We analyze two years (mid-2010 to mid-2012) of OGLE-IV data covering ~65 square degrees 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).
|Top: Finding chart for supernova OGLE-2010-SN-037. Each image covers 60x60 arcsec. The left image shows the galaxy before the SN explosion, the middle image shows the SN at its peak (marked with cross hairs), and the right image shows the difference image. The SN is located 21.5 arcsec away from the elliptical galaxy 2MASX J02064540-7246329 at z=0.057. Bottom: OGLE-IV light curve for SN OGLE-2010-SN-037. It peaked at I=18.41 mag on 2010, October 11. The estimated absolute magnitude peak was MI=-18.7 mag. Both the shape of the light curve and the peak absolute magnitude point to the SN Type Ia.|
Based on the known SNe rates, SNe absolute magnitudes, galactic and host extinctions, and calculated K-corrections, we simulated the expected numbers of SNe in our survey. We then compared our cumulative number of SNe as a function of I-band magnitude to the simulated one, finding that our SNe detection efficiency 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 square degrees), we expect to find 24 SNe peaking above I<18 mag, 100 above I<19 mag, and 340 above I<20 mag, annually.
All data presented in this paper are available to the astronomical community from the OGLE Internet archive.
PLEASE cite the following paper when using the data or referring to these OGLE results:
Kozlowski et al. 2013, Acta Astronomica, 63, 1, (arXiv:1301.3909).
In October 2012, we implemented the OGLE-IV Transient Detection System (OTDS) running in a near-real-time at the Warsaw telescope in Las Campanas Observatory, Chile.
The OTDS transients are available from the following webpage OGLE-IV Transient Detection System
Any comments about the data and the form of their presentation are welcome as they can improve the future releases of transient events detected by the OGLE collaboration. Send your messages to this address.