Search Publications
A 1.4-GHz survey of the southern European Large-Area ISO Survey region
Genzel, R.; Cesarsky, C.; Danese, L. +13 more
A deep survey of the European Large-Area ISO Survey (ELAIS) field in the southern celestial hemisphere (hereinafter S1) has been carried out with the Australia Telescope Compact Array (ATCA) at 1.4 GHz. The S1 region, covering about 4 deg^2, has also been surveyed in the mid- and far-infrared (5-200 µm) with the Infrared Space Observatory (I…
Optical and ultraviolet observations of a strong flare in the young, single K2 dwarf LQ Hya
Montes, D.; Collier Cameron, A.; Saar, S. H. +1 more
We present high-resolution optical echelle spectra and IUE observations during a strong flare on 1993 December 22 in the very active, young, rapidly rotating, single K2 dwarf LQ Hya. The initial impulsive phase of the flare, which started sometime between 2:42 ut and 4:07 ut, was characterized by strong optical continuum enhancement and blueshifte…
High-resolution spectroscopy of ROSAT-discovered weak-line T Tauri stars near Lupus
Hauschildt, P. H.; Alcalá, J. M.; Covino, E. +3 more
We present high-resolution optical echelle spectroscopy for a large fraction of the Li-rich late-type stars recently discovered in the vicinity of the Lupus dark clouds. Our results confirm the high Liilambda6708 equivalent widths previously estimated from medium-resolution spectra, thus adding strength to the conclusion that the large majority of…
Properties of hot stars in the Wolf-Rayet galaxy NGC 5253 from ISO-SWS spectroscopy
Sutherland, Ralph S.; Conti, Peter S.; Morris, Patrick W. +3 more
ISO-SWS spectroscopy of the Wolf-Rayet galaxy NGC 5253 is presented, and analysed to provide estimates of its hot young star population. Our approach differs from previous investigations in that we are able to distinguish between the regions in which different infrared fine-structure lines form, using complementary ground-based observations. The h…
ISOGAL survey of Baade's Windows in the mid-infrared
Alard, C.; Blommaert, J. A. D. L.; Ganesh, S. +6 more
The ISOGAL mid-infrared survey of areas close to the Galactic plane aims to determine the stellar content of those areas, and its possible bearing on the history of the Galaxy. The NGC 6522 and Sgr I Baade's Windows of low obscuration towards the inner parts of the Galactic bulge represent ideal places in which to calibrate and understand the ISOG…
Identification of moving groups and member selection using HIPPARCOS data
Aguilar, Luis A.; Hoogerwerf, Ronnie
A new method to identify coherent structures in velocity space - moving groups - in astrometric catalogues is presented: the Spaghetti method. It relies on positions, parallaxes and proper motions, and is ideally suited to searching for moving groups in the Hipparcos Catalogue. No radial-velocity information is required. The method has been tested…
The colour-magnitude relation of early-type galaxies in the Hubble Deep Field
Bell, Eric F.; Kodama, Tadayuki; Bower, Richard G.
We present the rest-frame colour-magnitude diagram for 35 early-type galaxies in the Hubble Deep Field with median redshift 0.9. Although they have considerable scatter, a red sequence that is well described by the passive evolution of an intrinsically old stellar population is observed. Comparison with the passively evolved colour-magnitude relat…
The redshift evolution of clustering in the Hubble Deep Field
Magliocchetti, M.; Maddox, S. J.
We present a correlation function analysis for the catalogue of photometric redshifts obtained from the Hubble Deep Field image by Fernandez-Soto, Lanzetta & Yahil. By dividing the catalogue into redshift bins of width Deltaz=0.4 we measured the angular correlation function w(theta) as a function of redshift up to z~4.8. From these measurement…
A nuclear grand-design spiral within the normal disc spiral of NGC 5248
Knapen, J. H.; Laine, S.; Doyon, R. +2 more
We report the discovery of trailing grand-design nuclear spiral structure in the spiral galaxy NGC 5248. Two tightly wound red spiral arms, with widths less than 1 arcsec (~ 75 pc), emanate at 1 arcsec outside the quiescent nucleus of the galaxy, and can be followed for 3 arcsec, appearing to end before the radius of the circumnuclear starburst `r…
Optical and X-ray variability in the least luminous active galactic nucleus, NGC 4395
Terlevich, R.; Lira, P.; Lawrence, A. +3 more
We report the detection of optical and X-ray variability in the least luminous known Seyfert galaxy, NGC 4395. Between 1996 July and 1997 January the featureless continuum changed by a factor of 2, which is typical of more luminous AGN. The largest variation was seen at shorter wavelengths, so that the spectrum became `harder' during higher activi…