Astronomy and Astrophysics Supplement Series

https://aas.aanda.org/

List of Papers (Total 1,899)

Atlas of high-resolution emission and shell lines in Be stars. Line profiles and short-term variability

We present an atlas of high-, high-resolution ( km ) data of Be star emission and shell profiles. We have collected profiles of Hα and of Fe ii, mostly of the λ5317 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...

Surface photometry of binary galaxies. I. A multicolour study of morphologies due to the interaction

We present the multicolour (B, V, R) surface photometry of 53 double galaxies. All the pairs belong to the catalogue of Reduzzi & Rampazzo (1995) containing objects selected according to the Karachentsev (1972) criteria. We comment on the morphological, structural and photometric characteristics of pairs and their members. Different classes of interaction induced phenomena, both...

Optical positions of radio stars. I.

The optical positions of 31 radio stars obtained from the observations with the photoelectric astrolabe at Yunnan Observatory are presented in this paper. These are all the stars in the astrometric catalogue of radio stars observable by our astrolabe.

Understanding radio polarimetry. I. Mathematical foundations

The measurement of polarized radiation uses entirely different methods at optical and radio wavelengths. As a result, the algebraic analysis of polarimeter performance differs and, in the case of radio interferometry, is unnecessarily complicated. We demonstrate that the mathematical operation of outer matrix multiplication provides the missing link between the two approaches...

Evolutionary sequences of stellar models with new radiative opacities. VI.

We present a large grid of stellar evolutionary models with the initial chemical composition . These tracks are conceived to extend the grid of stellar models described in the previous papers of this series, and are computed with the new radiative opacities by Iglesias et al. (1992) and convective overshoot. The tracks span the range of initial masses from to , and extend from...

Determination of effective temperatures for an extended sample of dwarfs and subdwarfs (F0-K5)

We have applied the InfraRed Flux Method (IRFM) to a sample of 475 dwarfs and subdwarfs in order to derive their effective temperatures with a mean accuracy of about 1.5%. We have used the new homogeneous grid of theoretical model atmosphere flux distributions developed by Kurucz (1991, 1993) for the application of the IRFM. The atmospheric parameters of the stars cover, roughly...

Cellular Automaton experiments on local galactic structure. II. Numerical simulations

This paper is a step towards demonstrating that the multi–parameter Cellular Automaton framework designed for the simulation of local galactic structure, developed in a companion paper (Perdang & Lejeune 1996, Paper I), is capable of duplicating the local irregularities observed in the structure of flocculent spiral galaxies. The numerical simulations exhibit the development of...

A library of IUE white dwarf spectra for stellar population analyses

We present high Signal to Noise ratio IUE spectra of different classes of white dwarfs, to be used as templates for stellar population analyses in the ultraviolet region. We present average stellar parameters associated to each group. The library contains 6 groups for DA's, 2 for DO's and 5 for DB's. We also present equivalent widths of spectral features, and continuum...

Optical structure and star formation in blue compact dwarf galaxies. I. Observations and profile decomposition

We present new B and R CCD surface photometry for a sample of 4 Blue Compact Dwarf Galaxies (BCDs) and 2 higher luminosity starburst galaxies. We find that the BCD surface brightness profiles (SBPs) can be generally well fitted by the sum of the light of 3 distinct components: 1) an exponential component at large radii, with or without a central flattening which describes the...

Temperature and luminosity effects in photoelectric spectrum scanner measurements of F0-K5 stars

We study the possibility to classify the stars with the use of the photoelectric spectrum scanner designed at Astronomisches Institut at Bochum using a spectral resolution of about 10 Å. We analyse temperature and luminosity effects in two spectral indices which were expected to be promising as spectral classification criteria from previous studies.

Optical polarimetry, high–resolution spectroscopy and IR analysis of the Chamaeleon I dark cloud

We present optical polarimetry and high resolution spectroscopy of a sample of stars toward the Chamaeleon I dark cloud. We use our polarimetry which includes 33 stars to study the wavelength dependence of the degree and position angle of polarization.
From fits to the normalized wavelength dependence of interstellar polarization, we derive estimates of ranging from 4500 Å to...

Stark broadening of spectral lines of multicharged ions of astrophysical interest - XV. P IV spectral lines

Using a semiclassical approach, we have calculated electron-, proton-, and He III-impact line widths and shifts for 114 P IV multiplets for perturber densities and temperatures . The obtained results have been compared with results obtained by using various simpler approaches.

HL Aurigae: A near-contact binary system

Photoelectric observations of HL Aur were carried out with the 60 cm reflector of Beijing Astronomical Observatory in 1990 and 1994, and the first photoelectric BV light curves were obtained along with a newly derived ephemeris. The period of the system appears to be constant over the past 65 years. Using the Wilson-Devinney program a photometric analysis of the B and V light...

Optical astrometry of Benchmark radio sources - IV. New results in the southern hemisphere

Optical positions relative to the International Reference Stars Catalogue (IRS), and therefore in the system of the FK5, have been obtained for the optical counterparts of 40 compact extragalactic radio sources south of δ ∼ +6°. Many of these sources are being considered as possible Benchmark objects for the establishment of a quasi-inertial unified radio/optical reference frame...

Deep morphologies of type I planetary nebulae

Deep narrow band interference filters observations are presented for 7 type I galactic planetary nebulae (PNe). Except for the nearly circular planetary nebula A 39, the observations show overall dimensions appreciably larger than those quoted so far. The observed PN (NGC 6302 excepted) could have linear diameters larger than 1 pc. Our new observations imply ionized masses often...

New methods of forming and aligning the instrumental frames of absolute transit circle catalogs

A new method of defining the declination axis of the instrumental frame of an absolute transit circle catalog has been developed utilizing observations from stars over the entire sky rather than, as in the past, observations of just circumpolar stars. This method allows the planetary observations to be used directly to align the axes of the instrumental frame thus constructed...

VLA polarimetry of compact steep spectrum sources

We present the polarization properties at sub-arcsecond resolutions of 8 Compact Steep-spectrum Sources (CSSs) observed with the VLA A-array at 5, 8.4 and 15 GHz. We find that the three most compact sources, two of which are unresolved and have an angular diameter milliarcsec are not polarized. Of the remaining 5, the two associated with quasars have prominent radio jets while...

Effelsberg multifrequency pulsar polarimetry

A sample of 64 well-calibrated pulsar polarization profiles measured at cm-wavelengths with the Effelsberg radio telescope is presented. All profiles were measured using an adding and a multiplying polarimeter which enables polarimetry over wide-bandwidths. Gain imbalances introduced by the active components in the signal path, as well as system imperfections, alter the...

An Atlas of high resolution synthetic spectra in the wavelength region

We present an Atlas of high resolution (resolving power ) synthetic spectra based on the 1993 release of atmosphere models and codes by Kurucz. The spectra are given in the wavelength interval 4850-5400 Å  for eleven values of effective temperature in the range 4000-8000 K, for nine surface gravities in the interval 1.0-5.0 dex, and for seven metallicities spanning from -1.0 to...

Stark broadening of spectral lines of multicharged ions of astrophysical interest - XVI. S V spectral lines

Using a semiclassical approach, we have calculated electron-, proton-, and He III-impact line widths and shifts for 34 S V multiplets for perturber densities and temperatures . For lower perturber densities, the obtained results are linear with perturber density.

The electron impact broadening parameters in hot star atmospheres: Mn II, Mn III, Ga III, Ge III and Ge IV lines

The electron - impact line widths and shifts for 16 Mn II, 3 Mn III, 10 Ga III, 8 Ge III and 14 Ge IV multiplets, have been considered within a modified semiempirical approach. Moreover, using a semiclassical approach, we have considered electron-, pro ton-, and He III-im pact line widths and shifts for 3 Ge IV multiplets. The obtained results have been compared with other...

Measured Stark widths and shifts of NII, NIII and NIV spectral lines

Stark parameters (widths and shifts) of eight singly, seven doubly and five triply ionized nitrogen spectral lines have been measured in linear pulsed, low pressure, arc discharge in a nitrogen plasma at a 54 000 K electron temperature and a m-3 electron density. The measured values have been compared to the existing experimental and calculated data.

Searching for old neutron stars with ROSAT - I. Soft X-ray sources in molecular clouds at high galactic latitude

This is the first in a series of three papers aiming to put strong observational constraints on the number of old accreting neutron stars in the Galaxy. Old neutron stars have been predicted to be visible as soft X-ray sources. The brightest sources are expected where the density of the interstellar medium is high. I present an X-ray survey of a complete sample of molecular...

CCD photometry and distances of six resolved irregular galaxies in Canes Venatici

The results of detailed imaging of six nearby irregular galaxies with radial velocities  km/s are presented. Except for one all the galaxies have been resolved into stars for the first time. Based on photometry of the brightest blue stars we derived the following distances to the galaxies: 3.6 Mpc for NGC 4163, 3.5 Mpc for NGC 4190, 8.6 Mpc for UGC 7298, 4.8 Mpc for UGC 7577, 3.7...

B[e] stars - V. HD 50138 = MWC 158

On the basis of spectroscopic CCD material obtained at the Haute Provence Observatory, we provide line identifications and equivalent width measurements in the wavelength region 3738-10232 A of the spectrum of HD 50138 Over two hundred features are identified and a comparison of our results with those of other authors is provided. We also discuss the variability of the lines...