University of Minnesota
School of Physics & Astronomy

Physics and Astronomy Calendar

Monday, February 13th 2017
12:15 pm:
Speaker: Zhen Yuan, Shanghai Jiao Tong University
Subject: A possible formation mechanism of Fornax-like dSph: major merger after infall to Milky Way

The extended star formation history of some MW satellites (Fornax, Carina) is always a puzzle in galaxy formation theory on small scales. Similar cases can be also found in M31 satellites. Both Fornax and Carina are estimated to become MW satellites pretty early (~8, ~10 Gyr ago) from proper motion information. The extreme long SFH until recently contradicts the classic galaxy formation models. Some hints from zoom-in MW simulations suggest a possible mechanism of new gas supply is from a companion through major merger after satellite infall. Inspired by the empirical chemical evolution model, I found that Fornax-like dSph needs to be much more diffused in order to explain the elemental abundance pattern ([alpha/Fe] vs. [Fe/H]). It is consistent with the major merger scenario which makes the system expand and consequently a much more inhomogeneous chemical enrichment environment. My collaborators and I made artificial major merger cases of satellites when they infall to MW. Assuming the satellites have some initial stellar configuration, we tracked the evolution of both the dark matter and star particles under growing MW potential. I will discuss our current results and interesting implications.

Faculty Host: Yong-Zhong Qian

The weekly calendar is also available via subscription to the physics-announce mailing list, and by RSS feed.