Search Publications
The SAURON project - III. Integral-field absorption-line kinematics of 48 elliptical and lenticular galaxies
Krajnović, Davor; Emsellem, Eric; Miller, Bryan W. +9 more
We present the stellar kinematics of 48 representative elliptical and lenticular galaxies obtained with our custom-built integral-field spectrograph SAURON operating on the William Herschel Telescope. The data were homogeneously processed through a dedicated reduction and analysis pipeline. All resulting SAURON data cubes were spatially binned to …
Is the soft excess in active galactic nuclei real?
Done, Chris; Gierliński, Marek
We systematically analyse all publicly available XMM-Newton spectra of radio-quiet PG quasars. The soft X-ray excess in these objects is well modelled by an additional, cool, Compton scattering region. However, the remarkably constant temperature derived for this component over the whole sample requires a puzzling fine tuning of the parameters. In…
Comparing the temperatures of galaxy clusters from hydrodynamical N-body simulations to Chandra and XMM-Newton observations
Rasia, E.; Mazzotta, P.; Moscardini, L. +1 more
Theoretical studies of the physical processes guiding the formation and evolution of galaxies and galaxy clusters in the X-ray region are mainly based on the results of numerical hydrodynamical N-body simulations, which in turn are often directly compared with X-ray observations. Although trivial in principle, these comparisons are not always simp…
Combined long and short time-scale X-ray variability of NGC 4051 with RXTE and XMM-Newton
Papadakis, I. E.; Page, M. J.; Uttley, P. +2 more
We present a comprehensive examination of the X-ray variability of the narrow-line Seyfert 1 (NLS1) galaxy NGC 4051, one of the most variable active galactic nuclei (AGN) in the sky. We combine over 6.5 years of frequent monitoring observations by RXTE with a >100-ks continuous observation by XMM-Newton and so present an overall 2-10 keV power …
The star formation rate of the Universe at z~ 6 from the Hubble Ultra-Deep Field
Bunker, Andrew J.; McMahon, Richard G.; Ellis, Richard S. +1 more
We determine the abundance of i'-band dropouts in the recently released HST/ACS Hubble Ultra-Deep Field (UDF). Because the majority of these sources are likely to be z~ 6 galaxies whose flux decrement between the F775W i'-band and F850LP z'-band arises from Lyman-α absorption, the number of detected candidates provides a valuable upper limit to th…
Star formation history and dust content of galaxies drawn from ultraviolet surveys
Kong, X.; Brinchmann, J.; Charlot, S. +1 more
We compile a new sample of 115 nearby, non-Seyfert galaxies spanning a wide range of star formation activities, from starburst to nearly dormant, based on ultraviolet observations with various satellites. We combine these observations with infrared observations to study the relation between ratio of total far-infrared to ultraviolet luminosity and…
The local surface density of disc matter mapped by Hipparcos
Flynn, Chris; Holmberg, Johan
We determine the surface density of matter in the disc of the Galaxy at the solar position using K giant stars. The local space density and luminosity function of the giants is determined using parallaxes from the Hipparcos satellite; for more distant giants, observed in a cone at the South Galactic Pole, distances are determined using intermediat…
Comparing the properties of local globular cluster systems: implications for the formation of the Galactic halo
Mackey, A. D.; Gilmore, G. F.
We investigate the hypothesis that some fraction of the globular clusters presently observed in the Galactic halo formed in external dwarf galaxies. This is done by means of a detailed comparison between the `old halo', `young halo' and `bulge/disc' subsystems defined by Zinn and the globular clusters in the Large Magellanic Cloud, Small Magellani…
A long hard look at MCG-6-30-15 with XMM-Newton- II. Detailed EPIC analysis and modelling
Vaughan, S.; Fabian, A. C.
The bright Seyfert 1 galaxy MCG-6-30-15 has provided some of the best evidence to date for the existence of supermassive black holes in active galactic nuclei. Observations with ASCA revealed an X-ray iron line profile shaped by strong Doppler and gravitational effects. In this paper the shape of the iron line, its variability characteristics and …
High-resolution imaging of the HeII λ4686 emission line nebula associated with the ultraluminous X-ray source in Holmberg II
Zezas, A.; Kaaret, P.; Ward, M. J.
We present Hubble Space Telescope images of the HeIII region surrounding the bright X-ray source in the dwarf irregular galaxy Holmberg II. Using Chandra, we find a position for the X-ray source of (J2000) with an uncertainty of 0.6 arcsec. We identify a bright, point-like optical counterpart centred in the nebula with the X-ray source. The optica…