Colloq Abstract - Finlator

October 28

11am Mountain

 

Kristian Finlator

NMSU

 

Dwarf Galaxies During the First Billion Years

Theoretical models predict that, during the first billion years (z>6), dwarf galaxies assembled the stars, produced the metals, reionized and heated the intergalactic medium, and generally set the stage for the more massive populations that have dominated since cosmic noon (z=2).  Then, after all this work, they disappeared, either by merging with larger galaxies or by succumbing to their own heat.  A central goal of high-redshift galaxy studies is to test this picture observationally.  While the brighter ones (M_UV < -15) can be observed in emission, the fainter and most important ones were too dim even for the JWST.  How can we learn about galaxies that we cannot see?

 

One answer is to understand how observations in absorption and emission complement one another.  Even the faintest galaxies left deep radiative and chemical footprints.  I will describe how comparisons between recent observations and ab initio numerical simulations are teaching us to read these footprints.  In the process, I will address the following questions: How many faint galaxies were there? Where did they live? And what was their contribution to cosmological hydrogen reionization?

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