Siranush - From Armenian ser "love" and anush female particle (like Vardanush, Hranush). It is a spread name in Arm. The short forms are Siran, Sirush and Sirik.
Pogosyan - Poghossian, Pogossyan, Poghosyan, Poghosian, Pogosyan, etc., is an Armenian surname.
The Western Armenian equivalent is Boghossyan.