Search Publications
The SAURON project - IV. The mass-to-light ratio, the virial mass estimator and the Fundamental Plane of elliptical and lenticular galaxies
Krajnović, Davor; Emsellem, Eric; van de Ven, Glenn +12 more
We investigate the well-known correlations between the dynamical mass-to-light ratio (M/L) and other global observables of elliptical (E) and lenticular (S0) galaxies. We construct two-integral Jeans and three-integral Schwarzschild dynamical models for a sample of 25 E/S0 galaxies with SAURON integral-field stellar kinematics to about one effecti…
Elemental abundance survey of the Galactic thick disc
Lambert, David L.; Allende Prieto, Carlos; Reddy, Bacham E.
We have performed an abundance analysis for F- and G- dwarfs of the Galactic thick-disc component. A sample of 176 nearby (d<= 150pc) thick-disc candidate stars was chosen from the Hipparcos catalogue and subjected to a high-resolution spectroscopic analysis. Using accurate radial velocities combined with the Hipparcos astrometry, kinematics (U…
The SAURON project - V. Integral-field emission-line kinematics of 48 elliptical and lenticular galaxies
Bacon, Roland; Krajnović, Davor; Emsellem, Eric +10 more
We present the emission-line fluxes and kinematics of 48 representative elliptical and lenticular galaxies obtained with our custom-built integral-field spectrograph, SAURON, operating on the William Herschel Telescope. Hβ, [OIII]λλ4959,5007 and [NI]λλ5198,5200 emission lines were measured using a new procedure that simultaneously fits both the st…
The surprising magnetic topology of τ Sco: fossil remnant or dynamo output?
Bouret, J. -C.; Donati, J. -F.; Howarth, I. D. +9 more
We report the discovery of a medium-strength (~0.5 kG) magnetic field on the young, massive star τ Sco (B0.2V), which becomes the third-hottest magnetic star known. Circularly polarized Zeeman signatures are clearly detected in observations collected mostly with the ESPaDOnS spectropolarimeter, recently installed on the 3.6-m Canada-France-Hawaii …
An explanation for the soft X-ray excess in active galactic nuclei
Fabian, A. C.; Ross, R. R.; Gallo, L. +1 more
We present a large sample of type 1 active galactic nuclei (AGN) spectra taken with XMM-Newton, and fit them with both the conventional model (a power law and blackbody) and the relativistically blurred photoionized disc reflection model of Ross & Fabian. We find that the disc reflection model is a better fit. The disc reflection model success…
The Hubble Deep Field-North SCUBA Super-map - IV. Characterizing submillimetre galaxies using deep Spitzer imaging
Dickinson, Mark; Daddi, Emanuele; Chary, Ranga-Ram +9 more
We present spectral energy distributions (SEDs), Spitzer colours, and infrared (IR) luminosities for 850-µm selected galaxies in the Great Observatories Origins Deep Survey Northern (GOODS-N) field. Using the deep Spitzer Legacy images and new data and reductions of the Very Large Array-Hubble Deep Field (VLA-HDF) radio data, we find statist…
XMM-Newton observations of the brightest ultraluminous X-ray sources
Wilms, J.; Roberts, T. P.; Stobbart, A. -M.
We present an analysis of 13 of the best quality ultraluminous X-ray source (ULX) data sets available from XMM-Newton European Photon Imaging Camera (EPIC) observations. We utilize the high signal-to-noise in these ULX spectra to investigate the best descriptions of their spectral shape in the 0.3-10keV range. Simple models of an absorbed power la…
The nature of SS433 and the ultraluminous X-ray sources
King, A. R.; Pringle, J. E.; Begelman, M. C.
The periodic precession (162-d) and nodding (6.3-d) motions of the jets in SS433 are driven in the outer regions of the disc, whereas the jets themselves, being relativistic, are launched near the black hole at the disc centre. Given that the nutation period is comparable to the dynamical time-scale in the outer regions of the disc, it seems unlik…
Evidence for the strong effect of gas removal on the internal dynamics of young stellar clusters
Bastian, N.; Goodwin, S. P.
We present detailed luminosity profiles of the young massive clusters M82-F, NGC 1569-A and NGC 1705-1 which show significant departures from equilibrium (King and Elson, Fall & Freeman) profiles. We compare these profiles with those from N-body simulations of clusters that have undergone the rapid removal of a significant fraction of their ma…
Constraints on sterile neutrinos as dark matter candidates from the diffuse X-ray background
Neronov, A.; Boyarsky, A.; Ruchayskiy, O. +1 more
Sterile neutrinos with masses in the kilo-electronvolt range are viable candidates for the warm dark matter. We analyse existing data for the extragalactic diffuse X-ray background for signatures of sterile neutrino decay. The absence of a detectable signal within current uncertainties of background measurements puts model-independent constraints …