Nebular spectra and abundance tomography of the Type Ia supernova SN 2011fe: a normal SN Ia with a stable Fe core

A series of optical and one near-infrared nebular spectra covering the first year of the Type Ia supernova SN 2011fe are presented and modelled. The density profile that proved best for the early optical/ultraviolet spectra, ‘?-11fe’, was extended to lower velocities to include the regions that emit at nebular epochs. Model ?-11fe is intermediate between the fast deflagration model W7 and a low-energy delayed-detonation. Good fits to the nebular spectra are obtained if the innermost ejecta are dominated by neutron-rich, stable Fe-group species, which contribute to cooling but not to heating. The correct thermal balance can thus be reached for the strongest [Fe ii] and [Fe iii] lines to be reproduced with the observed ratio. The 56Ni mass thus obtained is ?0.47 ± 0.05?M?. The bulk of 56Ni has an outermost velocity of ?8500 km s?1. The mass of stable iron is ?0.23 ± 0.03?M?. Stable Ni has low abundance, ?10?2?M?. This is sufficient to reproduce an observed emission line near 7400 Å. A sub-Chandrasekhar explosion model with mass 1.02?M? and no central stable Fe does not reproduce the observed line ratios. A mock model where neutron-rich Fe-group species are located above 56Ni following recent suggestions is also shown to yield spectra that are less compatible with the observations. The densities and abundances in the inner layers obtained from the nebular analysis, combined with those of the outer layers previously obtained, are used to compute a synthetic bolometric light curve, which compares favourably with the light curve of SN 2011fe

Classification of Supernovae

The current classification scheme for supernovae is presented. The main observational features of the supernova types are described and the physical implications briefly addressed. Differences between the homogeneous thermonuclear type Ia and similarities among the heterogeneous core collapse type Ib, Ic and II are highlighted. Transforming type IIb, narrow line type IIn, supernovae associated with GRBs and few peculiar objects are also discussed.Comment: 16 Pages, 4 figures, to be published in "Supernovae and Gamma-Ray Bursters," ed. Kurt W. Weile

Optical Light Curves of Supernovae

Photometry is the most easily acquired information about supernovae. The light curves constructed from regular imaging provide signatures not only for the energy input, the radiation escape, the local environment and the progenitor stars, but also for the intervening dust. They are the main tool for the use of supernovae as distance indicators through the determination of the luminosity. The light curve of SN 1987A still is the richest and longest observed example for a core-collapse supernova. Despite the peculiar nature of this object, as explosion of a blue supergiant, it displayed all the characteristics of Type II supernovae. The light curves of Type Ib/c supernovae are more homogeneous, but still display the signatures of explosions in massive stars, among them early interaction with their circumstellar material. Wrinkles in the near-uniform appearance of thermonuclear (Type Ia) supernovae have emerged during the past decade. Subtle differences have been observed especially at near-infrared wavelengths. Interestingly, the light curve shapes appear to correlate with a variety of other characteristics of these supernovae. The construction of bolometric light curves provides the most direct link to theoretical predictions and can yield sorely needed constraints for the models. First steps in this direction have been already made.Comment: To be published in:"Supernovae and Gamma Ray Bursters", Lecture Notes in Physics (http://link.springer.de/series/lnpp

High luminosity, slow ejecta and persistent carbon lines: SN 2009dc challenges thermonuclear explosion scenarios

Sterrewacht - OU

Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF

The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at the Fermilab Long-Baseline Neutrino Facility (LBNF) is described

alpha3beta1-integrin regulates hair follicle but not interfollicular morphogenesis in adult epidermis.

alpha3beta1-integrin is abundantly expressed in the epidermis, and in mice, ablation of the alpha3 gene results in embryonic defects and perinatal lethality. To determine the role of alpha3-integrin in adult skin development, we grafted skin from newborn alpha3-integrin-deficient mice on to ICRF nu/nu recipients. We report that adult alpha3-integrin-deficient skin has severe abnormalities restricted to hair follicle morphology, which include stunted hair follicle growth, increased hair follicle fragility, aberrant pigment accumulation and formation of hair follicle clusters. These abnormalities are caused by a combination of defects in: (1) keratinocyte cytoskeletal organisation, (2) outer root sheath architecture and (3) integrity of the lamina densa. Our results indicate that alpha3beta1 is not essential for adult interfollicular epidermal differentiation, but it is required to direct several processes important in hair follicle maintenance and morphogenesis

ESC observations of SN 2005cf - I. Photometric evolution of a normal Type Ia supernova

We present early-time optical and near-infrared photometry of supernova (SN) 2005cf. The observations, spanning a period from about 12 d before to 3 months after maximum, have been obtained through the coordination of observational efforts of various nodes of the European Supernova Collaboration and including data obtained at the 2-m Himalayan Chandra Telescope. From the observed light curve we deduce that SN 2005cf is a fairly typical SN Ia with a post-maximum decline [Δm15(B)true= 1.12] close to the average value and a normal luminosity of MB,max=−19.39 ± 0.33. Models of the bolometric light curve suggest a synthesized 56Ni mass of about 0.7 M☉. The negligible host galaxy interstellar extinction and its proximity make SN 2005cf a good Type Ia SN template

Photoelectron diffraction study of the Ag(110)-(2×1)-O reconstruction

The structure of the (2×1)-O adsorption phase on Ag(110) has been determined using scanned-energy mode photoelectron diffraction. The oxygen atoms have been found to occupy the long-bridge site and are almost coplanar with the top layer of silver atoms. The best agreement between multiple-scattering theory and experiment has been obtained for a missing-row (or equivalently an ‘added-row’) reconstruction in which the first-to-second and second-to-third interlayer spacings are 1.55±0.06 Å and 1.33±0.06 Å, respectively. Alternative buckled-row and unreconstructed surface models can be excluded