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

TL;DR

This study analyzes two years of OGLE-IV data in the Magellanic Bridge, detecting 130 transient events including 126 supernovae, and evaluates detection efficiency and expected annual supernova discoveries.

Contribution

It provides the first comprehensive analysis of transient events in the Magellanic Bridge using OGLE-IV data and introduces a real-time transient detection system.

Findings

Detected 130 transient events, including 126 supernovae.

Detection efficiency is 100% for SNe brighter than I<18.8 mag.

Expected to find up to 340 supernovae annually above I<20 mag.

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.