NOAO >   Observing Info >   Approved Programs >   2011A-0417

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Proposal Information for 2011A-0417


PI: Arlin Crotts, Columbia University, arlin@astro.columbia.edu
Address: Department of Astronomy, 550 West 120th Street, New York, NY 10027, U.S.A.

Title: Evolution of the Light Echoes of Supernova 1987A

Abstract: We propose to continue a series of observations that for the past 22 years have yielded most of the results concerning the light echoes from SN 1987A, both on interstellar and circumstellar scales. These observations have been conducted every month or two, primarily on the CTIO 0.9-meter and Las Campanas 1-meter. We now propose to continue a series of new discoveries; among these we anticipate: 1) mapping of the detailed three-dimensional structure of a large supershell around a massive OB association near 30 Doradus, 2) a determination of where dense dust globules, perhaps the sites of incipient star formation, rest in relation to the large-scale shocks which likely produce them, 3) completion of the three-dimensional map of SN 1987A's circumstellar nebula, 4) help in using echoes from SN 1987A to establish a geometrically-determined distance to the SN and the LMC, and 5) in connection with Galex, a measurement of the vacuum-UV flux emitted by the SN explosion during its first hours, missed in 1987. These results will involve our demonstrated techniques in using echoes to extract the echoes from brighter, constant-flux environments. While we will make use of the recent SuperMACHO data of the same field, these observations are much more wavelength- and time-comprehensive. The upcoming semester is particularly crucial, because we have intensive observation of these echoes scheduled for late in 2010-B (explained in Figure 2). Photometry and morphology from imaging is particularly crucial in interpreting these results, by allowing us to calibrate the reflectivity of the echoing dust by comparing current echo intensity to the integrated spectral fluence of the original SN 1987A event. For instance, emission in the near UV (for instance at 4000\AA) precedes the optical-wavelength echo by 80 days. In order to interpret our detailed data in late 2010-B, therefore, we need imaging/photometry from early 2011-A.


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