Can someone please tell me what could be causing this noise?

 

Take off the power steering belt and start the car and if the noise goes away atleast you've narrowed it to the power steering pump.

 

You can buy just an alternator belt (sans AC) that'll help narrow down further, .. youcan start/run the car w/o the alternator spinning but don't do it for too long or with any accessories on because you will kill the battery.

 

its your power steering. its going bad.