Ion Signatures in Supernova Spectra

Hatano, K.; Branch, David; Fisher, Adam; Millard, Jennifer; Baron, E.

doi:10.1086/313190

Cited by 90 publications

(145 citation statements)

References 21 publications

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“…A very high density is required to achieve sufficient optical depth for absorption in the line. The oxygen abundance of high-velocity SN Ia material should be much higher than that found in the CSM (Hatano et al 1999); therefore, we conclude that the feature is most likely to originate within the SN ejecta.…”

Section: Csm Density Mass Size and Geometrymentioning

confidence: 58%

Nearby Supernova Factory Observations of SN 2005gj: Another Type Ia Supernova in a Massive Circumstellar Envelope

Aldering

Antilogus

Bailey

et al. 2006

ApJ

258

272

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We report Nearby Supernova Factory observations of SN 2005g j, the second confirmed case of a ''hybrid'' Type Ia/IIn supernova, which we interpret as the explosion of a white dwarf interacting with a circumstellar medium. Our early-phase photometry of SN 2005gj shows that the interaction is much stronger than for the prototype, SN 2002ic. Our first spectrum shows a hot continuum with broad and narrow H emission. Later spectra, spanning over 4 months from outburst, show clear Type Ia features combined with broad and narrow H , H , H , and He i kk5876, 7065 in emission. At higher resolution, P Cygni profiles are apparent. Surprisingly, we also observe an inverted P Cygni profile for [O iii] k5007. We find that the light curve and measured velocity of the unshocked circumstellar material imply mass loss as recently as 8 years ago. The early light curve is well described by a flat radial density profile for the circumstellar material. However, our decomposition of the spectra into Type Ia and shock emission components allows for little obscuration of the supernova, suggesting an aspherical or clumpy distribution for the circumstellar material. We suggest that the emission-line velocity profiles arise from electron scattering rather than the kinematics of the shock. This is supported by the inferred high densities and the lack of evidence for evolution in the line widths. Ground-and spacebased photometry and Keck spectroscopy of the host galaxy are used to ascertain that the host galaxy has low metallicity (Z /Z < 0:3; 95% confidence) and that this galaxy is undergoing a significant star formation event that began roughly 200 AE 70 Myr ago. We discuss the implications of these observations for progenitor models and cosmology using Type Ia supernovae.

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Section: Csm Density Mass Size and Geometrymentioning

confidence: 58%

Nearby Supernova Factory Observations of SN 2005gj: Another Type Ia Supernova in a Massive Circumstellar Envelope

Aldering

Antilogus

Bailey

et al. 2006

ApJ

258

272

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“…It is interesting to consider some of the implications of the fitting parameters, especially the line optical depths, in the context of the local thermodynamic equilibrium (LTE) calculations of Hatano et al (1999a). For example, Figure 5 of Hatano et al shows that in LTEs near 7500 K, the Si ii optical depth can exceed unity in a composition in which hydrogen and helium have burned to carbon and oxygen, while the mass fraction of other elements, including silicon, is only solar.…”

Section: Discussionmentioning

confidence: 99%

Comparative Direct Analysis of Type Ia Supernova Spectra. III. Premaximum

Branch¹,

Troxel²,

Jeffery³

et al. 2007

PUBL ASTRON SOC PAC

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ABSTRACT.A comparative study of spectra of 21 Type Ia supernovae (SNe Ia) obtained about 1 week before maximum light, and 8 spectra obtained 11 or more days before maximum, is presented. To a large extent, the premaximum spectra exhibit the defining characteristics of the four groups defined in Paper II (core normal, broad line, cool, and shallow silicon). Comparisons with SYNOW synthetic spectra show that all strong features and most weak ones can be accounted for in a plausible way. The issues of detached high-velocity features, the possible ubiquity of carbon clumps, the maximum detectable ejecta velocities, and the possibility of blueshifted emission-line peaks are discussed.

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“…As mentioned above, because parameterized expansion velocities, v line , are traced by blended atomic signatures over time, the convergence of vmin,Y (t) with SYNAPPS depends on the list of actively contributing atomic species used as input. However, since SYNAPPS does not solve for ionization balance, which is a necessary step for abundance determinations and more detailed analysis (Baron et al 1996), semi-empirical fits are devised by perturbing compositional constructs (Hatano et al 1999b). Synthetic fits for a given set of ions can then be processed forward and backward in phase space relative to maximum light.…”

Section: Application Of Synappsmentioning

confidence: 99%

“…These parameters were then free to vary near the end of our fitting procedure. We also allowed logmin to vary freely within appropriate ranges when minimizing vmin,Y toward a monotonically decreasing function of time (see Hatano et al 1999b;Branch et al 2005). …”

Section: Application Of Synappsmentioning

confidence: 99%

Comparative analysis of SN 2012dn optical spectra: days −14 to +114

Parrent¹,

Howell²,

Fesen³

et al. 2016

Mon. Not. R. Astron. Soc.

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SN 2012dn is a super-Chandrasekhar mass candidate in a purportedly normal spiral (SAcd) galaxy, and poses a challenge for theories of type Ia supernova diversity. Here we utilize the fast and highly parameterized spectrum synthesis tool, SYNAPPS, to estimate relative expansion velocities of species inferred from optical spectra obtained with six facilities. As with previous studies of normal SN Ia, we find that both unburned carbon and intermediate mass elements are spatially coincident within the ejecta near and below 14,000 km s −1 . Although the upper limit on SN 2012dn's peak luminosity is comparable to some of the most luminous normal SN Ia, we find a progenitor mass exceeding ∼ 1.6 M is not strongly favored by leading merger models since these models do not accurately predict spectroscopic observations of SN 2012dn and more normal events. In addition, a comparison of light curves and host-galaxy masses for a sample of literature and Palomar Transient Factory SN Ia reveals a diverse distribution of SN Ia subtypes where carbon-rich material remains unburned in some instances. Such events include SN 1991T, 1997br, and 1999aa where trace signatures of C III at optical wavelengths are presumably detected.

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Ion Signatures in Supernova Spectra

Cited by 90 publications

References 21 publications

Nearby Supernova Factory Observations of SN 2005gj: Another Type Ia Supernova in a Massive Circumstellar Envelope

Nearby Supernova Factory Observations of SN 2005gj: Another Type Ia Supernova in a Massive Circumstellar Envelope

Comparative Direct Analysis of Type Ia Supernova Spectra. III. Premaximum

Comparative analysis of SN 2012dn optical spectra: days −14 to +114

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