STUDY OF ROTATION CURVES DIVERSITY PROBLEM WITH SPARC AND LITTLE THINGSÂ INÂ 3DÂ CATALOGS

• Main Author: Julio Dante, Azriel
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/86553
• Institution: Institut Teknologi Bandung

Observations have shown that non-relativistic dark matter dominates the matter components in the standard ?CDM cosmological model. On galaxy scales, the flat velocity observed in the outer regions of spiral galaxy rotation curves implies the existence of dark matter. Although ?CDM successfully explains several phenomena, this cosmological model cannot explain certain small-scale phenomena, such as the diversity of dwarf spiral galaxy rotation curves. The ?CDM model predicts that galaxies with the same total mass (indicated by Vmax) will have similar rotation curve shapes. In this thesis, we study the effect of baryon and dark matter components on the shape of galaxy rotation curves, particularly in dwarf galaxies with stellar masses ? 1010M?. The galaxy rotation curve data were obtained from SPARC and LITTLE THINGS in the 3D catalog. The effect of the baryon components is examined by analyzing the relationship between the rotation curve shape parameter (?rot) and the baryon mass fraction. The galaxy rotation curves were fitted using the Markov Chain Monte Carlo (MCMC) method. Although the ?CDM model (specifically, the NFW profile) cannot explain the diversity of rotation curves, fitting the rotation curves while incorporating uncertainties in galaxy distance and disk inclination could result in a better fit, albeit with the consequence that the fitted galaxy distance and disk inclination may lie outside the range of observational errors. As alternatives, we use the cold dark matter (CDM) model with feedback, represented by the DC14 profile (Di Cintio dkk., 2014), and a dark matter model with non-gravitational interactions, specifically the self-interacting dark matter (SIDM) model. Both alternative models can adequately explain the diversity in the shapes of rotation curves and the variation in baryon contributions in the inner regions of galaxies. Furthermore, we test the radial acceleration relation (RAR), which can explain the diversity of rotation curves, but it does not account for the variation in baryonic contributions to the rotation curves.