L. Rosino

Properties of the Nova Population in M31

Observations of M31 novae are reviewed, and the implications of the results for the understanding of how novae distribute in galaxies and galactic subsystems are discussed. After correction for systematic errors, an annual rate of outbursts of 29 + or - 4 novae/yr is found. The data confirm that at least about 85 percent of the novae considered belong to the bulge (and the halo) of M31, and provide a distance modulus of (m - M)0 = 24.27 + or - 0.20 mag. 61 refs.

Distance of the Large Magellanic Cloud through the maximum magnitude versus rate of decline relation for novae

Le module de distance du Grand Nuage de Magellan (GNM) est determine en appliquant la relation magnitude maximum versus taux de declin (Capaccioli M. et al, 1989, A. J., 97) nouvellement calibree a un echantillon de novae. Les proprietes de cette methode de calibration sont analysees et comparees pour la Galaxie, M 31 et le GNM.

C-M diagram and luminosity function of the Galactic globular cluster NGC 7099. I. Photographic photometry

New photographic photometry of about 4400 stars in the field of the Galactic globular cluster NGC 7099 = M30 is presented. A C-M diagram and a luminosity function are obtained from this photometry. The distance modulus is estimated at 14.5 + or - 0.5 assuming V(HB) = 15.11 + or - 0.10 and E(B-V) = 0.03 + or - 0.03. The metallicity is (Fe/H) = 1.9 + or - 0.3 based on the dereddened color index (B-V)0,g = 0.71 + or - 0.03. The theoretical isochrones of VandenBerg and Bell (1985) give a better fit to the observations assuming (Fe/H) = -1.8, (m-M)V = 14.6, and E(B-V) = 0.02. A fair fit is also obtained using isochrones of low iron content with an oxygen enhancement of 0.7. From the fit, an age of 17 + or - 4 Gyr is deduced. 41 references.

Studies of blue objects at high galactic latitudes

Continuing the survey for faint blue objects at high galactic latitudes, a field of 25 square degrees centered at the Coma Cluster of Galaxies has been examined on two-color plates taken with the 90-67 cm Schmidt telescope of Asiago. 487 objects have been identified. A selected list of those with the largest negative color index is given in Table I. Identification charts, notes and comments follow.

Spectroscopic observations of Nova V443 Scuti 1989

Nova V443 Scuti 1989 reached its maximum, of visual magnitude about 7.5, very likely on September 13-14, 1989, displaying in its early decline brightness fluctuations of relatively large amplitude with a periodicity of about 17 days. In October the spectrum was characterized by the presence of the Balmer emission lines and by those of Fe II, Na I, Ti II, O I, N II accompanied by two systems of displaced P Cyg absorptions, having an average velocity of about -710 and -1460 km/s. The transition phase took place in November, with the appearance of forbidden N II 5755 and O II 7319 -30 and with the O I 6300 - 6364 flash. In March 1990, the nova was found in the nebular phase with wide emission lines of H, He I, He II, and collisionally excited lines of forbidden N II, O II, O III, and Ne III. From April to July, the degree of ionization having further progressed, forbidden lines of Fe VI, Fe VII, A III, A IV, A V, Ca V, and possibly also of Fe X, emerged. 30 refs.

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]).

Maximum magnitude vs. rate of decline for novae of the LMC

We derive the distance modulus of the Large Magellanic Cloud (LMC) by applying the new calibrated relationship between maximum magnitude and rate of decline (MMRD). The result, (m−M)o = 18.70±â .20, is in close agreement with the most recent .25 determinations based on RR Lyrae and Cepheids. We also discuss the properties of the MMRD of M31 and of the LMC.