2008/04/09 by D. Milisavljevic, D. Milisavljević, R. Fesen +3 · 2 citations
Physics and Astronomy · #Astro and Planetary Science #Gamma-ray bursts and supernovae #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/590426
4 pages, 3 figures. Submitted to the Astrophysical Journal (Letters)
arxiv created 2008/04/09 · openalex publication_date 2008/09/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We present late-time optical images and spectra of the Type IIn supernova SN 1986J. HST ACS/WFC images obtained in 2003 February show it to be still relatively bright, with m F606W = 21.4 and m F814W = 20.0 mag. Compared to 1994 December HST WFPC2 images, SN 1986J shows a decline of only ≲1 mag in brightness over 8 years. Ground-based spectra taken in 1989, 1991, and 2007 show a 50% decline in Hα emission between 1989 and 1991, and an order of magnitude drop between 1991 and 2007, along with the disappearance of He I line emissions during the period 1991-2007. The object's [O I] λλ6300, 6364, [O II] λλ7319, 7330 and [O III] λλ4959, 5007 emission lines show two prominent peaks near –1000 and –3500 km s −1 , with the more blueshifted component declining significantly in strength between 1991 and 2007. The observed spectral evolution suggests two different origins for SN 1986J's late-time optical emission: dense, shock-heated circumstellar material, which gave rise to the initially bright Hα, He I, and [N II] λ5755 lines, and reverse-shock-heated O-rich ejecta on the facing expanding hemisphere, dominated by two large clumps generating two blueshifted emission peaks in the [O I], [O II], and [O III] lines.