_version_ 1866915004031172608
author 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
author_facet 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
contents We present two cases of Ly$α$ 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$α$ 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$α$ remained, the broad C {\sc iv} may still persist after a CL event occurs in Ly$α$, making the physical origin of the CL and ionization mechanism event more puzzling and interesting.
format Preprint
id arxiv_https___arxiv_org_abs_2411_01949
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The first identification of Lyman $α$ 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, 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
Astrophysics of Galaxies
We present two cases of Ly$α$ 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$α$ 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$α$ remained, the broad C {\sc iv} may still persist after a CL event occurs in Ly$α$, making the physical origin of the CL and ionization mechanism event more puzzling and interesting.
title The first identification of Lyman $α$ Changing-look Quasars at high-redshift in DESI
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2411.01949