Modelling probes of the Epoch of Reionization: Lyman Alpha and 21cm Emission

Lead Research Organisation: University of Cambridge
Department Name: Institute of Astronomy

Abstract

I will be using simulations and analytical models to explore the use of Lyman Alpha emission (from LAE galaxies) and 21 cm emission (from neutral Hydrogen) as probes of the Epoch of Reionization.

The first area I am looking into is how the ionization state of the intergalactic medium (IGM) will affect our observations of LAE galaxies, throughout this epoch. Specific examples include the effects on clustering of observed LAEs, the reduction of measured equivalent widths (EWs) as we probe higher redshifts, and also the effect on observed luminosity functions. In order to do this, I will use the Sherwood suite of hydrodynamical simulations as a basis, and then apply 'semi-analytic' techniques to model the progress of reionization. This essentially creates a statistically realistic snapshot of the universe at different times during the epoch, which I can use to test the effects of ionization. This area interfaces with the cutting edge of observational work, and so it is important for our understanding of current observations.

After looking into LAEs, I plan to work on 21cm emission, and its use for probing reionization. This is an area that is more prospective than LAEs, as observations of 21cm emission will only become truly viable as a probe over the coming decade. It is important that we are theoretically ready with forward models for when future telescopes like JWST and SKA come online. I will continue to model this epoch using simulations and semi-analytic techniques.

Publications

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Weinberger L (2018) Lyman-a emitters gone missing: the different evolution of the bright and faint populations in Monthly Notices of the Royal Astronomical Society

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Keating L (2020) Long troughs in the Lyman-a forest below redshift 6 due to islands of neutral hydrogen in Monthly Notices of the Royal Astronomical Society

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Haehnelt M (2020) Probing delayed-end reionization histories with the 21-cm LAE cross-power spectrum in Monthly Notices of the Royal Astronomical Society

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Baxter E (2021) The correlation of high-redshift galaxies with the thermal Sunyaev-Zel'dovich effect traces reionization in Monthly Notices of the Royal Astronomical Society

Studentship Projects

Project Reference Relationship Related To Start End Student Name
ST/N503988/1 01/10/2015 31/03/2021
1791046 Studentship ST/N503988/1 01/10/2016 30/06/2020 Lewis Weinberger
 
Description The work funded by this award has advanced the understanding of the evolution of the Universe, in particular the early evolution of galaxies and their surrounding environments. This has been achieved by constructing new and improved theoretical models in combination with advanced computer simulations. This work has culminated in 5 published journal papers detailing the new knowledge generated by this research.
Exploitation Route The outcomes of this research can be taken forward via academic routes. The theoretical models created during this work can be used for further research in this field. More generally, the knowledge generated by this research will help shape the future research on this topic area.
Sectors Other