Search Publications
Observations of the Hubble Deep Field with the Infrared Space Observatory - V. Spectral energy distributions, starburst models and star formation history
Elbaz, D.; Danese, L.; Franceschini, A. +16 more
We have modelled the spectral energy distributions of the 13 Hubble Deep Field (HDF) galaxies reliably detected by the Infrared Space Observatory (ISO). For two galaxies the emission detected by ISO is consistent with being starlight or the infrared `cirrus' in the galaxies. For the remaining 11 galaxies there is a clear mid-infrared excess, which…
First results from HIPPARCOS trigonometrical parallaxes of Mira-type variables
van Leeuwen, F.; Whitelock, P. A.; Feast, M. W. +1 more
HIPPARCOS trigonometrical parallaxes are given for 16 pre-selected Mira variables. Linear diameters are derived for eight oxygen-rich Miras with known angular diameters. Comparison with pulsation theory shows that two of them (both with periods over 400d) are fundamental pulsators, while the others (all with periods of less than 400d) pulsate in a…
EUVE J0317-855: a rapidly rotating, high-field magnetic white dwarf
Christian, D. J.; Wickramasinghe, D. T.; Vennes, S. +2 more
Spectropolarimetric observations of the extreme-ultraviolet (EUV) source and high-field magnetic white dwarf EUVE J0317-855 (=RE J0317-853) in the wavelength range 4200-7200 A reveal a strongly structured circular polarization spectrum with a peak polarization of 8 per cent. The strongest features in the polarization spectrum are attributed to Hα …
A multiwavelength study of the Seyfert 1 galaxy MCG-6-30-15
Fabian, A. C.; Reynolds, C. S.; Celotti, A. +1 more
We present a multiwaveband spectroscopic study of the nearby Seyfert 1 galaxy MCG-6-30-15. New optical spectra from the Anglo-Australian Telescope are presented which clearly show the effects of dust extinction/reddening on both the emission-line spectrum and the non-stellar AGN continuum. The reddening is constrained to be in the range E(B-V)=0.6…
HST, radio and infrared observations of 28 3CR radio galaxies at redshift z~ - I. The observations
Best, P. N.; Longair, M. S.; Roettgering, H. J. A.
Hubble Space Telescope images are presented of a sample of 28 3CR radio galaxies with redshifts in the range 0.6<z<1.8, together with maps at comparable angular resolution of their radio structure, taken using the Very Large Array. Infrared images of the fields, taken with the United Kingdom InfraRed Telescope, are also presented. The optica…
Observations of the Hubble Deep Field with the Infrared Space Observatory - III. Source counts and P(D) analysis
Elbaz, D.; Danese, L.; Franceschini, A. +19 more
We present source counts at 6.7 and 15 µm from our maps of the Hubble Deep Field (HDF) region, reaching 38.6 muJy at 6.7 µm and 255 muJy at 15 mum. These are the first ever extragalactic number counts to be presented at 6.7 mum, and are three decades fainter than IRAS at 12 mum. Both source counts and a P(D) analysis suggest that we ha…
Kinematic ages of OB associations
Brown, A. G. A.; de Zeeuw, P. T.; Dekker, G.
Astrometric data from the HIPPARCOS mission include measurements of early-type stars in nearly all OB associations within 1kpc from the Sun, and are available as of 1996. In anticipation thereof we studied the determination of kinematic ages and initial sizes of OB associations. These studies have traditionally been done using proper motion data. …
Evidence for an outflow from the Seyfert galaxy NGC 4051
Steffen, W.; Mundell, C. G.; Meaburn, J. +5 more
New observations using narrow-band imaging, long-slit spectroscopy and MERLIN observations of the nuclear region of the Seyfert galaxy NGC 4051 have been made. An edge-brightened, triangular region of ionized gas extending 420 pc from the centre of the galaxy has been detected. Long-slit spectra of this ionized gas, taken at 1.5 arcsec from the co…
GX17+2: X-ray spectral and timing behaviour of a bursting Z source
van Paradijs, J.; van der Klis, M.; Lewin, W. H. G. +2 more
We have investigated the properties of the Z pattern of the low-mass X-ray binary GX17+2 in the X-ray colour-colour diagrams (CDs) and hardness-intensity diagrams (HIDs), and of the power spectra as a function of position in the Z. We used all EXOSAT ME data on GX17+2, a total of six observations during 1983-86. We find that the Z pattern in the C…
HST observations of the field star population in the Large Magellanic Cloud
Elson, Rebecca A. W.; Gilmore, Gerard F.; Santiago, Basilio X.
We present V and I photometry, obtained with the Hubble Space Telescope, for ~15 800 stars in a field in the inner disc of the Large Magellanic Cloud. We confirm previous results indicating that an intense star formation event, probably corresponding to the formation of the LMC disc, occurred a few times 10^9 yr ago. We find a small but real diffe…