R. Weinberger

HaTr 10, a Planetary Nebula with Extremely Strong Nitrogen Lines

ABSTRACT Optical spectra and direct images reveal that a very faint, scarcely studied object (HaTr 10) which appears as an incomplete elliptical ring of 0 \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

CG J1720–67.8: A Detailed Analysis of Optical and Infrared Properties of a New Ultracompact Group of Galaxies*

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A New Ultradense Group of Obscured Emission-Line Galaxies

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IRAS 18456-0223 -a flare star in a new star forming region

We present here optical spectroscopy and BVRJHKs photometry of the recently discovered ultracompact group of galaxies CG J1720-67.8. This work represents a considerable extension of the preliminary results we presented in a previous paper. Despite the complicated morphology of the group, a quantitative morphological classification of the three brightest members of the group is attempted based on photometric analysis. We find that one galaxy is consistent with a morphological type S0, while the other two are most probably late-type spiral galaxies that are already losing their identity because of the interaction process. Information on the star formation activity and dust content derived from both spectroscopic data and optical and near-infrared colors is complemented with a reconstruction of far-infrared maps from IRAS raw data. Enhanced star formation activity is revealed in all the groups members, including the early-type galaxy and the extended tidal tail, along which several tidal dwarf galaxy candidates are identified. The metallicity of the gaseous component is investigated, and photoionization models are applied to the three main galaxies of the group, while a detailed study of the tidal dwarf candidates will appear in a companion paper. Subsolar metal abundances are found for all the three galaxies, the highest values being shown by the early-type galaxy (Z ~ 0.5 Z☉).

Asymmetric Mass-Loss on the AGB: Examples from IRAS Data

We present the discovery of an isolated compact group of galaxies that is extremely dense (median projected galaxy separation: 6.9 kpc), that has a very low velocity dispersion (σ2D = 67 km s-1), and in which all observed members show emission lines and are morphologically disturbed. These properties, together with the lack of spiral galaxies and the presence of a prominent tidal tail, make this group one of the most evolved compact groups.

A new large high latitude cone-like far-IR nebula

We report the discovery of a new conspicuous flare star coincident with the position of the IRAS PSC source 18456-0223 that is located in or projected on a dark cloud. In the immediate vicinity of the source, a very faint nebula and a small group of stars are detected in the optical. We carried out rough red band photometry and accurate astrometry of those stellar objects. In addition, near-infrared images were obtained with the DENIS survey instrument in I (0.8), J (1.25) and K s (2.15 μ m) that show an increasing number of stars which appear to constitute a small cluster around the position of the IRAS source; the flare star itself (

G247.8+4.9: A Newly Discovered Optical Supernova Remnant in Puppis

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Expansion Velocities and Characteristics of Galactic Planetary Nebulae

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DISCOVERY OF A RING GALAXY IN BOOTES.

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A photo-ionised canopy for the shock-excited Criss-Cross nebula

22 fraction of minute5) however, could not be traced. We assume that the flare star is enshrouded in a dust cloud of