Deep Space Physics & Cosmology

Dark matter is a hypothetical form of matter which is though to account around 85% of matter in the universe or 27% of mass-energy density in the universe. Its effects can be seen in various astrophysical phenomena e.g. galactic rotation curves, galaxy clusters, cosmic microwave background, but it has not yet been observed directly. This research aims to look into various candidates for dark matter e.g. WIMPS. 

Galactic rotation curve is the radial distribution of orbital speeds in galaxies. These measurements can be used to determine the composition of dark matter in galaxies or in the case of merging galaxies, to observe their evolution. Observing the evolution of mergers can give an insight in star formation, formation of galaxies, and cosmological phenomena.

Galaxy clusters play a big role in fields such as cosmological studies and large-scale structures in the universe. Advances in observational capabilities have ushered in a new era of multi-wavelength multi-physics probes of galaxy clusters and large scale surveys are providing researchers with a large sample of galaxy clusters. This allows for more detailed analysis in the dynamics of galaxy clusters.

AGNs are active supermassive black holes in the middle of galaxies. AGNs emit bright jets and winds, as well as affecting their galaxies. AGNs can be seen to affect star formation by heating up the galaxies' gases, and understanding this could allow us to understand the origins of modern galaxies. However, their small size and distance from Earth means that very high resolution images of AGNs are required. Recently, very-long-baseline-interferometry (VLBI) techniques i.e. combining multiple telescopes at large distances, are used to achieve this feat, and an example is the famous M87 black hole image. 

Galaxy evolution looks into the ways galaxies change over time, and usually via two ways, Passive evolution where the galaxy is undisturbed, then stars become fainter and evolve into red giants, lowering the luminosity, or interactions/mergers which may/may not increase star formation. To measure this, radio source counts and radio luminosity functions can be used, which can also be used to compare between star forming galaxy (SFG) dominant galaxies and AGN dominant galaxies. A specific case which is looked into here are galaxy clusters in cosmic filaments i.e. dense slender strands of dark matter and galaxies which connect the cosmic web, also referred to as the universe's largest known structures.

FRBs are mysterious bright pulses of radio waves ranging from milliseconds or less. FRBs seem to originate from outside the galaxy based on their frequency dependent delay due to dispersion. Researchers are still puzzled on its origin or emission mechanism, but their properties and localization seem to point to magnetars or neutron stars with strong magnetic fields. Larger population of FRBs will be beneficial in confirming their progenitor. FRBs have a lot of promising applications in cosmology too.

Stellar formation and evolution depend on various conditions and aren't very well understood. One way to study them is to look into the change in chemical composition in young star-forming regions i.e. looking at the formation of different molecules at different stages of star formation. This can be achieved by obtaining the spectrum of these objects, and comparing the different molecule abundances. Bow shocks or the collision between the magnetosphere of these young stars and ambient plasma can also give an insight in this topic.

High-redshift radio galaxies are extremely distant, powerful astronomical sources that were originally discovered in the late 1960s. These objects emit strong radio waves, offering a unique window into the universe at early times. The intense activity observed in high-redshift radio galaxies has presented astronomers with many challenges. For example, a large fraction of these objects, particularly the most optically faint ones, contain active galactic nuclei, which may suggest associations with quasars that are difficult to explain. Studies of high-redshift radio galaxies allow us to gain insights into how galaxies form and evolve in the early universe, and provide further evidence of the cosmic evolution of large scale structure. In order to fully understand these mysterious objects, astronomers use a variety of techniques, such as optical imaging, spectroscopy, and radio astronomy, to build an integrated picture of their formation and evolution over the course of cosmic history.