Final Spitzer IRAC Observations of the Rise and Fall of SN 1987A

Abstract

Spitzer's final Infrared Array Camera (IRAC) observations of SN 1987A show the 3.6 and 4.5 µm emission from the equatorial ring (ER) continues a period of steady decline. Deconvolution of the images reveals that the emission is dominated by the ring, not the ejecta, and is brightest on the west side. Decomposition of the marginally resolved emission also confirms this, and shows that the west side of the ER has been brightening relative to the other portions of the ER. The infrared (IR) morphological changes resemble those seen in both the soft X-ray emission and the optical emission. The integrated ER light curves at 3.6 and 4.5 µm are more similar to the optical light curves than the soft X-ray light curve, though differences would be expected if dust is responsible for this emission and its destruction is rapid. Future observations with the James Webb Space Telescope will continue to monitor the ER evolution, and will reveal the true spectrum and nature of the material responsible for the broadband emission at 3.6 and 4.5 µm. The present observations also serendipitously reveal a nearby variable source, subsequently identified as a Be star, that has gone through a multi-year outburst during the course of these observations.

Mid-infrared imaging of Supernova 1987A

“…The measurements at 31 µm are solely from SOFIA, while those at 10-12 µm and 19 µm were collected from different instruments with slightly different filter systems, so that they are not a completely uniform sample. Nevertheless, these light curves generally follow those estimated from Spitzer 3.6 and 4.5 µm measurements (Arendt et al 2020). Arendt et al (2020) demonstrated that the 3.6 and 4.5 µm light curves are well represented by a convolution of exponential decay and a Gaussian function.…”

“…Nevertheless, these light curves generally follow those estimated from Spitzer 3.6 and 4.5 µm measurements (Arendt et al 2020). Arendt et al (2020) demonstrated that the 3.6 and 4.5 µm light curves are well represented by a convolution of exponential decay and a Gaussian function. These fittings are extended to the 8 and 24 µm Spitzer bands, too.…”

“…6. Spitzer monitoring at 3.6 and 4.5 𝜇m continued after Spitzer's helium coolant was exhausted, showing that their fluxes reached a peak at about day 8500-9000 in 2009-2010 (Arendt et al 2020). Other Spitzer bands were last observed on day 7975-7983, just before these bands would have peaked in brightness (Arendt et al 2020).…”

Rescued from oblivion: detailed analysis of archival {\it Spitzer} data of SN~1993J

“…Kotak et al 2009;Fabbri et al 2011;Meikle et al 2011;Szalai et al 2011;Szalai & Vinkó 2013), but also for e.g. SNe 1978K (Tanaka et al 2012), 1980K (Sugerman et al 2012), and for the famous SN 1987A (Bouchet et al 2006;Dwek et al 2010;Arendt et al 2016Arendt et al , 2020.…”

Possible post-kick jets in SN 1987A

“…The expansion of the supernova (SN) remnant of SN 1987A (SNR 1987A) allows observations in recent years to better resolve the geometrical structure of the ejecta (e.g., Frank et al 2016;Larsson et al 2019;Miceli et al 2019;Arendt et al 2020), as well as to establish the properties of dust (e.g., Dwek & Arendt 2015;Matsuura et al 2019). These observations reveal a complicated non-spherical morphology of the ejecta.…”