Metallicity is a key physical property of galaxies, it can yield information about galaxy formation
and chemical evolution. The metallicity abundance has been observed to decrease with
galactocentric distance, which can be explained with the inside-out evolution model, in which stellar mass first builds up in
the center of galaxies and slowly makes its way out. The gradients of the metallicity profiles can further explain the role of gas inflow, gas accretion and AGN feedback
in the evolution and morphology of a galaxy. During this six-week project, I studied the effects that different levels of winds
can have in flattening the metallicity gradients in Illustris TNG simulations. I calculated and plotted several
metallicity profiles of galaxies in the simulations, as well as the kinematics and physical properties
such as different star formation radii, gas and stellar mass, disk mass, age and gas fraction. Most of the project was spent testing and developing analysis pipelines to accurantely construct the
profiles with simulations of different resolutions and developing algorithms to accurately interpret the metallicity gradients. Figure 1 shows three distinct 2D histograms for a random galaxy. The first
panel from the left plots the mass distribution, the middle panel plots the oxygen abundance and the panel on the right includes only the hydrogen abundance.
Fig. 1:
An illustration of the metal distribution in sample galaxies from the simulations at redshift 1.
From left to right, the first 2D Histogram illustrates the mass distribution, the middle is the oxygen abundance and
the rightmost plot the hydrogen abundance.
Figure 2 illustrates the metallicity profile for two random galaxies in the simulation dataset.
The metallicity as a function of distance distance from the center of the galaxy is calculated using equation 1, where ϵ is the abundance ratio and NO and NH are the number of oxygen and hydrogen nuclei, respectively.
In these two metallicity profiles you can clearly identify the negative metallicity gradient, with metallicity decreasing as we move further away from the center of the galaxy.
Fig. 2:
Sample metallicity profiles acquired from the L35n1080TNG simulation. These profiles belong to two random subhalos at redshift 1.
Future Work
Due to time constraints, this project is currently on hold. Future work includes developing a pipeline suitable for TNG simulations of lower resolutions that will yield accurate metallicity profiles
as well as running several simulations varying specific wind parameters. If you have any specific questions about this project, feel free to contact me using the information at the bottom of the Homepage!
Acknowledgments
I would like to thank Prof. Torrey and Zach Hemler for very valuable guidance. This project used the HiPerGator Computing Resources.
