Project Title: Accurate removal of line interlopers for reliable cosmological and astrophysical constraints from line intensity mapping data
Keywords: theoretical cosmology, cosmic large-scale structure, line intensity mapping
Where: Laboratoire d'Annecy-le-Vieux de Physique Théorique (CNRS-UMR 5108)
Group: Astroparticle Physics and Cosmology
Contact Person: Azadeh Moradinezhad (azadeh.moradinezhad@lapth.cnrs.fr)
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Context & Project Description:
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The observed cosmic large-scale structure (LSS) is formed under the influence of gravity from small fluctuations in the matter density that originated from quantum fluctuations in the very early Universe. Therefore, the LSS provides an incredibly rich trove of information about the origin of the Universe, its constituents, and its evolution. The two now-matured observational techniques to map the LSS consist of measuring shape and clustering statistics of galaxies or quasars at different redshift epochs, as done in galaxy surveys. A new observational technique of line intensity mapping (LIM) could revolutionize our understanding of the Universe by enabling us to map the LSS over a range of spatial scales and redshifts beyond what is achievable with galaxy surveys. Instead of individually resolving galaxies/quasars, LIM relies on measuring cumulative light from an ensemble of sources or intergalactic medium, enabling us to efficiently probe an unprecedented cosmological volume. The spatial fluctuations in the intensity of a given emission line and the precise determination of the frequency of the spectral lines, provide a 3-dimensional map of the LSS. The clustering statistics of these fluctuations capture information about the origin of primordial fluctuations, properties of neutrinos and light relics, the nature of dark energy, and the law of gravity determining the evolution of the Universe.
Despite the considerable potential of LIM, in addition to experimental challenges, there remain many theoretical questions regarding the accurate modeling of the signal, the treatment of foregrounds and systematics, and the quantification of synergies with other observations. The goal of this internship is to become familiar with LIM as a cosmological probe and to contribute to the research project focused on developing robust and effective methods to disentangle cosmological signals from astrophysical foregrounds. More specifically, the project concerns the optimal removal of contributions of the so-called “interloper lines”, which are line emissions (other than the line of interest) origination from different redshifts that are projected to the observed frequency and thus contaminate the observed signal. Interlopers are shown to degrade cosmological and astrophysical constraints from LIM considerably. Therefore, their efficient removal is of immediate and significant relevance for ongoing pathfinder and future wide-field LIM surveys. We will investigate the efficiency of two approaches to mitigate the interlopers at the level of summary statistics and the map itself by applying the developed tools to simulated intensity maps.
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Candidate Profile: We seek highly-motivated students who are enthusiastic about research. Programming skills (in Python or C) and familiarity with general analytical and numerical techniques are desired. Knowledge of cosmological perturbation theory and its application to LSS and/or previous experience with cosmological numerical simulations are considered pluses.
Start Date: Flexible
Opening Towards a PhD: Yes
Funding Resources: To be determined
Modifié 2 fois. Dernière modification le 19/12/23 11:18 par Azadeh Moradinezhad.