【1.15; Seminar】2026年粒子天体物理全国重点实验室系列学术报告 #3&4：Galaxy Quenching in substructures of low-z Clusters & The link between host morphology and radio luminosity of Euclid quasars

时间/Time: 1月15日周四上午9:30/Thursday, January 15, 9:30 a.m.

地点/Location: 多学科楼229会议室/Meeting Room 229, Multidisciplinary Building

报告人/Speaker: 余恒（北京师范大学）

题目/Title: Galaxy Quenching in substructures of low-z Clusters

主持人/Host: 李承奎

摘要/Abstract: 

Cluster environments are known to effectively quench star formation in member galaxies. However, the existence of infalling groups and substructures adds complexity to this picture. Using the hierarchical Blooming Tree Algorithm on spectroscopic data, we can reliably identify these substructures and disentangle the quenching effects of subhalos. The substructures identified by this method are consistent with observations from X-ray satellites. Based on a large spectroscopic galaxy sample of 25 low-redshift, X-ray-luminous, massive clusters, we find that substructures affect quenching in two ways: pre-processing of galaxies prior to cluster infall, and protection of star formation within the cluster environment. Using this information, we can further constrain the dynamical state of infalling X-ray groups.

个人简介/Biography: 

Dr. Heng Yu, associate professor of Beijing Normal University. He got his PhD from the Beijing Normal University in July 2011. He studied galaxy clusters successively at the International Center for Theoretical Physics (ICTP), the Trieste Observatory, and the University of Turin in Italy. His main research interests are the physics of galaxy clusters and galaxies therein.  He developed a X-ray redshift measurement technique and a hierarchical optical substructure identification method, and unveiled complex kinematic status of clusters with multi-wavelength (optical, X-ray, radio) data.

时间/Time: 1月15日周四上午10:40/Thursday, January 15, 10:40 a.m.

地点/Location: 多学科楼229会议室/Meeting Room 229, Multidisciplinary Building

报告人/Speaker: 潘桐（Leiden University）

题目/Title: The link between host morphology and radio luminosity of Euclid quasars

主持人/Host: 李承奎

摘要/Abstract: 

We combine the Euclid Q1 spectroscopic quasar sample with LOFAR EDF-N radio data and identify 194 quasars with radio emission. To investigate the host galaxy morphology, we perform multi-band AGN–host decomposition with GALFITM and classify the hosts as early-type, late-type, indeterminate, interacting, and AGN-dominated systems. Using the Euclid morphology catalogue, we further analyse the structural parameters (CAS and related metrics). For early-type hosts, radio luminosity increases with higher Gini, suggesting that radio activity is preferentially associated with galaxies having more centrally concentrated light distributions. For late-type hosts, radio luminosity correlates with higher asymmetry and M20, implying that radio emission may be triggered by gas disturbances or mergers. These results indicate that the origin of radio emission differs between morphological types and that different feedback processes may be linked to the host galaxy’s evolutionary stage.

个人简介/Biography: 

I am currently a PhD candidate at Leiden University. My research primarily focuses on radio AGNs and their host galaxies. I study the connection between radio emission properties and optical morphology and photometric characteristics using large multiwavelength surveys. Another major aspect of my research concerns the large-scale environments of radio AGNs. Through these studies, I aim to better understand the co-evolution of radio AGNs and their surrounding environments.