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Episodic dust formation by HD 192641 (WR 137) - II
Caldwell, J. J.; Morris, P. W.; van der Hucht, K. A. +9 more
We present new infrared photometry of the WC7-type Wolf-Rayet star HD 192641 (WR137) from 1985 to 1999. These data track the cooling of the dust cloud formed in the 1982-84 dust-formation episode from 1985 to 1991, the increase of the infrared flux from 1994.5 to a new dust-formation maximum in 1997 and its subsequent fading. From these and earlie…
The early-type galaxy population in Abell 2218
Smail, Ian; Davies, Roger L.; Bower, Richard G. +2 more
We present high signal-to-noise, moderate-resolution spectroscopy of 48 early-type members of the rich cluster Abell 2218 at z=0.18, taken with the LDSS2 spectrograph on the 4.2-m William Herschel Telescope. This sample both is larger and spans a wider galaxy luminosity range, down to MB*+1, than previous studies. In addition to the relatively lar…
SCUBA photometry of candidate Vega-like sources
Barlow, M. J.; Sylvester, R. J.; Dunkin, S. K.
New SCUBA measurements at millimetre wavelengths are presented for a sample of Vega-like stars. Six stars were detected, while sensitive upper limits were obtained for a further 11 sources. Most of the sample selected from a recent catalogue of Vega-like stars have infrared excesses similar to those of the prototype Vega-like stars α Lyr and α PsA…
The stellar content and distance of UGC 4483
Sarajedini, A.; Dolphin, A. E.; Grebel, E. K. +7 more
We present HST/WFPC2 observations of UGC 4483, an irregular galaxy in the M81/NGC 2403 complex. Stellar photometry was carried out with HSTphot, and is complete to V~=26.0 and I~=24.7. We measure the red giant branch tip at I=23.56+/-0.10, and calculate a distance modulus of µ0=27.53+/-0.12 (corresponding to a distance of 3.2+/-0.…
Morphological and kinematic signatures of a binary central star in the planetary nebula Hu2-1
Guerrero, Martín A.; Miranda, Luis F.; Vázquez, Roberto +2 more
We present Hα, [Nii] and [Oiii] ground-based and HST archive images, VLA-A 3.6-cm continuum and H92α emission-line data and high-resolution long-slit [Nii] spectra of the planetary nebula Hu2-1. A large number of structural components are identified in the nebula: an outer bipolar and an inner shell, two pairs of collimated bipolar structures at d…
Nuclear star formation in the hotspot galaxy NGC 2903
Knapen, J. H.; Alonso-Herrero, A.; Ryder, S. D.
We present high-resolution near-infrared imaging obtained using adaptive optics and HST/NICMOS, and ground-based spectroscopy of the hotspot galaxy NGC 2903. Our near-infrared resolution imaging enables us to resolve the infrared hotspots into individual young stellar clusters or groups of these. The spatial distribution of the stellar clusters is…
Resolving Sirius-like binaries with the Hubble Space Telescope
Bond, Howard E.; Barstow, M. A.; Holberg, J. B. +1 more
We present initial results from a Hubble Space Telescope ultraviolet imaging survey of stars known to have hot white dwarf companions which are unresolved from the ground. The hot companions, discovered through their EUV or UV emission, are hidden by the overwhelming brightnesses of the primary stars at visible wavelengths. Out of 17 targets obser…
X-ray and extreme-ultraviolet emission from the coronae of Capella
Mathioudakis, M.; Keenan, F. P.; Phillips, K. J. H. +3 more
The primary objective of this work is the analysis and interpretation of coronal observations of Capella obtained in 1999 September with the High Energy Transmission Grating Spectrometer on the Chandra X-ray Observatory and the Extreme Ultraviolet Explorer (EUVE). He-like lines of O (Ovii) are used to derive a density of 1.7×1010cm…
The European Large Area ISO Survey - IV. The preliminary 90-µm luminosity function
Rigopoulou, D.; Serjeant, S.; Morel, T. +11 more
We present the luminosity function of 90-µm-selected galaxies from the European Large Area ISO Survey (ELAIS), extending to z=0.3. Their luminosities are in the range 109< h 65 -2L/Lsolar<1012, i.e. non-ultraluminous. From our sample of 37 reliably detected galaxies in the ELAIS S1 region from the Efsta…
Deep Hubble Space Telescope imaging surveys and the formation of spheroidal galaxies
Franceschini, Alberto; Rodighiero, Giulia; Fasano, Giovanni
We have extended our previous analysis of morphologically selected elliptical and S0 galaxies in the Hubble Deep Field (HDF) North to include Hubble Space Telescope (HST) data in the HDF South and the HDFS-NICMOS areas. Our final sample amounts to 69 E/S0 galaxies with K<20.15 over an area of 11arcmin2. Although a moderately small nu…