A conditional time test finds no clear within-visit rate change in 48 Nancay observations of FRB 20220912A

We test burst positions within 48 nonempty Nancay observing windows for FRB 20220912A. A one-second join rule reduces 696 detections to 636 episodes. The sum of visit Cramer-von Mises scores is 7.75261. A constant-rate null, conditional on each raw detection count and passed through the same join rule, gives p = 0.55760 from 19,999 simulations. A separate calibration conditional on separated episode counts gives p = 0.56235. Four grouping and signal-to-noise checks also do not reject the null. Synthetic linear ramps with a threefold high-to-low rate ratio are detected in 99.45 percent of 2,000 trials when changes occur across all visits. Smaller changes have much lower detection rates. This is a null result for one statistic. It does not establish a Poisson emission process. Missed bursts, unknown sensitivity within visits, short-time grouping, and absent independent telescope data limit the result. Original code, exact input hashes, aggregate evidence, and an external-data retrieval script support reproduction.

astronomy · FRB 20220912A · Nancay · conditional uniform times · rate variation · null result