LAUSR

We report our correlation analysis for the \gr\ blazars detected with the Large Area Telescope (LAT) onboard the {\it Fermi Gamma-ray Space Telescope (Fermi)}, for which we use the \fermi-LAT data and the optical $zr$ and $zg$ band data from the Zwicky Transient Facility survey in the time period approximately from 2018 July to 2022 February. We start from the full sample of the \fermi-LAT blazars and find $\sim$38\% of them as significant variables in the both \gr\ and optical bands. Among the variables, which are 705 blazars, 95 are selected as our targets based on the requirement for the \gr\ brightnesses. Then 15 out of the 95 blazars are found to show the \gr--optical correlations in the $\sim$3.7-yr time period. Most of the 15 blazars are classified as low synchrotron peaked (LSP) ones with the time lags between the \gr\ and optical bands in a range of from $-19$ to $+25$\,d. The results generally fit the often-considered emission scenario for the LSP blazars. Three cases of showing $\sim -100$\,d time lags are discussed, which require further studies for confirmation. Our analysis results suggest that among the detected significant variables, $\sim$27\% LSPs when requiring the average \gr\ fluxes above $\sim 4\times 10^{-8}$\,photon\,cm$^{-2}$\,s$^{-1}$ can show the \gr\ and optical correlations.