Wrist Arthrography

Fransson, S.-G.

doi:10.1177/028418519303400201

Cited by 21 publications

(24 citation statements)

References 39 publications

(76 reference statements)

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“…Obvious possibilities include free-free emission and Comptonization of photospheric photons by hot (T ≈ 10 9 K) electrons in the shocked gas, sources which have been invoked to explain flux excesses seen in the far ultraviolet (λ < 1500Å) in previous SNe interacting with dense circumstellar environments (e.g., 1979C; Fransson 1982), and even SN 1998S itself later in its evolution (Lentz et al 1998). The amount these processes are predicted to contribute to the total flux spectrum at the optical wavelengths considered here, however, is probably 1% (c.f., Fransson 1982), although a detailed model with conditions specific to SN 1998S has not been done. A more likely contributor may be the wavelength dependence of the continuum absorptive opacity, which increases with wavelength for both bound-free (i.e., the Paschen continuum) and free-free processes through most of the spectral range observed (see, e.g., Eastman et al 1994).…”

Section: Early-time Continuummentioning

confidence: 99%

Evidence for Asphericity in the Type IIn Supernova SN 1998S

Leonard

Filippenko

Barth

et al. 2000

ApJ

270

405

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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 SN is found to exhibit a high degree of linear polarization, implying significant asphericity for its continuum-scattering environment. Prior to removal of the interstellar polarization, the polarization spectrum is characterized by a flat continuum (at p ≈ 2%) with distinct changes in polarization associated with both the broad (symmetric, half width near zero intensity 10, 000 km s −1 ) and narrow (unresolved, full width at half maximum < 300 km s −1 ) line emission seen in the total flux spectrum. When analyzed in terms of a polarized continuum with unpolarized broad-line recombination emission, an intrinsic continuum polarization of p ≈ 3% results, suggesting a global asphericity of 45% from the oblate, electron-scattering dominated models of Höflich (1991). The smooth, blue continuum evident at early times is shown to be inconsistent with a reddened, single-temperature blackbody, instead having a color temperature that increases with decreasing wavelength. Broad emission-line profiles with distinct blue and red peaks are seen in the total flux spectra at later times, suggesting a disk-like or ring-like morphology for the dense (n e ≈ 10 7 cm −3 ) circumstellar medium, generically similar to what is seen directly in SN 1987A, although much denser and closer to the progenitor in SN 1998S. Implications of the circumstellar scattering environment for the spectropolarimetry are discussed, as are the effects of uncertainty in the removal of interstellar polarization; the importance of obtaining multiple spectropolarimetric epochs to help constrain the interstellar polarization value is particularly stressed. Using information derived from the spectropolarimetry and the total flux spectra, an evolutionary scenario for SN 1998S and its progenitor are presented.

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Section: Early-time Continuummentioning

confidence: 99%

Evidence for Asphericity in the Type IIn Supernova SN 1998S

Leonard

Filippenko

Barth

et al. 2000

ApJ

270

405

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“…The latter model computes the optical luminosity, produced as a result of reprocessing the X-ray radiation from the outer and inner shocks. This model is upgraded here to include the Compton cooling of the post-shock gas (Fransson 1982) and the reprocessing of the X-ray radiation by the wind material as well. The dynamics of the ejecta deceleration in a thin-shell approximation (Chevalier 1982) is solved numerically, which yields the thin-shell radius R s (t ) and its velocity v(t ).…”

Section: T H E I N T E R Ac T I O N a N D L I G H T-c U Rv E M O D E Lmentioning

confidence: 99%

Broad emission lines from the opaque electron-scattering environment of SN 1998S

Chugai¹

2001

Monthly Notices RAS

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A B S T R A C TI propose that broad narrow-topped emission lines with full width at zero intensity .20 000 km s 21 revealed by early-time spectra of SN 1998S originate from a dense circumstellar shell (CS) with an outer radius R < 10 15 cm. The tremendous line width is the result of multiple scattering of the photons of the narrow line by the thermal electrons of the opaque CS gas. The Ha line on 1998 March 6 is reproduced by Monte Carlo simulations, provided that the Thomson optical depth of the CS shell is 3 -4 at this epoch. The high density of the CS shell implies that a cool dense shell (CDS), which forms at the ejecta -wind interface, is opaque in the Paschen continuum for about 40-50 d after the explosion. This explains why strong lines from the supernova ejecta were not seen during an initial period of about 40 d after the discovery of this object. The Thomson optical depth recovered from the electron-scattering wings is consistent with observational constraints imposed by the bolometric luminosity, photospheric radius and expansion velocity of the CDS.

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“…CC-SNe are classified in two groups according to the absence (SNe Ib/c : Filippenko et al 1993;Dessart et al 2011;Bersten et al 2014;Kuncarayakti et al 2015) or presence (SNe II) of H I lines (Minkowski 1941;Filippenko 1997 and references therein). Additional of the SNe IIP and SNe IIL which are discussed later, SNe II are composed by SNe IIb which evolve spectroscopically from SNe IIP at early time to H I deficient few weeks to a month past maximum (Woosley et al 1987) and SNe IIn which have narrow H I emission lines (Chevalier 1981;Fransson 1982;Schlegel 1990;Chugai & Danziger 1994;Van Dyk et al 2000;Kankare et al 2012;de Jaeger et al 2015).…”

Section: Introductionmentioning

confidence: 99%

AHUBBLEDIAGRAM FROM TYPE II SUPERNOVAE BASED SOLELY ON PHOTOMETRY: THE PHOTOMETRIC COLOR METHOD

Jaeger

González–Gaitán

Anderson

et al. 2015

ApJ

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We present a Hubble diagram of type II supernovae using corrected magnitudes derived only from photometry, with no input of spectral information. We use a data set from the Carnegie Supernovae Project I (CSP) for which optical and near-infrared light-curves were obtained. The apparent magnitude is corrected by two observables, one corresponding to the slope of the plateau in the V band and the second a colour term. We obtain a dispersion of 0.44 mag using a combination of the (V − i) colour and the r band and we are able to reduce the dispersion to 0.39 mag using our golden sample. A comparison of our photometric colour method (PCM) with the standardised candle method (SCM) is also performed. The dispersion obtained for the SCM (which uses both photometric and spectroscopic information) is 0.29 mag which compares with 0.43 mag from the PCM, for the same SN sample. The construction of a photometric Hubble diagram is of high importance in the coming era of large photometric wide-field surveys, which will increase the detection rate of supernovae by orders of magnitude. Such numbers will prohibit spectroscopic follow-up in the vast majority of cases, and hence methods must be deployed which can proceed using solely photometric data.

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Wrist Arthrography

Cited by 21 publications

References 39 publications

Evidence for Asphericity in the Type IIn Supernova SN 1998S

Evidence for Asphericity in the Type IIn Supernova SN 1998S

Broad emission lines from the opaque electron-scattering environment of SN 1998S

AHUBBLEDIAGRAM FROM TYPE II SUPERNOVAE BASED SOLELY ON PHOTOMETRY: THE PHOTOMETRIC COLOR METHOD

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