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Stephanie Greis

I'm a final year PhD student in the Astronomy and Astrophysics group at the University of Warwick and my supervisor is Dr Elizabeth Stanway.

Studying Local Analogues of some of the First Galaxies

In my PhD project I'm investigating local analogues to high-redshift Lyman break galaxies (LBGs): Lyman break galaxies are some of the earliest star-forming galaxies in the Universe, and it is therefore possible to gain insights into the formation and evolution of galaxies, their star formation histories and other aspects by studying these objects. Due to their high redshifts (the ones whose analogues I am looking at have redshifts of around z~5 - meaning that they are about 12.5 billion lightyears away), it is difficult to observe these LBGs directly. Therefore, in order to learn more about them, it becomes necessary to look for local analogues which exhibit similar star formation density and spectra.

Spectral Energy Distribution Fitting

Having established a sample of local ultraviolet-luminous galaxies, I wrote a Python program to fit their spectral energy distributions (SED) in order to derive their physical properties, such as masses, star formation rates, dust reddening, dominant stellar population age and metallicity.

LBA

The SED fitting confirmed that the estalished local analogues sample indeed gives a valid analogous way of studying this kind of galaxy (see link to the paper below).

Radio Observations

In order to learn more about the dust content and star formation rate densities within these objects, I undertook radio observations of a subset of the galaxies. These were done with the VLA and ATCA, showing that these systems are indeed star formation driven, with no strong indications of the presence of active galactic nuclei. I am awaiting the completion of further VLA observations before publishing the results of this analysis...

Spectroscopy

To determine how reliably the photometric selection criteria produce spectroscopically confirmed Lyman break analogues, I am working on the analysis of AAOmega spectra of ~200 potential LBA candidates.


Publications & Presentations

Greis et al 2016 Physical Properties of Local Star-Forming Analogues to z~5 Lyman Break Galaxies

Stanway, Greis et al 2014 Interpreting high [O III]/Hbeta ratios with maturing starbursts


March 2015 - presentation, Dissecting Galaxies Near & Far (ESO conference); Santiago, Chile

June 2014 - poster, National Astronomy Meeting; Portsmouth, UK

May 2014 - presentation, High Redshift Workshop; Warwick, UK

Posters about my work

Research Postgraduate Poster Showcase 2014 (for which I won the Science faculty prize worth £150)

National Astronomy Meeting 2014

Outreach & Volunteering

Dec 2015 - current: author and editor for astrobites blog

summer 2014 - current: outreach to local primary and secondary schools

October 2014 - current: Postgraduate Student Staff Liason Committee reprentative for Athena Swan

October 2013 - October 2014: Postgraduate Student Staff Liason Committee reprentative for astronomy

Proposal Experience

I've written and co-written proposals for various telescopes, including ALMA, HST, IRAM, VLA, WHT, VLT, AAO, and APEX.

Explaining my Research to School Students

The following is a brief explanation of my work which I wrote when trying to explain my work to school students:

I use light of many different wavelengths - from UV (which is the stuff that can give you sunburn - though in my case it's much much weaker) to radio waves - to study galaxies which resemble the first galaxies that formed in the universe. Some of the telescopes I use are in deserts, while others are orbiting the Earth in outer space. Since the very first galaxies that formed are really really far away, not a lot of light reaches us from them. So instead of studying them directly, I look at slightly more nearby ones which look similar - though those "nearby" ones are still about 3 billion light years away! I then use models of many different kinds of stars to see what mixture of young and old stars fits best to the observations. This helps us understand not only the earliest galaxies in the universe, but also the origins of our galaxy, the Milky Way.

At the WHT, La Palma




Write to:

Stephanie Greis,
Department of Physics,
University of Warwick,
Coventry CV4 7AL
UK
 

Contact details:

E-Mail: S.M.L.Greis AT warwick.ac.uk