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JWST NIRCam Observations of SN 1987A: Spitzer Comparison and Spectral Decomposition Published: 9/22/2023 8:18:26 PM Updated: 9/22/2023 8:18:26 PM

Paper abstract: JWST NIRCam observations at 1.5-4.5 \mum have provided broad and narrowband imaging of the evolving remnant of SN 1987A with unparalleled sensitivityand spatial resolution. Comparing with previous marginally spatially resolvedSpitzer IRAC observations from 2004-2019 confirms that the emission arises fromthe circumstellar equatorial ring (ER), and the current brightness at 3.6 and4.5 \mum was accurately predicted by extrapolation of the decliningbrightness tracked by IRAC. Despite the regular light curve, the NIRCamobservations clearly reveal that much of this emission is from a newlydeveloping outer portion of the ER. Spots in the outer ER tend to lie atposition angles in between the well-known ER hotspots. We show that the bulk ofthe emission in the field can be represented by 5 standard spectral energydistributions (SEDs), each with a distinct origin and spatial distribution.This spectral decomposition provides a powerful technique for distinguishingoverlapping emission from the circumstellar medium (CSM) and the supernova (SN)ejecta, excited by the forward and reverse shocks respectively.