2025ApJ...981L...8G

Query : 2025ApJ...981L...8G

2025ApJ...981L...8G - Astrophys. J., 981, L8 (2025/March-1)

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

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., GAZTANAGA E., GONTCHO A GONTCHO S., HONSCHEID K., KEHOE R., KISNER T., LAMBERT A., LANDRIAU M., LE GUILLOU L., MANERA M., MEISNER A., MOUSTAKAS J., MUNOZ-GUTIERREZ A., MYERS A., NIE J., PALANQUE-DELABROUILLE N., POPPETT C., PRADA F., REZAIE M., ROSSI G., SANCHEZ E., SCHUBNELL M., SEO H.-J., SILBER J.H., SPRAYBERRY D., TARLE G., WEAVER B.A., ZHOU Z. and ZOU H.

Abstract (from CDS):

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 ($\mathop{\,}\limits^{{\mathscr{M}}}\,\approx 2\times 1{0}^{-3}$), which suggests that the inner region of the accretion disk might be in transition between the advection dominated accretion flow ($\dot{\,{\mathscr{M}}}\,\lt 1{0}^{-3}\sim 1{0}^{-2}$) 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.

Abstract Copyright: © 2025. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Accretion - Active galaxies - Supermassive black holes - Quasars

Simbad objects: 7

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Number of rows : 7
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 NGC 863 Sy2 02 14 33.5604714720 -00 46 00.181845336   14.48 13.81 17.9   ~ 770 0
2 SDSS J130643.24+561842.1 QSO 13 06 43.250 +56 18 42.15           ~ 8 0
3 NGC 5548 Sy1 14 17 59.5400291832 +25 08 12.603122268   14.35 13.73     ~ 2895 0
4 Z 296-15 Sy1 14 36 22.0820611632 +58 47 39.394934844   14.19 13.79     ~ 592 0
5 SDSS J151122.19+291321.8 QSO 15 11 22.1950248264 +29 13 21.832264668           ~ 8 0
6 SDSS J151205.89+374627.7 QSO 15 12 05.890 +37 46 27.71           ~ 2 0
7 SDSS J160222.63+174905.5 QSO 16 02 22.633 +17 49 05.56           ~ 7 0

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