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Astrophysics Luncheon Seminar

Extended Diffuse Emission as a Probe of Galaxy and Reionization Physics
Presented by Lluis Mas Ribas
University of Oslo

Monday, April 9, 2018
12:00 noon in 169-336

Abstract
Two of the main questions for studies of the Epoch or Reionzation are: (i) what sources reionized the Universe? and (ii) what is the escape fraction of ionizing photons from galaxies into the intergalactic medium (IGM)? Detailed observations of these early epochs are not possible and thus strong constrains still remain elusive. I will present our results showing the use of the spatially extended Lya, Ha, and stellar continuum emission, nowadays observed ubiquitously around star-forming galaxies from z~2 to z~7, to answer these two questions. Modeling the expected emission and comparing it to future James Webb Space Telescope observations will allow to probe the existence of faint (otherwise undetectable) satellite sources clustered around more massive objects, similar to the approach of Intensity Mapping but at smaller scales. Furthermore, this method enables to assess the fraction of ionizing radiation escaping from bright galaxies and contributing to the diffuse component, altogether disentangling the impact of faint and bright galaxies during this period. Applying the same formalism, now at lower redshifts, can also result in improved constraints for the cosmic star-formation rate and photon budget at any epoch.

JPL Contact: Tzu-Ching Chang

About the Speaker
Lluis Mas Ribas earned a physics degree followed by a Master's in Particle Physics and Gravitation in Barcelona (Spain), supervised by Prof. Jordi Miralda-Escudé. He moved to Oslo (Norway) where he is in the final year for his PhD, working on high-redshift Galaxies, reionization and radiative processes with Mark Dijkstra.

He is concurrently working on observational cosmology projects connected to quasar spectroscopy, specifically studying metal properties of Damped Lyman Alpha (DLA) systems, Broad Absorption Line (BAL) systems, and the Lyman Alpha Forest, as well as the metal enrichment of the large-scale intergalactic medium. Most of his work is theoretical (analytical) but also includes data analysis, and numerical and radiative transfer simulations.

Next September Lluis will be joining JPL to work with Tzu-Ching Chang. His work will introduce all he has learned on galaxy and radiative transfer physics into the Intensity Mapping formalism, to improve the predictions and the interpretation of future experiments and data in this field.


SVCP Astrophysics


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