Seminar 2021/09/01

Speaker: Dr. Daichi Kashino (Nagoya University, Japan)

Title：Chemical evolution of galaxies at cosmic noon and the link with Galactic archaeology

Date/Time : Sep. 01, 2021 (Wed.) 10:30-12:30

Place：ES606/Zoom

Abstract:

I would like to present a recent result from the zCOSMOS-deep project, a large spectroscopic survey of ~10^4 star-forming galaxies using VLT/VIMOS. Using the unique dataset of the rest-frame UV spectra, we measured the stellar metallicities for 1336 star-forming galaxies at 1.6<z<3.0 (median z=2.2) using a full spectral fitting with the BPASS stellar population synthetic spectra. The inferred metallicities are ~0.8 dex lower than the local value at a given stellar mass. A clear positive correlation with galaxy mass, i.e., the stellar MZR, has been established. Comparing the gas-phase MZ relation, we estimate [O/Fe] (alpha-enhancement) for z~2.2 galaxies and their local counterparts and demonstrate that the evolution of metallicity and O/Fe can be explained by a simple gas-flow chemical evolution model. Comparison with the data of the Galactic stars exhibits a beautiful concordance between the observations of high-z star-forming galaxies and the results of Galactic archaeology, but leaving an open question about the origin of the (possible) metal-rich bulge-like component.

Presentation: slides (PDF)