Lunch Seminar：The measurements of the extragalactic background light

时间：6月21日中午11：30 - 13：00

地点：天体楼三楼会议室

报告人：巩岩博士

报告题目：The measurements of the extragalactic background light

摘要：

The attenuation of high-energy gamma-ray spectrum due to the electron-positron pair production against the extragalactic background light (EBL) provides an indirect method to measure the EBL of the universe. We use the measurements of the absorption features of the gamma-rays from blazars as seen by Fermi Gamma-ray Space Telescope to explore the EBL flux density and constrain the EBL spectrum, star formation rate density (SFRD) and photon escape fraction from galaxies out to z=6. Our results are basically consistent with the existing determinations of the quantities. We find a larger escape fraction at high redshifts, especially at z=3, compared to the result from the recent Lyman-alpha measurements. The average SFRD we obtain at z>3 is higher than the results from the UV data but agrees well with that from the gamma-ray burst observations. Our SFRD at z~6 has a trend that it is sufficiently high enough to reionize the universe.

报告人简介：巩岩博士于2010年在中国科学院国家天文台获得博士学位，2010至今在University of Califorlia, Irvine从事博士后研究，主要从事宇宙背景辐射，再电离，暗能量等研究。