Supernovae and Other Transients in the OGLE-IV Magellanic Bridge Data

Abstract

We analyze two years (mid-2010 to mid-2012) of OGLE-IV data covering ~65 deg^2 of the Magellanic Bridge (the area between the Magellanic Clouds) and find 130 transient events including 126 supernovae (SNe), two foreground dwarf novae and another two SNe-like transients that turned out to be active galactic nuclei (AGNs). We show our SNe detection efficiency as a function of SN peak magnitude based on available SNe rate estimates. It is 100% for SNe peak magnitudes I<18.8 mag and drops to 50% at I=~19.7 mag. With our current observing area between and around the Magellanic Clouds (~600 deg^2), we expect to find 24 SNe peaking above I<18 mag, 100 above I<19 mag, and 340 above I<20 mag, annually. We briefly introduce our on-line near-real-time detection system for SNe and other transients, the OGLE Transient Detection System.