Anatomy of galaxies during rapid transformation

Po-Feng Wu^1*

¹Institute of Astrophysics, National Taiwan University, Taipei, Taiwan

* Presenter:Po-Feng Wu, email:wupofeng@phys.ntu.edu.tw

How galaxies transform from disk, rotational-supported, star-forming to elliptical, dispersion-support, quiescent galaxies is a long-standing question in galaxy formation and evolution. Empirical evidence shows that some current-day quiescent galaxies must have gone through a short period of violent transformation in the past, during which the star-formation rates rose more than an order of magnitude and fell to quiescent within a few hundred million years and the morphologies and kinematical properties also altered during the same period.

Absorption-line spectroscopy serves as a natural clock and provides us a proxy to date the age of galaxies with high precision. From SDSS MaNGA IFU survey of nearby galaxies, I identify galaxies with either rapid rising or falling recent star-formation histories. The 3D imaging spectroscopy data cubes characterize how the star-formation activities proceed, the internal kinematic properties, gas enrichment, as well as gas flows in these galaxies. The characterization of the physical properties of galaxies provides quantitative tests for numerical simulation working on the key phase of galaxy evolution.

Keywords: galaxy evolution, star formation history, integral field unit