The First Identification of Lyα Changing-look Quasars at High Redshift in DESI

Guo, Wei-Jian; Pan, Zhiwei; Siudek, Małgorzata; Aguilar, Jessica Nicole; Ahlen, Steven; Bianchi, Davide; Brooks, David; Claybaugh, Todd; Dawson, Kyle; de la Macorra, Axel; Doel, Peter; Fanning, Kevin; Forero-Romero, Jaime E.; Gaztañaga, Enrique; Gontcho A Gontcho, Satya; Honscheid, Klaus; Kehoe, Robert; Kisner, Theodore; Lambert, Andrew; Landriau, Martin; Le Guillou, Laurent; Manera, Marc; Meisner, Aaron; Moustakas, John; Muñoz-Gutiérrez, Andrea; Myers, Adam; Nie, Jundan; Palanque-Delabrouille, Nathalie; Poppett, Claire; Prada, Francisco; Rezaie, Mehdi; Rossi, Graziano; Sanchez, Eusebio; Schubnell, Michael; Seo, Hee-Jong; Silber, Joseph Harry; Sprayberry, David; Tarlé, Gregory; Weaver, Benjamin Alan; Zhou, Zhimin; Zou, Hu
Referencia bibliográfica

The Astrophysical Journal

Fecha de publicación:
3
2025
Número de autores
41
Número de autores del IAC
1
Número de citas
0
Número de citas referidas
0
Descripción
We present two cases of Lyα changing-look (CL) quasars (J1306 and J1512) along with two additional candidates (J1511 and J1602), all discovered serendipitously at z > 2 through the Dark Energy Spectroscopic Instrument and the Sloan Digital Sky Survey. It is the first time to capture CL events in Lyα at high redshift, which is crucial for understanding the underlying mechanisms driving the CL phenomenon and the evolution of high-redshift quasars and galaxies. We find that the accretion rate in the dim state for these CL objects corresponds to a relatively low value ( ), which suggests that the inner region of the accretion disk might be in transition between the advection dominated accretion flow ( ) and the canonical accretion disk (optically thick, geometrically thin). However, unlike in C IV CL quasars in which broad Lyα remained, the broad C IV may still persist after a CL event occurs in Lyα, making the physical origin of the CL and ionization mechanism event more puzzling and interesting.