Multiwavelength Timing Analysis of the Recurrent Nova T CrB

We present a short-timescale multiwavelength timing study of the symbiotic recurrent nova T Coronae Borealis (T CrB), based on Swift/X-Ray Telescope (XRT), Swift/UltraViolet Optical Telescope (UVOT), and Transiting Exoplanet Survey Satellite (TESS) observations obtained across the high state, the 2023–2024 optical/UV dip, and the subsequent recovery. We use high-cadence event-mode and TESS data to search specifically for sub-kilosecond variability and simultaneous UV–optical correlations. The UVM2 event-mode data show a candidate variability timescale near 445 s during MJD 59,954.1–60,276.9.The folded extrema correspond to a descriptive fractional modulation amplitude of about 9.9%. The feature remains at approximately the same timescale when 20 s, 10 s, and 5 s event-mode bins are used, while no corresponding 445 s peak is found in the spacecraft-pointing diagnostic, the background light curve, or a nearby comparison star. Nevertheless, we do not establish phase coherence across observations separated by days to weeks, and no UVW1 or UVW2 event-mode data are available for an equivalent high-cadence test; the feature is therefore treated as a tentative QPO-like timescale rather than a secure coherent period. No significant 445 s peak is present in the XRT or TESS Lomb–Scargle periodograms. Injection–recovery tests give a 90% coherent-sinusoid fractional semi-amplitude sensitivity of about 34.3% for the 0.3–10 keV XRT light curve and cadence-corrected limits of about 0.054%, 0.056%, 0.022%, and 0.012% for TESS Sectors 24, 25, 51, and 78, respectively. The only strictly contemporaneous UVM2–TESS Sector 78 overlap spans JD 2,460,442.1159722–2,460,442.1260764 (873 s); after excluding the final incomplete UVM2 bin, 840 s is used for the cross-correlation function (CCF). A phenomenological Gaussian fit to the CCF trough gives a dimensionless coefficient of −0.41±0.09 and a lag of 84±31 s (90% confidence; Δχ2=2.7). The sign of the anti-correlation persists after simple linear and quadratic detrending, although the inferred lag is sensitive to detrending and edge effects. We therefore regard both the 445 s feature and the UV–optical lag as tentative. The present data do not uniquely identify the emitting regions or establish a propagation mechanism. These results highlight T CrB as a valuable target for simultaneous high-cadence ultraviolet, optical, and X-ray monitoring before and during its next nova eruption.