Bibliographic Details
| Title: |
The first identification of Lyman $\alpha$ Changing-look Quasars at high-redshift in DESI |
| Authors: |
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, Satya Gontcho A, Honscheid, Klaus, Kehoe, Robert, Kisner, Theodore, Lambert, Andrew, Landriau, Martin, Guillou, Laurent Le, 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, Schubnelll, Michael, Seo, Hee-Jong, Silber, Joseph Harry, Sprayberry, David, Tarlé, Gregory, Weaver, Benjamin Alan, Zhou, Zhimin, Zou, Hu |
| Publication Year: |
2024 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Astrophysics of Galaxies |
| More Details: |
We present two cases of Ly$\alpha$ 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 (DESI) and the Sloan Digital Sky Survey (SDSS). It is the first time to capture CL events in Ly$\alpha$ at high redshift, which is crucial for understanding underlying mechanisms driving the CL phenomenon and the evolution of high-redshift quasars and galaxies. The variability of all four sources is confirmed by the significant change of amplitude in the $r$ band ($|r_{\rm DESI}-r_{\rm SDSS}| >0.5 \ \rm mag$). We find that the accretion rate in the dim state for these CL objects corresponds to a relatively low value ($\mathscr{\dot M} \approx 2\times10^{-3}$), which suggests that the inner region of the accretion disk might be in transition between the Advection Dominated Accretion Flow ($\mathscr{\dot M}<10^{-3}\sim 10^{-2}$) and the canonical accretion disk (optically thick, geometrically thin). However, unlike in C {\sc iv} CL quasars in which broad Ly$\alpha$ remained, the broad C {\sc iv} may still persist after a CL event occurs in Ly$\alpha$, making the physical origin of the CL and ionization mechanism event more puzzling and interesting. |
| Document Type: |
Working Paper |
| Access URL: |
http://arxiv.org/abs/2411.01949 |
| Accession Number: |
edsarx.2411.01949 |
| Database: |
arXiv |
