article published yes Max E. Lee author Zoltán Haiman author 7c006e8c-cc0d-11ee-8322-cb904ef76f360000-0003-3633-5403 Shivam Pandey author Shy Genel author ZoHa department The next generation of weak-gravitational-lensing surveys has the potential to place stringent constraints on cosmological parameters. However, their analysis is limited by systematics such as the intrinsic alignments of galaxies, which alter weak-lensing convergence and can lead to biases in cosmological parameter estimations. For the first time, in this work, we investigate the impact of intrinsic alignments on non-Gaussian statistics of the weak-lensing field using galaxy shapes derived from the IllustrisTNG hydrodynamical simulation. We create two catalogs of ray-traced convergence maps: one that includes the measured intrinsic shape of each galaxy and another where all galaxies are randomly rotated to eliminate intrinsic alignments. We compare a range of weak-lensing statistics between the two catalogs, including the shear–shear correlation function, the map-level angular power spectrum, one-point, peak count, and minimum distribution functions, and Minkowski functionals. For each statistic, we assess the level of statistical distinguishability between catalogs for a set of future survey angular areas. Our results reveal strong small-scale correlation in the alignment of galaxies and statistically significant boosts in weak-lensing convergence in both positive and negative directions for high-significance peaks and minima, respectively. We note that our analysis is at a fixed number density of ˜ 5 arcmin^-2, drawn from a single realization of initial conditions, and does not include observational uncertainties or supersample covariance contributions. Weak-lensing analyses utilizing non-Gaussian statistics must account for intrinsic alignments to avoid significantly compromised cosmological inferences. https://research-explorer.ista.ac.at/download/21724/21732/2025_AstrophysicalJournal_Lee.pdf application/pdfno IOP Publishing2025 eng 0004-637X 1538-4357 2504.1246010.3847/1538-4357/ae1ca7 9961 Lee, M. E., Haiman, Z., Pandey, S., &#38; Genel, S. (2025). The effect of intrinsic alignments on weak-lensing statistics in hydrodynamical simulations. <i>The Astrophysical Journal</i>. IOP Publishing. <a href="https://doi.org/10.3847/1538-4357/ae1ca7">https://doi.org/10.3847/1538-4357/ae1ca7</a> Lee, Max E., et al. “The Effect of Intrinsic Alignments on Weak-Lensing Statistics in Hydrodynamical Simulations.” <i>The Astrophysical Journal</i>, vol. 996, no. 1, 36, IOP Publishing, 2025, doi:<a href="https://doi.org/10.3847/1538-4357/ae1ca7">10.3847/1538-4357/ae1ca7</a>. M. E. Lee, Z. Haiman, S. Pandey, and S. Genel, “The effect of intrinsic alignments on weak-lensing statistics in hydrodynamical simulations,” <i>The Astrophysical Journal</i>, vol. 996, no. 1. IOP Publishing, 2025. M.E. Lee, Z. Haiman, S. Pandey, S. Genel, The Astrophysical Journal 996 (2025). Lee, Max E., Zoltán Haiman, Shivam Pandey, and Shy Genel. “The Effect of Intrinsic Alignments on Weak-Lensing Statistics in Hydrodynamical Simulations.” <i>The Astrophysical Journal</i>. IOP Publishing, 2025. <a href="https://doi.org/10.3847/1538-4357/ae1ca7">https://doi.org/10.3847/1538-4357/ae1ca7</a>. Lee ME, Haiman Z, Pandey S, Genel S. The effect of intrinsic alignments on weak-lensing statistics in hydrodynamical simulations. <i>The Astrophysical Journal</i>. 2025;996(1). doi:<a href="https://doi.org/10.3847/1538-4357/ae1ca7">10.3847/1538-4357/ae1ca7</a> Lee ME, Haiman Z, Pandey S, Genel S. 2025. The effect of intrinsic alignments on weak-lensing statistics in hydrodynamical simulations. The Astrophysical Journal. 996(1), 36. 217242026-04-12T22:01:52Z2026-04-13T08:30:52Z