2025ApJ...992...78Z -
Astrophys. J., 992, 78 (2025/October-2)
A Reidentification of Six Candidate Gravitationally Lensed Gamma-Ray Bursts.
ZHAO Y., PENG Z.-Y., CHEN J.-M., YIN Y. and LI T.
Abstract (from CDS):
The gravitational lensing effect of gamma-ray bursts (GRBs) holds significant and diverse applications in the field of astronomy. Nevertheless, the identification of millilensing events in GRBs presents substantial challenges. We re-evaluate the gravitational lensing candidacy of six previously proposed GRBs (GRB 081122A, GRB 081126A, GRB 090717A, GRB 110517B, GRB 200716C, and GRB 210812A) using a comprehensive set of temporal and spectral diagnostics. These include χ2 light-curve similarity tests, photon-count-based hardness ratio (HRcount) comparisons, T90 duration measurements, spectral lag, Norris pulse-shape fitting, and both time-resolved and time-integrated spectral analyses. We propose an evaluation framework in which any single test that reveals a statistically significant inconsistency between the two pulses is sufficient to reject the lensing hypothesis for that burst. Although certain diagnostics, such as T90 and parametric model fits, have known limitations, they are applied and interpreted in conjunction with the more robust, model-independent χ2 and HRcount tests. For all six GRBs, at least one diagnostic shows a significant discrepancy, leading us to conclude that none are consistent with a gravitational lensing interpretation.
Abstract Copyright:
© 2025. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
Gamma-ray bursts
Simbad objects:
7
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