Light Echoes and the Environments of SNe 2014J and 2016adj
Abstract
Light echoes are one of the most powerful and efficient probes of the structure and composition of dust in circumstellar and interstellar environments. Observations of light echoes provide exact three-dimensional (3-D) positions of dust while constraining its density, grain-size and chemical make-up. These can be used to study the evolutionary history of supernova (SN) progenitors, produce high-resolution maps of the structure and composition of interstellar media (ISM), and geometrically measure extragalactic distances. However, echoes pass through a given point only once, and only illuminate a thin slice of a complete structure at any given time, thus accomplishing meaningful science requires carefully-planned, repeated observations. The Type Ia SN 2014J in M82, and the core-collapse SN 2016adj in Cen A are both nearby (~3.5 Mpc), highly reddened (A_V=2-4 mags), and were reported within the last year to have produced resolved light echoes. With 12 orbits of HST and 2.4 hours of Spitzer follow-up observations proposed here, we will map out much more of the 3-D geometry and measure the dust properties of numerous independent structures within the ISM of the host galaxies, and map out or constrain the presence of circumstellar material around each SN. These results can be further used to investigate why the extinction toward SN 2014J (R_V=1.4) differs from Galactic values; measure the geometric distances to both host galaxies; constrain the progenitor properties; test competing models of Type Ib/IIb SNe; and benchmark whether echoes can help us understand galactic feedback, by comparing the actual structures they reveal to ISM simulations.
- Publication:
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Spitzer Proposal
- Pub Date:
- August 2016
- Bibcode:
- 2016sptz.prop13151S