The centers of galaxies like our own are usually dominated by disk structures at scales of tens to hundreds of parsecs - and thus orbits near the galactic center are in axisymmetric potentials which conserve only one component of their angular momentum if an orbit comes close enough the central super massive black hole there can be disruptions, leading to the creation of hyper-velocity stars,...
Hypervelocity stars (HVSs) are stars which have been ejected from the Galactic Centre (GC) at velocities of up to a few thousand km/s. They are tracers of the Galactic potential and can be used to infer properties of the GC, such as the initial-mass function and dynamical history. HVSs are rare, however, with only about a dozen promising candidates discovered so far. Discovering and...
The study of our galaxy has been revolutionised in the last few decades by the advent of large scale spectroscopic surveys, providing kinematic and chemical information for hundreds of thousands of stars. The design of each survey is different with unique advantages and tradeoffs. The APOGEE survey is the only stellar spectroscopic survey that uses infrared spectra, which enables observations...
NGC 5253 is a Blue Compact Dwarf (BCD) galaxy located at a distance of just 3.6 Mpc. The galaxy is well-known for its three super massive young super star clusters (SSCs), and nitrogen enrichment found in its centre. Given its similarity with extreme star forming galaxies at high redshift, studying this object at high spatial resolution can give insight on the chemical enrichment processes at...
Dust, a material that makes up only 1\% of the interstellar medium, yet it plays a key role in the evolution of galaxies by absorbing interstellar emission to allow molecular gas to cool and reach density thresholds to form stars. This absorption and eventually re-emission causes dust to be responsible for up to 50\% of the emission we gather from galaxies, making it one of the largest drivers...
I will present high resolution, ultra-deep HI images of the nearby, newly discovered interacting NGC 4781 triplet, observed by MeerKAT as part of the MHONGOOSE survey. The triplet is situated at 11 Mpc, and consists of two late types and one dwarf irregular galaxy. The global properties and scaling relations are consistent with other late type, star forming galaxies of the same stellar mass....
Detailed studies of the composition, kinematics and physical conditions of cold gas in extreme irradiated and shocked environments, such as close to an active galactic nucleus (AGN), provide new insights into the chemical pathways which are not observed in other environments. I will present the discovery of an unusually strong absorption feature at a rest frequency of ~97.88 GHz in a...
The MIRI instrument onboard JWST is changing our understanding of extragalactic astronomy, thanks to its unprecedented sensitivity and angular resolution. The Cosmic Evolution Early Release Science Survey (CEERS) JWST program has a total of 8 MIRI imaging pointings in the EGS field. All of the MIRI observations have been performed, and we have reduced the data (Yang et al. 2023). Based on...
One of the most remarkable discoveries in extra-galactic astronomy from the past two decades is the existence of a population of quiescent galaxies at z ~ 2 and beyond. Observations have shown that compared to their local counterparts, these distant quiescent galaxies have lower metallicities, and have rotating disc structures similar to star-forming galaxies. These results challenge our...
I present a multi-disciplinary study of the filamentary network around the Fornax-Eridanus Complex to probe the influence of the large-scale environment on galaxy morphology. To extract filaments from real data, we employ the novel machine-learning tool, 1-DREAM (1-Dimensional, Recovery, Extraction, and Analysis of Manifolds). We then use the morphology-density relation of galaxies to examine...
