Special Notice #256: Request for fast optical time series of SN 2011fe

September 16, 2011: Dr. Bradley Schaefer (LSU) requests fast time series of SN 2011fe over the next several weeks to attempt the detection of fast optical variations in supernova light.

The following request was prepared by Dr. Schaefer which we forward at his request:

"Fast variations (dips, flares, oscillations) are not expected from expanding supernovae shells, because the parts of the shell cannot 'communicate' or 'coordinate' across the now-large shell on short timescales.  But perhaps flares could occur if a particularly hot blob of gas reaches the photosphere and then is bright before it cools fast?  Perhaps flares only happen near the peak, or late in the decline, or only for Type Ia supernovae?  But few fast time series observations have ever been made of any supernovae, so we do not know what the reality is.  The discovery of any fast variations would be a surprise and a challenge to theory.  To make fast time series, we need a very bright supernova, and SN2011fe is the brightest in over a decade.  This is our chance, and who knows what we will find.

"Observations made in a single filter with a cadence of 60 seconds or less are suggested; observers should try to obtain good signal to noise data (S/N > 50) if possible.  The observational task is to accumulate as long a time on target as possible, because we do not know the frequency of any fast variations.  Also, with long time series, there will be greater overlap between observers so any flare or such can be confirmed independently.  For this, the observations must be with a CCD and done differentially with respect to an appropriate AAVSO comparison star in the field of view.  The V-filter is preferred (if you can get enough signal), and running without filters is OK.  Do not worry about going to high airmass, as long as you are getting good signal-to-noise.  Submit your full time series to the AAVSO as normal, but if you spot any obvious fast variations, then please highlight these to us with an
independent note."

SN 2011fe is located at the following (J2000) coordinates:

RA: 14 03 05.81 , Dec: +54 16 25.4

Please report all observations to the AAVSO using the name "SN 2011fe".

This Special Notice was prepared by Dr. Bradley Schaefer and distributed by Dr. Matthew Templeton.



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