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Tracing back the cosmic history of galaxy formation with the large ALMA interferometer

Description

The aim of this thesis was to better understand the cosmic history of galaxy formation thanks to the largest cosmological survey with the large ALMA interferometer. This observation was preformed in a region of the sky, the GOODS-South field, which benefits from the deepest observations of the Hubble Space Telescope, the Spitzer and Herschel infrared space observatories, as well as data from the Chandra X-ray telescope and the VLA Radio Interferometer. These observations at 1.1 mm with ALMA therefore complete this multi-wavelength panorama, and make this region of the sky a leading laboratory for the study of the evolution of galaxies. The observation with ALMA allows us to observe this region of the sky without being affected by the confusion limit that affected Herschel, and to search for more distant galaxies. For the first time, we can study dust-obscured star formation at z > 2 over a large enough area to reduce different observational biases. A large part of this thesis was devoted to the scientific exploitation of this 1.1 mm cosmological image. This was done by analysing the image from the interferometric data, precisely characterising the survey, defining detectability thresholds and indicators that can quantify the credibility of detections, and carrying out simulations on these images. We then extracted and identified the galaxies present in the image. This analysis shows that ALMA surveys can reveal new galaxies that are not detected by the deepest surveys conducted with the Hubble Space Telescope. These 'dark' galaxies are among the most massive and distant galaxies in this region of the sky. The discovery of these new dark galaxies, which represent of the order of 10 - 20% of the ALMA detections, suggests that the number of massive star-forming galaxies in the distant universe may be much larger than previously expected. This work has also made it possible to determine properties of the galaxies detected by ALMA, through the modelling of their spectral energy distributions: the star formation rate, the masses of gas and dust, the dust temperature, the time required for a galaxy to consume its gas, the relationship between the infrared luminosity and the radio luminosity, and the excess of the infrared component in the spectrum of a galaxy. Analysis of these findings suggests that massive galaxies at high redshift consume their gas slowly to form stars and indicate that these galaxies are the ideal progenitors of passive galaxies at z∼2. (author)

Abstract (French)

Le but de cette these a ete de mieux comprendre l'histoire cosmique de la formation des galaxies grace au plus grand sondage cosmologique realise avec l'interferometre ALMA. Cette observation a ete realisee dans une region du ciel, le champ GOODS-Sud, qui beneficie des observations les plus profondes du telescope spatial Hubble, des observatoires infrarouges Spitzer et Herschel, ainsi que des donnees de l'observatoire X Chandra et l'interferometre radio VLA. Ces observations a 1.1 mm avec ALMA completent donc ce panorama multi-longueurs d'onde, et font de cette region du ciel un laboratoire de premier plan pour l'etude de l'evolution des galaxies. L'observation avec ALMA nous permet d'observer cette region du ciel sans etre affecte par la limite de confusion qui affectait les observations du satellite Herschel, et de chercher des galaxies plus eloignees. Pour la premiere fois, nous pouvons etudier la formation d'etoiles obscurcie par la poussiere a z > 2 sur une surface assez grande pour reduire les differents biais d'observation. Une grande partie de cette these a ete consacree a l'exploitation scientifique de cette image cosmologique a 1.1 mm. Pour ce faire, nous avons analyse les donnees interferometriques, caracterise precisement le sondage, defini des seuils de detectabilite et des indicateurs permettant de quantifier la credibilite des detections, et effectue des simulations. Nous avons ensuite extrait et identifie les galaxies presentes sur l'image. Cette analyse montre que les releves ALMA peuvent reveler de nouvelles galaxies qui ne sont pas detectees par les releves les plus profonds effectues avec le telescope spatial Hubble. Ces galaxies 'sombres' comptent parmi les galaxies les plus massives et les plus distantes de cette region du ciel. La decouverte de ces nouvelles galaxies sombres, qui representent de l'ordre de 10 a 20 % des detections ALMA, suggere que le nombre de galaxies massives formant des etoiles dans l'univers lointain pourrait etre beaucoup plus important que prevu. Ces travaux ont egalement permis de determiner les proprietes des galaxies detectees par ALMA, a travers la modelisation de leurs distributions d'energie spectrale : le taux de formation d'etoiles, les masses de gaz et de poussieres, la temperature des poussieres, le temps necessaire a une galaxie pour consommer son gaz, la relation entre la luminosite infrarouge et la luminosite radio, l'exces de la composante infrarouge dans le spectre d'une galaxie. L'analyse de ces resultats suggere que les galaxies massives a fort decalage vers le rouge epuisent leur gaz par la formation d'etoiles et conduit a penser que ces galaxies sont les ancetres ideales des galaxies passives a z∼2

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Additional details

Additional titles

Original title (French)
Remonter l'histoire cosmique de la formation des galaxies avec l'interferometre ALMA

Publishing Information

Imprint Pagination
329 p.
Report number
FRCEA-TH--13181

INIS

Country of Publication
France
Country of Input or Organization
France
INIS RN
52064377
Subject category
S46: INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; S79: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY;
Resource subtype / Literary indicator
Thesis
Descriptors DEI
ASTRONOMY; DUSTS; ENERGY SPECTRA; EVOLUTION; GALAXIES; GASES; INTERFEROMETERS; MASS; SIMULATION; TELESCOPES
Descriptors DEC
FLUIDS; MEASURING INSTRUMENTS; SPECTRA

Optional Information

Notes
582 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses