The Patience to Prevent that Murmur

Hillier, Russell M.

doi:10.5840/renascence200759418

Cited by 25 publications

(35 citation statements)

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“…The intermediate component is significantly redshifted (by ≈140 km s −1 ) relative to the narrow component. The apparent redshift may be an artifact of electron scattering through high optical depths and is often seen in other dusty ILOTs, giants, Wolf-Rayet stars, and other stars experiencing significant mass loss (Hillier 1991;Humphreys et al 2011). The broadest component is only identified in Hα, which may be due to lower signal-to-noise in the other lines or additional scattering.…”

Section: Hydrogen Balmer Linesmentioning

confidence: 90%

The Intermediate Luminosity Optical Transient Sn 2010da: The Progenitor, Eruption, and Aftermath of a Peculiar Supergiant High-Mass X-Ray Binary

Villar

Berger

Chornock

et al. 2016

ApJ

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We present optical spectroscopy, ultraviolet-to-infrared imaging,and X-ray observations of the intermediate luminosity optical transient (ILOT) SN 2010da in NGC 300 (d = 1.86 Mpc) spanning from −6 to +6 years relative to the time of outburst in 2010. Based on the light-curve and multi-epoch spectral energy distributions of SN 2010da, we conclude that the progenitor of SN 2010da is a ≈10-12 M e yellow supergiant possibly transitioning into a blue-loop phase. During outburst, SN 2010da had a peak absolute magnitude of M bol −10.4 mag, dimmer than other ILOTs and supernova impostors. We detect multi-component hydrogen Balmer, Paschen, and Ca II emission lines in our high-resolution spectra, which indicate a dusty and complex circumstellar environment. Since the 2010 eruption, the star has brightened by a factor of ≈5 and remains highly variable in the optical. Furthermore, we detect SN 2010da in archival Swift and Chandra observations as an ultraluminous X-ray source (L X ≈ 6 × 10 39 erg s −1). We additionally attribute He II 4686 Å and coronal Fe emission lines in addition to a steady X-ray luminosity of ≈10 37 erg s −1 to the presence of a compact companion.

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Section: Hydrogen Balmer Linesmentioning

confidence: 90%

The Intermediate Luminosity Optical Transient Sn 2010da: The Progenitor, Eruption, and Aftermath of a Peculiar Supergiant High-Mass X-Ray Binary

Villar

Berger

Chornock

et al. 2016

ApJ

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“…The Monte Carlo code has been previously described by Hillier (1991, 1994), although some important changes have been made since then. The code can run in 1D, 2D or 3D.…”

Section: Polarization Modelling and Numerical Codesmentioning

confidence: 99%

“…Our detailed simulations constitute a reliable physical basis for the computation of polarization signatures, which we perform with two different polarized radiative‐transfer codes: a Monte Carlo approach (Hillier 1991) and a long characteristic method (Hillier 1994, 1996). At present, both solvers assume an axial symmetry, adopt but do not require a top/bottom symmetry and work for arbitrary viewing angles.…”

Section: Introductionmentioning

confidence: 99%

Synthetic line and continuum linear-polarization signatures of axisymmetric Type II supernova ejecta

Dessart

Hillier

2011

Monthly Notices of the Royal Astronomical Society

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International audienceWe present synthetic single-line and continuum linear-polarization signatures due to electron scattering in axially symmetric Type II supernovae (SNe) which we calculate using a Monte Carlo and a long characteristic radiative-transfer code. Aspherical ejecta are produced by prescribing a latitudinal scaling or stretching of SN ejecta inputs obtained from recent 1D non-local thermodynamic equilibrium (non-LTE) time-dependent calculations. We study polarization signatures as a function of inclination, shape factor, wavelength, line identity and post-explosion time. At early times, cancellation and optical-depth effects make the polarization intrinsically low, even causing complicated sign reversals with inclination or continuum wavelength, and across line profiles. While the line polarization is positive (negative) for an oblate (prolate) morphology at the peak and in the red wing, the continuum polarization may be of any sign. These complex polarization variations are produced not just by the asymmetric distribution of scatterers but also of the flux. Our early-time signatures are in contradiction with predictions for a centrally illuminated aspherical nebula, although this becomes a better approximation at nebular times. For a fixed asymmetry, our synthetic continuum polarization is generally low, may evolve non-monotonically during the plateau phase, but it systematically rises as the ejecta become optically thin and turn nebular. Thus changes in polarization over time do not necessarily imply a change in the asymmetry of the ejecta. The SN structure (e.g. density and ionization) critically influences the level of polarization. Importantly, a low polarization (\textless 0.5 per cent) at early times does not necessarily imply a low degree of asymmetry as usually assumed. Asphericity influences line-profile morphology and the luminosity, and thus may compromise the accuracy of SN characteristics inferred from these

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“…Alternatively, individual spectral lines, formed at ∼ 10R * , can be used to estimate volume filling factors f in WR winds (Hillier 1991). This technique permits an estimate of wind clumping factors from a comparison between line electron scattering wings (which scale linearly with density) and recombination lines (density-squared).…”

Section: Clumpingmentioning

confidence: 99%

Physical Properties of Wolf-Rayet Stars

Crowther

2007

Annu. Rev. Astron. Astrophys.

916

953

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The striking broad emission line spectroscopic appearance of Wolf-Rayet (WR) stars has long defied analysis, due to the extreme physical conditions within their line and continuum forming regions. Recently, model atmosphere studies have advanced sufficiently to enable the determination of stellar temperatures, luminosities, abundances, ionizing fluxes and wind properties. The observed distributions of nitrogen (WN) and carbon (WC) sequence WR stars in the Milky Way and in nearby star forming galaxies are discussed; these imply lower limits to progenitor masses of ∼25, 40, 75 M⊙ for hydrogen-depleted (He-burning) WN, WC, and H-rich (H-burning) WN stars, respectively. WR stars in massive star binaries permit studies of wind-wind interactions and dust formation in WC systems. They also show that WR stars have typical masses of 10-25M⊙, extending up to 80M⊙ for H-rich WN stars. Theoretical and observational evidence that WR winds depend on metallicity is presented, with implications for evolutionary models, ionizing fluxes, and the role of WR stars within the context of core-collapse supernovae and long-duration gamma ray bursts.

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The Patience to Prevent that Murmur

Cited by 25 publications

References 0 publications

The Intermediate Luminosity Optical Transient Sn 2010da: The Progenitor, Eruption, and Aftermath of a Peculiar Supergiant High-Mass X-Ray Binary

The Intermediate Luminosity Optical Transient Sn 2010da: The Progenitor, Eruption, and Aftermath of a Peculiar Supergiant High-Mass X-Ray Binary

Synthetic line and continuum linear-polarization signatures of axisymmetric Type II supernova ejecta

Physical Properties of Wolf-Rayet Stars

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