Astronomy and Astrophysics Supplement Series

https://aas.aanda.org/

List of Papers (Total 2,129)

An astrometric catalogue for the area of Coma Berenices

A catalogue of stellar positions and proper motions down to the 14th photographic magnitude in the area of the open cluster in Coma Berenices is compiled from data of 12 different sources. The accuracy of the proper motion data is comparable to that of the Hipparcos Catalogue.

A nonlinear convective model for radial stellar pulsations - I. The physical description

The physical and numerical ingredients of the Vienna nonlinear model for radially pulsating stars are presented. Stellar pulsations are investigated by solving the full system of radiation hydrodynamics including a time-dependent formulation of turbulent convection. The numerical solution method comprises a state-of-the-art adaptive grid algorithm which provides a powerful tool...

ASCA observations of massive medium-distant clusters of galaxies - I. A 1300 and A 1732

We have selected a sample of 10 medium distant () clusters for deep, high-resolution, multi-wavelength observations in order to investigate in detail their dynamical state. This paper presents the analysis of the ASCA data for the two sample clusters observed under the ESA time allocation. For A 1300 and A 1732 we find temperatures and metal abundances for the intra-cluster...

The central black hole masses and Doppler factors of the γ-ray loud blazars

In this paper, the central black hole masses and the Doppler factors are derived for PKS 0528+134, PKS 0537-441, 3C 279, PKS 1406-074, PKS 1622-297, Q1633+382, Mkn 501, and BL Lacertae. The masses obtained are in the range of () and compared with that obtained with the Klein-Nishina cross section considered (Dermer & Gehrels 1995). If we considered only the Thomson cross section...

Evolution of the "efficiency” when different data sets are combined into a unified adjustment

Using a sample of binaries which were observed visually (VB) as well as spectroscopically for both components (SB2), we show that the efficiency almost always increases when a combined VB-SB2 solution replaces one based only on VB.

New spectroscopic components in 8 multiple systems

New close sub-systems are discovered in 8 visual late-type double stars. Elements of spectroscopic orbits (4 double-lined and 4 single-lined) are given for the components of quadruple systems ADS 1134 and 11163, for the components of triple systems ADS 455, 497, 5436, 8236, 10044, and for the primary of the optical pair ADS 9444. Magnitudes, colors, spectral types, masses of...

High density molecular clumps around protostellar candidates

There are several indications that strong H2O maser emission arises at the very beginning of the evolution of a massive star and disappears when an Hii region becomes detectable in the radio continuum. If this is the case, one expects to find dense hot molecular gas surrounding embedded far IR sources coincident with H2O masers. In order to test this hypothesis, we have used the...

uvby photometry of the mCP stars HD 35298, 19 Lyrae, HD 192678, and HR 8216

Differential Strömgren uvby observations from the Four College Automated Photoelectric Telescope are presented for the mCP stars HD 35298, 19 Lyr, HD 192678, and HR 8216. The period for HD 35298 of 1.85457 days is a revision of North's value while that for 19 Lyr of 7.0980 days is alias of that found by Winzer. HD 192678 is found to be a small amplitude photometric variable with...

On the nature of the Herbig Be star V 380 Orionis

We discuss new and archive spectroscopic and photometric observations of the Herbig Ae star V 380 Ori obtained between 1978 and 1995 and covering at different epochs the wavelength range from 1200 Å to 5 μm. The coordinated JHKLM and CVF infrared observations and optical spectroscopy made at ESO of March 1985 confirm the presence of a strong IR excess due to emission from hot...

New catalogue of Wolf-Rayet galaxies and high-excitation extra-galactic Hii regions

We present a new compilation of Wolf-Rayet (WR) galaxies and extra-galactic Hiiregions showing broad emission drawn from the literature. Relevant information on the presence of other broad emission lines (N iii λ4640, C iv λ5808 and others) from WR stars of WN and WC subtypes, and other existing broad nebular lines is provided. In total we include 139 known WR galaxies. Among...

Atomic data from the Iron Project - XXXVII. Electron impact excitation collision strengths and rate coefficients for Fe VI

Collision strengths and Maxwellian-averaged rate coefficients have been calculated for 3 160 non-vanishing transitions among 80 fine structure levels, dominated by configurations , and p in Fe VI. Collision strengths are calculated using the R-matrix method with a 34-term close-coupling target expansion and for electron energies up to 10 Rydbergs. Detailed comparisons of rate...

Atomic data from the IRON Project - XXXIV. Electron impact excitation of Fe xvi

As part of the IRON Project, electron impact excitation effective collision strengths are computed for the ion Fe xvi familiar in solar spectra. A Breit–Pauli R-matrix calculation is performed with a 12-level () target representation. The calculation for this relatively simple ion is approached as a test case where we can analyze in detail most of the effects that contribute to...

uvby photometry of the magnetic CP stars 45 Leonis, HR 4330, 49 Herculis, and HR 6718

Differential Strömgren uvby photometric observations from the Four College Automated Photoelectric Telescope are presented for the magnetic CP stars 45 Leo, HR 4330, 49 Her, and HR 6718. We refined Winzer's periods for 45 Leo and HR 6718 to 1.443820 days and 0.51899 days, respectively. For HR 4330 our period of 3.516 days is quite different from that of Winzer. That for 49 Her, 0...

New spectroscopic components in 8 multiple systems

New close sub-systems are discovered in 8 visual late-type double stars. Elements of spectroscopic orbits (4 double-lined and 4 single-lined) are given for the components of quadruple systems ADS 1134 and 11163, for the components of triple systems ADS 455, 497, 5436, 8236, 10044, and for the primary of the optical pair ADS 9444. Magnitudes, colors, spectral types, masses of...

High density molecular clumps around protostellar candidates

There are several indications that strong H2O maser emission arises at the very beginning of the evolution of a massive star and disappears when an Hii region becomes detectable in the radio continuum. If this is the case, one expects to find dense hot molecular gas surrounding embedded far IR sources coincident with H2O masers. In order to test this hypothesis, we have used the...

Spectroscopic observations of young open clusters: IC 1805, NGC 654 and NGC 6823

Spectroscopic observations were made for a sample of 263 stars from three young open clusters IC 1805, NGC 654 and NGC 6823 with CCD detectors in the blue and yellow-red spectral regions. MKK types were properly determined for these stars by carefully comparing spectra of program stars with those of a complete grid of MKK standards, which were observed with the same instruments...

Gravitational lensing statistics with extragalactic surveys - II. Analysis of the Jodrell Bank-VLA Astrometric Survey

We present constraints on the cosmological constant from gravitational lensing statistics of the Jodrell Bank-VLA Astrometric Survey (JVAS). Although this is the largest gravitational lens survey which has been analysed, cosmological constraints are only comparable to those from optical surveys. This is due to the fact that the median source redshifts of JVAS are lower, which...

photometry of Nova V723 Cassiopeiae 1995

We discuss the evolution of nova V723 Cassiopeiae 1995 based on JHK photometry covering a period of 15 months beginning two months following outburst. The first two post-outburst flares are covered by these observations.

A ROSAT PSPC X-ray survey of the Small Magellanic Cloud

We present the results of a systematic search for point-like and moderately extended soft (0.1-2.4 keV) sources in a raster of nine pointings covering a field of and performed with the ROSAT  PSPC between October 1991 and October 1993 in the direction of the Small Magellanic Cloud (SMC). We detect 248 objects which we include in the first version of our SMC catalogue of soft X...

Predicted HST FOC and broad band colours for young and intermediate simple stellar populations

This paper presents theoretical HST and broad band colours from population synthesis models based on an homogeneous set of stellar evolutionary tracks as computed under canonical (no overshooting) assumptions, covering the range of cluster ages from Myr to Gyr for three different metallicities (, 0.006, and 0.001). Statistical fluctuations in the cluster population have been...

An astrometric catalogue for the area of Coma Berenices

A catalogue of stellar positions and proper motions down to the 14th photographic magnitude in the area of the open cluster in Coma Berenices is compiled from data of 12 different sources. The accuracy of the proper motion data is comparable to that of the Hipparcos Catalogue.

Extension of Tycho catalog for low-extinction windows in the galactic bulge

We present in this work secondary catalogs up to based on the Tycho reference frame (ESA, 1997) for 12 selected low-extinction fields towards the galactic bulge. The observations have been performed with the Askania-Zeiss Meridian Circle equiped with a CCD camera, located at the Abrahão de Moraes Observatory (Valinhos, Brazil) and operated by the Institute of Astronomy and...