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|
Identifier |
000433409 |
Title |
Study of the impact of the interstellar cloud shapes on CMB polarization foregrounds |
Alternative Title |
Μελέτη της επιρροής του σχήματος των διαστρικών νεφών στις παρεμβολές της πόλωσης της κοσμικής ακτινοβολίας υποβάθρου |
Author
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Κωνσταντίνου, Άννα Κ.
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Thesis advisor
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Τάσσης, Κωνσταντίνος
Pelgrims, Vincent
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Reviewer
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Χαρμανδάρης, Βασίλης
Diaz-Santos, Tanio
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Abstract |
In the quest for the primordial B-mode in the polarization of cosmic microwave
background (CMB) radiation, the understanding and characterization of Galactic foregrounds has become of utmost importance. On this subject, we have noticed that the
dust clouds of the magnetized interstellar medium are generally considered as filamentary structures by the CMB community whereas it has been established for some time
that they are most likely sheet structures by the radio astrophysics community.
In this project, we investigate whether the morphology of the dust clouds has
an impact on the statistical characterization of the polarized emission. To that end, we
simulate interstellar clouds with both filamentary and sheet-like structure, using the
software "Asterion" which is dedicated to this work and we generate synthetic polarization maps. We then explore some characteristics of the power spectra, such as the E/B
power asymmetry, quantified through the EE/BB ratio and the correlation coefficient between intensity and E mode power rT E, and lead a statistical analysis.
Our results about filaments are consistent with theoretical expectation (e.g. Zaldarriaga 2001). For the first time we carry a statistical analysis for sheet-like interstellar
clouds. The behaviour of sheets present similarities and differences as compared to filaments. Finally, we found that there is degeneracy between sheets and filaments in
quantities extracted from their power spectra as well as with their apparent shape, at
the map level. In a sense, we have set the stage for future and more detailed investigations that will be needed to fully characterize the latter.
|
Language |
English |
Subject |
B Mode |
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Filaments |
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Interstellar dust clouds |
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Polarization maps |
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Power spectra |
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Sheets |
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Διαστρικά νέφη |
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Δομές υμενίων |
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Νηματώδεις δομές |
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Φάσματα ισχύος |
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Χάρτες πόλωσης |
Issue date |
2021-03-24 |
Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Post-graduate theses
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Type of Work--Post-graduate theses
|
Permanent Link |
https://elocus.lib.uoc.gr//dlib/0/0/a/metadata-dlib-1603440144-106872-27895.tkl
|
Views |
487 |