Universe is a phenomenon perceived by the observer who not only perceives the former but also affirms its existence & disects its structure. My question is: Can this phenomenon I.e. universe exist in the absence of the observer? Your thoughts?

If there is a god, then maybe, maybe not. If there isn't a god, then definitely yes, because it would have to have existed before there were any observers in order to give rise to them.

 

Unless you're using the definition that has anything which interacts with anything else as an observer, in which case no because the entirety of the known universe is then made up of observes, and nothing can exist without itself existing.

I think it depends on what you mean by "observer'. If you mean a conscious being, then I would argue the universe can and does exist without an observer. After all, it existed for billions of years before life began on this planet.