%R 1996A&AS..116..193C
%J-202
%A Casoli F., Dickey J., Kazes I., Boselli A., Gavazzi G., Jore K.
%T A ^12^CO(1-0) survey of spiral galaxies in the region of the Coma supercluster.
%F 1996.04.02
%B We present observations of the ^12^CO(J=1-0) line at 2.6mm of 65 galaxies located in the Coma supercluster region: 33 actually belong to the Coma supercluster while 32 are either foreground or background objects. These data have been obtained using the NRAO 12m telescope at Kitt Peak (United States), and for four galaxies, using the IRAM 30m telescope at Pico Veleta (Spain). Out of these 65 galaxies, 54 had never been observed in the CO(1-0) line; 49 have been detected
by us, of which 37 are new detections. We give molecular gas masses deduced from the CO line integrated intensities, and upper limits for the 16 undetected objects, computed with a Galactic conversion factor N(H_2_)=2.3x10^20^I(CO) and H_0_=75km/s/Mpc.
%K galaxies: clusters: individual: Coma cluster - galaxies: interstellar medium - radio lines: galaxies

%R 1996A&AS..116..203S
%J-209
%A Stein P.
%T Structure and kinematics of galaxy clusters. I. The redshift catalogue.
%F 1996.04.02
%B An extensive redshift survey has been conducted on a sample of 15 nearby (0.01<~z<~0.05) clusters of galaxies. A total number of 860 redshifts were determined by fitting of emission-lines and/or cross-correlation techniques. Of this sample, 735 galaxies are within 0.2-0.8Mpc (H_0_=50km/s/Mpc) of the center of clusters. Approximate morphological types are available for most of the galaxies. A comparison of the present redshifts with published data allows an
extensive error analysis. The agreement is excellent with the most modern data, showing a zero point error of 5km/s and an overall consistency of the measurements and their uncertainties. We estimate our redshifts to have mean random errors around 30km/s. A population analysis of the clusters will be given in a forthcoming paper.
%K galaxies: clusters: general - galaxies: redshifts - catalogues

%R 1996A&AS..116..211M
%J-238
%A Moscadelli L., Catarzi M.
%T Time variability of five strong 12GHz methanol masers.
%F 1996.04.02
%B Five intense 12 GHz methanol masers with structured profile have been monitored during the period 90 Nov.-92 Apr., in order to study the variability on time scales ranging from one week to about 2years. The integrated flux density of W3(OH), G188.94+0.89, NGC 7538 remains constant (within the measurement uncertainties) during our period of observation. By amplitude normalization and removal of instrumental velocity shifts, we could investigate variations of flux density
as small as a few per cent. For W3(OH) and G188.94+0.89, we find that the flux density varies up to a maximum of 8% over 1.5years; for NGC 7538, we obtain an upper limit of 10% over 1.5years. The integrated flux density of the remaining two sources, Cep A and W48, varies up to a factor of 2-3 and both show an intensity increase which varies with velocity. We could study the dependence of the intensity variation on the velocity with a precision limited only by the noise. We
interpret the small time variability presented by the first three sources as due to proper motions of the maser spots. To explain the velocity dependence of the intensity variation of the two more variable sources, we suggest, for Cep A, the presence of still unsaturated emission components and, for W48, an edge-on disk configuration.
%K masers - ISM: HII region - ISM: molecules - radio lines: interstellar

%R 1996A&AS..116..239D
%J-248
%A Dallier R., Boisson C., Joly M.
%T A library of H band stellar spectra for stellar population analysis purposes.
%F 1996.04.02
%B A sample of 37 stars of luminosity classes I, III, V, including few SMR stars observed in the H band with a medium resolution (R=1500-2000) is presented. This sample of flux calibrated spectra is intended to widen existing stellar libraries. A new IR spectrograph, ISIS/IR, foreseen for CFHT has been used. Its main characteristics are briefly described. Stellar spectra obtained with this new spectrograph are compared to similar data obtained with the ESO NTT IRSPEC
spectrograph. The behaviour of some prominent features is described and it is shown that the CO{lambda}1.60/SiI{lambda}1.60 line ratio is a good luminosity indicator for stellar types later than K0.
%K line: identification - stars: fundamental parameters: classification - stars: late type - Infrared: stars - atlases

%R 1996A&AS..116..249C
%J-256
%A Costa R.D.D., Chiappini C., Maciel W.J., de Freitas Pacheco J.A.
%T New abundances of southern planetary nebulae.
%F 1996.04.02
%B As a continuation of a long-term observational program with the purpose of deriving the chemical abundances of southern planetary nebulae (PN), we present here the line fluxes, colour excesses, electron temperatures and densities, and abundances of He, O, N, S, Ar and Ne for 15 PN. These objects were classified according to the Peimbert classification scheme, taking into account the chemical and kinematical properties as well as distance-independent correlations.
%K planetary nebulae: general - ISM: abundances

%R 1996A&AS..116..257K
%J-287
%A Kaper L., Henrichs H.F., Nichols J.S., Snoek L.C., Volten H., Zwarthoed G.A.A.
%T Long- and short-term variability in O-star winds. I. Time series of UV spectra for 10 bright O stars.
%F 1996.04.02
%B An atlas of time series of ultraviolet spectra is presented for 10 bright O stars. The spectra were obtained with the International Ultraviolet Explorer during seven observing campaigns lasting several days over a period of 6years. The UV P Cygni lines in 9 out of the 10 studied stars exhibit a characteristic pattern of variability in the form of discrete absorption components (DACs) migrating through the absorption troughs on a timescale of a day to a week. This pattern
is significantly different for each star, but remains relatively constant during the time span of our observations for a given star. A quantitative evaluation of the statistical significance of the variability is given. The winds of a number of stars appear to vary over the full range of wind velocities: from 0km/s up to velocities exceeding the terminal velocity v_{infinity}_ of the wind as measured by the asymptotic velocity reached by DACs. The amplitude of
variability reaches a maximum at about 0.75v_{infinity}_ in the unsaturated resonance lines of stars showing DACs. In saturated resonance lines we find distinct changes in the steep blue edge. This edge variability is also found, although with smaller amplitude, in unsaturated resonance lines. The subordinate line of N IV at 1718 A in {xi} shows weak absorption enhancements at low velocities in the blue-shifted absorption that are clearly associated with the DACs in the UV
resonance lines. We interpret these three manifestations of variation as reflecting a single phenomenon. The DACs are the most conspicuous form of the variability. The changes at the edge can often be interpreted as DACs, but superposed on a saturated underlying wind profile; in many cases, however, at the same time two or more absorption events in different stages of their evolution can be identified in the unsaturated profiles, hampering a detailed interpretation of the
edge variability. The low velocity absorption enhancements in the subordinate lines are the precursors of DACs when they are formed close to the star. The constancy of the pattern of variability over the years and the (quasi-)periodic recurrence of DACs strongly suggest that rotation of the star is an essential ingredient for controlling wind variability. The observation of low-velocity variations in subordinate lines, which are supposedly formed at the base of the stellar
wind, indicate an origin of wind variability close to or at the photosphere of the star.
%K stars: early type - stars: mass loss - ultraviolet: stars

%R 1996A&AS..116..289Z
%J-293
%A Zhang Y.H., Xie G.Z.
%T CCD photometry and long-term optical variability of PKS 2155-304.
%F 1996.04.02
%B The paper presents the first evidence for long-term optical variability and colour behaviour of the X-ray-selected BL Lacertae object PKS 2155-304, which is the first example of its class. Our results show that the amplitude of the optical variations of PKS 2155-304 has been only about 1.4 magnitudes from its photometric history; no significant correlation between brightness and colours is found for PKS 2155-304. Our recent CCD photometry of PKS 2155-304 during
September-October 1993 and July 1994 showed that it was the same brightness state as that in November 1991 (Smith et al. 1992).
%K BL Lacertae objects: general individual (\object{PKS 2155-304})

%R 1996A&AS..116..295S
%J-300
%A Scarpa R., Falomo R., Pesce J.E.
%T Redshift of southern radio galaxies.
%F 1996.04.02
%B We report optical spectroscopy and redshift determination for 22 radio galaxies, extracted from the Ekers et al. (1989) compilation. Selected sources, which have both Fanaroff & Riley type I and II radio morphology and are classified as elliptical or S0, have a typical early-type spectrum with strong absorption lines as generally observed in non-radio elliptical galaxies. Only in two cases, 0344-345 and 1521-300, moderately strong emission lines are observed.
%K galaxies: distances and redshift

%R 1996A&AS..116..301R
%J-308
%A Rousseau J.M., Perie J.P., Gachard M.T.
%T Stars of the southern hemisphere proposed for the Hipparcos mission.
%F 1996.04.02
%B As part of the preparation for the Hipparcos mission, we determined the positions of 96800 already listed stars and 21265 previously unlisted companions, using information gathered by the ESO Quick Blue Survey. B1950 and J2000 system coordinates are given for each star. The magnitudes and spectral types are given in addition to the exact date of the observation (approximately 1976). PPM, HIC, SAO, HD, CoD, CPD, CPC, ADS, IDS, BD, LHS and V* identifiers are given
systematically whenever they exist as well as two supplementary identifiers selected from 43 other catalogues. Comments where necessary to complete the information. This catalogue is available from the Centre for Astronomic Data at Strasbourg.
%K astrometry - catalogues

%R 1996A&AS..116..309H
%J-358
%A Hanuschik R.W., Hummel W., Sutorius E., Dietle O., Thimm G.
%T Atlas of high-resolution emission and shell lines in Be stars. Line profiles and short-term variability.
%F 1996.04.02
%B We present an atlas of high-S/N, high-resolution ({DELTA}v=6km/s) data of Be star emission and shell profiles. We have collected profiles of H{alpha} and of Fe II, mostly of the {lambda}5317 transition. These lines have been selected to provide measures for the overall emission strength and for the velocity field in these disks. We have collected data for 77 southern and equatorial programme stars, covering the period 1982-1993. This is the most comprehensive
overview of profile shapes in Be disks. We propose a three-dimensional scheme in which most observed profiles can be classified. The parameters are i) inclination, ii) optical depth, and iii) the pattern of the velocity field. A search for short-term variability (timescales between five days and a few minutes) in six stars ended with negative result. Shortest observed timescale for variability is a few days for well-developed disks in binary systems (HR 1910, HR 2142).
%K atlas - stars: Be - lines: profiles

%R 1996A&AS..116..359P
%J-365
%A Popovic L.C., Dimitrijevic M.S.
%T Stark broadening of Xe II lines.
%F 1996.04.02
%B We present here Stark widths and shifts for 20 Xe II multiplets which are of interest for laboratory plasma research as well as for the analysis of Hg-Mn stars spectra. For calculations the modified semiempirical approach was used. The obtained results are compared with the available experimental data.
%K atomic data - plasmas - stars: chemically peculiar

%R 1996A&AS..116..367G
%J-371
%A Grundahl F., Sorensen A.N.
%T Detection of scattered light in telescopes.
%F 1996.04.02
%B We present a simple, but powerful method to test for the presence of scattered light in telescopes. Scattered light can seriously hamper any attempt to achieve a proper flat fielding of CCD data. The method consists of making a pinhole camera (camera obscura) by placing a pinhole mask in front of the CCD window. Exposing the CCD in this configuration gives an image of the light sources in the optical path. Tests made at the Nordic Optical Telescope have led to a reduction
of large scale flat field variations due to scattered light from a total of ~5% to below 1% by improving the telescope baffles.
%K instruments: miscellaneous - telescopes

%R 1996A&AS..116..373L
%J-380
%A Loiseau S., Malbet F.
%T Global astrometry with OSI.
%F 1996.04.02
%B The Orbiting Stellar Interferometer is a proposed space-based interferometer which makes very accurate wide-angle astrometric measurements on several thousand stars. As opposed to Hipparcos, OSI does not have a "basic angle" between two separate field-of-views but three separate interferometers and a highly accurate metrology system. The questions addressed in this paper are whether it is possible to perform global astrometry with such an instrument and what kind of
results could then be expected. A time-independent observing scenario, leading to a solution for positions and ignoring effects of proper motion and parallax, as well as a global astrometric data analysis technique are presented and a covariance study is performed. We show that a gain of a factor of at least 4 on the final astrometric accuracy could be achieved if such a technique was used. With an initial single measurement precision of 10 micro-arcseconds, our solution
leads to an astrometric accuracy of 2-3 micro-arcseconds.
%K astrometry - instrumentation: interferometers - techniques: interferometry - methods: data analysis

%R 1996A&AS..116..381M
%J-393
%A Mariotti J.-M., Coude du Foresto V., Perrin G., Zhao P., Lena P.
%T Interferometric connection of large ground-based telescopes.
%F 1996.04.02
%B In this article, we argue that the recent advent of two technological breakthroughs in the field of Optics, namely the development of Adaptive Optics and of infrared single-mode fibers, is likely to modify our conception of astronomical interferometry at optical wavelengths. In particular, it should become possible to realize the coherent combination of the giant telescopes that tend to cluster at the best ground-based astronomical sites. Although more limited in their
scope than the dedicated interferometric systems, these potential arrays could achieve impressive performances in terms of sensitivity and angular resolution. As an example, we discuss in more details the case of a Mauna Kea cluster of large telescopes.
%K telescopes - techniques: interferometry - techniques: adaptive optics - instrumentation: interferometers - optical fibers: single-mode - infrared: general

%R 1996A&AS..116..395F
%J-402
%A Faundez-Abans M., Ormeno M.I., de Oliveira-Abans M.
%T Classification of planetary nebulae by cluster analysis and artificial neural networks.
%F 1996.04.02
%B According to the chemical composition, a sample of 192 Planetary Nebulae of different types has been re-classified, and 41 others have been classified for the first time, by means of two methods not employed so far in this field: hierarchical cluster analysis and supervised artificial neural network. The cluster analysis reveals itself as a good first guess for grouping Planetary Nebulae, while an artificial neural network provides reliable automated classification of this
kind of objects.
%K planetary nebulae: general - methods: miscellaneous