| 2. |
- Taddia, Francesco, et al.
(författare)
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Carnegie Supernova Project : Observations of Type IIn supernovae
- 2013
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 555, s. A10-
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Tidskriftsartikel (refereegranskat)abstract
- Aims. The observational diversity displayed by various Type IIn supernovae (SNe IIn) is explored and quantified. In doing so, a more coherent picture ascribing the variety of observed SNe IIn types to particular progenitor scenarios is sought. Methods. Carnegie Supernova Project (CSP) optical and near-infrared light curves and visual-wavelength spectroscopy of the Type IIn SNe 2005kj, 2006aa, 2006bo, 2006qq, and 2008fq are presented. Combined with previously published observations of the Type IIn SNe 2005ip and 2006jd, the full CSP sample is used to derive physical parameters that describe the nature of the interaction between the expanding SN ejecta and the circumstellar material (CSM). Results. For each SN of our sample, we find counterparts, identifying objects similar to SNe 1994W (SN 2006bo), 1998S (SN 2008fq), and 1988Z (SN 2006qq). We present the unprecedented initial u-band plateau of SN 2006aa, and its peculiar late-time luminosity and temperature evolution. For each SN, mass-loss rates of 10(-4)-10(-2) M-circle dot yr(-1) are derived, assuming the CSM was formed by steady winds. Typically wind velocities of a few hundred km s(-1) are also computed. Conclusions. The CSP SN IIn sample seems to be divided into subcategories rather than to have exhibited a continuum of observational properties. The wind and mass-loss parameters would favor a luminous blue variable progenitor scenario. However, the assumptions made to derive those parameters strongly influence the results, and therefore, other progenitor channels behind SNe IIn cannot be excluded at this time.
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| 3. |
- Taddia, Francesco, et al.
(författare)
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Supernova 2008J : early time observations of a heavily reddened SN 2002ic-like transient
- 2012
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 545, s. L7-
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Tidskriftsartikel (refereegranskat)abstract
- Aims: We provide additional observational evidence that some Type Ia supernovae (SNe Ia) show signatures of circumstellar interaction (CSI) with hydrogen-rich material. Methods: Early phase optical and near-infrared (NIR) light curves and spectroscopy of SN 2008J obtained by the Carnegie Supernova Project are studied and compared to those of SNe 2002ic and 2005gj. Our NIR spectrum is the first obtained for a 2002ic-like object extending up to 2.2 μm. A published high-resolution spectrum is used to provide insight on the circumstellar material (CSM). Results: SN 2008J is found to be affected by AV ~ 1.9 mag of extinction and to closely resemble SN 2002ic. Spectral and color comparison to SNe 2002ic and 2005gj suggests RV < 3.1. Spectral decomposition reveals the underlying SN emission matches a 1991T-like event and, since SN 2008J is as luminous as SN 2005gj (Vmax = -20.3 mag), we conclude that their CSI emissions are similarly robust. The high-resolution spectrum reveals narrow emission lines produced from un-shocked gas characterized by a wind velocity of ~50 km s-1. We conclude that SN 2008J best matches an explosion of a SN Ia that interacts with its CSM. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile (ESO Programme 080.A-0516).Figure 4 and Tables 1-6 are available in electronic form at http://www.aanda.org
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