Upper limits on the escape fraction of ionizing radiation from galaxies at 2 ? <i>z</i> &amp;lt; 6

In this work, we investigate upper limits on the global escape fraction of ionizing photons ($f_{\rm esc/global}^{\rm abs}$) from a sample galaxies probed for Lyman-continuum (LyC) emission characterized as non-LyC and LyC leakers. We present 9 clean non-contaminated (by low redshift interlopers, CCD problems internal reflections instrument) which do not show significant ($>$ $3\sigma$) flux between 880\AA\ $<\lambda_{rest}<$ 910\AA. The galaxy stacked spectrum reveals no with an limit $f_{\rm esc}^{\rm abs} \leq 0.06$. next step our analysis, join all estimates abs}$ derived different samples $2\lesssim z < 6$ literature reported in last $\sim$20 years include presented work. find $\leq$ 0.084 recognized After including known detections 0.088 examined flux. Furthermore, groups indicate that strongest emitters could be classified Lyman alpha emitters. also discuss possible existence correlation among observed density ratio $(F_{\nu}^{LyC}/F_{\nu}^{UV})_{\rm obs}$ equivalent width EW(Ly$\alpha)$, where confirm moderately