapor structures are blown by the wind and the final signal is the convolution of the telescope scanning strategy and the displacement of water vapor structures along the line of sight of the telescope. IIn this work I just develop a model for assessing the the atmospheric brightness temperature with a statistical approach and I didn't go thought the problem of how to get rid of these fluctuations from the scientific signal. For cleaning the data from the spurious correlated signal of the atmosphere, a new model of mapmaking has to be developed focusing on that specific signal. From initial simulations made by colleagues from Lawrence Berkeley National Laboratory seems that the more promising approach is to use the atmospheric signal and using it as a signal template (prior) for a modified mapmaking algorithm. Unfortunately it is a very challenging problem and the studies on it are still ongoing.
23-set-2024
Settore FIS/05 - Astronomia e Astrofisica
Cosmology;CMB;Atmosphere;Simulations
MENNELLA, ANIELLO
MENNELLA, ANIELLO
Doctoral Thesis
ATMOSPHERIC CHARACTERIZATION FOR LSPE/Strip OBSERVATIONS / S. Mandelli ; SUPERVISOR: A. MENNELLA ; PHD COORDINATOR: A. MENNELLA. - Dipartimento di Fisica Aldo Pontremoli - Universita' degli Studi di Milano. Dipartimento di Fisica Aldo Pontremoli, 2024 Sep 23. 34. ciclo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/1100748
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