Search Publications
Hipparcos open clusters and stellar evolution
Prada Moroni, P. G.; Degl'Innocenti, S.; Castellani, V. +1 more
By relying on recently improved Hipparcos parallaxes for the Hyades, Pleiades and Ursa Major clusters we find that stellar models with updated physical inputs reproduce nicely the location in the colour-magnitude diagram of main-sequence stars of different metallicities. Stars in the helium-burning phase are also discussed, showing that the lumino…
XMM-Newton Reflection Grating Spectrometer observations of the prototypical starburst galaxy M82
Stevens, Ian R.; Read, Andrew M.
We present results from XMM-Newton Reflection Grating Spectrometer observations of the prototypical starburst galaxy M82. These high-resolution spectra represent the best X-ray spectra to date of a starburst galaxy. A complex array of lines from species over a wide range of temperatures is seen, the most prominent being due to Lyman α emission fro…
UBV(RI)C photometry of Hipparcos red stars
Kilkenny, D.; Marang, F.; Koen, C. +2 more
We present homogeneous and standardized UBV(RI)C photometry for nearly 550 M stars selected from the Hipparcos satellite data base using the following selection criteria: lack of obvious variability (no Hipparcos variability flag); δ<+10°(V-I)>1.7 and V magnitude fainter than about 7.6. Comparisons are made between the current pho…
The Galactic distribution of asymptotic giant branch stars
Knapp, G. R.; Ivezić, Željko; Jackson, Tom
We study the Galactic distribution of ~10000 candidate asymptotic giant branch (AGB) stars selected by IRAS colours and variability index. The distance to each star is estimated by assuming a narrow luminosity function and a model-derived bolometric correction. The characteristic AGB star luminosity, LAGB, is determined from the conditi…
The peculiar cooling flow cluster RX J0820.9+0752
Fabian, A. C.; Allen, S. W.; Edge, A. C. +2 more
We present observations of the cluster of galaxies associated with the X-ray source RX J0820.9+0752 and its dramatic central cluster galaxy in the optical and X-ray wavebands. Unlike other cooling flow central cluster galaxies studied in detail, this system does not contain a powerful radio source at its core, and so provides us with an important …
A radio study of neutral gas and dust in the radio galaxy 3C 293
Beswick, R. J.; Holloway, A. J.; Pedlar, A.
We have observed broad HI absorption in the radio galaxy 3C 293 using Multi-Element Radio Linked Interferometric Network (MERLIN) at 0.2-arcsec angular resolution and the Giant Meterwavelength Radio Telescope (GMRT) at arcsec resolution. Extensive HI is found in absorption across the centre of this peculiar radio galaxy, allowing a detailed study …
A Hubble Space Telescope lensing survey of X-ray luminous galaxy clusters - III. A multiply imaged extremely red galaxy at z=1.6
Kneib, J. -P.; Smith, Graham P.; Smail, Ian +4 more
We present near-infrared spectroscopy and Hubble Space Telescope (HST) imaging of galaxy J003707+0909.5, the brightest of three gravitationally lensed images of an extremely red object (ERO) at z=1.6, in the field of the massive cluster A68 (z=0.255). We exploit the superlative resolution of our HST data and the enhanced spatial resolution and sen…
The OIV and SIV intercombination lines in the ultraviolet spectra of astrophysical sources
Doyle, J. G.; Madjarska, M. S.; Mathioudakis, M. +8 more
New electron density diagnostic line ratios are presented for the OIV 2s22p 2P-2s2p24P and SIV 3s23p 2P-3s3p24P intercombination lines around 1400Å. A comparison of these with observational data for the symbiotic star RR Telescopii (RR Tel), obtained with the Space Telescope Imaging…
The symbiotic star CH Cygni - II. The ejecta from the 1998-2000 active phase
Davis, R. J.; Eyres, S. P. S.; Bode, M. F. +7 more
We present Hubble Space Telescope (HST) imaging, a Very Large Array (VLA) radio map (4.74 GHz), optical high-resolution (echelle) spectroscopy and UBV photoelectric photometry of the symbiotic star CH Cyg obtained during its 1998-2000 active phase. The HST imaging, taken during eclipse, shows the central stars are embedded in a nebula extending to…
XMM-Newton EPIC observations of Her X-1
Ramsay, Gavin; Hailey, C. J.; den Herder, Jan-Willem +2 more
We present spin-resolved X-ray data of the neutron star binary Her X-1 taken using the EPIC detectors on XMM-Newton. The data were taken at three distinct epochs through the 35-d precession period. The energy-dependent light curves of this source vary significantly from epoch to epoch. It is known that the relative phasing of the soft (<~1 keV)…