A wide-field investigation into the Hi content of galaxies

Abstract:

In this thesis I present new multi-wavelength scaling relations between the neutral hydrogen content (Hi) and the stellar properties of nearby galaxies selected from the Hi Parkes All-Sky Survey (HIPASS). I investigate the environmental dependency of the Hi content of galaxies and find that at a fixed stellar mass, galaxies in high density environments tend to have on average less Hi than galaxies in the low density environment. To demonstrate possible applications of Hi scaling relations, I identify individual galaxies, as well as group/cluster environments, that have an ‘anomalous’ Hi content. I present maps of the global distribution of Hi-deficient and Hi-excess galaxies on the sky and find that Hi-deficient regions tend to correlate with galaxy clusters and Hi-excess regions with the surrounding regions of galaxy clusters. I demonstrate the potential of using Hi scaling relations to pbkp_redict future Hi surveys based on an optical redshift survey. I apply the scaling relations to 16709 galaxies in the 6dF Galaxy Survey (6dFGS) that lie in the HIPASS volume and compare the pbkp_redictions to the measurements. I find that scaling relations are a good method to estimate the outcome of Hi surveys. To gain a better understanding of how environment affects the gas content of galaxies, I identify a sample of six Hi-deficient galaxies from HIPASS for follow up observations. These galaxies are among the most Hi-deficient galaxies in HIPASS and are all located in intermediate density environments. I present new high resolution Hi observations with the Australia Telescope Compact Array (ATCA) of these galaxies. I find that the sample galaxies have truncated Hi disks …

Año de publicación:

2015

Keywords:

Fuente:

google