At late times (200 days), when the photosphere of continuum emission has disappeared from the envelope, the radiation of the supernova 1987A is powered by $\gamma$-rays resulting from 56Co decays. The spectrum formation at such a late time is a highly non-linear process (XU [1]). The $\gamma$-ray photons first lose their energy due to Compton scattering and photoelectric absorption, generating non-thermal energetic electrons. These energetic electrons are then slowed down by Coulomb scattering or ionizing and exciting different ions in the envelope. The ions will recombine and de-excite, radiating away their energy in infrared (IR), optical and primarily ultraviolet (UV) wavebands.
CY - New York, NY DO - 10.1007/978-1-4612-2988-9_65 N2 -At late times (200 days), when the photosphere of continuum emission has disappeared from the envelope, the radiation of the supernova 1987A is powered by $\gamma$-rays resulting from 56Co decays. The spectrum formation at such a late time is a highly non-linear process (XU [1]). The $\gamma$-ray photons first lose their energy due to Compton scattering and photoelectric absorption, generating non-thermal energetic electrons. These energetic electrons are then slowed down by Coulomb scattering or ionizing and exciting different ions in the envelope. The ions will recombine and de-excite, radiating away their energy in infrared (IR), optical and primarily ultraviolet (UV) wavebands.
PB - Springer New York PP - New York, NY PY - 1991 SN - 978-1-4612-2988-9 SP - 444 EP - 453 TI - Late Time Spectrum of SN 1987A ER -