Search Publications
A non-local thermodynamic equilibrium spherical line-blanketed stellar atmosphere model of the early B giant beta CMa
Hauschildt, P. H.; Baron, E.; Aufdenberg, J. P.
The observed multiwavelength spectrum of the B1II--III star beta CMa is successfully reproduced, including the extreme ultraviolet (EUV) continuum observed by Extreme Ultraviolet Explorer (EUVE), with a non-local thermodynamic equilibrium fully line-blanketed spherical hydrostatic model atmosphere. The available spectrophotometry of beta CMa from …
Lines of OIV and SIV in the Goddard High-Resolution Spectrograph spectrum of RR Tel: constraints on atomic data
Judge, P. G.; Carpenter, K. G.; Jordan, C. +3 more
High signal-to-noise ratio spectra of RR Tel obtained at medium resolution with the Goddard High-Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST) are used to test available atomic data for the OIV 2s^22p ^2P-2s2p^2 ^4P multiplet (UV 0.01). The fine-structure intervals of the 2s2p^2 ^4P term given by Moore (1983) appear to need re…
Consistency of accretion discs with Seyfert 1 UV fluxes and Hβ emission-line profiles
Boisson, C.; Rokaki, E.
This paper presents accretion disc fits to the UV continuum and Hβ emission line in a complete sample of broad-emission-line AGN sources. Disc fits to the UV continuum emission leave an ambiguity between the central mass and the orientation of the disc in that more massive black holes mimic more edge-on discs. The opposite dependence between mass …
Neutral gas and dust in the central region of the ultraluminous infrared galaxy Mrk273
Mundell, C. G.; Holloway, A. J.; Pedlar, A. +1 more
We have used MERLIN to observe neutral hydrogen absorption against the central region of the ultraluminous infrared galaxy (ULIRG) galaxy Mrk273 with an angular resolution of 0.2arcsec. This represents a factor of 5 increase in resolution compared with previous work. Absorption has been resolved against two of three radio continuum components. A H…
Globular cluster system erosion and nucleus formation in elliptical galaxies
Capuzzo-Dolcetta, R.; Tesseri, A.
The radial distribution of globular clusters in galaxies is always less peaked to the centre than that of the halo stars. Extending previous work to a sample of Hubble Space Telescope globular cluster systems in ellipticals, we evaluate the number of clusters potentially lost to the galactic centre as the integrals of the difference between the ob…
Optical and ROSAT X-ray observations of the dwarf nova OY Carinae in superoutburst and quiescence
Hassall, B. J. M.; Naylor, T.; Wood, Janet H. +2 more
We present ROSAT X-ray and optical light curves of the 1994 February superoutburst of the eclipsing SU UMa dwarf nova OY Carinae. There is no eclipse of the flux in the ROSAT HRI light curve. Contemporaneous `wide B'-band optical light curves show extensive superhump activity and dips at superhump maximum. Eclipse mapping of these optical light cu…
Discovery of pulsations in the AM star HD 13079
Leone, F.; Sagar, R.; Kurtz, D. W. +8 more
Pulsation in cool main-sequence Am stars is a rare phenomenon observed in a few marginal Am stars and only one classical Am star. The chemically peculiar star HD 13079 is shown to be pulsating with a 78-min period and a peak-to-peak B amplitude of 0.02mag. The Hipparcos parallax, uvbyβ photometry and pulsations together suggest that HD 13079 is an…
Modelling ISO galaxy counts with luminosity and merger rate evolution
Eales, Stephen A.; Roche, Nathan
We model galaxy evolution in the 6.75- and 15-µm passbands of the ISO satellite, by combining models of galaxy evolution at optical wavelengths (which are consistent with the optical galaxy counts) with observed spectral energy distributions in the infrared. Our model is consistent with the local 12-µm galaxy luminosity function (from …
Mapping the gas kinematics and ionization structure of four ultraluminous IRAS galaxies
Abraham, R. G.; Crawford, C. S.; Wilman, R. J.
We present a study of the morphology, kinematics and ionization structure of the extended emission-line regions in four intermediate-redshift (0.118<z<0.181) ultraluminous infrared galaxies, derived from ARGUS two-dimensional fibre spectroscopy. The gas kinematics in the hyperluminous system IRAS F20460+1925 lack coherent structure, with a f…
Ionized ultraviolet and soft X-ray absorption in the low-redshift active galactic nucleus PG 1126-041
Wamsteker, W.; Brinkmann, W.; Wang, J. X. +2 more
We present here the analysis of ultraviolet spectra from IUE and an X-ray spectrum from ROSAT PSPC observations of the X-ray-weak, far-infrared-loud AGN, PG 1126-041 (Mrk 1298). The first UV spectra taken in 1992 June, simultaneously with ROSAT, show strong absorption lines of Nv, Civ and Siiv, extending over a velocity range from -1000 to -5000km…