Search Publications
2D modelling of the light distribution of early-type galaxies in a volume-limited sample - II. Results for real galaxies
D'Onofrio, M.
In this paper we analyse the results of the two-dimensional (2D) fit of the light distribution of 73 early-type galaxies belonging to the Virgo and Fornax clusters, a sample volume- and magnitude-limited down to MB=-17.3, and highly homogeneous. In our previous paper (Paper I) we have presented the adopted 2D models of the surface-brigh…
Optical spectroscopy of X-Mega targets - II. The massive double-lined O-type binary HD 93205
Morel, T.; Rauw, G.; Barbá, R. H. +8 more
A new high-quality set of orbital parameters for the O-type spectroscopic binary HD 93205 has been obtained combining échelle and coudé CCD observations. The radial velocity orbits derived from the Heii λ4686Å (primary component) and Hei λ4471Å (secondary component) absorption lines yield semi-amplitudes of 133+/-2 and 314+/-2kms-1 for …
An XMM-Newton observation of the extreme narrow-line Seyfert 1 galaxy Mrk 359
O'Brien, P. T.; Reeves, J. N.; Pounds, K. +3 more
We present XMM-Newton observations of Mrk 359, the first narrow-line Seyfert 1 galaxy (NLS1) discovered. Even among NLS1s, Mrk 359 is an extreme case with extraordinarily narrow optical emission lines. The XMM-Newton data show that Mrk 359 has a significant soft X-ray excess which displays only weak absorption and emission features. The (2-10)keV …
Young star clusters in the Large Magellanic Cloud: NGC 1805 and 1818
Santiago, B. X.; Tanvir, N. R.; Gilmore, G. F. +4 more
We present colour-magnitude diagrams for two rich (~104Msolar) Large Magellanic Cloud star clusters with ages ~107yr, constructed from optical and near-infrared data obtained with the Hubble Space Telescope. These data are part of an HST project to study LMC clusters with a range of ages. In this paper we investiga…
Stellar models and Hyades: the Hipparcos test
Prada Moroni, P. G.; Degl'Innocenti, S.; Castellani, V.
We compare theoretical stellar models for main sequence (MS) stars with the Hipparcos data base for the Hyades cluster to give a warning against the uncritical use of available theoretical scenarios and to show how formal MS fittings can be fortuitous if not fictitious. Moreover, we find that none of the current theoretical scenarios appears able …
Chemical abundances of planetary nebulae from optical recombination lines - II. The neon abundance of NGC 7009
Barlow, M. J.; Liu, X. -W.; Luo, S. -G.
We present high-quality observations of Neii optical recombination lines (ORLs) for the bright Saturn Nebula NGC 7009. The measured line fluxes are used to determine Ne2+/H+ abundance ratios. The results derived from individual multiplets of the 3s-3p and 3p-3d configurations agree reasonably well, although values derived fro…
SwSt 1: an O-rich planetary nebula around a C-rich central star
Crowther, P. A.; Barlow, M. J.; de Koter, A. +2 more
The hydrogen-deficient [WCL] type central star HD 167362 and its planetary nebula (PN) SwSt 1 are investigated. The central star has a carbon-rich emission-line spectrum, and yet the nebula exhibits a 10-µm emission feature from warm silicate dust, perhaps indicating a recent origin for the carbon-rich stellar spectrum. Its stellar and nebul…
A complete relativistic ionized accretion disc in Cygnus X-1
Young, A. J.; Fabian, A. C.; Ross, R. R. +1 more
The galactic black hole candidate Cygnus X-1 is observed to be in one of two X-ray spectral states: either the low/hard (low soft X-ray flux and a flat power-law tail) or high/soft (high blackbody-like soft X-ray flux and a steep power-law tail) state. The physical origin of these two states is unclear. We present here a model of an ionized accret…
Changes to low-ll solar p-mode frequencies over the solar cycle: correlations on different time-scales
Chaplin, W. J.; Elsworth, Y.; Isaak, G. R. +3 more
We have studied variations in the frequencies of low-l solar p modes through the analysis of nine years of helioseismic data collected by the Birmingham Solar Oscillations Network (BiSON)†. This is the first time that such a long data set has been explored with the extra accuracy afforded by fitting the modes to asymmetric profiles. The epoch cove…
B2114+022: a distant radio source gravitationally lensed by a starburst galaxy
Hjorth, Jens; Patnaik, Alok R.; Jackson, Neal J. +8 more
We have discovered a radio source (B2114+022) with a unique structure during the course of the JVAS gravitational lens survey. VLA, MERLIN, VLBA and MERLIN+EVN radio maps reveal four compact components, in a configuration unlike that of any known lens system, or, for that matter, any of the ~15000 radio sources in the JVAS and CLASS surveys. Three…