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The morphological identification of the rapidly evolving population of faint galaxies
Ellis, Richard; Glazebrook, Karl; Griffiths, Richard +1 more
The excess numbers of blue galaxies at faint magnitudes are a long-standing cosmological puzzle. We present new number-magnitude counts as a function of galactic morphology from the first deep fields of the Cycle 4 Hubble Space Telescope Medium Deep Survey project. From a sample of 301 galaxies we define counts for elliptical, spiral and irregular…
HST observations of three radio galaxies at redshift z~=1
Best, P. N.; Rottgering, H. J. A.; Longair, M. S.
The first results of a programme to image a sample of radio galaxies at redshift z~=1 with the Hubble Space Telescope are reported in this Letter. The images of the three galaxies presented here (3C368, 3C324 and 3C265) show a wealth of fine structure down to the resolution limit of the HST. All three systems show a clear alignment of the optical …
An independent calibration of stellar ages: Hubble Space Telescope observations of white dwarfs at V=25
Gilmore, Gerard; Jones, D. H. P.; von Hippel, Ted
The white dwarf luminosity function of a stellar cluster will have a sharp truncation at a luminosity which is determined by the time since formation of the first white dwarfs in that cluster. Calculation of the dependence of this limiting luminosity on age requires relatively well-understood physics and is independent of stellar evolutionary mode…
Eclipse observations of an accretion disc wind
Knigge, C.; Horne, Keith; Mason, K. O. +5 more
The Goddard High Resolution Spectrometer on the Hubble Space Telescope has been used to monitor, through eclipse, the C iv 1550-A and He ii 1640-A lines in the spectrum of the nova-like cataclysmic variable UX UMa. Previous work has suggested that the Civ line arises in an accretion disc wind. The HST data confirm this, in that the line shows a br…
High-resolution radio images of the symbiotic star R Aquarii
Davis, R. J.; Bode, M. F.; Dougherty, S. M. +2 more
We present MERLIN radio observations of the nearby symbiotic star R Aquarii at 5 and 1.7 GHz with respective nominal resolutions of ~0.04 and 0.13 arcsec, comparable to the resolution of the optical and ultraviolet images obtained with the HST. Comparison with the HST images shows that the radio emission is associated with features observed at opt…
A model for the circumstellar nebula of SN 1987A
O'Brien, T. J.; Kahn, F. D.; Lloyd, H. M.
Supernova 1987A in the Large Magellanic Cloud is surrounded by an extended region of nebulosity likely to be composed of material ejected during the evolution of the progenitor star, and which has been subsequently illuminated by the supernova event itself. Recent Hubble Space Telescope (HST) images have revealed the presence of two large elliptic…
MERLIN observations of bipolar outflow from HM Sagittae
Davis, R. J.; Eyres, S. P. S.; Bode, M. F. +4 more
MERLIN maps of HM Sagittae at 6-cm and 18-cm wavelengths are presented. At 6 cm, the inner nebula has been mapped at a resolution of 60 milli-arcsec (mas), revealing two parallel ridge structures to the north and south of a deep central minimum. In addition, these central features are surrounded by a complex, weak structure. The ridges and many of…
The discovery of high-velocity flares in NV and the detection of carbon in the double degenerate binary GP COM
Horne, Keith; Marsh, T. R.; Wood, Janet H. +1 more
We present time-resolved ultraviolet spectra of the ultrashort-period binary GP Com taken with the Hubble Space Telescope. During our observations GP Com displayed spectacular variability in the dominant NV emission line which showed three large flares in 13h of observations. We isolate the flare spectrum which reveals CIV emission at a level of 0…
The HST ultraviolet spectrum of the nucleus of NGC 1275: Fermi-accelerated Lyalpha emission
Fabian, A. C.; Johnstone, R. M.
We present an HST FOS spectrum of the nucleus of NGC 1275. The narrow part of the Lyalpha line is double-peaked, with one emission line centred at the systemic velocity of the 5000 km s^-1 system and the other blueshifted by ~450 km s^-1. We show that the short-wavelength component is probably formed by Fermi acceleration across a shock front. The…
Photoionization modelling based on HST images of Magellanic Cloud planetary nebulae - I. SMCN2 and SMCN5
Barlow, M. J.; Blades, J. C.; Liu, X. -W. +2 more
We construct fully self-consistent, detailed photoionization models for two planetary nebulae (PNe) in the Small Magellanic Cloud (SMC), namely SMC N 2 and SMC N 5, to fit optical and UV spectrophotometric observations as well as HST Faint Object Camera (FOC) narrow-band images taken in the light of Hβ. The derived density structure shows that bot…