Related papers: Mass-loss histories of Type IIn supernova progenit…
Type IIP supernova progenitors are often surrounded by dense circumstellar media that may result from mass-loss enhancement of the progenitors shortly before their explosions. Previous light-curve studies suggest that the mass-loss rates…
Type IIn supernovae occur when stellar explosions are surrounded by dense hydrogen-rich circumstellar matter. The dense circumstellar matter is likely formed by extreme mass loss from their progenitors shortly before they explode. The…
Several Type IIb supernovae (SNe IIb) have been extensively studied, both in terms of the progenitor radius and the mass-loss rate in the final centuries before the explosion. While the sample is still limited, evidence has been…
We present VLA observations of 16 Type IIn and Type II-L supernovae (SNe IIn and SNe II-L) at ~1000--7000 days after explosion, probing circumstellar matter (CSM) at distances >10^16 cm from the progenitor corresponding to mass-loss over…
The interaction of post-explosion supernova ejecta with the surrounding circumstellar medium creates emission across the electromagnetic spectrum. Since the circumstellar medium is created by the mass lost from the progenitor star, it…
We present new pre-maximum and late-time optical photometry of the Type Ia/IIn supernova 2002ic. These observations are combined with the published V-band magnitudes of Hamuy et al. (2003) and the VLT spectrophotometry of Wang et al. (2004)…
We present a bolometric light curve model of Type IIn supernovae powered by supernova ejecta colliding with a circumstellar medium. We estimate the conversion efficiency of the ejecta's kinetic energy to radiation at the reverse and forward…
Supernovae characterized by enduring narrow optical hydrogen emission lines (SNe IIn) are believed to result primarily from the core-collapse of massive stars undergoing sustained interaction with a dense circumstellar medium (CSM). While…
I discuss observational clues concerning episodic mass-loss properties of massive stars in the time before the final supernova explosion. In particular, I will focus on the mounting evidence that LBVs and related stars are candidates for…
Spectroscopic detection of narrow emission lines traces the presence of circumstellar mass distributions around massive stars exploding as core-collapse supernovae. Transient emission lines disappearing shortly after the supernova explosion…
Searching for the presence of circumstellar material is currently the only direct way to discriminate between the different types of possible progenitor systems for Type Ia supernovae. We have therefore looked for narrow H-alpha in a…
We investigate circumstellar and explosion properties of Type Ibn supernovae (SNe) by analyzing their bolometric light curves. Bolometric light curves of Type Ibn SNe generally have a large contrast between peak luminosity and late-phase…
I summarize what we have learned about the nature of stars that ultimately explode as core-collapse supernovae from the examination of images taken prior to the explosion. By registering pre-supernova and post-supernova images, usually…
Recent observations of a large fraction of Type II supernovae show traces of dense circumstellar medium (CSM) very close to the progenitor star. If this CSM is created by eruptive mass loss several months before core-collapse, the eruption…
Hydrogen-rich, core-collapse supernovae are typically divided into four classes: IIP, IIL, IIn, and IIb. In general, interaction with circumstellar material is only considered for Type IIn supernovae. However, recent hydrodynamic modeling…
This work utilizes established models of synchrotron-powered light curves for core-collapse supernovae in dense circumstellar environments, namely type IIn and Ibn, to demonstrate the potential for detecting millimeter emission from these…
Mass loss of massive helium stars is not well understood even though it plays an essential role in determining their remnant neutron-star or black-hole masses as well as ejecta mass of Type Ibc supernovae. Radio emission from Type Ibc…
We compute an extensive set of early-time spectra of supernovae interacting with circumstellar material using the radiative transfer code CMFGEN. Our models are applicable to events observed from 1 to a few days after explosion. Using these…
The Type IIn supernovae (SNe IIn) have been found to be associated with significant amounts of dust. These core-collapse events are generally expected to be the final stage in the evolution of highly-massive stars, either while in an…
Some supernovae (SNe) show evidence for mass-loss events taking place prior to their explosions. Measuring their pre-outburst mass-loss rates provide essential information regarding the mechanisms that are responsible for these events. Here…