Search Publications
X-ray spectral properties of the AGN sample in the northern XMM-XXL field
Shen, Yue; Nandra, Kirpal; Streblyanska, Alina +7 more
In this paper we describe and publicly release a catalogue consisting of 8445 point-like X-ray sources detected in the XMM-XXL north survey. For the 2512 AGN which have reliable spectroscopy from SDSS-III/BOSS, we present the X-ray spectral fitting which has been computed with a Bayesian approach. We have also applied an X-ray spectral stacking me…
Baryon cycling in the low-redshift circumgalactic medium: a comparison of simulations to the COS-Halos survey
Kollmeier, Juna A.; Davé, Romeel; Tumlinson, Jason +8 more
We analyse the low-redshift (z ≈ 0.2) circumgalactic medium (CGM) by comparing absorption-line data from the COS-Halos survey to absorption around a matched galaxy sample from two cosmological hydrodynamic simulations. The models include different prescriptions for galactic outflows, namely hybrid energy/momentum driven wind (ezw), and constant wi…
HerMES: a search for high-redshift dusty galaxies in the HerMES Large Mode Survey - catalogue, number counts and early results
Pérez-Fournon, I.; Ivison, R. J.; Clements, D. L. +25 more
Selecting sources with rising flux densities towards longer wavelengths from Herschel/Spectral and Photometric Imaging Receiver (SPIRE) maps is an efficient way to produce a catalogue rich in high-redshift (z > 4) dusty star-forming galaxies. The effectiveness of this approach has already been confirmed by spectroscopic follow-up observations, …
Shining a light on galactic outflows: photoionized outflows
Chisholm, John; Leitherer, Claus; Chen, Yanmei +2 more
We study the ionization structure of galactic outflows in 37 nearby, star-forming galaxies with the Cosmic Origins Spectrograph on the Hubble Space Telescope. We use the O I, Si II, Si III, and Si IV ultraviolet absorption lines to characterize the different ionization states of outflowing gas. We measure the equivalent widths, line widths, and ou…
Deep XMM observations of Draco rule out at the 99 per cent confidence level a dark matter decay origin for the 3.5 keV line
Profumo, Stefano; Jeltema, Tesla
We searched for an X-ray line at energies around 3.5 keV in deep, ∼1.6 Ms XMM-Newton observations of the dwarf spheroidal galaxy Draco. No line was found in either the Metal Oxide Semi-conductor (MOS) or the p-type/n-type semiconductor (PN) detectors. The data in this energy range are completely consistent with a single, unfolded power-law modelli…
Deep Chandra observations of Pictor A
Stawarz, Ł.; Hardcastle, M. J.; Croston, J. H. +7 more
We report on deep Chandra observations of the nearby broad-line radio galaxy Pictor A, which we combine with new Australia Telescope Compact Array (ATCA) observations. The new X-ray data have a factor of 4 more exposure than observations previously presented and span a 15 yr time baseline, allowing a detailed study of the spatial, temporal and spe…
Mid-infrared luminous quasars in the GOODS-Herschel fields: a large population of heavily obscured, Compton-thick quasars at z ≈ 2
Daddi, E.; Elbaz, D.; Alexander, D. M. +10 more
We present the infrared (IR) and X-ray properties of a sample of 33 mid-IR luminous quasars (νL6 µm ≥ 6 × 1044 erg s-1) at redshift z ≈ 1-3, identified through detailed spectral energy distribution analyses of distant star-forming galaxies, using the deepest IR data from Spitzer and Herschel in the GOODS-Hers…
Constraining gravity at the largest scales through CMB lensing and galaxy velocities
Ho, Shirley; Alam, Shadab; Pullen, Anthony R. +1 more
We demonstrate a new method to constrain gravity on the largest cosmological scales by combining measurements of cosmic microwave background (CMB) lensing and the galaxy velocity field. EG is a statistic, constructed from a gravitational lensing tracer and a measure of velocities such as redshift-space distortions (RSD), that can discri…
The deepest X-ray view of high-redshift galaxies: constraints on low-rate black hole accretion
Lehmer, B. D.; Bauer, F. E.; Brandt, W. N. +16 more
We exploit the 7 Ms Chandra observations in the Chandra Deep Field-South (CDF-S), the deepest X-ray survey to date, coupled with CANDELS/GOODS-S data, to measure the total X-ray emission arising from 2076 galaxies at 3.5 ≤ z < 6.5. This aim is achieved by stacking the Chandra data at the positions of optically selected galaxies, reaching effect…
A disc wind interpretation of the strong Fe Kα features in 1H 0707-495
Done, Chris; Takahashi, Tadayuki; Hagino, Kouichi +3 more
1H 0707-495 is the most convincing example of a supermassive black hole with an X-ray spectrum being dominated by extremely smeared, relativistic reflection, with the additional requirement of strongly supersolar iron abundance. However, here we show that the iron features in its 2-10 keV spectrum are rather similar to the archetypal wind dominate…