I have migrated my iPhoto library to Photos library. Is it ok to delete the iPhoto library?

Yes, while the two libraries share files, they are hard linked, so the Photos Library is not dependent on the iPhoto Library. This also means you won't get as much file space back as you might think. Just make sure that you have all your images. I suggest you keep a backup just in case.

i have a related question. my Photos Library was recently updated and i would like to delete the IPhoto Event Album. is this safe to do? will i put photographs at jeopardy? i've backed up my library, but i was hoping this wouldn't cause any problems. thanks.

Deleting albums has no effect on the images in the library.