FAST data retain a positive within-day dispersion and frequency relation for FRB 20220912A after four catalog controls

We test a within-day relation between fitted dispersion measure and burst peak frequency in independent FAST and CHIME catalogs for FRB 20220912A. In 1076 FAST bursts on 17 days, the slope is 0.468 pc cm^-3 per 100 MHz, with a nominal 95% day-bootstrap interval of 0.362 to 0.575. Four catalog controls give 0.364, with an interval of 0.241 to 0.496. Frequency, error, flux and burst-spacing cuts retain a positive FAST slope. A fresh CHIME fit gives the same unadjusted direction, but its adjusted interval includes zero. A constant intrinsic emission-delay slope gives unequal unadjusted cubic-frequency coefficients across the bands; the adjusted comparison remains uncertain. Independent receivers support the catalog association, not a common physical cause. Joint fitting errors, band selection, different burst definitions, non-simultaneous samples and only 17 FAST days limit interpretation. We find no new source or proved plasma change. Code, frozen events, raw paths and hashes, figures, controls and offline instructions are included.

astronomy · FRB 20220912A · FAST · CHIME · dispersion measure · frequency association · independent telescope test