Short-Lived Radioisotope Tc 98 Synthesized by the Supernova Neutrino Process
Not Available
Hayakawa, Takehito↗
Engineering topics
Tolstov, Alexey
Publications and source records attributed to Tolstov, Alexey.
Ultraviolet Light Curves of Gaia16apd in Superluminous Supernova Models
Observations of Gaia16apd revealed extremely luminous ultraviolet emission among superluminous supernovae (SLSNe). Using radiation hydrodynamics simulations, we perform a comparison of UV light curves, color temperatures, and photospheric velocities between the most popular SLSN models: pair-instability supernova, magnetar, and interaction with circumstellar medium. We find that the interaction model is the most promising to explain the extreme UV luminosity of Gaia16apd. The differences in late-time UV emission and in color evolution found between the models can be used to link an observed SLSN event to the most appropriate model. Observations at UV wavelengths can be used to clarify the nature of SLSNe and more attention should be paid to them in future follow-up observations.
79 ASTRONOMY AND ASTROPHYSICS↗
Pulsational Pair-instability Model for Superluminous Supernova PTF12dam:Interaction and Radioactive Decay
Being a superluminous supernova, PTF12dam can be explained by a {sup 56}Ni-powered model, a magnetar-powered model, or an interaction model. We propose that PTF12dam is a pulsational pair-instability supernova, where the outer envelope of a progenitor is ejected during the pulsations. Thus, it is powered by a double energy source: radioactive decay of {sup 56}Ni and a radiative shock in a dense circumstellar medium. To describe multicolor light curves and spectra, we use radiation-hydrodynamics calculations of the STELLA code. We found that light curves are well described in the model with 40 M {sub ⊙} ejecta and 20–40 M {sub ⊙} circumstellar medium. The ejected {sup 56}Ni mass is about 6 M {sub ⊙}, which results from explosive nucleosynthesis with large explosion energy (2–3)×10{sup 52} erg. In comparison with alternative scenarios of pair-instability supernova and magnetar-powered supernova, in the interaction model, all the observed main photometric characteristics are well reproduced: multicolor light curves, color temperatures, and photospheric velocities.
79 ASTRONOMY AND ASTROPHYSICS↗
Fast evolving pair-instability supernovae
With an increasing number of superluminous supernovae (SLSNe) discovered the ques- tion of their origin remains open and causes heated debates in the supernova commu- nity. Currently, there are three proposed mechanisms for SLSNe: (1) pair-instability supernovae (PISN), (2) magnetar-driven supernovae, and (3) models in which the su- pernova ejecta interacts with a circumstellar material ejected before the explosion. Based on current observations of SLSNe, the PISN origin has been disfavoured for a number of reasons. Many PISN models provide overly broad light curves and too reddened spectra, because of massive ejecta and a high amount of nickel. In the cur- rent study we re-examine PISN properties using progenitor models computed with the GENEC code. We calculate supernova explosions with FLASH and light curve evolu- tion with the radiation hydrodynamics code STELLA. We find that high-mass models (200 M⊙ and 250 M⊙) at relatively high metallicity (Z=0.001) do not retain hydro- gen in the outer layers and produce relatively fast evolving PISNe Type I and might be suitable to explain some SLSNe. We also investigate uncertainties in light curve modelling due to codes, opacities, the nickel-bubble effect and progenitor structure and composition.
79 ASTRONOMY AND ASTROPHYSICS↗
TYPE I SUPERLUMINOUS SUPERNOVAE AS EXPLOSIONS INSIDE NON-HYDROGEN CIRCUMSTELLAR ENVELOPES
A number of Type I (hydrogenless) superluminous supernova (SLSN) events have been discovered recently. However, their nature remains debatable. One of the most promising ideas is the shock interaction mechanism, but only simplified semi-analytical models have been applied so far. We simulate light curves for several Type I SLSN (SLSN-I) models enshrouded by dense, non-hydrogen circumstellar (CS) envelopes, using a multi-group radiation hydrodynamics code that predicts not only bolometric, but also multicolor light curves. We demonstrate that the bulk of SLSNe-I including those with relatively narrow light curves like SN 2010gx or broad ones like PTF09cnd can be explained by the interaction of the SN ejecta with the CS envelope, though the range of parameters for these models is rather wide. Moderate explosion energy (∼(2–4) × 10{sup 51} erg) is sufficient to explain both narrow and broad SLSN-I light curves, but ejected mass and envelope mass differ for those two cases. Only 5–10 M {sub ⊙} of non-hydrogen material is needed to reproduce the light curve of SN 2010gx, while the best model for PTF09cnd is very massive: it contains almost 50 M {sub ⊙} in the CS envelope and only 5 M {sub ⊙} in the ejecta. The CS envelope for each case extends from 10 R {sub ⊙} to ∼10{sup 5} R {sub ⊙} (7 × 10{sup 15} cm), which is about an order of magnitude larger than typical photospheric radii of standard SNe near the maximum light. We briefly discuss possible ways to form such unusual envelopes.
79 ASTRONOMY AND ASTROPHYSICS↗