TY - JOUR
T1 - The First Photometric Evidence of a Transient/Variable Source at z > 5 with JWST
AU - DeCoursey, Christa
AU - Egami, Eiichi
AU - Sun, Fengwu
AU - Akhtarkavan, Arshia
AU - Bhatawdekar, Rachana
AU - Bunker, Andrew J.
AU - Coulter, David A.
AU - Engesser, Michael
AU - Fox, Ori D.
AU - Gomez, Sebastian
AU - Inayoshi, Kohei
AU - Johnson, Benjamin D.
AU - Karmen, Mitchell
AU - Larison, Conor
AU - Lin, Xiaojing
AU - Lyu, Jianwei
AU - Mattila, Seppo
AU - Moriya, Takashi J.
AU - Pierel, Justin D.R.
AU - Puskás, Dávid
AU - Rest, Armin
AU - Rieke, George H.
AU - Robertson, Brant
AU - Salamat, Sepehr
AU - Strolger, Louis Gregory
AU - Tacchella, Sandro
AU - Vassallo, Christian
AU - Williams, Christina C.
AU - Zenati, Yossef
AU - Zhang, Junyu
N1 - Publisher Copyright:
© 2025. The Author(s). Published by the American Astronomical Society.
PY - 2025/8/22
Y1 - 2025/8/22
N2 - The James Webb Space Telescope (JWST) discovered 79 transients out to z ∼ 4.8 through the JADES Transient Survey (JTS), but the JTS did not find any z > 5 transients. We present the first photometric evidence of a z > 5 transient/variable source with JWST. The source, AT 2023adya, resides in a zspec = 5.274 galaxy in GOODS-N, which dimmed from mF356W = 26.05 ± 0.02 mag to 26.24 ± 0.02 mag in the rest-frame optical over approximately 2 rest-frame months, producing a clear residual signal in the difference image (mF356W = 28.01 ± 0.17 mag; SNvar = 6.09) at the galaxy center. Shorter-wavelength bands (F090W/F115W) show no rest-frame UV brightness change. Based on its rest-frame V-band absolute magnitude (MV = −18.48 mag), AT 2023adya could be any core-collapse supernova (SN) subtype or an SN Ia. However, due to low SN Ia rates at high redshift, the SN Ia scenario is unlikely. Alternatively, AT 2023adya may be a variable active galactic nucleus (AGN). The NIRCam/Grism spectrum shows no broad Hα emission line (FWHM = 130 ± 26 km s−1), but we cannot exclude the existence of a faint broad line and therefore cannot exclude the AGN scenario. AT 2023adya is unlikely to be a tidal disruption event (TDE) because the TDE models matching the observed brightness changes have low event rates. Although it is not possible to determine AT 2023adya’s nature based on the two-epoch single-band photometry alone, this discovery pushes the transient/variable science frontier past z = 5 and toward the Epoch of Reionization.
AB - The James Webb Space Telescope (JWST) discovered 79 transients out to z ∼ 4.8 through the JADES Transient Survey (JTS), but the JTS did not find any z > 5 transients. We present the first photometric evidence of a z > 5 transient/variable source with JWST. The source, AT 2023adya, resides in a zspec = 5.274 galaxy in GOODS-N, which dimmed from mF356W = 26.05 ± 0.02 mag to 26.24 ± 0.02 mag in the rest-frame optical over approximately 2 rest-frame months, producing a clear residual signal in the difference image (mF356W = 28.01 ± 0.17 mag; SNvar = 6.09) at the galaxy center. Shorter-wavelength bands (F090W/F115W) show no rest-frame UV brightness change. Based on its rest-frame V-band absolute magnitude (MV = −18.48 mag), AT 2023adya could be any core-collapse supernova (SN) subtype or an SN Ia. However, due to low SN Ia rates at high redshift, the SN Ia scenario is unlikely. Alternatively, AT 2023adya may be a variable active galactic nucleus (AGN). The NIRCam/Grism spectrum shows no broad Hα emission line (FWHM = 130 ± 26 km s−1), but we cannot exclude the existence of a faint broad line and therefore cannot exclude the AGN scenario. AT 2023adya is unlikely to be a tidal disruption event (TDE) because the TDE models matching the observed brightness changes have low event rates. Although it is not possible to determine AT 2023adya’s nature based on the two-epoch single-band photometry alone, this discovery pushes the transient/variable science frontier past z = 5 and toward the Epoch of Reionization.
UR - https://www.scopus.com/pages/publications/105013851712
U2 - 10.3847/1538-4357/ade78c
DO - 10.3847/1538-4357/ade78c
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AN - SCOPUS:105013851712
SN - 0004-637X
VL - 990
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 31
ER -