Project F6: "Dark matter and gas in galaxies"

For a long time the standard picture of galaxy formation has been that gas condenses in the potential wells of dark-matter halos, eventually forming stars. Dark matter, being the dominant mass component in the Universe, is the background on which this galaxy formation takes place. The details of this process are, however, still poorly understood. Galaxy-galaxy lensing (GGL) provides a crucial tool for studying the galaxy-to-dark matter connection. In this project, we will utilize GGL to explore the connection between gas and dark matter for galaxies of stellar mass \(M\ll 10^{8}M_{\odot}\,\), a regime that is only accessible with the latest generation of imaging surveys. We will explore fundamental questions in galaxy evolution:

• Does the relation between stellar and halo mass for luminous galaxies hold down to dwarf-scale stellar mass systems?
• Do the galaxies of interest to the CRC exhibit alignment between their dark and luminous components?
• What is the extent and shape of the baryonic halos (traced by gas and dust) around galaxies?

Using existing data from the Kilo-Degree Survey (KiDS), early data from the Rubin Observatory Legacy Survey of Space and Time (LSST), and early data from Euclid, we will perform a study to measure the dark-matter and stellar profiles of galaxies down to low stellar masses and out to intermediate redshifts. Additionally, we will utilize a sample of the 100 largest edge-on galaxies to explore the profile and extent of the galaxy halo-dust distributions. Leveraging the combined power of early LSST and Euclid data, we will then perform measurements of the distribution of dust in galaxy halos (in terms of extent, profile, and density) to higher resolution than is possible with current surveys. Finally, we will utilize the full power of LSST and Euclid to measure the baryon/dark-matter connection, halo triaxiality, and the distribution of inter-/intra-galactic dust in bins of galaxy mass and morphology, thereby providing key insight into the joint evolution of dark-matter, luminous-matter, and dust.