Erlangen 2026 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 2: Astrophysics II

EP 2.1: Talk

Monday, March 16, 2026, 16:15–16:30, KH 01.019

Modeling the low-ionization broad-line region in a sample of OI/CaII emitters detected by VLT/MUSE and DESI — •Tianyu Zhao — Institut für Astrophysik Georg-August-Universität Göttingen Friedrich-Hund-Platz 1 D-37077 Göttingen Germany

Broad emission-line (BEL) profiles in active galactic nuclei (AGN) contain information about the structure and kinematics of the broad-line region (BLR), where these lines are emitted, as the BEL shape is governed by the BEL-emitting gas moving in the potential of the supermassive black hole (SMBH). The study of BEL profiles is thus a powerful tool to study accretion processes onto SMBHs. However, for the largest part of the AGN population, it is impossible to directly *read-of* information from the line profiles as additional effects such as turbulence or optical-depths effects distort the clear kinematic signature of the moving BLR gas. Only recently, the profiles of O I 8446 and the near-infrared Ca II triplet have been recognized as a powerful diagnostic tool for BLR kinematics, because these line presumably arise in the dense atmosphere/corona of the accretion disk. Novel studies suggest, that these line are not significantly influenced by internal turbulence, thus clearly revealing the kinematic signature*namely double-peaked profiles*of a line-emitting BLR disk. In this master*s thesis, I aim to extend the sample of known OI and Ca II emitters with complex, i.e., not single-peaked, profiles, and constrain the kinematics of the OI/CaII-emitting regions.

Keywords: AGN; BLR; Broad emission-line