27) On the very faint edge of Milky Way-like galaxies

Abstract: The hierarchical model of galaxy formation suggests that galaxies are continuously growing. However, our position inside the Milky Way prevents the study of its disk edges. The whole picture can only be obtained from extragalactic sources. We show our team's advances in the quantification of the disk growth of the nearby, edge-on, Milky Way-like galaxy NGC 4565. We use the deepest available data to perform a vertical study of the galaxy disk edge, well above the mid-plane, in unprecedented detail. Truncations are low surface brightness features located on the disk outskirts, and whose location is thought to change dynamically. In previous analyses of Milky Way-like galaxies we detected disk truncations up to 3 kpc above the mid-plane and established, for the first time, an upper limit to their disk growth rate of 0.5 kpc/Gyr. However, our images were not as deep as the current data. In this work, we determine whether truncations can be detected above 3 kpc, and thus, establish the actual disk thickness, by exploring their position at different heights above the NGC 4565 disk plane (0 < z < 8 kpc) and at different wavelengths.

Bio: Cristina Martinez-Lombilla got her PhD in 2018 at the Instituto de Astrofísica de Canarias in Spain. After 1 year in the same institution in a postdoctoral position, she is currently Postdoctoral Research Associate at the University of New South Wales (UNSW) in Sydney. She is interested in understanding the formation and evolution of galaxies studying their low surface brightness regions. She develops new techniques to detect the dimmest structures in galaxies (like thick discs and truncations), or within clusters of galaxies (as the intra-cluster light). She is part of the LSST Galaxies Science Collaboration, co-chair of Astronomy & Programming workshops in developing countries, and very active in women in STEM outreach activities.