Needles in a Haystack: Searching for Exotic Transients in the Era of Wide-Field Surveys

Peter Blanchard (Harvard)
Thursday, September 13, 2018 - 12:15pm

In this talk I will present an overview of my thesis project focusing on identifying and studying rare transients such as superluminous supernovae (SLSNe) and tidal disruption events (TDEs).  This program draws on data streams from all ongoing optical time-domain surveys using a custom aggregator software to select promising candidates and develop techniques that will be essential in the LSST era.  Using a suite of small to large aperture ground- and space-based telescopes, we obtain well-sampled multi-wavelength data on identified SLSNe and TDEs near peak and to late times.  In addition to increasing the identification rate of SLSNe and TDEs, science goals include connecting the early time behavior and diversity of SLSNe with their late-time properties to form a complete picture of the power sources and ejecta properties, and to understand the influence of host environments on TDE properties.  To date, our program has significantly increased the identification efficiency of these rare transients, and has led to new insights.  From deep late-time Magellan observations we have placed the most stringent constraints to date on the presence of radioactive material in SLSNe.  While this firmly rules out the decay of nickel as the dominant power source of the peak luminosities, at least some SLSNe have a large iron-group element abundance similar to SNe associated with long gamma-ray bursts.  In addition, we have found more SLSNe which show deviations from a uniform decline, helping to map out their diverse light curves.  Finally, our program uncovered a TDE in a Seyfert galaxy, leading to interaction of the stellar debris with the pre-existing accretion disk.

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