R. Barbon

Photometric behavior of evolved supernovae

The late-time photometric behavior of supervovae has been analyzed combining observations obtained during a dedicated program with photometric data available in the literature at phase later than 100 days after maximum. Comparing the late light curves of different types of supernovae, it is found that: (1) SN Ia maintain common characteristics even at late stages, declining with a similar rate both in B and in V bands, gamma of about 1.5 mag/100 days; (2) the decline rate of SN Ib in the B band is similar to that of SN Ia; (3) the average decline of SN II in V is close to that expected from the radioactive decay of Co-56, gamma (v) = 0.89 mag/100 days, while gamma (B) is significantly lower; and (4) a comparable mass of Ni appears to be synthesized by all SN II, whereas SN Ia produce a larger amount of radioactive material. 76 refs.

Asiago Supernova classification program: blowing out the first two hundred candles

We present the compilation of the first 221 supernovae classified during the Asiago Classification Program (ACP). The details of transients classification and the preliminarily reduced spectra, in fits format, are immediately posted on the Padova-Asiago SN group web site. The achieved performances for the first 2 years of the ACP are analysed, showing that half of all our classifications were made within 5 days from transient detection. The distribution of the supernova types of this sample resembles the distribution of the general list of all the supernovae listed in the Asiago SN catalog (ASNC, Barbon et al. 1999). Finally, we use our subsample of 78 core-collapse supernovae, for which we retrieve the host-galaxy morphology and r -band absolute magnitudes, to study the observed subtype distribution in dwarf compared to giant galaxies. This ongoing program will give its contribution to the classification of the large number of transients that will be soon delivered by the Gaia mission. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The Asiago Supernova Catalog

The large number of supernovae (SNe) discovered in the last years, i.e. since the publication of the Revised Supernova Catalogue [1] which contained all SNe discovered up to 1983, led us to publish a new version including all SNe discovered up to 1988 December 31. The number of listed supernovae amounts to 661, of which 267 have been classified.

Mean Evolution and Characteristics of Type I Supernova Spectra

The growing interest on the issue of type I supernova homogeneity (see e.g. BRANCH et al. [1] and references therein) has suggested us to use all the spectroscopic material obtained at Asiago Observatory in the past years, through a fairly homogenous set of instrumentation, to give a contribution to the understanding of this important problem. Our first goal was to produce a temporal sequence of spectra defining a standard evolution for SNeI to be used as reference in search for peculiarities and, afterwards, to correlate these ones with other SN features such as the photometric parameters.

Late Time Photometric Behavior of Supernova

In a previous paper BARBON et al. [1] have shown, from the analysis of the light curves of few well studied supernovae (SNe), that the blue luminosities of SNe in the range 200–400 days after maximum light fade linearly with a decline rate which seems a characteristic for each SN type. The average decline rates in the blue band were found γsni = 1.52, and γSNII = 0.81 [mag/100d]. Due to the scanty material available no distinction was made for the different subtypes of SNe, neither was possible to analyze the behaviour in different photometric bands. To improve that work, we started a program of photometric observations of SNe at late stages, using the ESO telescopes at La Silla (DELLA VALLE et al. [2]). In the first run, we observed a sample of ten SNe, i.e. 1985P, 1986G, 1986E, 1986I, 1986L, 1986N, 1986O,1987D, 1987F, 1987K, that, at the time of observations, were at phase ranging from six months to two years. A full account of the observations and of the reduction technique will be presented elsewhere (TURATTO et al. [3]), while the detailed photometric and spectroscopic study of three SNe of the sample (SN 1986E, SN1987D and SN 1987F) has been given in a previous paper (CAPPELLARO et al. [4]).