NOAO >   Observing Info >   Approved Programs >   2012B-0396

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Proposal Information for 2012B-0396


PI: Arlin Crotts, Columbia University, arlin@astro.columbia.edu
Address: Department of Astronomy, Columbia Astrophysics Lab, New York, NY 10027, United States

CoI: Stephen Lawrence, Hofstra University
CoI: Steve Heathcote, NOAO/SOAR
CoI: Kevin France, CASA, U. of Colorado

Title: Spectroscopic Evolution of SNR 1987A

Abstract: The collision between SN1987A’s ejecta and circumstellar ring is underway. Over several years, we have seen radical changes in the circumstellar nebula as it is overrun by high-speed ejecta, giving birth to a supernova remnant (SNR). We have already discovered (and published), via this observational program, new interactions between ejecta and nebula, as several hot spots appearing every year, and see now the whole innermost nebula beginning to interact. The collision is predicted (and observed) to produce intense IR/optical emission, in new and previously-observed lines. Depending on whether these arise in the ejecta or nebula, and whether shock or EUV-excited, they have linewidths ~10 to 15,000 km/s; frequent moderate-dispersion spectra are required. With the interaction region now spanning the full inner ring, ionizing radiation is beginning to flood the entire structure; this enhances the value of ground observations relative to the finer spatial resolutions of HST. GMOS is ideal for this, covering velocity scales, wavelengths and time intervals unavailable to HST, allowing the first ever study of creation of a nearby SNR. In particular we need timely, good-seeing GMOS spectra the reverse shock of SN 1987A’s circumstellar/ejecta interaction in this semester to combine with recent HST/COS FUV spectra and thereby obtain measurements of compositon of deep layers in the SN progenitor star.


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