报告题目：Measuring gas-phase metallicity gradients in star-forming galaxies at z=1.2~2.3 in the deepest field probed by HST spectroscopy

报 告 人：王鑫 (UCLA)

报告时间：2016年6月23日下午2：00

报告地点：蒙民伟科技南楼S727

报告摘要： With the HST near-infrared grism spectroscopy from the supernova Refsdal follow-up program and the Grism Lens-Amplified Survey from Space, we observe the cycle of baryons and metals in the low-mass regime of galaxies at the peak epoch of cosmic star formation. I will present the first results on the gas-phase oxygen abundance (metallicity) radial gradient measurements in a sample of 12 star-forming galaxies at z=1.2~2.3, with high spatial sampling (sub-kpc scales in the source plane), in the field of the Hubble Frontier Field cluster MACS1149.6+2223. The synergy of ultra deep diffraction-limited exposure and lensing magnification offers a great gain in source plane angular resolution and emission line limiting flux, which makes this study unique in all high-z metallicity gradient analyses so far. We obtain a number of flat metallicity gradients in isolated galaxies, suggesting strong radial mixing and disfavoring weak galactic feedback models.