A Luminous Red Optical Flare and Hard X-Ray Emission in the Tidal Disruption Event AT 2024kmq

Abstract We present the optical discovery and multiwavelength follow-up observations of AT 2024kmq, a likely tidal disruption event (TDE) associated with a supermassive ( M BH ∼ 10 8 M ⊙ ) black hole in a massive galaxy at z = 0.192. The optical light curve of AT 2024kmq exhibits two distinct peaks: an early fast (timescale 1 day) and luminous ( M ≈ −20 mag) red peak, then a slower (timescale 1 month) blue peak with a higher optical luminosity ( M ≈ −22 mag) and featureless optical spectra. The second component is similar to the spectroscopic class of “featureless TDEs” in the literature, and during this second component we detect highly variable, luminous ( L X ≈ 10 44 erg s −1 ), and hard ( f ν ∝ ν −1.5 ) X-ray emission. Luminous (10 29 erg s −1 Hz −1 at 10 GHz) but unchanging radio emission likely arises from an underlying active galactic nucleus. The luminosity, timescale, and color of the early red optical peak can be explained by synchrotron emission, or alternatively by thermal emission from material at a large radius ( R ≈ a few × 10 15 cm). Possible physical origins for this early red component include an off-axis relativistic jet, and shocks from self-intersecting debris leading to the formation of the accretion disk. Late-time radio observations will help distinguish between the two possibilities.

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Publication Details

Journal
The Astrophysical Journal
Published
2025-08-05
DOI
https://doi.org/10.3847/1538-4357/ade8f2
Citations
6
Primary Topic
Astrophysical Phenomena and Observations
Type
article
Field-Weighted Citation Impact
6.93

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article

A Luminous Red Optical Flare and Hard X-Ray Emission in the Tidal Disruption Event AT 2024kmq

Reed Riddle, J. D. Lyman, Vikram Ravi, X. Chen et al.
6 citations
The Astrophysical Journal
Astrophysical Phenomena and Observations
6.93
article

A Luminous Red Optical Flare and Hard X-Ray Emission in the Tidal Disruption Event AT 2024kmq

Reed Riddle, J. D. Lyman, Vikram Ravi, X. Chen, Jean J. Somalwar, Jacob Wise, Gokul P. Srinivasaragavan, J. Sollerman, Yuhan Yao, Dan Jarvis, M. Gilfanov, Kaustav K. Das, Frank J. Masci, R. Michael Rich, K-Ryan Hinds, C. Fremling, Genevieve Schroeder, D. A. Perley, R. Chornock, Igor Andreoni, R. Sunyaev, Eric R. Coughlin, Seokjun Yun, Anna Y. Q. Ho, Eric C. Bellm, Thomas A. Prince, Sofia Covarrubias, Jason Sevilla, Chang Liu, Roger M. Smith, M. M. Kasliwal, Tatsuya Matsumoto, Jada L. Vail
article en
6 citations

Abstract

Abstract We present the optical discovery and multiwavelength follow-up observations of AT 2024kmq, a likely tidal disruption event (TDE) associated with a supermassive ( M BH ∼ 10 8 M ⊙ ) black hole in a massive galaxy at z = 0.192. The optical light curve of AT 2024kmq exhibits two distinct peaks: an early fast (timescale 1 day) and luminous ( M ≈ −20 mag) red peak, then a slower (timescale 1 month) blue peak with a higher optical luminosity ( M ≈ −22 mag) and featureless optical spectra. The second component is similar to the spectroscopic class of “featureless TDEs” in the literature, and during this second component we detect highly variable, luminous ( L X ≈ 10 44 erg s −1 ), and hard ( f ν ∝ ν −1.5 ) X-ray emission. Luminous (10 29 erg s −1 Hz −1 at 10 GHz) but unchanging radio emission likely arises from an underlying active galactic nucleus. The luminosity, timescale, and color of the early red optical peak can be explained by synchrotron emission, or alternatively by thermal emission from material at a large radius ( R ≈ a few × 10 15 cm). Possible physical origins for this early red component include an off-axis relativistic jet, and shocks from self-intersecting debris leading to the formation of the accretion disk. Late-time radio observations will help distinguish between the two possibilities.

The Astrophysical JournalVol. 989(1)
Northwestern University (US), University of North Carolina at Chapel Hill (US), California Institute of Technology (US), Goddard Space Flight Center (US), University of California, Los Angeles (US), Stockholm University (SE), University of Washington (US), Cornell University (US), Kyoto University (JP), Miller College (US), University of Warwick (GB), Max Planck Institute for Astrophysics (DE), Joint Space Science Institute (US), AlbaNova (SE), Infrared Processing and Analysis Center (US), Deleted Institution, City University of Seattle (US), Liverpool John Moores University (GB), University of Maryland, College Park (US), Syracuse University (US), University of Sheffield (GB), University of California, Berkeley (US)
UK Research and Innovation
Openalex Percentile: Top 3%
Astrophysical Phenomena and Observations
6.93
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