Search Publications
Combining weak and strong cluster lensing: applications to simulations and MS 2137
Meneghetti, M.; Bartelmann, M.; Merten, J. +2 more
Aims: While weak lensing cannot resolve cluster cores and strong lensing is almost insensitive to density profiles outside the scale radius, combinations of both effects promise to constrain density profiles of galaxy clusters well, and thus to allow testing of the CDM expectation on dark-matter halo density profiles.
Methods: We develop an al…
The spatial clustering of X-ray selected AGN in the XMM-COSMOS field
Finoguenov, A.; Kneib, J. -P.; Maccagni, D. +70 more
We study the spatial clustering of 538 X-ray selected AGN in the 2 deg2 XMM-COSMOS field that are spectroscopically identified with I_AB<23 and span the redshift range z=0.2-3.0. The median redshift and X-ray luminosity of the sample are z = 0.98 and L0.5-10=6.3× 1043 erg s-1, respectively. A strong c…
Determining the spin of two stellar-mass black holes from disc reflection signatures
Fabian, A. C.; Miller, J. M.; Reis, R. C. +1 more
We present measurements of the dimensionless spin parameters and inner-disc inclination of two stellar-mass black holes. The spin parameter of SWIFT J1753.5-0127 and GRO J1655-40 is estimated by modelling the strong reflection signatures present in their XMM-Newton observations. Using a newly developed, self-consistent reflection model which inclu…
A fresh look at the seismic spectrum of HD49933: analysis of 180 days of CoRoT photometry
Auvergne, M.; Baudin, F.; García, R. A. +18 more
Context: Solar-like oscillations have now been observed in several stars, thanks to ground-based spectroscopic observations and space-borne photometry. CoRoT, which has been in orbit since December 2006, has observed the star HD49933 twice. The oscillation spectrum of this star has proven difficult to interpret.
Aims: Thanks to a new timeserie…
High-Redshift Quasars in the COSMOS Survey: The Space Density of z > 3 X-Ray Selected QSOs
Ilbert, O.; Salvato, M.; Merloni, A. +19 more
We present a new measurement of the space density of high-redshift (zsime 3.0-4.5), X-ray-selected quasi-stellar objects (QSOs) obtained by exploiting the deep and uniform multiwavelength coverage of the COSMOS survey. We have assembled a large (40 objects), homogeneous sample of z > 3 QSOs with X-ray flux F 0.5-2 keV > 10-15…
Isotropic Luminosity Indicators in a Complete AGN Sample
Rieke, George H.; Rigby, Jane R.; Diamond-Stanic, Aleksandar M.
The [O IV] λ25.89 µm line has been shown to be an accurate indicator of active galactic nucleus (AGN) intrinsic luminosity in that it correlates well with hard (10-200 keV) X-ray emission. We present measurements of [O IV] for 89 Seyfert galaxies from the unbiased revised Shapley-Ames (RSA) sample. The [O IV] luminosity distributions of obsc…
Characterization of phyllosilicates observed in the central Mawrth Vallis region, Mars, their potential formational processes, and implications for past climate
Murchie, Scott L.; Ehlmann, Bethany L.; Mustard, John F. +7 more
Mawrth Vallis contains one of the largest exposures of phyllosilicates on Mars. Nontronite, montmorillonite, kaolinite, and hydrated silica have been identified throughout the region using data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). In addition, saponite has been identified in one observation within a crater. These …
Constraints on turbulent pressure in the X-ray haloes of giant elliptical galaxies from resonant scattering
Simionescu, A.; Kaastra, J. S.; Churazov, E. +5 more
The dense cores of X-ray emitting gaseous haloes of large elliptical galaxies with temperatures kT <~ 0.8 keV show two prominent FeXVII emission features, which provide a sensitive diagnostic tool to measure the effects of resonant scattering. We present here high-resolution spectra of five bright nearby elliptical galaxies, obtained with the r…
Kinematics of OB-associations and the new reduction of the Hipparcos data
Dambis, A. K.; Mel'Nik, A. M.
The proper motions of OB-associations computed using the old and new reductions of the Hipparcos data are in good agreement with each other. The Galactic rotation curve derived from an analysis of the line-of-sight velocities and proper motions of OB-associations is almost flat in the 3-kpc neighbourhood of the Sun. The angular rotation velocity a…
Solar-like oscillations with low amplitude in the CoRoT target HD 181906
Auvergne, M.; Baudin, F.; Jiménez-Reyes, S. J. +23 more
Context: The F8 star HD 181906 (effective temperature ∼6300 K) was observed for 156 days by the CoRoT satellite during the first long run in the direction of the galactic centre. Analysis of the data reveals a spectrum of solar-like acoustic oscillations. However, the faintness of the target (mv = 7.65) means the signal-to-noise (S/N) i…