Yi-Fang Liang, Ye Li, Bao Wang, Xuan Yang, Yuan-Pei Yang, Xue-Feng Wu

Fast radio bursts (FRBs) and gamma-ray bursts (GRBs) are both linked to compact-object activity, yet their possible connection remains unclear. Here we perform a systematic search for spatial and temporal associations between FRBs in the second CHIME/FRB catalog and Swift GRBs. Instead of using the positional ellipses reported in the catalog, the full CHIME localization probability maps are adopted for spatial cross-matching. This yields 130 candidate pairs and increases the number of spatially consistent matches by a factor of several. A redshift consistency requirement reduces the sample to 45 pairs. Applying an additional temporal criterion, requiring long GRBs to precede FRBs and short GRBs to follow them, further reduces the sample to 26 candidates. Monte Carlo simulations show that the overall excess of associations is not statistically significant, and the distribution of matches across localization confidence levels is consistent with random expectations. However, potential associations may be diluted by localization uncertainties and a dominant background of chance coincidences. These results place constraints on any FRB-GRB connection and highlight the need for improved localization and larger samples.