A search for gamma ray remnants candidates in spiral galaxy M101

Gamma ray bursts (GRBs) are the most energetic events in the universe within the energy range (1049 – 1054) ergs since the Big Bang. GRBs are expected to leave behind remnants similar to the case of supernovae. Identification of GRB remnants in nearby galaxies could provide knowledge about their birth place and progenitors. In this study, 15 GRB remnant candidates in M101 spiral galaxy are examined in the optical band. Photometric and spectral observations have been made using RTT150 telescope at TUG (TÜBİTAK Ulusal Gözlemevi) and 6 m BTA telescope at SAO (Special Astrophysical Observatory). According to the identified line flux ratio ([O III]λ5007⁄H_β and (He II λ4686)⁄H_β ) in the photo-ionized regions the possible nature of 15 GRB remnant candidates are discussed by comparing them with the known positions of other conventional emission sources (supernova remnants, X-ray sources, planetary nebulae, H II regions).