Early dust formation and a massive progenitor for SN 2011ja?

Abstract

SN 2011ja was a bright (I = -18.3) Type II supernova occurring in the nearby edge on spiral galaxy NGC 4945. Flat-topped and multi-peaked Hα and Hβ spectral emission lines appear between 64 -84 days post-explosion, indicating interaction with a disc-like circumstellar medium inclined 30-45 degrees from edge-on. After day 84 an increase in the H-and K-band flux along with heavy attenuation of the red wing of the emission lines are strong indications of early dust formation, likely located in the cool dense shell created between the forward shock of the SN ejecta and the reverse shock created as the ejecta plows into the existing CSM. Radiative transfer modeling reveals both ≈ 1.5 × 10 −4 M ⊙ of pre-existing dust located ∼ 10 16.7 cm away and ≈ 5 × 10 −5 M ⊙ of newly formed dust. Spectral observations after 1.5 years reveal the possibility that the fading SN is located within a young (3-6 Myr) massive stellar cluster, which when combined with tentative 56 Ni mass estimates of 0.2 M ⊙ may indicate a massive (≥ 25 M ⊙ ) progenitor for SN 2011ja.

A Systematic Study of Mid-Infrared Emission From Core-Collapse Supernovae With Spirits

“…, and 2011ja (II-P; Andrews et al 2016). Additional discussion of a well-sampled subset of these old SNe follows in Section 4.4.…”

“…For a detailed discussion of SN 2013df, see Szalai et al (2016). SN 2013am and SN 2011ja (Andrews et al 2016) rebrighten in different epochs. SN 2013am re-brightens slightly in the 4.5 μm band at around 370 days post-discovery, but not in the 3.6 μm band.…”

“…They deduced from the observations that the progenitor was likely a red supergiant (RSG) with initial mass M  12 M e . Andrews et al (2016) performed multi-band follow-up observations in the optical, near-IR, and mid-IR. The first 4 out of 10 epochs of the Spitzer observations used in this work were also presented in their paper.…”

“…In addition to Type IInSNewhose CSM interactions were discovered early on, recent late time observations reveal that many SNe interact with the CSM later in their evolution, providing additional channels for dust production. Andrews et al (2016) presented spectroscopic evidence for CSM interactions in the Type II-P SN 2011ja at 64-84 days post explosion accompanied by an episode of dust production between the forward and the reverse shocks. These interactions with dust production have also been observed in a small number of Type Ibc SNe, such as SN 2006jc (see, e.g., Foley et al 2007;Mattila et al 2008;Smith et al 2008;Sakon et al 2009 and references therein).…”

The dust mass in Cassiopeia A from a spatially resolvedHerschelanalysis

“…With the recent advent of far-infrared (FIR) and submillimetre (submm) observing facilities (e.g., Herschel, ALMA), the ability to also detect the emission from colder dust in CCSN remnants opened up and resulted in the detection of dust masses on the order of 0.1-1.0 M (Barlow et al 2010;Matsuura et al 2011;Gomez et al 2012;Indebetouw et al 2014;Matsuura et al 2015) in some nearby supernova remnants (SN 1987A, Crab Nebula, Cassiopeia A). Some supernova remnants show evidence for dust formation in the supernova ejecta once the ejecta material has sufficiently cooled after expansion to allow grain growth to take place (e.g., Andrews et al 2016). Recent work by Gall et al (2014), Wesson et al (2015) and Be-van & Barlow (2016) suggest that the dust mass in CCSN ejecta grows in time possibly due to accretion of material onto and coagulation of grain species.…”