Thesis topic: Planetary nebulae populations, dynamics and star formation histories of dwarf galaxies

Thesis Supervisor: Magda Arnaboldi

Abstract

Our understanding of galaxy formation and evolution is largely based on detailed studies of bright and  large galaxies. Over the past decades though, properties of dwarfs and low surface brightness (m> 24 mag/arcsec2) galaxies poses new challenges for the galaxy formation models in Lambda CDM cosmology. While many nearby Local Group dwarfs have been found to be among the most dark matter dominated systems, the discovery of two dwarf galaxies with (possibly) very low or lacking dark matter in the NGC 1052 group have stimulated a lively debate in the community. The debate about the amount of dark matter in these systems includes the uncertainties of their stellar populations, the assumptions on the distribution of orbits of the stars these systems and errors in the estimated distances. With this thesis, the goal is to establish a robust Local Group analog of dwarf galaxies for which HST observations and planetary nebulae population measurements (from FORS2@VLT and the Planetary Nebulae Spectrograph PN.S@WHT) can be used to firmly constrain their star formation histories, orbital distribution and planetary nebulae luminosity functions, to find the root of the dichotomy between dark matter rich vs dark matter poor dwarfs. This thesis requires active participation to the data acquisition, reduction and analysis, and comparison between observations and predictions from dynamical/ cosmological simulations.

figure1_arnaboldi2

Figure 1: This image shows the positions of the ultra-diffuse dwarf galaxies and of the bright galaxies in the NGC 1052 group – from Müller et al. 2019 arxiv1903.07285. The zoomed-in inserts shows the FORS2 imaging data which will provide the Planetary Nebulae sample in these galaxies.