can i delete iphoto events from photos?

These are albums made from the Events you had in iPhoto. Yes you can delete them and no the photos are not deleted.

And can I delete them? Will this delete the photo?

Just make sure you do not accidentally select the photos photos when deleting.

Select the folder "IPhoto Events", ctrl-click it, then select "delete Folder".

Confirm tha you want to delete the folder and the albums inside.

You might want to hold off on that to see if you'd like to use those albums as part of your organization. Since Events are no longer used by Photos all you have to keep photos of different dates grouped together (like Events do) is to use albums.

Moments in Photos are the new Events, i.e. groupings of photos sorted by date taken.

When the iPhoto Library was first migrated to Photos there is a folder created in the sidebar titled iPhoto Events and all migrated iPhoto Events (which are now Moments) are represented by an album in that folder. To open the sidebar if it's not already open use the Option+Command+S key combination.

There's a way to simulate events in Photos.

When new photos are imported into the Photos library go to the Last Import smart album, select all the photos and use the File ➙ New Album menu option or use the key combination Command+N. Name it as desired. It will appear just above the iPhoto Events folder where you can drag it into the iPhoto Events folder

When you click on the iPhoto Events folder you'll get a simulated iPhoto Events window.

The downside to the simulation is that the Albums/Events can only be sorted automatically by Title. But they can also be sorted manually, either in the sidebar or in the folder's window at the right.

But once Photos 2 is released with El Capitan we'll be able to sort the albums by date so when you clic on the iPhoto Events folder you'll get a window just like the Events window in iPhoto:

Tell Apple what missing features you'd like restored or new features added in Photos via https://www.apple.com/feedback/photos.html.