Studying HI properties of some of the lowest mass galaxies.

Project Description:

Low-mass galaxies are important testbeds for understanding galaxy formation and evolution, in addition to our cosmological model. With their low gravitational potentials, dwarf galaxies are extremely susceptible to feedback processes and the loss of their baryons. Indeed, the mismatch between the predicted number of dark matter halos and the observed number of dwarf galaxies is largely explained by baryon loss from low mass dark matter halos. However, the exact mass scales at which this happens, and how many baryons are retained by dark matter halos is still not well constrained. Neutral hydrogen (HI) is an excellent tracer for finding isolated, gas-rich dwarf galaxies in the field and resolved HI observations provide measurements of the galaxy’s rotation velocity, and, hence, its dark matter halo mass. This project involves reducing and analysing MeerKAT HI data of one of the lowest mass, gas-rich galaxies first detected by the ALFALFA survey, AGC189144. For this project the student will measure the HI properties, distribution and kinematics of the galaxy and compare it with the properties of other low-mass and high-mass galaxies. Combined with additional data on other galaxies, we can then start to address three questions: 1. Is the baryonic mass-halo mass relation tighter than the stellar mass-halo mass relation? 2. What role does the gas fraction play in scaling relations for the lowest mass galaxies? 3. What controls star formation in low mass galaxies?

Research Area:

Astronomy

Project Level:

Honours

This Project Is Offered At The Following Node(s):

(UCT)

Special Requirements:

For this Honours project, students will be expected to use CARACal to produce HI data cubes of this galaxy on the ilifu cluster. They will need to be familiar with Linux and have some Python programming experience. They should be willing to learn how to use radio astronomy data reduction and analysis packages.