Deciphering the Evolution of Galaxy Kinematics and Clustering Behaviour over Cosmic Time using Observed Lyman-α Relationships

Garry Foran (Swinburne)
Friday, May 31, 2019 - 12:15pm to 1:00pm

Lyman-α (Lyα) is the strongest, and sometimes the only, spectral feature of high
redshift galaxies. Due to the complex radiative transport mechanism by which it
escapes, the Lyα radiation observed from a given galaxy encodes information about
a variety of internal and external galactic properties. Though the potential utility of
Lyα to elucidate the mechanisms by which galaxies evolve over cosmic time is
tantalising, observed relationships between Lyα equivalent width (EW) and the
properties of high redshift galaxies are of little practical use if the Lyα observables
cannot be used to confidently predict the properties of any particular galaxy or galaxy
population. Using a method that isolates pure samples of galaxies with Lyα in
emission and Lyα in absorption using broadband photometry alone, my research is
doing just that!
I will present two aspects of my work in which I am exploring the relationships
between Lyα and more than 10 different intrinsic and extrinsic properties of Lyman
break galaxies (LBGs). Specifically, I will show how Lyα can be a powerful predictive
tool to understand both galactic kinematics and the large-scale clustering behaviour
of z ~ 2 and z ~ 3 LBGs — results that are not only consistent with the same
relationship reported recently for local high-redshift galaxy analogs, but are also
suggestive of the Morphology-Density Relation that is observed in the modern-day

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