CFHTLenS: The relation between galaxy dark matter haloes and baryons from weak gravitational lensing
ArXiv 1304.4265 (2013)
Abstract:
We present a study of the relation between dark matter halo mass and the baryonic content of host galaxies, quantified via luminosity and stellar mass. Our investigation uses 154 deg2 of Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS) lensing and photometric data, obtained from the CFHT Legacy Survey. We employ a galaxy-galaxy lensing halo model which allows us to constrain the halo mass and the satellite fraction. Our analysis is limited to lenses at redshifts between 0.2 and 0.4. We express the relationship between halo mass and baryonic observable as a power law. For the luminosity-halo mass relation we find a slope of 1.32+/-0.06 and a normalisation of 1.19+0.06-0.07x10^13 h70^-1 Msun for red galaxies, while for blue galaxies the best-fit slope is 1.09+0.20-0.13 and the normalisation is 0.18+0.04-0.05x10^13 h70^-1 Msun. Similarly, we find a best-fit slope of 1.36+0.06-0.07 and a normalisation of 1.43+0.11-0.08x10^13 h70^-1 Msun for the stellar mass-halo mass relation of red galaxies, while for blue galaxies the corresponding values are 0.98+0.08-0.07 and 0.84+0.20-0.16x10^13 h70^-1 Msun. For red lenses, the fraction which are satellites tends to decrease with luminosity and stellar mass, with the sample being nearly all satellites for a stellar mass of 2x10^9 h70^-2 Msun. The satellite fractions are generally close to zero for blue lenses, irrespective of luminosity or stellar mass. This, together with the shallower relation between halo mass and baryonic tracer, is a direct confirmation from galaxy-galaxy lensing that blue galaxies reside in less clustered environments than red galaxies. We also find that the halo model, while matching the lensing signal around red lenses well, is prone to over-predicting the large-scale signal for faint and less massive blue lenses. This could be a further indication that these galaxies tend to be more isolated than assumed. [abridged]The radio source count at 93.2 GHz from observations of 9C sources using AMI and CARMA
Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 430:3 (2013) 1961-1969
The Suzaku view of highly ionized outflows in AGN - I. Statistical detection and global absorber properties
Monthly Notices of the Royal Astronomical Society 430:1 (2013) 60-80
Abstract:
We present the results of a new spectroscopic study of Fe K-band absorption in active galactic nuclei (AGN). Using data obtained from the Suzaku public archive we have performed a statistically driven blind search for Fe XXV Heα and/or Fe XXVI Lyα absorption lines in a large sample of 51 Type 1.0-1.9 AGN. Through extensive Monte Carlo simulations we find that statistically significant absorption is detected at E ≳ 6.7 keV in 20/51 sources at the PMC ≥ 95 per cent level, which corresponds to ~40 per cent of the total sample. In all cases, individual absorption lines are detected independently and simultaneously amongst the two (or three) available X-ray imaging spectrometer detectors, which confirms the robustness of the line detections. The most frequently observed outflow phenomenology consists of two discrete absorption troughs corresponding to Fe XXV Heα and Fe XXVI Lyα at a common velocity shift. From xstar fitting the mean column density and ionization parameter for the Fe K absorption components are log (NH/cm-2) ≈ 23 and log (ξ/erg cm s-1) ≈ 4.5, respectively. Measured outflow velocities span a continuous range from <1500 km s-1 up to ~100 000 km s-1, with mean and median values of ~0.1 c and ~0.056 c, respectively. The results of this work are consistent with those recently obtained using XMM-Newton and independently provides strong evidence for the existence of very highly ionized circumnuclear material in a significant fraction of both radio-quiet and radio-loud AGN in the local universe. © 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.CFHTLenS tomographic weak lensing cosmological parameter constraints: Mitigating the impact of intrinsic galaxy alignments
ArXiv 1303.1808 (2013)
Abstract:
We present a finely-binned tomographic weak lensing analysis of the Canada-France-Hawaii Telescope Lensing Survey, CFHTLenS, mitigating contamination to the signal from the presence of intrinsic galaxy alignments via the simultaneous fit of a cosmological model and an intrinsic alignment model. CFHTLenS spans 154 square degrees in five optical bands, with accurate shear and photometric redshifts for a galaxy sample with a median redshift of zm =0.70. We estimate the 21 sets of cosmic shear correlation functions associated with six redshift bins, each spanning the angular range of 1.5CFHTLenS: Mapping the Large Scale Structure with Gravitational Lensing
ArXiv 1303.1806 (2013)