NEAR-INFRARED SPECTROSCOPY OF THE TYPE IIn SN 2010jl: EVIDENCE FOR HIGH VELOCITY EJECTA

Abstract

The Type IIn supernova SN 2010jl was relatively nearby and luminous, allowing detailed studies of the near-infrared (NIR) emission. We present 1 − 2.4 µm spectroscopy over the age range of 36 -565 days from the earliest detection of the supernova. On day 36, the H lines show an unresolved narrow emission component along with a symmetric broad component that can be modeled as the result of electron scattering by a thermal distribution of electrons. Over the next hundreds of days, the broad components of the H lines shift to the blue by 700 km s −1 , as is also observed in optical lines. The narrow lines do not show a shift, indicating they originate in a different region. He I λ10830 and λ20587 lines both show an asymmetric broad emission component, with a shoulder on the blue side that varies in prominence and velocity from −5500 km s −1 on day 108 to −4000 km s −1 on day 219. This component may be associated with the higher velocity flow indicated by X-ray observations of the supernova. The absence of the feature in the H lines suggests that this is from a He rich ejecta flow. The He I λ10830 feature has a narrow P Cygni line, with absorption extending to ∼ 100 km s −1 and strengthening over the first 200 days, and an emission component which weakens with time. At day 403, the continuum emission becomes dominated by a blackbody spectrum with a temperature of ∼ 1900 K, suggestive of dust emission.

A Long-duration Luminous Type IIn Supernova KISS15s: Strong Recombination Lines from the Inhomogeneous Ejecta–CSM Interaction Region and Hot Dust Emission from Newly Formed Dust*

“…The velocity width of the broad component gradually decreases as a function of time from FWHM ∼ 14, 000 km s −1 to ∼ 10, 000 km s −1 , and the velocity shift only shows weak variability. It is interesting to note that the velocity widths of the intermediate and blue-shift excess components are consistent with each other, suggesting that the two components The coexistence of these two emission line components implies that the emission region has a spherically asymmetric geometry, which may be related to the inhomogeneous structure of the CSM produced by the intrinsic non-spherically-symmetric progenitor's stellar wind (see Section 4.3 for further discussion; Borish et al 2015;Smith 2017, and references therein). Figure 22 presents the light curves of the decomposed Hα emission line luminosities.…”

“…Instead, the observed line profile of KISS15s is most likely due to the presence of an additional blue-shifted symmetric intermediate Gaussian emis-sion component with respect to the symmetric narrow, intermediate, and broad Gaussians, which may be related to the inhomogeneity of the CSM distributions (Smith et al 2015;Andrews et al 2016). There is no evidence of Lorenzianlike broad wing components in the observed line profiles of KISS15s, suggesting that the electron scattering in opticallythick ejecta-CSM regions is not relevant in KISS15s (see e.g., Smith et al 2010;Fransson et al 2014;Borish et al 2015;Huang & Chevalier 2018). Considering the better fitting for the observed spectra compared to the three Gaussians model, below we focus on the fitting results from the "additional Gaussian model" or the four Gaussians model (Table 10 and Figure 20).…”

Type IIn SN 2010jl: probing dusty line-emitting shell

“…We now consider an interesting case of the He I 1.083 µm line. At the early stage (t < 400 d) He I 1.083 µm and He I 2.06 µm lines show a pronounced broad component unlike smooth hydrogen line profiles (Borish et al 2015). A reasonable suggestion is that this component is caused by the emission of the SN ejecta (Borish et al 2015).…”

“…At the early stage (t < 400 d) He I 1.083 µm and He I 2.06 µm lines show a pronounced broad component unlike smooth hydrogen line profiles (Borish et al 2015). A reasonable suggestion is that this component is caused by the emission of the SN ejecta (Borish et al 2015). Figure 3 demonstrates satisfactory fits He I 1.083 µm and Paβ on day 178 in the models with the same parameters except for the ejecta emission fraction, f sn = 0.68 for He I 1.083 µm compared to 0.3 for for Paβ, and the index, q = 1.5 for He I 1.083 µm compared to q = 0.9 for Paβ.…”

“…We will use this term, keeping in mind that it has nothing to do with the Lorentz distribution of frequencies of the damping oscillator radiation. Fortunately, in He I 1.083 µm line the component ratio of BC/IC is large, so both components are easily distinguished (Borish et al 2015), which keeps safe canonical three-component structure of emission lines for SN 2010jl.…”