====================================================
Title: "Discovery, 
 Observations and Theory of Over Luminous Supernovae and Peculiar Transients"

Manolis Chatzopoulos
The University of Texas at Austin, USA
=====================================================

When:  Monday, July 26 at 2.00 p.m.
Where: 2nd Floor Seminar Room

=====================================================

Abstract:

Modern wide-field imaging transient search pro jects led to the discovery
of a new class of rare, over-luminous stellar explosions. Events like SN
2005ap, SN 2006gy, SN 2006tf, SN 2008am, SN 2008es, SN 2008fz, and SN
2008iy introduced us new evidence about stellar death, since traditional
ideas about the mechanisms that can power these phenomena are found to
be inadequate to explain the observed properties. The Texas Supernova
Search Pro ject and its successor, the ROTSE-Supernova Verification Pro
ject  discovered most of the above mentioned over-luminous supernovae
(OLSNe) over the past five years of their operation. The advantage of
this pro ject is that it is essentially free of selection bias or the
limits of a targeted search; the automated wide field (≥ 3 square
degrees) ROTSE-III telescopes, scan the whole sky blindly, looking for
transients down to unfiltered magnitude ∼19 mag and they do not focus on
pre-selected galaxies. An estimated rate for these exceptionally
luminous supernovae is ∼ 2.6 × 10−7  events/Mpc3/yr. Current and future
transient search pro jects such as the SDSS-II Supernova Survey, the
Palomar Transient Factory, SkyMapper, PanSTARRS and Large Synoptic
Survey Telescope are expected to increase the number of rare
over-luminous (or, under-luminous) supernove and to discover new,
unusual transients.