Title: Revealing AGN at Cosmic Noon Using the Untargeted HETDEX Spectroscopic Survey

Speaker: 刘辰旭

Institute: 云南大学

Host: 高玉龙

Time: 2025.12.19 周五 15:30 - 17:00

Location: 睿智楼三楼会议室

Abstract: I aim to highlight the unique capabilities of the HETDEX survey through several AGN-related science results. HETDEX is an untargeted, blind spectroscopic survey employing a 78-IFU array, with observations carried out from January 2017 to August 2024. The final data set covers 87 deg² down to a depth of g ≈ 25. I am responsible for producing and releasing the AGN catalogs. Our final catalog contains ~18,000 AGN at z ≈ 2, making it the most complete wide-area spectroscopic AGN sample available at this epoch. (1) We find that the AGN luminosity function at z ~ 2 exhibits a clear faint-end turnover, indicating a decreasing space density toward low luminosities; this behavior may reflect a combination of physical drivers. (2) The large sample also shows that AGN inhabit environments statistically similar to those of normal LAEs. (3) From a parent sample of 890,777 LAEs, we identify 11,000 large-scale Lyα nebulae (LAN; ~1% at our surface-brightness limit of 2-5 × 10⁻¹⁸erg s⁻¹ cm⁻² arcsec⁻²), of which only ~20% host AGN. Taken together, these results suggest that AGN may not be the dominant source of ionizing photons at z ≈ 2.

Bio: 刘辰旭目前在云南大学任助理研究员。本科毕业于中国科学技术大学；研究生毕业于上海天文台主要研究大尺度环境对星系演化的影响；之后在德州大学奥斯汀分校从事博士后研究，负责HETDEX巡天项目中的AGN catalog发布。目前共发表文章39篇，被引592次。