A. Della Valle

SN 2004aw: confirming diversity of Type Ic supernovae

Optical and near-infrared (near-IR) observations of the Type Ic supernova (SN Ic) 2004aw are presented, obtained from -3 to +413 d with respect to the B-band maximum. The photometric evolution is characterized by a comparatively slow post-maximum decline of the light curves. The peaks in redder bands are significantly delayed relative to the bluer bands, the I-band maximum occurring 8.4 d later than that in B. With an absolute peak magnitude of -18.02 in the V band the SN can be considered fairly bright, but not exceptional. This also holds for the U through I bolometric light curve, where SN 2004aw has a position intermediate between SNe 2002ap and 1998bw. Spectroscopically SN 2004aw provides a link between a normal SN Ic like SN 19941 and the group of broad-lined SNe Ic. The spectral evolution is rather slow, with a spectrum at day +64 being still predominantly photospheric. The shape of the nebular [OI] λλ6300, 6364 line indicates a highly aspherical explosion. Helium cannot be unambiguously identified in the spectra, even in the near-IR. Using an analytical description of the light-curve peak we find that the total mass of the ejecta in SN 2004aw is 3.5-8.0 M ⊙ , significantly larger than that in SN 19941, although not as large as in SN 1998bw. The same model suggests that about 0.3 M ⊙ of 56 Ni has been synthesized in the explosion. No connection to a GRB can be firmly established.

A multiwavelength study of the IRAS Deep Survey galaxy sample - III. Spectral classification and dynamical properties

The infrared deep sample (IDS), in the north ecliptical polar region (NEPR), is the first complete, far--IR selected sample, on which numerous studies of galaxy evolution are based. Here we present and analyze the spectral classification of several galaxies in the IDS sample together with rotation curves which allow estimating the lower mass limits of a subsample of objects. We measured fluxes and intensity ratios of the emission lines in the visible region of the spectrum (lambda 4000-9000 A) for 75 galaxy members. Moreover, for some of them (55%), the spectra obtained with the Keck II telescope have sufficient wavelength and spatial resolution to derive their rotation curve. These galaxies turn out to be disk like systems, with a high fraction (~50%) of interacting systems. The spectroscopic classification of 42 galaxies, using the emission-line ratio diagnostic diagrams, shows that the NEPR sample is predominantly composed of starburst galaxies (71%), while the fraction of AGNs (7%) and LINERs (21%) is small. The dynamical analysis allows us to estimate the lower mass limits of 39 galaxies. The rest-frame FIR luminosity distribution of these galaxies spans the same range as that of the FIR selected complete sample, i.e. three orders of magnitude, with the same mean value, log(L_FIR)=10.2. This emphasizes that such galaxies represent FIR properties of the whole sample well. Moreover, their optical properties are typical of the sample itself since 62% of these belong to the 60mu selected complete sample.

The new TNG-DIMM: calibrations and first data analysis

Since 2011 a new differential image motion monitor (DIMM) works at Roque de los Muchachos Observatory close to Telescopio Nazionale Galileo (TNG). The purpose of this instrument is to provide useful information about the optical turbulence for the astronomical observations at TNG. We present the instrument and the first statistical results including a relationship between the principal components analysis of local-ground atmospheric parameters and seeing.