报告题目：Investigating star formation quenching with spatially-resolved UV-optical photometry

    报 告 人：Dr. Zhizheng Pan  (Shanghai Astronomical Observatory, CAS)

    摘    要：In this talk, I will introduce our two recent works. Combining the GALEX and SDSS data, we study how galaxy evolves from the blue cloud to the red sequence in a spatially-resolved point of view. In the first work, we show that in the green valley of color-magnitude diagram, late-type galaxies are mostly composed of red bulge plus extended blue disc components, suggesting an inside-out assembly picture. However, a large fraction of the early type galaxies have centrally concentrated star formation, showing a different quenching picuture. In another work, we find that, in the green valley, galaxies with M < 10^10 M_sun have positive or flat color gradients, while those with M > 10^10.5 M_sun have negative color gradients. While their central D4000 index exceed 1.6, M < 10^10 M_sun galaxies have been fully assembled and lain on the red sequence, while a large fraction of the M > 10^10.5 ones still lie on the blue sequence or the green valley. We conclude that the main galaxy assembly mode is transiting from the outside-in mode to the inside-out mode at M < 10^10 M_sun and M > 10^10.5 M_sun.

    时    间：2015年06月04日（星期四）10:30

    地    点：（北京西路2号）紫台大楼619教室

    联 系 人：赵奥（83332112）

欢迎大家积极参加！

                                                 紫金山天文台学术委员会