%R 1995A&AS..109..425C
%J-440
%A Clausen J.V., Gimenez A., van Houten C.J.
%T Four-colour photometry of eclipsing binaries. XXVIIb. A photometric analysis of the (possible) Ap system AO Velorum.
%F 1995.02.16
%B Photometric elements and apsidal motion parameters of the southern detached eclipsing binary AO Vel (HD 68826) have been determined from complete uvby light curves (Gronbech 1987; Paper I), and photometric observations for additional times of minimum included in this paper. The relative radii of the components are 0.214+/-0.006 and 0.193+/-0.006, respectively. The orbit is slightly eccentric, e=0.0761+/-0.0017, and shows apsidal motion with a short period of U=56.8+/-1.9yr. 
Small asymmetries are present in the v, b and y light curves, whereas significant effects are seen in u, causing the results from this band to be unreliable. Inhomogeneities like e.g. spots may be present on (one of) the stellar surfaces. A third component is member of the system. It has a wide orbit of a sini=7.0+/-1.0AU; the orbital period is 25.6+/-2.5yr. Its contribution to the total light is about 30% and its luminosity thereby between those of the
eclipsing components. AO Vel is located within the field of Cr 173, but we find it too faint for membership. Only rough estimates of the absolute dimensions of the components can be given (Sect. 5), since radial velocity observations are not yet available. We strongly recommend that such data - as well as high resolution spectra for abundance analyses - are obtained, mainly because AO Vel is mentioned as one of the 3-5 known Ap eclipsing binaries and furthermore the only
example of the Si-type.
%K binaries: eclipsing - stars: chemically peculiar - stars: evolution - stars: fundamental parameters - stars: individual: \object{AO Vel}

%R 1995A&AS..109..441C
%J-446
%A Claret A.
%T Stellar models for a wide range of initial chemical compositions until helium burning. I. From X=0.60 to X=0.80 for Z=0.02.
%F 1995.02.16
%B New grids of stellar evolutionary models are presented for a wide range of initial hydrogen content around the solar composition. These compositions are (X, Z) = (0.80, 0.02), (0.70, 0.02) and (0.60, 0.02). Recent OPAL opacities with LS coupling and Grevesse composition were adopted, and Alexander's tables were used for lower temperatures. We consider models with core overshooting with {alpha}_ov_=0.20, and mixing length parameter l/H_p_=1.52 that seems to represent well
double-lined eclipsing binary stars. Mass loss during the main sequence and in the red giant phase were taken into account. The nuclear network treats 14 isotopes and optionally the lithium burning to study its depletion in less massive models during pre main sequence evolution. The mass range covered goes from 1 up to 40M_{sun}_ and the more massive models were followed until helium burning. The main aim of the present series of papers is, besides the inclusion of the new
opacities, to explore the effects on different outputs of the stellar models, of a change of the helium content at a given metallicity. We also present isochrones in the plane logg-logM which are very useful to compare the best parameters known for binary stars (masses and radii) with theoretical predictions. The internal structure constants for apsidal motion investigations are also presented.
%K stars: binaries: general; evolution; interiors; fundamental parameters - abundances

%R 1995A&AS..109..447G
%J-469
%A Grison P., Beaulieu J.-P., Pritchard J.D., Tobin W., Ferlet R., Vidal-Madjar A., Guibert J., Alard C., Moreau O., Tajahmady F., Maurice E., Prevot L., Gry C., Aubourg E., Bareyre P., Brehin S., Gros M., Lachieze-Rey M., Laurent B., Lesquoy E., Magneville C., Milsztajn A., Moscoso L., Queinnec F., Renault C., Rich J., Spiro M., Vigroux L., Zylberajch S., Ansari R., Cavalier F., Moniez M.
%T EROS catalogue of eclipsing binary stars in the bar of the Large Magellanic Cloud.
%F 1995.02.16
%B We present a catalogue of 79 certain or probable eclipsing binary stars located in the bar of the Large Magellanic Cloud. The stars were identified from the French EROS microlensing project's 1991-92 season of CCD observations using Grison's (1994) period-searching procedure, which incorporates higher harmonics into the periodogram search of photometric time sequences. Only one of the systems was previously identified and our catalogue doubles the number of known eclipsing
binaries in the LMC. The systems mostly range from 15^th^ to 18^th^ mag., exhibit blue colours and have periods less than 10 days. At least ten systems are eccentric. Coordinates and ephemerides are presented, as well as identification charts and light curves at 490 and 670nm. The catalogue and light curves are available electronically from the CDS, Strasbourg.
%K catalogues - binaries: eclipsing - Magellanic Clouds

%R 1995A&AS..109..471M
%J-477
%A Mishenina T.V., Klochkova V.G., Panchuk V.E.
%T Elemental abundances in the atmospheres of three metal-deficient giants.
%F 1995.02.16
%B High dispersion high resolution CCD spectra have been used for the determination of the elemental abundances in three metal-deficient stars. The following results were obtained: 1) an overabundance of O is found; 2) Si, Ca, Ti are overabundant with respect to iron in stars with [Fe/H]= -1.5; 3) halo stars show an underabundance of the odd elements Na and Al relative to the abundance of the even element Mg); 4) Ni and Mn are slightly overdeficient; 5) an underabundance of
Cu is found in all three stars ; 6) s-process elements are slightly overabundant.
%K stars: individual: HD 170737, HD 175305, HD 232078 - stars: abundances - Galaxy: evolution; abundances

%R 1995A&AS..109..479S
%J-486
%A Samus N., Kravtsov V., Pavlov M., Alcaino G., Liller W.
%T A new photographic C-M diagram for NGC 4833.
%F 1995.02.16
%B A color-magnitude diagram for the galactic globular cluster NGC 4833, based on the photographic BV photometry of about 868 stars in a 12'x12' field with an automatic measuring machine, is presented. It reaches the cluster main sequence turn-off point at V=~19.2mag ; the difference in V magnitudes between the turn-off and the horizontal branch being normal. This diagram, reaching near three magnitudes fainter is clearly an improvement over the only two previous CMDs
available in the literature, both published more than two decades ago by Alcaino [A&A 13 (1971) 287] and Menzies [MNRAS 156 (1972) 207], from photographic photometry reduced with an iris photometer down to V=~16.5. Indications have been found of the presence of a red giant branch bump, approximately at the same position with respect to the horizontal branch and main sequence turn-off as in NGC 5897. There is also some hint of the deficiency of stellar population of the
subgiant branch just above the turn-off point, similar to that observed in some other metal-poor globular clusters.
%K globular clusters: individual: \object{NGC 4833} - HR diagram

%R 1995A&AS..109..487S
%J-499
%A Samus N., Kravtsov V., Pavlov M., Alcaino G., Liller W.
%T A new photographic color-magnitude study of M 22 = NGC 6656.
%F 1995.02.16
%B A new photographic C-M diagram for the globular cluster M 22 based on automatic plate measurements has been obtained. It reaches the main sequence turn-off point at V=~17.7mag , (B-V)=~0.75. Systematic difference in color with photometry by Cudworth (1986) has been revealed, which is probably due to insufficient account of color equation in that study. The position of the red giant branch bump in M 22 is at V =~13.9mag , its magnitude differences with the horizontal branch
and the turn-off point are normal for a cluster with intermediate metallicity. The comparison of our color-magnitude diagrams for M 22 and NGC 4833 has been undertaken. The difference of the color-magnitude diagram morphology between the two clusters is attributed to somewhat higher metallicity of M 22.
%K globular clusters: individual: \object{M 22} - HR diagram

%R 1995A&AS..109..501C
%J-503
%A Carrasco G., Loyola P.
%T SANTIAGO 91, a right ascension catalogue of 3387 stars (equinox J2000).
%F 1995.02.16
%B The positions in right ascension of 3387 stars belonging to the Santiago 67 Catalogue, observed with the Repsold Meridian Circle at Cerro Calan, National Astronomical Observatory, during the period 1989 to 1994, are given. The average mean square error of a position, for the whole Catalogue, is +/-0.009 s. The mean epoch of the catalogue is 1991.84.
%K astrometry, catalogues

%R 1995A&AS..109..505H
%J-510
%A Hauck B., Ballereau D., Chauville J.
%T Three other {lambda} Bootis stars with a shell.
%F 1995.02.16
%B High signal-to-noise ratio spectra have been taken to detect a possible circumstellar shell around {lambda} Boo stars. It is more and more assumed that circumstellar matter can be found around such stars. We have considered the CaII K, H{gamma} and CaI {lambda}4427 lines. Two spectra of {lambda} Boo stars (HD 16955 and HD 104965) show circumstellar shell features in the K-line. Such features could also be present in the spectrum of HD 220061 and we confirm the
circumstellar shell recently found for 131 Tau by Bohlender & Walker (1994).
%K stars: chemically peculiar; circumstellar matter; individual: \object{HD 16955}, \object{HD 104965}, \object{HD 220061}

%R 1995A&AS..109..511R
%J-521
%A Roukema B.F., Peterson B.A.
%T A survey for low surface brightness galaxies in the field.
%F 1995.02.16
%B We report the results of a preliminary survey for low surface brightness galaxies (LSBG's) in the field, visually selected from film copies of SERC J Schmidt plates. Spectroscopy and photometry indicate that the resulting sample consists of dwarf galaxies. These galaxies of low surface brightness are also of low total luminosity, as found in the Virgo and Fornax galaxy clusters. The population sampled by this survey extends to redshifts of z=~0.05 and has a number density
of n=~(8+/-5)x10^-3^h^3^/Mpc^3^. This is about 6+/-4% of the number density for normal galaxies in the corresponding magnitude range of -14>=M_B_>=-20 represented in a standard (Efstathiou et al. 1988) luminosity function. About half of the population is already represented in the general galaxy luminosity function, making the new contribution of our population fairly small. This density is too low to explain the excess of galaxies observed at B>24 (e.g., Tyson &
Seitzer 1988), though magnitudes and diameters of our galaxies are consistent with those of the excess galaxies. We conclude that on the basis of its space number density, the population we have surveyed does not contribute significantly to the general galaxy luminosity function and so is not a candidate for explaining the excess of faint galaxies.
%K galaxies: luminosity function, mass function - galaxies: distances and redshifts - cosmology: observations - galaxies: fundamental parameters - surveys

%R 1995A&AS..109..523S
%J-536
%A Schulz H., Muecke A., Boer B., Dresen M., Schmidt-Kaler T.
%T Kinematical line broadening and spatially resolved line profiles from AGN.
%F 1995.02.16
%B We study geometrical effects for emission-line broadening in the optically thin limit by integrating the projected line emissivity along prespecified lines of sight that intersect rotating or expanding disks or cone-like configurations. Analytical expressions are given for the case that emissivity and velocity follow power laws of the radial distance. The results help to interpret spatially resolved spectra and to check the reliability of numerical computations. In the
second part we describe a numerical code applicable to any geometrical configuration. Turbulent motions, atmospheric seeing and effects induced by the size of the observing aperture are simulated with appropriate convolution procedures. An application to narrow-line H{alpha} profiles from the central region of the Seyfert galaxy NGC 7469 is presented. The shapes and asymmetries as well as the relative strengths of the H{alpha} lines from different spatial positions can be
explained by emission from a nuclear rotating disk of ionized gas, for which the distribution of H{alpha} line emissivity and the rotation curve are derived. Appreciable turbulent line broadening with a Gaussian {sigma} of ~40% of the rotational velocity has to be included to obtain a satisfactory fit.
%K line profiles - galaxies: active - galaxies: Seyfert - galaxies: kinematics and dynamics - galaxies: individual: NGC 7469

%R 1995A&AS..109..537H
%J-549
%A Hopp U., Kuhn B., Thiele U., Birkle K., Elsaesser H., Kovachev B.
%T A redshift survey for faint galaxies towards voids of galaxies.
%F 1995.02.16
%B We present the redshift and photometric data of a survey for intrinsically faint galaxies towards three nearby voids and the Hercules supercluster. The project is aimed at finding galaxies of absolute faint magnitudes or of low surface brightness within these voids. The selection of the voids and the search strategy for the galaxies are outlined. B and R magnitudes, major and minor diameters, as well as the morphology are determined. The diameter distribution of the
galaxies is discussed. Optically measured redshifts of 174 galaxies are given. Most of the galaxies found show emission lines and late-type morphology. Several have low-surface brightness features. Our survey identified a higher percentage of nearby galaxies than magnitude or diameter limited surveys.
%K large scale structure of universe - galaxies: general; redshifts surveys

%R 1995A&AS..109..551D
%J-552
%A Dimitrijevic M.S., Sahal-Brechot S.
%T Stark broadening of spectral lines of multicharged ions of astrophysical interest. XII. O IV and O V.
%F 1995.02.16
%B Using a semiclassical approach, we have calculated electron-, proton-, and He III-impact line widths and shifts for 5 O IV and 19 O V multiplets.
%K lines: profile - atomic and molecular data

%R 1995A&AS..109..553K
%J-556
%A Kentischer T.J.
%T The multichannel narrowband filter system at the Vacuum Tower Telescope.
%F 1995.02.16
%B A Multichannel Filter System (MSF) was built for use at the Vacuum Tower Telescope (VTT) of the Kiepenheuer Institut fuer Sonnenphysik at the Observatorio del Teide/Tenerife. The purpose of this new post focus instrument is the simultaneous two-dimensional observation of the solar chromosphere and the upper photosphere in different strong absorption lines.
%K instrumentation: miscellaneous

%R 1995A&AS..109..557A
%J-562
%A Agabi A., Borgnino J., Martin F., Tokovinin A., Ziad A.
%T G.S.M: A Grating Scale Monitor for atmospheric turbulence measurements. II. First measurements of the wavefront outer scale at the O.C.A.
%F 1995.02.16
%B The spatial and temporal properties of atmospherically degraded wavefronts are relevant for high angular resolution techniques like adaptive optics or long baseline interferometry. The wavefront outer scale has been estimated on two sites by a new instrument described in the previous paper. The normalized covariance of angle of arrival fluctuations at two wavefront points separated by a variable distance from 0.14 m to 10 m is measured and compared to theoretical set of
curves computed in the framework of Von Karman or Greenwood-Tarazano turbulence models. At the Calern site of Observatoire de la Cote d'Azur (O.C.A.) G.S.M. was installed near the long-baseline interferometer GI2T. The results from two nights show that in stable seeing conditions, and taking in account the models, the normalized angle of arrival covariance corresponds to turbulence outer scale L_0_ = 300 m. Systematic deviation from the models was observed on another night,
corresponding to L_0_ from 10 m to 300 m. Similar results were obtained on two nights at the Mont Gros site of O.C.A., giving L_0_ = 50 m. Extensions of the technique and plans are briefly discussed.
%K atmospheric effects - methods: observational - site testing

%R 1995A&AS..109..563B
%J-570
%A Borra E.F., Moretto G., Wang M.
%T An optical corrector design that allows a fixed telescope to access a large region of the sky.
%F 1995.02.16
%B We discuss a family of two-mirror correctors that can greatly extend the field accessible to a fixed telescope such as a liquid mirror telescope. The performance of the corrector is remarkable since it gives excellent images in patches contained within a field greater than 45 degrees. We argue that this performance makes fixedtelescopes competitive with tiltable ones.
%K instrumentation: miscellaneous - telescopes

%R 1995A&AS..109..571A
%J-583
%A Aristidi E., Aime C.
%T The effects of clipped photon detection in speckle interferometry and speckle masking techniques.
%F 1995.02.16
%B This paper presents numerical illustrations of the effects of clipping of photoevents in speckle interferometry and speckle masking. The clipping is due to a saturation of the photon-counting detectors that cannot count more than one photon per pixel, causing the image to be composed of "0" and "1". The theoretical basis for this study has been published by Aime & Aristidi (1992). Clipping effects are investigated numerically on real star data. As predicted by theory,
the clipping introduces several effects on auto and triple correlation functions, such as a linear global loss of energy, and non linear terms which affect mainly the high frequencies. Attention is focussed on the way the astronomical information is affected by this kind of detection, especially for the case of the double stars.
%K techniques: interferometric - instrumentation: detecteurs; interferometers

%R 1995A&AS..109..585C
%J-591
%A Cerroni P., Coradini A.
%T Multivariate classification of multispectral images: an application to ISM Martian spectra.
%F 1995.02.16
%B The powerful statistical multifactorial method Gmode is described and its application to the problem of the classification of multispectral imaging is discussed. An application to the classification of Martian multispectral data obtained by the imaging spectrometer ISM on board the spacecraft PHOBOS2 is presented; a test region is analysed in this paper, the region of Pavonis Mons. The application of Gmode to the classification of multispectral images has been found to be
very promising. Automatic mapping of mineralogically different provinces can be performed using our classification procedure; also, it is possible to search for a specific spectral signature within an otherwise homogeneous region. The most important factors affecting ISM spectra were automatically identified by the Gmode classification as follows: 1)"Albedo" effects; 2) Atmospheric effects; 3) Slope and overall shape of the spectra.
%K Plantes and satellites: individual: \objnS{Mars} - methods: data analysis; observational - techniques: spectroscopic - infrared: solar system

%R 1995A&AS..109..593S
%J-595
%A Sault R.J., Noordam J.E.
%T Eliminating solar interference in radio interferometric spectrometry.
%F 1995.02.16
%B The presence of a strong source, such as the sun or Cassiopeia A, in the distant sidelobes of a radio telescope can limit the image quality achieved with these observations. Conventional methods of subtracting out the response of these sources have limited success. In part this is because the instrumental response a large distance from the pointing centre is generally poorly understood and time variable. In the case of the sun it is also because the sun's complex and
variable nature. We present an approach, based on a continuum subtraction technique, which can substantially reduce the interference caused by such sources for spectral line experiments. We present an observation where the solar interference has been reduced by a substantial amount.
%K techniques: interferometric - methods: data analysis

%R 1995A&AS..109..597D
%J-610
%A Dominik M.
%T Improved routines for the inversion of the gravitational lens equation for a set of source points.
%F 1995.02.16
%B For the inversion of the lens equation, a method using contour plots has been proposed by Schramm & Kayser (1987). This method is discussed further and its deeper properties are used to construct routines, which allow both efficient and safe searches. A new interpretation of the routines of Schramm and Kayser is presented which overcomes some of its limits. A method is proposed, which stores the data obtained by a contour plot in a suitable data structure, tries to test
the data on consistency with the critical curves and caustics and corrects the data if possible. It is shown how these routines can be used for calculating images of extended sources and point sources, light curves and for analyzing the images of an extended source. For the transport of images, Powell's routine is introduced. Its properties are the base for constructing the routines mentioned above. Since `image' gets different meanings, different expressions for `images' of
points, curves and areas are defined. Finally, it is shown that contour plot methods do not miss bright area images.
%K gravitational lensing - methods: numerical