TY - JOUR
T1 - The intermediate nebular phase of SN 2014J
T2 - Onset of clumping as the source of recombination
AU - Mazzali, P. A.
AU - Bikmaev, I.
AU - Sunyaev, R.
AU - Ashall, C.
AU - Prentice, S.
AU - Tanaka, M.
AU - Irtuganov, E.
AU - Melnikov, S.
AU - Zhuchkov, R.
N1 - Funding Information:
The authors thank TUBITAK, KFU, IKI, and AST for partial support in using RTT150 (Russian-Turkish 1.5-m telescope in Antalya). This work was partially funded by the Russian Government Program of Competitive Growth of Kazan Federal University. PAM would like to dedicate this paper to the memory of his mother, Maria Luigia Zanardi.
Publisher Copyright:
© 2020 Oxford University Press. All rights reserved.
PY - 2020
Y1 - 2020
N2 - At the age of about 1 yr, the spectra of most Type Ia supernovae (SNe Ia) are dominated by strong forbidden nebular emission lines of Fe II and Fe III. Later observations (at about 2 yr) of the nearby SN 2011fe showed an unexpected shift of ionization to Fe I and Fe II. Spectra of the very nearby SN Ia 2014J at an intermediate phase (1-1.5 yr) that are presented here show a progressive decline of Fe III emission, while Fe I is not yet strong. The decrease in ionization can be explained if the degree of clumping in the ejecta increases significantly at ∼1.5 yr, at least in the Fe-dominated zone. Models suggest that clumps remain coherent after about one year, behaving like shrapnel. The high density in the clumps, combined with the decreasing heating rate, would then cause recombination. These data may witness the phase of transition from relatively smooth ejecta to the very clumpy morphology that is typical of SN remnants. The origin of the increased clumping may be the development of local magnetic fields.
AB - At the age of about 1 yr, the spectra of most Type Ia supernovae (SNe Ia) are dominated by strong forbidden nebular emission lines of Fe II and Fe III. Later observations (at about 2 yr) of the nearby SN 2011fe showed an unexpected shift of ionization to Fe I and Fe II. Spectra of the very nearby SN Ia 2014J at an intermediate phase (1-1.5 yr) that are presented here show a progressive decline of Fe III emission, while Fe I is not yet strong. The decrease in ionization can be explained if the degree of clumping in the ejecta increases significantly at ∼1.5 yr, at least in the Fe-dominated zone. Models suggest that clumps remain coherent after about one year, behaving like shrapnel. The high density in the clumps, combined with the decreasing heating rate, would then cause recombination. These data may witness the phase of transition from relatively smooth ejecta to the very clumpy morphology that is typical of SN remnants. The origin of the increased clumping may be the development of local magnetic fields.
KW - Radiative transfer
KW - Supernovae: General
KW - Supernovae: Individual (SN 2014J)
KW - Techniques: Spectroscopic
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U2 - 10.1093/MNRAS/STAA839
DO - 10.1093/MNRAS/STAA839
M3 - Article
AN - SCOPUS:85098271516
SN - 0035-8711
VL - 494
SP - 2809
EP - 2822
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -