Search Publications
Simulation tests of galaxy cluster constraints on chameleon gravity
Zhao, Gong-Bo; Bacon, David; Romer, A. Kathy +3 more
We use two new hydrodynamical simulations of Λ cold dark matter (ΛCDM) and f(R) gravity to test the methodology used by Wilcox et al. (W15) in constraining the effects of a fifth force on the profiles of clusters of galaxies. We construct realistic simulated stacked weak lensing and X-ray surface brightness cluster profiles from these cosmological…
Geologic mapping of the Comet 67P/Churyumov-Gerasimenko's Northern hemisphere
Jorda, L.; Lamy, P. L.; Lara, L. M. +52 more
The Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS), the scientific imaging system onboard the Rosetta mission, has been acquiring images of the nucleus of the comet 67P/Churyumov-Gerasimenko since 2014 August with a resolution which allows a detailed analysis of its surface. Indeed, data reveal a complex surface morphology whi…
Spectrophotometry of the Khonsu region on the comet 67P/Churyumov-Gerasimenko using OSIRIS instrument images
Jorda, L.; Lamy, P. L.; Bertaux, J. -L. +47 more
Our work focuses on the spectrophotometric analysis of selected terrain and bright patches in the Khonsu region on the comet 67P/Churyumov-Gerasimenko. Despite the variety of geological features, their spectrophotometric properties appear to indicate a similar composition. It is noticeable that the smooth areas in Khonsu possess similar spectropho…
Probing dark matter crests with white dwarfs and IMBHs
Schödel, R.; Amaro-Seoane, P.; Casanellas, J. +2 more
White dwarfs (WDs) are the most promising captors of dark matter (DM) particles in the crests that are expected to build up in the cores of dense stellar clusters. The DM particles could reach sufficient densities in WD cores to liberate energy through self-annihilation. The extinction associated with our Galactic Centre makes it impossible to det…
Changing physical conditions in star-forming galaxies between redshifts 0 < z < 4: [O III]/H β evolution
Bowler, R. A. A.; Cullen, F.; McLure, R. J. +3 more
We investigate the redshift evolution of the [O III]/H β nebular emission line ratio for a sample of galaxies spanning the redshift range 0 < z < 4. We compare the observed evolution to a set of theoretical models which account for the independent evolution of chemical abundance, ionization parameter and interstellar medium (ISM) pressure in…
Evidence for large-scale subsurface convection in the Sun
Woodard, M. F.
A helioseismic statistical waveform analysis of subsurface flow was performed on two 720-day time series of SOHO/Michelson Doppler Imager medium-l spherical-harmonic coefficients. The time series coincide with epochs of high and low solar activity. Time-dependent coupling-strength coefficients b^t_s(n,l) of modes of the same radial order n and deg…
The nature of the torus in the heavily obscured AGN Markarian 3: an X-ray study
Harrison, F.; Stern, D.; Bauer, F. E. +22 more
In this paper, we report the results of an X-ray monitoring campaign on the heavily obscured Seyfert galaxy, Markarian 3, carried out between the fall of 2014 and the spring of 2015 with NuSTAR, Suzaku and XMM-Newton. The hard X-ray spectrum of Markarian 3 is variable on all the time-scales probed by our campaign, down to a few days. The observed …
The NuSTAR view of the non-thermal emission from PSR J0437-4715
Harrison, F. A.; Boggs, S.; Stern, D. +11 more
We present a hard X-ray Nuclear Spectroscopic Telescope Array (NuSTAR) observation of PSR J0437-4715, the nearest millisecond pulsar. The known pulsations at the apparent pulse period {∼ }5.76{ ms} are observed with a significance of 3.7σ, at energies up to 20 keV above which the NuSTAR background dominates. We measure a photon index Γ = 1.50 ± 0.…
The bulge-disc decomposition of AGN host galaxies
Dunlop, J. S.; Kocevski, D. D.; Rosario, D. J. +3 more
We present the results from a study of the morphologies of moderate luminosity X-ray-selected active galactic nuclei (AGN) host galaxies in comparison to a carefully mass-matched control sample at 0.5 < z < 3 in the CANDELS GOODS-S field. We apply a multiwavelength morphological decomposition analysis to these two samples and report on the d…
The view of AGN-host alignment via reflection spectroscopy
Fabian, Andrew C.; Reynolds, Christopher S.; Middleton, Matthew J. +2 more
The fuelling of active galactic nuclei (AGN) - via material propagated through the galactic disc or via minor mergers - is expected to leave an imprint on the alignment of the sub-pc disc relative to the host galaxy's stellar disc. Determining the inclination of the inner disc usually relies on the launching angle of the jet; here instead we use t…