Related papers: Moderate Asphericity of the SN 2002ic Circumstella…

Aims. Core-collapse supernovae may show significant polarization that implies non-spherically symmetric explosions. We observed the type II-plateau SN 2005af using optical polarimetry in order to verify whether any asphericity is present in…

Some supernova (SN) explosions show evidence for interaction with pre-existing non-spherically symmetric circumstellar medium (CSM) in their light curves, spectral line profiles, and polarization signatures. To better understand the…

We present the first multi-epoch spectropolarimetry of a type II plateau supernova (SN II-P), with optical observations of SN 1999em on days 7, 40, 49, 159, and 163 after discovery. These data are used to probe the geometry of the…

We present polarization spectra near maximum light for the strongly subluminous Type Ia supernova 1999by that show that the supernova is intrinsically polarized. SN 1999by has an observed, overall level of polarization of ~0.3 to 0.8%, a…

Supernovae of type IIn possess spectral signatures that indicate an intense interaction between the supernova ejecta and surrounding dense circumstellar material cast off by the star in pre-explosion mass-loss episodes. Studying this…

Optical spectroscopy of the Type Ia supernova SN 2002ic obtained on 2003 June 27.6 UT, i.e., about 222 rest-frame days after explosion, is presented. Strong H emission indicates an interaction between the expanding SN ejecta and an H-rich…

SN 2002ic is a unique supernova which shows the typical spectral features of Type Ia supernovae (SNe Ia) near maximum light, but also apparent hydrogen features that have been absent in SNe Ia. We have calculated hydrodynamical models for…

Synthetic polarization and flux spectra are presented for aspherical, electron scattering-dominated photospheres of Type II supernovae (SN II) in general and the specific case of SN 1993J using a Monte Carlo scheme. The observed luminosity…

We present spectropolarimetry of the Type Ic supernova SN 2002ap and give a preliminary analysis: the data were taken at two epochs, close to and one month later than the visual maximum (2002 February 8). In addition we present June 9…

We present spectropolarimetric observations of the Type IIb SN 2001ig in NGC 7424; conducted with the ESO VLT FORS1 on 2001 Dec 16, 2002 Jan 3 and 2002 Aug 16 or 13, 31 and 256 days post-explosion. These observations are at three different…

Optical polarimetry is an effective way of probing the environment of supernova for dust. We acquired linear HST ACS/WFC polarimetry in bands $F475W$, $F606W$, and $F775W$ of the supernova (SN) 2014J in M82 at six epochs from $\sim$277 days…

We present multi-epoch spectropolarimetry and spectra for a sample of 14 Type IIn supernovae (SNe IIn). We find that after correcting for likely interstellar polarization, SNe IIn commonly show intrinsic continuum polarization of 1--3% at…

Close binary systems often show linear polarization varying over the binary period, usually attributed to light scattered from electrons in circumstellar clouds. One of the brightest close binary systems is Spica (Alpha Virginis) consisting…

Geometry of circumstellar (CS) medium around supernovae (SNe) provides important diagnostics to understand the nature of their progenitors. In this paper, properties of CS dust around SN 2012dn, a super-Chandrasekhar candidate Type Ia…

We briefly review the existing database of supernova spectropolarimetry, concentrating on recent data and on results from our group's research. Spectropolarimetry provides the only direct known probe of early-time supernova geometry. To…

We present optical spectropolarimetry obtained at the Keck-II 10-m telescope on 1998 March 7 UT along with total flux spectra spanning the first 494 days after discovery (1998 March 2 UT) of the peculiar type IIn supernova (SN) 1998S. The…

The measurement of non-zero polarization can be used to infer the presence of departures from spherical symmetry in supernovae (SNe). The origin of the majority of the intrinsic polarization observed in SNe is in electron scattering, which…

Among the important issues in identifying the progenitor system of Type Ia supernovae (SNe Ia), we focus mostly on circumstellar interaction in SN 2002ic, and give brief discussion on the controversial issues of the effects of rotation in…

Type II supernovae (SNe) interacting with disklike circumstellar matter (CSM) have been suggested as an explanation of some unusual Type II SNe, e.g., the so-called "impossible" SN, iPTF14hls. There are some radiation hydrodynamics…

There is increasing evidence that massive stars may exhibit an enhanced mass loss shortly before their termination explosion. Some of them also indicate the enhancement of their circumstellar matter (CSM) is not spherically symmetric.…