Forty-one ALeRCE non-detection records for SN 2023ixf have bright forced measurements at the same times

We tested whether public non-detection records for SN 2023ixf can serve as limits on its flux. An ALeRCE API snapshot taken on 23 October 2026 UTC has 183 non-detection records and 179 forced measurements. A unique match by filter and time links 96 pairs. Forty-one pairs have positive forced flux, processing status 0, magnitude between 14 and 19, magnitude error below 0.1 mag, and a measured magnitude more than 2 mag brighter than the nominal limit. There are 40 r-band pairs and one i-band pair. All reported match times are equal. The magnitude gaps are 2.02 to 5.36 mag, or flux ratios of 6.4 to 140 relative to the nominal limit. Three independent LCO observations within 0.5 day support the bright forced values. The counts are stable under the tested time and error cuts. ZTF documentation already describes conflicting limits in alert histories. This study adds a measured case, an audit table, and code that checks limits against forced photometry. We did not inspect source pixels or establish the cause of each conflict. The sample does not give a survey-wide error rate. These 41 records must not be used as independent evidence that the source was faint. The package preserves exact source data, hashes, code, results, figures, and offline reproduction steps.

SN 2023ixf · ZTF · ALeRCE · forced photometry · non-detections · data quality · supernovae · reproducible research