%R 1998A&AS..133..299D %J-316 %A Damineli A., Stahl O., Kaufer A., Wolf B., Quast G., Lopes D.F. %T Long-term spectroscopy of {eta} Carinae. I. The high and low excitation phases. %M ds1568 %F 1998.12.10 %B Quantitative measurements of line parameters in the spectrum of \object{{eta} Carinae} are presented for both the broad and narrow line components. A total of 655 spectral features were measured in the spectral range 3850{AA} to 11000{AA}, giving a comprehensive view of the behavior of atomic transitions ranging from a few to tens of electron volts. The spectrum on the phase of maximum intensity in the high excitation lines (1995) is compared with that on minimum intensity (June 1992), showing that at this phase the high excitation lines disappear but the broad components of low excitation lines strengthens. We reject a number of previous line identifications and propose several new ones, including FeII, [FeII], [FeIII], [NII], and the near-infrared CaII triplet. Some lines commonly used to diagnose density, temperature, chemical composition, and reddening were found to be blended, urging a revision of the results based on previous data. The existence of double-peaked lines, suggested in previous papers, is ruled out. In the case of hydrogen lines, the apparent double-peaks are shown to be real absorption components. The velocity field in the inner 2" around the central star shows additional components previously unknown. The phases of high and low excitation in {eta} Carinae are discussed in light of a recently proposed binary system. We suggest a temperature T~16000K for the primary star, what indicates that it is close to the beginning of the core helium-burning evolutionary stage. %K stars: emission-line, Be - stars: Hertzsprung-Russel (HR) diagram - stars: individual: {eta} Carinae - binaries: general %R 1998A&AS..133..317H %J-323 %A Heraudeau P., Simien F. %T Stellar kinematical data for the central region of spiral galaxies. I. %M ds1541 %F 1998.12.10 %B We present the results of absorption spectroscopy on the inner region of 34 Sa-Sc galaxies. We have determined the central velocity dispersion and, for 32 of these objects, stellar rotation curves and velocity-dispersion profiles. Some of these profiles are limited to the bulge, some others do reach a region dominated by the luminosity of the disk. These data are intended to provide basic material for the study of the mass distribution and dynamical status in the central regions of spiral galaxies. Although no elaborate bulge-and-disk photometric decomposition is performed, we estimate the effects of limited resolution and contamination by disk light on the central velocity dispersion of the bulge. %K galaxies: spiral - galaxies: general - galaxies: kinematics & dynamics %R 1998A&AS..133..325G %J-336 %A Graham A.W., Colless M.M., Busarello G., Zaggia S., Longo G. %T Extended stellar kinematics of elliptical galaxies in the Fornax cluster. %M ds7478 %F 1998.12.10 %B We present extended stellar kinematics for a sample of elliptical galaxies in the Fornax cluster. Out of the 13 galaxies presented here, five (FCC 119, FCC 136, NGC 1373, NGC 1428, FCC 335) have no previously published kinematical data. Major-axis velocity dispersion profiles (VDPs) and rotation curves (RCs) are given for 12 of the galaxies. A major feature of this data is the spatial extension: for 8 galaxies the data extends beyond 1R_e_, and for 5 it extends beyond 2R_e_. Compared to the previously available data, this corresponds to an increase in spatial coverage by a factor from 1 to 5. The present sample represents 86% of the ellipticals in Fornax brighter than B_T_=15mag. Five of the ellipticals in the sample turn out to be rotationally-supported systems, having positive rotation parameter log((V)/({sigma}))^*^. One of these five, and another 3 galaxies from the remaining sample, display evidence for bar-like kinematics. The data indicate that the true number of ``dynamically hot'' stellar systems, is much lower than previously thought: of the Es in the present sample only 1/4 are confirmed as ``pressure-supported'' systems. The data reveal a host of individual peculiarities, like: wiggles, strong gradients, and asymmetries in the rotation curve and/or in the velocity dispersion profile, thus showing that the presence of kinematically distinct components and/or triaxiality is a common characteristic of this class of object. %K galaxies: kinematics and dynamics - galaxies: elliptical and lenticular, cD - galaxies: clusters: individual: \objS{Fornax cluster}{Fornax} - galaxies: structure - galaxies: fundamental parameters %R 1998A&AS..133..337Z %J-352 %A Zinchenko I., Pirogov L., Toriseva M. %T Studies of dense molecular cores in regions of massive star formation. VII. Core properties on the galactic scale. %M ds1560 %F 1998.12.10 %B We surveyed 55 northern non-stellar H_2_O masers in the CS J=2-1 line with the 20-m Onsala radio telescope and detected 47 CS cores associated probably with 50 masers. The CS emission for this sample is weaker on the average than for the similar southern sample studied by us earlier at SEST. Most of the detected cores were mapped in CS. The CS peaks were observed also in the C^34^S J=2-1 and in the CO J=1-0 lines. We present CS maps as well as CO, CS and, when available, C^34^S spectra for the 26 best studied cores. From the CS maps and optically thin C^34^S emission we derive the basic physical parameters of the cores: size, LTE mass, mean density, virial mass. Combining the present results with the previous SEST data we obtain statistical distributions of the core parameters. The CO brightness temperature distribution for most cores ranges from ~15K to ~50K with a peak at 20-30K. The typical sizes of the cores are L~1.0-1.5pc. The mean density lies in the range n~10^3^-10^5^cm^-3^ which is much lower than densities needed for CS excitation from multitransitional analysis. The slope of the mass spectrum for M>1000M_{sun}_ is 1.6+/-0.3. The ratio of the IR luminosity of associated IRAS point sources to mass peaks at ~10L_{sun}_/M_{sun}_. The CS line widths are highly supersonic (~1.5-9km/s). We analyze the dependences of these parameters on galactocentric distance R. The mean density of the cores drops with increasing R in the interval R=~7-14kpc. It is consistent with an exponential law with a scale length of ~3kpc. The IR luminosity to mass ratio changes probably in a similar way. The core size increases with R in accordance with the density decrease and constant mass. The comparison of the CS and C^34^S data shows almost no broadening of the CS lines due to optical depth effects. This can be probably explained by small scale clumpiness in the cores. The velocity difference between the CS cores and H_2_O masers is close to zero on the average with the standard deviation of ~7km/s. %K stars: formation - ISM: clouds - ISM: molecules - radio lines: interstellar %R 1998A&AS..133..353H %J-359 %A Hagen-Thorn V.A., Marchenko S.G., Takalo L.O., Sillanpaeae A., Pursimo T., Boltwood P., Kidger M., Gonzalez-Perez J.N. %T The variable sources responsible for the photometric behaviour of OJ 287 in the IR-optical-UV region during 1993-1996. %M ds7211 %F 1998.12.10 %B An analysis is performed of multicolour observations of OJ 287 carried out during the OJ-94 Project. It is found that in the optical region the variable sources have the same power-law spectrum (F_{nu}_~{nu}^-1.5^) irrespective of flux level. In the IR the spectrum flattens during the flare possibly because of synchrotron self-absorption. The comparison of the outburst of 1994 with those of 1971 and 1983 shows that there is a clear correlation between the power of outburst and colour indices of the variable component in each event: the larger is the outburst, the bluer is the variable source, i.e. in more powerful outbursts the energy spectrum of relativistic electrons is flatter. %K BL Lac objects; \object{OJ 287} - infrared: galaxies %R 1998A&AS..133..361H %J-380 %A Hua C.T., Dopita M.A., Martinis J. %T Detection of new emission structures around planetary nebulae. %M ds7743 %F 1998.12.10 %B Deep monochromatic observations are presented for 22 galactic planetary nebulae (PNe) performed through narrow-band interference filters, in the direct imaging mode with i) the New Zealand (MJUO) f/7.8 Mc-Lellan telescope, ii) the Observatoire de Haute Provence (OHP) f/6 120-cm telescope, and iii) and the Siding Spring Observatory (SSO) ATT 2.3 metre telescope. Some of them are observed for the first time. Conspicuous secondary structures are detected far around the conventional nebular pictures. Such features could be relics of early mass ejections during the post-AGB phase of the progenitors. Alternatively, they are more plausibly projections of external loops/bubbles of the ``bar-bell'' shape upon the waist (for face-on PNe). We suggest that such structures (cf. Sh 1-89, Hua, 1997A&AS..125..355H) are intrinsic to all PNe. Their apparently diverse morphologies would ``simply'' result from projections of a same PN intrinsic structure at different view angles onto the plane of sky and with respect to the major axis as well. In addition we report the detection of a new nebula in the field of NGC 3699 (50'' distant). Absolute fluxes are provided for three emission lines. %K planetary nebulae - ISM: structure %R 1998A&AS..133..381P %J-386 %A Phillips J.P., Cuesta L. %T The density and shock characteristics of NGC 2818. %M ds7447 %F 1998.12.10 %B We report the results of narrow band imaging of the bipolar outflow source NGC 2818 in transitions of [NII], [OIII], [SII], and HI. As a consequence, we are able to assess the overall excitation properties of the shell, and determine that line ratios towards the nebular periphery are anomalous, and characteristic of planar shocks with velocity V_s_>=110km/s. Pre-shock densities are likely to be modest, and of order 10^2^7arcsec. The minor axis distribution, on the other hand, appears to be somewhat more extended and bilobal. It is probable that complexities in the density mapping reflect the presence of condensations and filaments within the primary shell structure, and that these are also responsible for apparent variations in density as a function of forbidden and permitted line transition. %K planetary nebula: individual: NGC 2818 - ISM: jets and outflows %R 1998A&AS..133..387B %J-394 %A Balaguer-Nunez L., Tian K.P., Zhao J.L. %T Determination of proper motions and membership of the open clusters NGC 1817 and NGC 1807. %M ds7389 %F 1998.12.10 %B Relative proper motions, their corresponding observed errors and membership probabilities of 722 stars in the old open cluster NGC 1817 region are determined from PDS measurements of 12 plate pairs. The plates have the maximum epoch difference of 81 years and were taken with the double astrograph at Zo-Se station of Shanghai Observatory, which has an aperture of 40cm, a focal length of 6.9m and a plate scale of 30"/mm. The average proper motion accuracy is 1.6mas/yr. These proper motions are used to determine the membership probabilities of stars in the region. The existence of two clusters in the region (NGC 1817, NGC 1807) is discussed. The number of stars with membership probability higher than 0.7 is 416 for NGC 1817 and 14 for NGC 1807. %K open clusters - \object{NGC 1807}; \object{NGC 1817} - astrometry %R 1998A&AS..133..395B %J-402 %A Boccaletti A., Moutou C., Labeyrie A., Kohler D., Vakili F. %T Present performance of the dark-speckle coronagraph. %M ds7614 %F 1998.12.10 %B We present the recent developments of the dark speckle coronagraph and results obtained on two close binary stars. The central star is occulted by a Lyot coronagraphic system and the residual speckle pattern is detected on a photon-counting camera. Achromaticity is achieved across a wide spectral band, using a Wynne corrector. We observed the relatively faint companions of {delta} Per and {eta} Psc and give an independent estimate of their position and magnitude difference. %K planetary systems - stars: individual: {delta} Per, {eta} Psc, {eta} And - instrumentation: interferometers; miscellaneous %R 1998A&AS..133..403M %J-409 %A Mazzotta P., Mazzitelli G., Colafrancesco S., Vittorio N. %T Ionization balance for optically thin plasmas: Rate coefficients for all atoms and ions of the elements H to Ni. %M ds1529 %F 1998.12.10 %B We present in this paper new and updated calculations of the ionization equilibrium for all the elements from H to Ni. We collected for these elements all the data available in the literature for the ionization and radiative plus dielectronic recombination rates. In particular, the dielectronic rates have been fitted with a single formula and the related coefficients are tabulated. Our results are compared with previous works. %K atomic data - plasmas - radiation mechanisms: thermal - X-rays: general %R 1998A&AS..133..411L %J-425 %A Landi E., Landini M. %T The Arcetri spectral code for thin plasmas. %M ds7531 %F 1998.12.10 %B The Arcetri spectral code allows to evaluate the spectrum of the radiation emitted by hot and optically thin plasmas in the spectral range 1 - 2000 {AA}. The database has been updated including atomic data and radiative and collisional rates to calculate level population and line emissivities for a number of ions of the minor elements; a critical compilation of the electron collision excitation for these elements has been performed. The present version of the program includes the CHIANTI database for the most abundant elements, the minor elements data, and Fe III atomic model, radiative and collisional data. %K atomic data - plasmas - solar atmosphere - stellar atmosphere - ultraviolet: general - astronomical data bases: miscellaneous %R 1998A&AS..133..427V %J-430 %A Voitsekhovich V.V., Orlov V.G., Cuevas S., Avila R. %T Efficiency of off-axis astronomical adaptive systems: Comparison of theoretical and experimental data. %M ds1561 %F 1998.12.10 %B The efficiency of off-axis adaptive astronomical systems is estimated using both the theoretical Hufnagel model and recently obtained experimental C_n_^2^ profiles. The efficiency of interest is considered through the Strehl ratio of the corrected image. The experimental C_n_^2^ profile used in calculations is a result of measurements carried out at the Observatorio Astronomica Nacional at San Pedro Martir (Mexico). It is found that there is a significant difference in the efficiency calculated from both profiles because they differ strongly in structure. The experimental one has a pronounced layered structure with a great amount of the turbulence strength concentrated near the ground, while the theoretical profile suggests more smooth behavior of C_n_^2^ with altitude. %K atmospheric effects - telescope - instrumentation: adaptive optics %R 1998A&AS..133..431H %J-436 %A Harris D.E., Silverman J.D., Hasinger G., Lehmann I. %T Spatial corrections of ROSAT HRI observations. %M ds7906 %F 1998.12.10 %B X-ray observations with the ROSAT High Resolution Imager (HRI) often have spatial smearing on the order of 10", Morse, 1994PASP..106..675M). This degradation of the intrinsic resolution of the instrument (5") can be attributed to errors in the aspect solution associated with the wobble of the space craft or with the reacquisition of the guide stars. We have developed a set of IRAF/PROS and MIDAS/EXSAS routines to minimize these effects. Our procedure attempts to isolate aspect errors that are repeated through each cycle of the wobble. The method assigns a ``wobble phase" to each event based on the 402 second period of the ROSAT wobble. The observation is grouped into a number of phase bins and a centroid is calculated for each sub-image. The corrected HRI event list is reconstructed by adding the sub-images which have been shifted to a common source position. This method has shown ~30% reduction of the full width half maximum (FWHM) of an X-ray observation of the radio galaxy 3C 120. Additional examples are presented. %K techniques: image processing - X-rays: general %R 1998A&AS..133..437M %J-444 %A Manley S.P., Migliorini F., Bailey M.E. %T An algorithm for determining collision probabilities between small solar system bodies. %M ds7564 %F 1998.12.10 %B The introduction of surveys (e.g. Spacewatch, OCA-DLR) dedicated to the discovery of asteroids and other small bodies is likely to increase the number of known objects to many times the current figure of roughly 30000. Previous methods for determining collision probabilities amongst these objects (e.g. those due to Oepik, Wetherill, Greenberg and Kessler) all have idiosyncrasies which make them inappropriate for analyses of interactions between large numbers of solar system bodies. Here we present an adaptation of the Wetherill and Greenberg methods, which avoids approximations made by Oepik but which remains accurate and fast enough in its implementation to allow the direct analysis of the collision probabilities and impact velocities of thousands of potentially colliding objects. %K minor planets, asteroids - solar system: general - methods: analytical, numerical %R 1998A&AS..133..445P %J-445 %A Phillips J.P., Guzman V. %T (Erratum) Spectral trends in planetary nebulae: The roles of radiative and shock excitation. %F 1998.12.10 %B Erratum to Astron. Astrophys. Suppl. Ser. 130 (1998) 465-476.