Search Publications
Spectroscopy of the near-nuclear regions of Cygnus A: estimating the mass of the supermassive black hole
Marconi, A.; Axon, D.; Jackson, N. +3 more
We use a combination of high spatial resolution optical and near-infrared spectroscopic data to make a detailed study of the kinematics of the narrow-line region (NLR) gas in the near-nuclear regions of the powerful, FRII radio galaxy Cygnus A (z= 0.0560), with the overall goal of placing limits on the mass of any supermassive black hole in the co…
Surface brightness profiles and structural parameters for 10 rich stellar clusters in the Small Magellanic Cloud
Mackey, A. D.; Gilmore, G. F.
As a follow-up to our recent study of a large sample of Large Magellanic Cloud (LMC) clusters, we have conducted a similar study of the structures of 10 Small Magellanic Cloud (SMC) clusters, using archival Hubble Space Telescope snapshot data. We present surface brightness profiles for each cluster and derive structural parameters, including core…
Multiwavelength observations revealing the evolution of the outburst of the black hole XTE J1118+480
Chaty, S.; Cui, W.; Shrader, C. R. +3 more
We report multiwavelength observations of the soft X-ray transient XTE J1118+480, which we observed with UKIRT, Hubble Space Telescope (HST), RXTE, Extreme Ultraviolet Explorer (EUVE) and many other instruments and facilities. Adding radio (Ryle Telescope, VLA), submillimetre (JCMT) and X-ray (Chandra and SAX) data from the literature, we assemble…
Surface brightness profiles and structural parameters for globular clusters in the Fornax and Sagittarius dwarf spheroidal galaxies
Mackey, A. D.; Gilmore, G. F.
We present radial surface brightness profiles for all five globular clusters in the Fornax dwarf spheroidal galaxy, and for the four present members of the Sagittarius dwarf spheroidal galaxy. These profiles are derived from archival Hubble Space Telescope observations, and have been calculated using the same techniques with which we measured prof…
A star-forming galaxy at z= 5.78 in the Chandra Deep Field South
Bunker, Andrew J.; McMahon, Richard G.; McCarthy, Patrick J. +2 more
We report the discovery of a luminous z= 5.78 star-forming galaxy in the Chandra Deep Field South. This galaxy was selected as an `i-drop' from the GOODS public survey imaging with the Hubble Space Telescope/Advanced Camera for Surveys (object 3 in the work of Stanway, Bunker & McMahon 2003). The large colour of (i'-z')AB= 1.6 indic…
Numerical modelling of gamma radiation from galaxy clusters
Miniati, Francesco
We investigate the spatial and spectral properties of non-thermal emission from clusters of galaxies at γ-ray energies. We estimate the radiation flux between 10 keV and 10 TeV due to inverse-Compton (IC) emission, π0-decay and non-thermal bremsstrahlung (NTB) from cosmic ray (CR) ions and electrons accelerated at cosmic shocks as well …
Physical conditions in the planetary nebula Abell 30
Barlow, M. J.; Liu, X. -W.; Wesson, R.
We have analysed optical spectra of two of the hydrogen-deficient knots (J1 and J3) in the born-again planetary nebula Abell 30, together with ultraviolet (UV) spectra of knots J3 and J4. We determine electron temperatures in the knots based on several diagnostics. The [OIII] nebular-to-auroral transition ratio yields temperatures of the order of …
Periodicities in solar coronal mass ejections
Wang, Shui; Fan, Zuhui; Lou, Yu-Qing +2 more
Mid-term quasi-periodicities in solar coronal mass ejections (CMEs) during the most recent solar maximum cycle 23 are reported here for the first time using the four-year data (1999 February 5 to 2003 February 10) of the Large Angle Spectrometric Coronagraph on board the Solar and Heliospheric Observatory. In parallel, mid-term quasi-periodicities…
Star cluster formation and evolution in nearby starburst galaxies - I. Systematic uncertainties
Bastian, N.; Gallagher, J. S.; de Grijs, R. +4 more
The large majority of extragalactic star cluster studies performed to date have essentially used two- or three-passband aperture photometry, combined with theoretical stellar population synthesis models, to obtain age, mass and extinction estimates, and sometimes also metallicities. The accuracy to which this can be performed depends on the choice…
Heavy-element abundance patterns in hot DA white dwarfs
Barstow, M. A.; Bruhweiler, F. C.; Holberg, J. B. +5 more
We present a series of systematic abundance measurements for 25 hot DA white dwarfs in the temperature range ~20 000-110 000 K, based on far-ultraviolet spectroscopy with the Space Telescope Imaging Spectrograph (STIS)/Goddard High Resolution Spectrograph (GHRS) on-board Hubble Space Telescope, IUE and FUSE. Using our latest heavy-element blankete…