Spiral-arm instability

by Dr Shigeki Inoue (the National Astronomical Observatory of Japan)

Tuesday 9 Jun 2020, 12:45 → 13:45 Asia/Shanghai

ONLINE

Abstract

Disc galaxy with spiral arms is a common galaxy type in the local Universe. However, spiral galaxies are rarely observed in the high-redshift Universe and have massive giant clumps in their disc regions instead of spiral arms. Such clumpy galaxies become rare as redshift decreases. Thus, abundances of spiral and clumpy galaxies seem to indicate anti-correlation from redshift z=0 to ~2. In this talk, I will discuss the evolution of disc galaxies from the viewpoint of "spiral arm instability".

First, I will introduce our linear perturbation theory of spiral arms and analytically derive ynamical instability conditions of arms. Then, I adopt our analysis to isolated galaxy simulations and show its ability to characterize the fragmentation of spiral arms. Next, I apply the analysis to observations and cosmological simulations of proto-planetary discs. Finally, I would like to talk about the volution process of disc galaxies driven by spiral-arm instability, from clumpy to spiral galaxies, and discuss the difference from and connection to Toomre instability.

Biography

Bio:

Apr. 2019 -- the National Astronomical Observatory of Japan, ALMA Project Fellow (secondment to University of Tsukuba, w/ Hidenobu Yajima)

Apr. 2016 -- Mar. 2019  Kavli Institute for the Physics and Mathematics of the Universe, the University of Tokyo, CREST fellow (w/ Naoki Yoshida)

Dec. 2013 -- Mar. 2016  the Hebrew University of Jerusalem, the Lady Davis Fellow (w/ Avishai Dekel)

Mar. 2013 -- Nov. 2013  the Korea Astronomy and Space Science Institute, Postdoctoral Research Fellow (w/ Jongsoo Kim)

Apr. 2012 -- Feb. 2013  the National Astronomical Observatory of Japan, Postdoctoral Research Fellow (w/ Naoteru Gouda)

Apr. 2011 -- Mar. 2012 the Mullard Space Science Laboratory, University College London, JSPS fellow (w/ Daisuke Kawata)

Mar. 2011  Doctor of Science (Astronomy) at Tohoku University

Chair

Dr. Jiaxin Han

Division

Astronomy and Astrophysics

Other information

Video record available for viewing within the university:

part 1:

https://vshare.sjtu.edu.cn/play/d49f52de5754b4a4337563cd538ea806

part 2:

https://vshare.sjtu.edu.cn/play/0ecc77330ac527cba7ea2563a52ff5ad