%R 1998A&AS..132....1U
%J-12
%A Ulla A., Thejll P.
%T Infrared flux excesses from hot subdwarfs. II. 72 more objects.
%M ds6013
%F 1998.09.25
%B In our search, started in February, 1994, for JHK excess fluxes among the hot subdwarf population as an indicator for the presence of binary companions, results for 72 more hot objects (=63 hot subdwarfs + 1 Horizontal Branch B star + 7 white dwarfs + 1 non-subdwarf object) observed with the Carlos Sanchez CVF IR photometer (in June and October, 1994), are presented. The exact number of binary hot subdwarfs has gained renewed importance after the recent discovery of
pulsators with G-F companions. The total number of candidates we propose may help to set some constraints; for example, out of 41 objects with excesses, 13 may have G-type binary companions. From our new sample, 14 discoveries of binary candidates have been found: BD+25 4655, Feige 108, HD4539, HD149382, HD216135, KPD2109+440, LSI+63 198, LSIV+10 9, LSV+22 38, PG 0011+221, PG 0116+242, PG 0314+103, PG 2151+100 and TON 139. Besides, 2 more from reanalysis of February, 1994,
data - BD+37 1977 and BD+48 1777, may now be found to be IR excess candidates. Two suspected binaries, PB 8555 and SB 7, are also confirmed. By fitting Kurucz (1993, Kurucs CD-ROM No. 13) model spectra and assuming zero-age main sequence companions, we find upper limits on the subdwarf gravities. The distributions of upper limits on log(g), mostly between about 5.25 and 6.5, are nearly identical for both sdBs and sdOs.
%K surveys - stars: subdwarfs - binaries: spectroscopic - white dwarfs - infrared: stars

%R 1998A&AS..132...13D
%J-20
%A Durand S., Acker A., Zijlstra A.
%T The kinematics of 867 galactic planetary nebulae.
%M ds1391
%F 1998.09.25
%B We present a compilation of radial velocities of 867 galactic planetary nebulae. Almost 900 new measurements are included. Previously published kinematical data are compared with the new high-resolution data to assess their accuracies. One of the largest samples in the literature shows evidence for a systematic velocity offset. We calculate weighted averages between all available data. Of the final values in the catalogue, 90% have accuracies better than 20km/s. We use
this compilation to derive kinematical parameters of the galactic differential rotation obtained from least-square fitting and to establish the Disk rotation curve; we find no significal trend for the presence of an increasing external rotation curve. We examine also the rotation of the bulge; the derived curve is consistent with a linearly increasing rotation velocity with l: we find V_b,r_=(9.9+/-1.3)l-(6.7+/-8.5)km/s. A possible steeper gradient in the innermost
region is indicated.
%K catalogues - planetary nebulae - Galaxy (the): kinematics of

%R 1998A&AS..132...21S
%J-27
%A Schmidtobreick L., Schlosser W., Koczet P., Wiemann S., Juette M.
%T Photographic surface photometry of the Southern. Milky Way IX. High-resolution surface photometries at 217nm and 280nm.
%M ds1512
%F 1998.09.25
%B We present the first surface photometries of the Southern Milky Way (100{deg}<=l>=270{deg}; -40{deg}<=b<=40{deg}) at 217nm and 280nm. The resolution is 0.25deg x 0.25deg. They are based on photographs obtained with the shuttle-borne GAUSS-Camera as part of the German Spacelab Mission D-2. These photometries are the extensions of the earth-bound U,B,V,R photometries (Kimeswenger et al., 1993A&AS...97..517K = Paper VII; Hoffmann et al., 1998A&AS..128..417H = Paper VIII) to the ultraviolet. The data processing
was modified to adapt it to the new data. Both photometries are strongly affected by interstellar extinction especially of local dark clouds. Hence, they provide a comprehensive overview of scattering caused light emission in our Galaxy.
%K Galaxy (the): structure - Galaxy (the): open clusters and associations - techniques: photometry - interstellar medium: dust - interstellar medium: reflection nebulae - ultraviolet: general

%R 1998A&AS..132...29T
%J-30
%A Thorel J.-C.
%T Mesures d'etoiles doubles effectuees a la lunette de 50 cm de l'Observatoire de Nice (2^e^ serie). Measures of visual double stars made with the 50 cm refractor at the Nice Observatory (2^nd^ series).
%M ds1536
%F 1998.09.25
%B 66 measures of 38 visual double stars made at the Observatoire de la Cote d'Azur, at Nice, in september et december 1997, with the 50 cm equatorial refractor equipped with filar micrometer and electronic recording device. Observation programmes of stars suspected double and new binaries discovered by Hipparcos, and measures of double stars which have seldom or never been observed since the epoch of their discovery.
%K astrometry - visual binaries

%R 1998A&AS..132...31N
%J-37
%A Nilsson K.
%T Kinematical models of double radio sources and the unified scheme. II. The database.
%M h0894
%F 1998.09.25
%B A large database of 1038 edge-brightened double radio sources has been collected from the literature with special emphasis on finding the best radio map for each source and on obtaining flux information of the extended radio lobes and the core component. The data are collected with two goals in mind. The first goal is to provide the data for our statistical study of double radio source symmetry and the unified scheme in the theoretical framework of Baryshev & Teerikorpi (1995A&A...295...11B,
Paper I). It is also believed that the data are useful to the research community and thus extensive data are given in tabular form.
%K galaxies: active - jets - radio continuum: galaxies

%R 1998A&AS..132...39M
%J-43
%A Mantegazza L., Antonello E.
%T Search for second overtone mode Cepheids in the Magellanic Clouds. I. Study of three candidates in the Small Magellanic Cloud.
%M ds1510
%F 1998.09.25
%B Accurate CCD observations of three Cepheids in the SMC were made with the purpose of confirming their nature of second overtone mode Cepheids. The stars were suspected pulsating in the second overtone mode owing to the unusual light curve and short period reported by Payne-Gaposchkin & Gaposchkin (1966SAOCo...9....1P). The analysis of the new data shows that for two stars the previous periods are wrong, and in the three cases the new light curves are normal. According to the new
observations, HV 1353 is a fundamental mode pulsator with small amplitude, and HV 1777 and HV 1779 are first overtone mode pulsators.
Also the star HV 1763, whose nature was unknown, was observed in the field of HV 1777. The new data show that it is a first overtone mode Cepheid with P=2.117d.
%K stars: oscillations - Cepheids - Magellanic Clouds - stars: individual: \object{HV 1353} (SMC); \object{HV 1777} (SMC); \object{HV 1779} (SMC)

%R 1998A&AS..132...45P
%J-54
%A Peraiah A., Srinivasa Rao M.
%T A series of theoretical line profiles formed in the irradiated expanding atmospheres of close binary components.
%M ds1378
%F 1998.09.25
%B We studied the effects of irradiation on the line formation in the expanding atmospheres of the components of close binary systems. We considered a two-level atom approximation in Non-LTE situation. The thickness of the atmosphere is assumed to be twice that of the stellar radius. Expansion velocities are assumed to be as large as 50 mean thermal units. We have computed the lines using total optical depths 10^3^, 10^4^ and 10^5^ at the line centre. The irradiation from the
secondary is assumed to be one, five and ten times the self radiation. The line fluxes in the line of sight are calculated by using the total source function which is the sum of the source functions due to self radiation and that due to irradiation. We notice that the expansion of the medium produces P Cygni type profiles and the irradiation enhances the emission in the lines although the equivalent widths reduce considerably.
%K radiative transfer - lines: formation; profiles - binaries: close

%R 1998A&AS..132...55B
%J-63
%A Bennett S.M., Moss C.
%T H{alpha} objective prism survey of Abell 1060.
%M ds7438
%F 1998.09.25
%B As part of a continuing study of the effect of cluster environment on the star formation properties of galaxies, we have undertaken an H{alpha} objective prism survey of the nearby cluster, Abell 1060. We detect 33 galaxies in emission, 24 of which are cluster members. We present new radial velocity measurements and H{alpha}+[NII] equivalent widths and fluxes for a number of these galaxies. We distinguish between galaxies with diffuse and compact emission, the latter
having been associated in previous work with a disturbed morphology of the galaxy and most likely resulting from tidally-induced star formation from galaxy-galaxy or cluster-galaxy interactions. The fraction of cluster spirals in Abell 1060 detected with compact emission agrees with the expected fraction for a cluster of its richness, as derived from results of a previous survey of 8 clusters. Some of the detected cluster early-type spirals exhibit anomalously high global
H{alpha} equivalent widths, as compared to galaxies of similar type in the field.
%K galaxies: clusters: general - galaxies: clusters: individual: Abell 1060 - galaxies: spiral - galaxies: starburst

%R 1998A&AS..132...65H
%J-81
%A Heck A.
%T Astronomy-related organizations over the world.
%M ds1548
%F 1998.09.25
%B The geographical distribution of astronomy-related organizations is illustrated from comprehensive and up-to-date samples. Results for professional institutions, for public observatories, for planetariums, and for associations are commented and compared to an earlier study involving only observational locations (observing and receiving stations). Specific distributions of astronomy-related publishers and software producers are also illustrated. There is a reinforcement of
the tendencies pointed out in the previous study with very high densities in Europe and Northeastern U.S.A. Comments are offered on specific concentrations and national differences. It is also clear that numerous institutions and associations are not involved in direct observing. The astronomy-related publishers and software producers are interestingly concentrated in only a few places.
%K sociology of astronomy - astronomical datbases: miscellaneous

%R 1998A&AS..132...83B
%J-92
%A Bai J.M., Xie G.Z., Li K.H., Zhang X., Liu W.W.
%T The intraday variability in the radio-selected and X-ray-selected BL Lacertae objects.
%M ds7304
%F 1998.09.25
%B Seven BL Lac objects have been photometrically observed in an effort to study the difference of optical intraday variability between the radio-selected BL Lac objects (RBLs) and X-ray-selected BL Lac objects (XBLs). The objects we observed are selected arbitrarily. They are four RBLs, PKS 0735+178, PKS 0754+101, OJ 287 and BL Lac, and three XBLs, H 0323+022, H 0548-322 and H 2154-304. During the observation all of them exhibited microvariation, and H 0323+022 and H
0548-322 sometimes showed brightness oscillation. PKS 0735+178 and BL Lac were in their faint states and not very active. It seems that RBLs do not show microvariability more frequently than XBLs.
%K BL Lacertae objects: general - galaxies: photometry

%R 1998A&AS..132...93A
%J-97
%A Adelman S.J.
%T On the Hipparcos photometry of chemically peculiar B, A, and F stars.
%M ds7532
%F 1998.09.25
%B The Hipparcos photometry of the Chemically Peculiar main sequence B, A, and F stars is examined for variability. Some non-magnetic CP stars, Mercury-Manganese and metallic-line stars, which according to canonical wisdom should not be variable, may be variable and are identified for further study. Some potentially important magnetic CP stars are noted.
%K stars: early type - stars: chemically peculiar

%R 1998A&AS..132...99K
%J-105
%A Kimura E., Ohsaki A., Nakazaki S., Itikawa Y.
%T Electron-impact excitation rates of Na-like ions.
%M h0858
%F 1998.09.25
%B Electron excitation collision strengths for all the transitions among 3s, 3p, 3d, 4s, 4p, 4d, 4f states of the five Na-like ions Al III, Si IV, S VI, Ar VIII and Ca X are calculated in the R-matrix approximation. Eleven target terms are included in the expansion of the total wavefunction. These collision strengths are averaged over a Maxwellian velocity distribution to obtain effective collision strengths as a function of electron temperature. The resulting values are
compared with the results of previous less elaborate calculations to find some disagreements.
%K atomic data

%R 1998A&AS..132..107A
%J-119
%A Appourchaux T., Gizon L., Rabello-Soares M.-C.
%T The art of fitting p-mode spectra. I. Maximum likelihood estimation.
%M ds7208
%F 1998.09.25
%B In this article we present our state of the art of fitting helioseismic p-mode spectra. We give a step by step recipe for fitting the spectra: statistics of the spectra both for spatially unresolved and resolved data, the use of Maximum Likelihood estimates, the statistics of the p-mode parameters, the use of Monte-Carlo simulation and the significance of fitted parameters. The recipe is applied to synthetic low-resolution data, similar to those of the LOI, using
Monte-Carlo simulations. For such spatially resolved data, the statistics of the Fourier spectrum is assumed to be a multi-normal distribution; the statistics of the power spectrum is not a {chi}^2^ with 2 degrees of freedom. Results for l=1 shows that all parameters describing the p modes can be obtained with negligible bias and with minimum variance provided that the leakage matrix is known. Systematic errors due to an imperfect knowledge of the leakage matrix are derived
for all the p-mode parameters.
%K methods: analytical; data analysis; statistical - Sun: oscillations

%R 1998A&AS..132..121A
%J-132
%A Appourchaux T., Rabello-Soares M.-C., Gizon L.
%T The art of fitting p-mode spectra. II. Leakage and noise covariance matrices.
%M ds7200
%F 1998.09.25
%B In Part I we have developed a theory for fitting p-mode Fourier spectra assuming that these spectra have a multi-normal distribution. We showed, using Monte-Carlo simulations, how one can obtain p-mode parameters using ``Maximum Likelihood Estimators". In this article, hereafter Part II, we show how to use the theory developed in Part I for fitting real data. We introduce 4 new diagnostics in helioseismology: the (m,{nu}) echelle diagram, the cross echelle diagram, the
inter echelle diagram, and the cross spectrum ratio. These diagnostics are extremely powerful to visualize and understand the covariance matrices of the Fourier spectra, and also to find bugs in the data analysis code. The diagrams are used to verify the computation of the leakage matrices, and also to measure quantitatively these matrices. Cross spectrum ratios are used to obtain quantitative information on the noise covariance matrices. Numerous examples using the LOI/SOHO
and GONG data are given.
%K methods: data analysis - statistical - observational - Sun: oscillations

%R 1998A&AS..132..133N
%J-143
%A Ng Y.K.
%T Stellar population synthesis diagnostics.
%M ds7245
%F 1998.09.25
%B A quantitative method is presented to compare observed and synthetic colour-magnitude diagrams (CMDs). The method is based on a {chi}^2^ merit function for a point (c_i_,m_i_) in the observed CMD, which has a corresponding point in the simulated CMD within n{sigma}(c_i_,m_i_) of the error ellipse. The {chi}^2^ merit function is then combined with the Poisson merit function of the points for which no corresponding point was found within the n{sigma}(c_i_,m_i_) error ellipse
boundary. Monte-Carlo simulations are presented to demonstrate the diagnostics obtained from the combined ({chi}^2^, Poisson) merit function through variation of different parameters in the stellar population synthesis tool. The simulations indicate that the merit function can potentially be used to reveal information about the initial mass function. Information about the star formation history of single stellar aggregates, such as open or globular clusters and possibly dwarf
galaxies with a dominating stellar population, might not be reliable if one is dealing with a relatively small age range.
%K methods: data analysis, numerical - stars: HR-diagram, statistics

%R 1998A&AS..132..145M
%J-153
%A McIntosh S.W., Diver D.A., Judge P.G., Charbonneau P., Ireland J., Brown J.C.
%T Spectral decomposition by genetic forward modelling.
%M h0844
%F 1998.09.25
%B We discuss the analysis of real and simulated line spectra using a genetic forward modelling technique. We show that this Genetic Algorithm (GA) based technique experiences none of the user bias or systematic problems that arise when faced with poorly sampled or noisy data. An important feature of this technique is the ease with which rigid a priori constraints can be applied to the data. These constraints make the GA decomposition much more accurate and stable, especially
at the limit of instrumental resolution, than decomposition algorithms commonly in use.
%K Sun: UV radiation - methods: data analysis - techniques: spectroscopic - line: identification - profiles