Search Publications
Dynamical modelling of luminous and dark matter in 17 Coma early-type galaxies
Saglia, R. P.; Thomas, D.; Thomas, J. +5 more
Dynamical models for 17 early-type galaxies in the Coma cluster are presented. The galaxy sample consists of flattened, rotating as well as non-rotating early-types including cD and S0 galaxies with luminosities between MB = -18.79 and -22.56. Kinematical long-slit observations cover at least the major-axis and minor-axis and extend to …
The Bullet Cluster 1E0657-558 evidence shows modified gravity in the absence of dark matter
Brownstein, J. R.; Moffat, J. W.
A detailed analysis of the 2006 November 15 data release X-ray surface density Σ-map and the strong and weak gravitational lensing convergence κ-map for the Bullet Cluster 1E0657-558 is performed and the results are compared with the predictions of a modified gravity (MOG) and dark matter. Our surface density Σ-model is computed using a King β-mod…
On the origin of soft X-rays in obscured AGN: answers from high-resolution spectroscopy with XMM-Newton
Guainazzi, Matteo; Bianchi, Stefano
We present results of a high-resolution soft X-ray (0.2-2 keV) spectroscopic study of a sample of 69 nearby obscured active galactic nuclei (AGNs) observed with the reflection grating spectrometer (RGS) onboard XMM-Newton. This is the largest sample ever studied with this technique so far. The main conclusions of our study can be summarized as fol…
A method for the direct determination of the surface gravities of transiting extrasolar planets
Wheatley, Peter J.; Southworth, John; Sams, Giles
We show that the surface gravity of a transiting extrasolar planet can be calculated from only the spectroscopic orbit of its parent star and the analysis of its transit light curve. This does not require additional constraints, such as are often inferred from theoretical stellar models or model atmospheres. The surface gravity of the planet can t…
The XMM-LSS survey: the Class 1 cluster sample over the initial 5 deg2 and its cosmological modelling
Maccagni, D.; Chiappetti, L.; Altieri, B. +30 more
We present a sample of 29 galaxy clusters from the XMM-LSS survey over an area of some 5 deg2 out to a redshift of z= 1.05. The sample clusters, which represent about half of the X-ray clusters identified in the region, follow well-defined X-ray selection criteria and are all spectroscopically confirmed. For all clusters, we provide X-r…
The Kormendy relation of massive elliptical galaxies at z ~ 1.5: evidence for size evolution
Mannucci, F.; Bender, R.; Longhetti, M. +6 more
We present the morphological analysis based on HST-NIC2 (0.075 arcsec pixel-1) images in the F160W filter of a sample of nine massive field (>1011Msolar) galaxies spectroscopically classified as early-types at 1.2 < z < 1.7. Our analysis shows that all of them are bulge-dominated systems. In particular, si…
An improved measurement of the flux distribution of the Lyα forest in QSO absorption spectra: the effect of continuum fitting, metal contamination and noise properties
Viel, M.; Carswell, R. F.; Kim, T. -S. +2 more
We have performed an extensive Voigt profile analysis of the neutral hydrogen (HI) and metal absorption present in a sample of 18 high-resolution, high signal-to-noise ratio quasi-stellar object (QSO) spectra observed with the Very Large Telescope Ultraviolet and Visual Echelle Spectrograph. We use this analysis to separate the metal contribution …
The strong transformation of spiral galaxies infalling into massive clusters at z ~ 0.2
Kneib, J. -P.; Egami, E.; Cortese, L. +8 more
We describe two peculiar galaxies falling into the massive galaxy clusters Abell1689 (z ~ 0.18) and Abell2667 (z ~ 0.23), respectively. Hubble Space Telescope (HST) images show extraordinary trails composed of bright blue knots (-16.5 < M < -11.5mag) and stellar streams associated with each of these systems. Combining optical, near- and mid-…
The fraction of binary systems in the core of 13 low-density Galactic globular clusters
Sarajedini, A.; Beccari, G.; Ferraro, F. R. +2 more
We used deep observations collected with Advanced Camera for Surveys (ACS) at Hubble Space Telescope (HST) to derive the fraction of binary systems in a sample of 13 low-density Galactic globular clusters. By analysing the colour distribution of main-sequence stars we derived the minimum fraction of binary systems required to reproduce the observe…
The stellar mass density at z ~ 6 from Spitzer imaging of i'-drop galaxies
Bunker, Andrew J.; Stark, Daniel P.; Ellis, Richard S. +4 more
We measure the ages, stellar masses, and star formation histories of z ~ 6 galaxies, observed within 1 Gyr of the big bang. We use imaging from the Hubble Space Telescope (HST) and the Spitzer Space Telescope from the public `Great Observatories Origins Deep Survey' (GOODS), coupled with ground-based near-infrared imaging, to measure their spectra…