The first identification of Lyα changing-look quasars at high redshift in DESI

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

doi:10.3847/2041-8213/adb426

The first identification of Lyα changing-look quasars at high redshift in DESI

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

Institute of Cosmology & Gravitation

Research output: Contribution to journal › Article › peer-review

Abstract

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 (M » 2 x 10^-3), which suggests that the inner region of the accretion disk might be in transition between the advection dominated accretion flow (M < 10^-3 ~ 10^-2) 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.

Original language	English
Article number	adb426
Number of pages	8
Journal	Astrophysical Journal Letters
Volume	981
Issue number	1
Early online date	24 Feb 2025
DOIs	https://doi.org/10.3847/2041-8213/adb426
Publication status	Published - 1 Mar 2025

Keywords

Accretion (14)
Active galaxies (17)
Quasars (1319)
Supermassive black holes (1663)
UKRI
STFC

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Guo_2025_ApJL_981_L8Final published version, 781 KBLicence: CC BY

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Guo, W. J., Pan, Z., Siudek, M., Aguilar, J. N., Ahlen, S., Bianchi, D., Brooks, D., Claybaugh, T., Dawson, K., de la Macorra, A., Doel, P., Fanning, K., Forero-Romero, J. E., Gaztañaga, E., Gontcho, S. G. A., Honscheid, K., Kehoe, R., Kisner, T., Lambert, A., ... Zou, H. (2025). The first identification of Lyα changing-look quasars at high redshift in DESI. Astrophysical Journal Letters, 981(1), Article adb426. https://doi.org/10.3847/2041-8213/adb426

@article{66a37ea15b674421a762b641223fa198,

title = "The first identification of Lyα changing-look quasars at high redshift in DESI",

abstract = "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 (M » 2 x 10-3), which suggests that the inner region of the accretion disk might be in transition between the advection dominated accretion flow (M < 10-3 ~ 10-2) 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.",

keywords = "Accretion (14), Active galaxies (17), Quasars (1319), Supermassive black holes (1663), UKRI, STFC",

author = "Guo, {Wei Jian} and Zhiwei Pan and Ma{\l}gorzata Siudek and Aguilar, {Jessica Nicole} and Steven Ahlen and Davide Bianchi and David Brooks and Todd Claybaugh and Kyle Dawson and {de la Macorra}, Axel and Peter Doel and Kevin Fanning and Forero-Romero, {Jaime E.} and Enrique Gazta{\~n}aga and Gontcho, {Satya Gontcho A.} and Klaus Honscheid and Robert Kehoe and Theodore Kisner and Andrew Lambert and Martin Landriau and {Le Guillou}, Laurent and Marc Manera and Aaron Meisner and John Moustakas and Andrea Mu{\~n}oz-Guti{\'e}rrez and Adam Myers and Jundan Nie and Nathalie Palanque-Delabrouille and Claire Poppett and Francisco Prada and Mehdi Rezaie and Graziano Rossi and Eusebio Sanchez and Michael Schubnell and Seo, {Hee Jong} and Silber, {Joseph Harry} and David Sprayberry and Gregory Tarl{\'e} and Weaver, {Benjamin Alan} and Zhimin Zhou and Hu Zou",

note = "Publisher Copyright: {\textcopyright} 2025. The Author(s).",

year = "2025",

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doi = "10.3847/2041-8213/adb426",

language = "English",

volume = "981",

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Guo, WJ, Pan, Z, Siudek, M, Aguilar, JN, Ahlen, S, Bianchi, D, Brooks, D, Claybaugh, T, Dawson, K, de la Macorra, A, Doel, P, Fanning, K, Forero-Romero, JE, Gaztañaga, E, Gontcho, SGA, Honscheid, K, Kehoe, R, Kisner, T, Lambert, A, Landriau, M, Le Guillou, L, Manera, M, Meisner, A, Moustakas, J, Muñoz-Gutiérrez, A, Myers, A, Nie, J, Palanque-Delabrouille, N, Poppett, C, Prada, F, Rezaie, M, Rossi, G, Sanchez, E, Schubnell, M, Seo, HJ, Silber, JH, Sprayberry, D, Tarlé, G, Weaver, BA, Zhou, Z & Zou, H 2025, 'The first identification of Lyα changing-look quasars at high redshift in DESI', Astrophysical Journal Letters, vol. 981, no. 1, adb426. https://doi.org/10.3847/2041-8213/adb426

TY - JOUR

T1 - The first identification of Lyα changing-look quasars at high redshift in DESI

AU - Guo, Wei Jian

AU - Pan, Zhiwei

AU - Siudek, Małgorzata

AU - Aguilar, Jessica Nicole

AU - Ahlen, Steven

AU - Bianchi, Davide

AU - Brooks, David

AU - Claybaugh, Todd

AU - Dawson, Kyle

AU - de la Macorra, Axel

AU - Doel, Peter

AU - Fanning, Kevin

AU - Forero-Romero, Jaime E.

AU - Gaztañaga, Enrique

AU - Gontcho, Satya Gontcho A.

AU - Honscheid, Klaus

AU - Kehoe, Robert

AU - Kisner, Theodore

AU - Lambert, Andrew

AU - Landriau, Martin

AU - Le Guillou, Laurent

AU - Manera, Marc

AU - Meisner, Aaron

AU - Moustakas, John

AU - Muñoz-Gutiérrez, Andrea

AU - Myers, Adam

AU - Nie, Jundan

AU - Palanque-Delabrouille, Nathalie

AU - Poppett, Claire

AU - Prada, Francisco

AU - Rezaie, Mehdi

AU - Rossi, Graziano

AU - Sanchez, Eusebio

AU - Schubnell, Michael

AU - Seo, Hee Jong

AU - Silber, Joseph Harry

AU - Sprayberry, David

AU - Tarlé, Gregory

AU - Weaver, Benjamin Alan

AU - Zhou, Zhimin

AU - Zou, Hu

PY - 2025/3/1

Y1 - 2025/3/1

N2 - 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 (M » 2 x 10-3), which suggests that the inner region of the accretion disk might be in transition between the advection dominated accretion flow (M < 10-3 ~ 10-2) 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.

AB - 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 (M » 2 x 10-3), which suggests that the inner region of the accretion disk might be in transition between the advection dominated accretion flow (M < 10-3 ~ 10-2) 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.

KW - Accretion (14)

KW - Active galaxies (17)

KW - Quasars (1319)

KW - Supermassive black holes (1663)

KW - UKRI

KW - STFC

UR - http://www.scopus.com/inward/record.url?scp=85218980784&partnerID=8YFLogxK

U2 - 10.3847/2041-8213/adb426

DO - 10.3847/2041-8213/adb426

M3 - Article

AN - SCOPUS:85218980784

SN - 2041-8205

VL - 981

JO - Astrophysical Journal Letters

JF - Astrophysical Journal Letters

IS - 1

M1 - adb426

ER -

The first identification of Lyα changing-look quasars at high redshift in DESI

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Keywords

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