开题报告 - BATC.pptVIP

Multicolor study of the interacting galaxies of Leo Triplet Leo Triplet Previous Studies Interaction of NGC 3627 and NGC 3628 Dynamical distortion Great Impact on gas content - infall Formation of the plume Questions Perturbation of gas ? any impact on the stellar content (star formation)? Is NGC 3623 interacting with the other two? Approach Stellar population synthesis: Age ? the SRH of the galaxies Mapping: ?spatial distribution of age SFH Looking for similar evolutionary history and Determining the relationship of the 3 galaxies Observation 2D SED Maps PEGASE IMF: Salpeter 1955 N(M) ~ M -2.35 0.1 M 120 Msun SFR: Instantaneous Burst Model Only relative age distribution is needed Initial Metallicity: 0.02, 0.008 and 0.0001 Intrinsic Reddening by Inclination: NGC 3623: 71° NGC 3627: 60° NGC 3628: 89° Results: relative age distribution Age Histograms Conclusions NGC 3623 is the oldest among the 3 galaxies, but its weak age gradient might indicate recent star formation in its bulge. ? This galaxy is not isolated. A potential bar is identified within the bulge of NGC 3623. NGC 3627 3628 exhibit strong evidence of synchronized evolution. ? interaction may have triggered star formation in them both. END! * * Zhiyu Duan 8/12/2005 Dist：6.7Mpc de Vaucoulers 1975 NGC3628 NGC3623 NGC3627 HI distribution map[1] 10’ Dynamical model of the interaction by Rots, 1978 View from North View from Earth Interaction happened 0.8Gyr ago. More than 220 images of U, d-p bands: 70 hours exposure. NGC 3623 NGC 3627 NGC 3628 Data from NED *