Now go to select>refine edge or you can press Ctrl+Alt+R/Cmd+Opt+R to open refine edge box. Increase your feather between 150-160 pixels. For smaller dimension images, 50-100 pixels will do great job. Press OK.
This will refine your selection. As our foreground color is black so just press Alt+Backspace/Opt+Delete to fill the selected area with black color. Now change the blend mode of “vertical vignette” to soft light.