Speaker
Description
Extra-galactic archaeology - elemental abundances of high-z galaxies
The James Webb Space Telescope (JWST) is expected to find the first galaxies - those hosting metal-free stars. Surprisingly, though, galaxies with strong metal lines have been detected indicating unusual chemical composition (e.g. high N/O ratio). Nitrogen can be enhanced not only by asymptotic giant branch (AGB) stars but also Wolf-Rayet (WR) stars. I show galactic chemical evolution models that can naturally reproduce N emitters with intermittent star formation. Wolf-Rayet stars are expected to enhance Fluorine as well. With Atacama Large Millimeter/submillimeter Array (ALMA), we show two submillimeter galaxies, one at z=4.4 with a high F abundance, while another at z=6.0 with no F enhancement, which further supports the intermittent star formation in early Universe. Although these do not require changing the initial mass function (IMF), I will discuss how other elements (C and Ar) can be used to constrain the IMF and the first stars.
| Category | Theory |
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