JWST NIRCam Observations of SN 1987A: Spitzer Comparison and Spectral Decomposition

Abstract

JWST Near Infrared Camera (NIRCam) observations at 1.5–4.5 μm have provided broadband and narrowband imaging of the evolving remnant of SN 1987A with unparalleled sensitivity and spatial resolution. Comparing with previous marginally spatially resolved Spitzer Infrared Array Camera (IRAC) observations from 2004 to 2019 confirms that the emission arises from the circumstellar equatorial ring (ER), and the current brightness at 3.6 and 4.5 μm was accurately predicted by extrapolation of the declining brightness tracked by IRAC. Despite the regular light curve, the NIRCam observations clearly reveal that much of this emission is from a newly developing outer portion of the ER. Spots in the outer ER tend to lie at position angles in between the well-known ER hotspots. We show that the bulk of the emission in the field can be represented by five standard spectral energy distributions, each with a distinct origin and spatial distribution. This spectral decomposition provides a powerful technique for distinguishing overlapping emission from the circumstellar medium and the supernova ejecta, excited by the forward and reverse shocks, respectively.

Hubble Space Telescope Images of SN 1987A: Evolution of the Ejecta and the Equatorial Ring from 2009 to 2022

“…A similar behavior was observed at all wavelengths-apart from radio and hard X-rays, which are still increasing in flux (Cendes et al 2018;Alp et al 2021;Maitra et al 2022). New small spots outside the ER show that the blast wave has propagated beyond the ring (Larsson et al 2019a;Arendt et al 2023). Signs of shock interaction outside the ER are also clearly seen in JWST/NIRCam images (Arendt et al 2023).…”

“…New small spots outside the ER show that the blast wave has propagated beyond the ring (Larsson et al 2019a;Arendt et al 2023). Signs of shock interaction outside the ER are also clearly seen in JWST/NIRCam images (Arendt et al 2023). The recent JWST/NIRSpec and JWST/MRS observations show that the inner ejecta have recently started to interact with the reverse shock at the inner edge of the ER in the southwest (Fransson et al 2024).…”

JWST MIRI Imager Observations of Supernova SN 1987A

“…Finally, no hint of the two outer rings can be seen in any of our four MIRI broadband images, although forbidden-line emission from the outer rings is seen at several wavelengths in the much higher resolving power MRS spectral images of SN 1987A (Jones et al 2023) where we could only see the outer rings in specific emission lines but not in dust continuum emission. We would therefore expect the NIRCam images reported by Arendt et al (2023) showing the outer rings to be those dominated by line emission. Of the eight filter images shown in Figure 1 of Arendt et al (2023), two show the outer rings: the F164N ([Fe II]+[Si I]); and F405N (Br-alpha) images.…”

“…We would therefore expect the NIRCam images reported by Arendt et al (2023) showing the outer rings to be those dominated by line emission. Of the eight filter images shown in Figure 1 of Arendt et al (2023), two show the outer rings: the F164N ([Fe II]+[Si I]); and F405N (Br-alpha) images.…”

The Impact of Effective Matter Mixing Based on Three-dimensional Hydrodynamical Models on the Molecule Formation in the Ejecta of SN 1987A

“…Actually, as mentioned in Section 1, there has been an approved proposal for Cycle 1 JWST observations of SN 1987A (Matsuura et al 2021); the observations will spatially resolve hot dust grains and may figure out how dust is destructed by the blast wave and the reverse shock. Resent JWST NIRCam imaging of SN 1987A and spectral decomposion have shown the potential to distinguish overlapping emisions from different components (Arendt et al 2023). There has also been an approved proposal for observations of Cas A by JWST (Milisavljevic et al 2021) for investigating the properties of dust, i.e., the dust survival against the passage of the reverse shock, grain size distribution, and clump size, and so on.…”