tokens: regular observations of SN 1987A continued for the purposes of monitoring the evolution of the interaction with the ER and to develop a clear picture of the evolving relationship between the IR emission at these wavelengths and emission at optical and X-ray wavelengths (Dwek et al. 2008 , 2010 ; Arendt et al. 2016 ). This paper reports on the complete set of Spitzer ’ s IRAC observations of SN 1987A and its ER. Section 2 briefly describes the observations and additional mosaicking procedures. The complete mid-IR light curves from Spitzer IRAC and MIPS photometry are presented and modeled with a simple empirical function in Section 3 . The final light curves extend a little over 4 yr (in eight epochs) beyond the results presented by Arendt et al. ( 2016 ). In Section 4 we employ high-resolution mapping and deconvolution that are enabled by the long-term repeated observations of SN1987A at a wide range of position angles. We model the marginally resolved ER to identify the separate evolution of the N, S, E, and W portions of the ER. Section 5 provides further discussion of some of the results, and the findings are summarized in Section 6 . The Appendix describes a strongly variable source that is unassociated with SN 1987A, but was serendipitously located within the field of view of the IRAC observations. 2. Data 2.1. Standard Post-basic Calibrated Data (pBCD) Mosaics and Photometry The initial targeted IRAC observations of SN 1987A employed 12 s frame times using the small-scale Spiral16 dither pattern. Guided by those results, subsequent SN 1987A observations continued the use of 12 s frame times, but switched to the slightly shallower medium-scale Reuleaux12 dither pattern, resulting in 125 s of total exposure (10.4 s of signal integration per 12 s frame time). These observations were repeated at roughly 6 month intervals. The basic calibrated date (BCD) individual frames were automatically mosaicked into pBCD images on 06 pixel scales. The SN brightness was measured from the pBCD mosaics using aperture photometry. Because the SN is not well resolved from nearby stars (Star 2 and Star 3 as designated by Walker Suntzeff 1990 ), the source aperture includes the SN and these stars, and estimates of their flux density (extrapolated from the observations by Walborn et al. 1993 ) are subtracted from the reported result for SN 1987A (Table 1 ). Table 1 SN 1987A Flux Densities Notes. Flux densities are in millijansky. Flux densities of [0.41, 0.26, 0.16, 0.09, 0.01] mJy have been subtracted at [3.6, 4.5, 5.8, 8, 24] μ m to account for the emission of Stars 2 and 3 in the aperture. This correction was not included in Table 1 of Arendt et al. ( 2016 ). a Day number 0 = 1987 Feb 23. b Spitzer astronomical observation request (AOR) number. c Spitzer program ID number. Bold numbers indicate programs specifically targeting SN 1987A. (This table is available in machine-readable form.) A machine-readable version of the table is available. Additional
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