The broad-lined Type-Ic supernova SN 2022xxf and its extraordinary two-humped light curves

Abstract

We report on our study of the supernova (SN) 2022xxf based on observations obtained during the first four months of its evolution. The light curves (LCs) display two humps of similar maximum brightness separated by 75 days, unprecedented for a broad-lined (BL) Type Ic supernova (SN IcBL). SN 2022xxf is the most nearby SN IcBL to date (in NGC 3705, z = 0.0037, at a distance of about 20 Mpc). Optical and near-infrared photometry and spectroscopy were used to identify the energy source powering the LC. Nearly 50 epochs of high signal-to-noise ratio spectroscopy were obtained within 130 days, comprising an unparalleled dataset for a SN IcBL, and one of the best-sampled SN datasets to date. The global spectral appearance and evolution of SN 2022xxf points to typical SN Ic/IcBL, with broad features (up to ~14 000 km s−1) and a gradual transition from the photospheric to the nebular phase. However, narrow emission lines (corresponding to ~ 1000–2500 km s−1) are present in the spectra from the time of the second rise, suggesting slower-moving circumstellar material (CSM). These lines are subtle, in comparison to the typical strong narrow lines of CSM-interacting SNe, for example, Type IIn, Ibn, and Icn, but some are readily noticeable at late times, such as in Mg I λ5170 and [O I] λ5577. Unusually, the near-infrared spectra show narrow line peaks in a number of features formed by ions of O and Mg. We infer the presence of CSM that is free of H and He. We propose that the radiative energy from the ejecta-CSM interaction is a plausible explanation for the second LC hump. This interaction scenario is supported by the color evolution, which progresses to blue as the light curve evolves along the second hump, and by the slow second rise and subsequent rapid LC drop. SN 2022xxf may be related to an emerging number of CSM-interacting SNe Ic, which show slow, peculiar LCs, blue colors, and subtle CSM interaction lines. The progenitor stars of these SNe likely experienced an episode of mass loss consisting of H/He-free material shortly prior to explosion.

Simulating Hydrogen-poor Interaction-powered Supernovae with CHIPS

“…We find that a second peak is typically seen for M Ni  0.4 M e , which is within the range of values inferred from broad-lined Type Ic SNe (e.g., Drout et al 2011;Prentice et al 2016;Taddia et al 2018Taddia et al , 2019. As explained in the next section, such double-peaked SNe Ibc are starting to be discovered by high-cadence surveys (Das et al 2023;Kuncarayakti et al 2023).…”

“…found that, depending on the progenitor and the CSM mass, these feedback processes can affect the fallback for t inj for several years or longer. Strong feedback creates a CSM detached from the star, consistent with what is seen in some Type Ic SNe with late-time CSM interaction, such as SN2021ocs and SN2022xxf (Kuncarayakti et al 2022(Kuncarayakti et al , 2023. In summary, we advise that the user should be cautious of the validity of this profile when modeling LCs with t inj ?…”

“…This is in line with previous studies on SNe Ibn and Icn (Moriya & Maeda 2016;Maeda & Moriya 2022;Pellegrino et al 2022;Perley et al 2022), which found M Ni to be much smaller than stripped-envelope SNe without interaction signatures. However, there is a growing population of Type Ibc SNe whose optical LCs appear as double peaked, which may be powered by both 56 Ni and CSM interaction (e.g., Nakar & Piro 2014;Das et al 2023;Kuncarayakti et al 2023). Our code is suited for numerical modeling of such transients, and we plan to explore such possibilities in detail in future work.…”

Collapsars as Sites of r-process Nucleosynthesis: Systematic Photometric Near-infrared Follow-up of Type Ic-BL Supernovae

“…Late-time interaction with the circumstellar medium (CSM) is also known to affect the color evolution of SNe (Ben-Ami et al 2014;Kuncarayakti et al 2022). While this is a rare phenomenon in SNe Ic-BL, SN 2022xxf showed evidence for a clear double-peaked light curve and narrow emission-line profiles in the later-phase spectra characteristic of interaction with a H/He-poor CSM (Kuncarayakti et al 2023). SN 2022xxf also exhibited a dramatic red-to-blue color evolution as a result of the interaction.…”

Dramatic Rebrightening of the Type-changing Stripped-envelope Supernova SN 2023aew

“…However, modern explosion models are unable to produce the amount of radioactive nickel required for the brighter Type Ibc SNe (Sollerman et al 2022), and some SESNe show light-curve features that are not compatible with the standard scenario. Such unusual SESNe have emerged from the large samples of SNe now available and include double-bump light curves (LCs), for example for SN 2019cad (Gutiérrez et al 2021), SN 2022xxf (Kuncarayakti et al 2023), and SN 2022jli (Chen et al 2024, where different powering mechanisms were suggested in each of these cases for explaining the second LC bump.…”