Search Publications
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)…
The symbiotic star CH Cygni - III. A precessing radio jet
Davis, R. J.; Eyres, S. P. S.; Bode, M. F. +3 more
VLA, MERLIN and Hubble Space Telescope imaging observations of the extended regions of the symbiotic system CH Cygni are analysed. These extensions are evidence of a strong collimation mechanism, probably an accretion disc surrounding the hot component of the system. Over 16 yr (between 1985 and 2001) the general trend is that these jets are seen …
The highly variable X-ray spectrum of the luminous Seyfert 1 galaxy 1H 0419-577
O'Brien, P. T.; Reeves, J. N.; Page, K. L. +1 more
An XMM-Newton observation of the luminous Seyfert 1 galaxy 1H 0419-577 is presented. We find that the spectrum is well fitted by a power law of canonical slope and three blackbody components (to model the strong soft excess). The XMM-Newton data are compared and contrasted with observations by ROSAT in 1992 and by ASCA and BeppoSAX in 1996. We fin…
Chandra observations of the nucleus of M33
Rutledge, Robert E.; Dubus, Guillaume
The nearby galaxy M33 hosts the most luminous steady X-ray source in the Local Group. The high spatial resolution of Chandra allows us to confirm that this ultra-luminous X-ray source is within the nucleus and rule out at the 4.6σ level a previously proposed possible counterpart located 1 arcsec away. The X-ray spectrum is well fitted by a disc bl…