Astronomy and Astrophysics Supplement Series

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List of Papers (Total 1,079)

B[e] stars - VIII. MWC 342

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 4095-8935 Å  of the spectrum of MWC 342. Two hundred eighty emission features are identified and eighteen absorption features. Nine interstellar bands could be identified. Some of the remaining absorption...

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...

The 3-D structure of the Coma–A 1367 supercluster: Optical spectroscopy of 102 galaxies

Optical spectroscopy of 117 CGCG galaxies, 102 of which are projected in the direction of the Coma–A 1367 supercluster, is reported. These new measurements, added to those found in the literature, bring to 1068 the number of CGCG galaxies in this region with available redshift, out of a total of 1085 objects with . We use these data to infer the 3-D structure of the Coma...

H I -rich dwarf galaxies in the Hydra I cluster - I. Photometric and H I data

We present H I, optical and near-infrared photometric data of a sample of H I–selected dwarf galaxy candidates in the Hydra I cluster. This database has been compiled in order to study environmental effects on dwarf galaxies in clusters, in particular the role of interactions between them and either the intracluster-medium or companion galaxies, hitherto studied mainly in massive...

3D mapping of optical turbulence using an atmospheric numerical model - I. A useful tool for the ground-based astronomy

These last years have seen the development of many devices to measure and monitor some atmospheric parameters characterizing the image degradation at the telescope focus. Many uncertainties about the possibility to forecast such parameters are real although this skill is fundamental for site testing, flexible scheduling and optimization of the performance of both interferometry...

1994-1996 CCD astrometric observations of Saturn's satellites and comparison with theories

In this paper, we publish 451 measurements of positions of the major satellites of Saturn made in 1994, 1995 and 1996 using a CCD detector attached to the 1.56 m reflector at the Sheshan Station near Shanghai. The observations we have made include the seven major satellites exclusive of the outermost satellite Iapetus. In our implementation the four contemporary theories were...

Hydrogen content in Kazarian galaxies

Several H I related astrophysical parameters such as neutral hydrogen total mass and hydrogen mean projected density, indicative total mass as well as usual ratios , and for 23 galaxies from Kazarian lists are derived. Their variation ranges are rather wide almost coinciding with those for normal galaxies belonging to the same morphological types. Kazarian galaxies do not...

A survey of UV-excess AGNs in the South Galactic Pole - A sample for the analysis of the QSO clustering

Spectra, position, magnitudes and colors are presented for 485 faint () emission line objects selected with the ultraviolet-excess (UVX) criterion on a area of 24.6 deg2 in the South Galactic Pole. The objects were selected from the analysis of pixel-to-pixel stacking of COSMOS scans of UKST U J and R plates. The candidates were observed with the Meudon-ESO Fiber Optics System...

An absolute calibration of DENIS (deep near infrared southern sky survey)

An absolute calibration of the DENIS photometric system is presented. It includes the determination of the overall transmission profiles in the 3 bands, namely i, J and Ks, combining contributions from atmosphere, telescope mirrors, instrument lenses and dichroics, filters, and detectors. From these normalized profiles, isophotal and effective wavelengths are computed, using the...

Interferometric imaging tests for the Large Binocular Telescope

We present an experiment of interferometric imaging for the Large Binocular Telescope (LBT), conducted at the 1.5 m TIRGO infrared telescope. The raw data were produced by simulating the LBT pupil with a mask on the secondary mirror. Two different conditions of , where is the single aperture diameter and the Fried parameter, were simulated by the choice of ; field rotation was...

HI observations of nearby galaxies - I. The first list of the Karachentsev catalog

We present HI observations of the galaxies in the first list of the Karachentsev catalog of previously unknown nearby dwarf galaxies (Karachentseva & Karachentsev 1998). This survey covers all known nearby galaxy groups within the Local Volume (i.e. within 10 Mpc) and their environment, that is about 25% of the total sky. A total of 257 galaxies have been observed with a...

Estimating the point spread function of the adaptive optics system ADONIS using the wavefront sensor measurements

Adaptive Optics (AO) has been developed to compensate the wavefront deformation due to the atmospheric turbulence. The wavefront correction, however, is often only partial and a residual blur is present in a long exposure image. It is therefore important to deconvolve the image to do accurate photometry or to detect faint structures. For this, the point spread function (PSF) has...

Micrometer measurements of double stars made at the Côte D'Azur and Calar Alto observatories

We report 312 micrometer measurements of 155 visual double stars made with the 50 cm refractor at the Côte D'Azur observatory (Nice, France) and with the 152 cm telescope at Calar Alto observatory (Almería, Spain).

Tuorla quasar monitoring

We present results of optical monitoring of quasars and blazars obtained at Tuorla Observatory between September 1995 and May 1997. The aim of our monitoring is to provide well sampled optical light curves for quasar and blazar studies. During the observing period the V-band brightness of S2 0109+224, 3C 66A, and ON 231 (W Comae) reached some of the brightest values ever measured...

Polarization for pair annihilation in strong magnetic fields

We derive the cross-section for one-quantum annihilation of polarized electrons and positrons. The electron and positron can occupy arbitrary Landau levels and have non-zero momentum parallel to the field, and the cross-section is calculated for any polarization of the radiation. When we take zero parallel momentum for the electron and sum over photon polarization we obtain...

A revised catalogue of δ Sct stars

An extensive and up-dated list of δ Sct stars is presented here. More than 500 papers, published during the last few years, have been revised and 341 new variables have been added to our last list, six years ago. This catalogue is intended to be a comprehensive review on the observational characteristics of all the δ Sct stars known until now, including stars contained in earlier...

Strömgren and Hβ photometry of O and B type stars in star-forming regions - III. Carina Spiral Feature

Strömgren and Hβ photometry of O and B type stars, generally brighter than 9.5 mag is reported for the field of the Carina Spiral Feature. The observations are based on the PPM catalogue identifications and are designed to improve the completeness of the existing data for the bright early-type stars in the field. We present new uvby photometry for 283 stars and Hβ photometry for...

Blind source separation and analysis of multispectral astronomical images

Celestial sources are studied by means of multispectral analysis, for which a pixel value can be considered as a mixture of different sources. We show that the application of blind source separation methods can display interesting features, which can help astronomers to improve their description of celestial sources. Experiments were carried out on Hubble Space Telescope images...

Time variability of five strong 12 GHz methanol masers

Five intense 12 GHz methanol masers with structured profile have been monitored during the period 90 Nov.-92 Apr., in order to study the variability on time scales ranging from one week to about 2 years. The integrated flux density of W3(OH), G188.94 +0.89, NGC 7538 remains constant (within the measurement uncertainties) during our period of observation. By amplitude...

TU Bootis: An ambiguous W Ursae Majoris system

The W UMa system TU Boo has a period of 0.32438 days and a spectral type G3. We present here the first photometric analysis, based on photoelectric B and V light curves. The q-search method was used to find the preliminary range of the mass-ratio in order to search for the final solution. The unspotted solution was found by using the unperturbed part of the light curve and...

Surface photometry of galaxies in low density regions

We perform detailed surface photometry, based on B- and/or R-band CCD images of 92 faint galaxies. They are a subsample of those galaxies which were studied by Hopp et al. (1994) in the direction of three nearby voids. We derive integral photometric parameters and radial surface brightness profiles and compare them to those of several faint galaxy samples, located in different...

Multi-colour photometric and spectroscopic monitoring of the WN5 star EZ Canis Majoris

We present and analyse photometric and spectroscopic observations of the WN5 star EZ Canis Majoris obtained over a period of 7 years. We discuss the changing light curve, the shift in phase of the maxima and point to flare type variability seen in one night. Small amplitude variations are reported in another night. We have investigated the change of the average visual magnitude...

New weak-line T Tauri stars in Orion from the ROSAT all-sky survey

We present results of the spectroscopic and photometric follow-up observations of the ROSAT all-sky survey in the direction of the Orion cloud complex. The main goal of these observations is the search for X-ray emitting pre-main sequence stars. 820 X-ray sources were detected with high confidence in about 450 square degrees. The mean density of X-ray sources in this region is a...

UBVRI photometric monitoring of 7 rapidly rotating late-type dwarfs in the Alpha Persei cluster

The UBVRI light curves of 7 late-type dwarfs amongst the fastest rotators of the Alpha Per cluster (vsini ≥140 km s-1) are presented. The shape of the light curves suggests that the photometric variations are most often dominated by a single group of cool spots located at intermediate or high latitude on the stellar surface. Assuming that starspots are good tracers of the stellar...

A 15 years monitoring program at 408 MHz

This is the second paper based on the 408 MHz monitoring program with the East-West arm of the Bologna interferometer. The monitoring concerned 125 radio sources measured approximately once a month for 15 years. We present the summary of the variability analysis concerning all the sample and the monitoring data, not yet published, of the variable sources.