Search Publications
Gaia 1 and 2. A pair of new Galactic star clusters
Belokurov, V.; Koposov, Sergey E.; Torrealba, G.
We present the results of the very first search for faint Milky Way satellites in the Gaia data. Using stellar positions only, we are able to re-discover objects detected in much deeper data as recently as the last couple of years. While we do not identify new prominent ultrafaint dwarf galaxies, we report the discovery of two new star clusters, G…
Tomographic reflection modelling of quasi-periodic oscillations in the black hole binary H 1743-322
Ingram, Adam; Middleton, Matthew; Altamirano, Diego +2 more
Accreting stellar mass black holes (BHs) routinely exhibit Type-C quasi-periodic oscillations (QPOs). These are often interpreted as Lense-Thirring precession of the inner accretion flow, a relativistic effect whereby the spin of the BH distorts the surrounding space-time, inducing nodal precession. The best evidence for the precession model is th…
A study of the sensitivity of shape measurements to the input parameters of weak-lensing image simulations
Hoekstra, Henk; Viola, Massimo; Herbonnet, Ricardo
Improvements in the accuracy of shape measurements are essential to exploit the statistical power of planned imaging surveys that aim to constrain cosmological parameters using weak lensing by large-scale structure. Although a range of tests can be performed using the measurements, the performance of the algorithm can only be quantified using simu…
Improved measurements of turbulence in the hot gaseous atmospheres of nearby giant elliptical galaxies
Kaastra, J. S.; de Plaa, J.; Fabian, A. C. +7 more
We present significantly improved measurements of turbulent velocities in the hot gaseous haloes of nearby giant elliptical galaxies. Using deep XMM-Newton Reflection Grating Spectrometer (RGS) observations and a combination of resonance scattering and direct line broadening methods, we obtain well bounded constraints for 13 galaxies. Assuming tha…
Change of outgassing pattern of 67P/Churyumov-Gerasimenko during the March 2016 equinox as seen by ROSINA
Mall, Urs; De Keyser, Johan; Berthelier, Jean-Jacques +18 more
As the spin axis of comet 67P/Churyumov-Gerasimenko (67P) is not normal to the orbital plane, 67P has strong seasonal changes in the illumination conditions on the nucleus' surface, with a short and intense summer in the Southern hemisphere. We have been monitoring these seasonal variations in the gas coma with the Rosetta Orbiter Spectrometer for…
Comet 67P outbursts and quiescent coma at 1.3 au from the Sun: dust properties from Rosetta/VIRTIS-H observations
Mottola, S.; Erard, S.; Crovisier, J. +15 more
We present 2-5 µm spectroscopic observations of the dust coma of 67P/Churyumov-Gerasimenko obtained with the VIRTIS-H instrument onboard Rosetta during two outbursts that occurred on 2015, 13 September 13.6 h ut and 14 September 18.8 h ut at 1.3 au from the Sun. Scattering and thermal properties measured before the outburst are in the mean o…
No evidence for Population III stars or a Direct Collapse Black Hole in the z = 6.6 Lyman-α emitter 'CR7'
Bowler, R. A. A.; McLure, R. J.; Dunlop, J. S. +4 more
The z = 6.6 Lyman α emitter 'CR7' has been claimed to have a Population III (Pop III) like stellar population, or alternatively, be a candidate direct collapse black hole (DCBH). In this paper, we investigate the evidence for these exotic scenarios using recently available, deeper, optical, near-infrared and mid-infrared imaging. We find strong Sp…
The life cycles of Be viscous decretion discs: time-dependent modelling of infrared continuum observations
Carciofi, A. C.; Rivinius, Th.; Vieira, R. G. +3 more
We apply the viscous decretion disc (VDD) model to interpret the infrared disc continuum emission of 80 Be stars observed in different epochs. In this way, we determined 169 specific disc structures, namely their density scale, ρ0, and exponent, n. We found that the n values range mainly between 1.5 and 3.5, and ρ0 varies bet…
The global mass functions of 35 Galactic globular clusters: I. Observational data and correlations with cluster parameters
Baumgardt, H.; Sollima, A.
We have derived the global mass functions of a sample of 35 Galactic globular clusters (GCs) by comparing deep Hubble Space Telescope photometry from the globular clusters treasury project (Sarajedini et al. 2007) with suitable multimass dynamical models. For a subset of 29 clusters with available radial velocity information, we were also able to …
Cross-correlating Planck CMB lensing with SDSS: lensing-lensing and galaxy-lensing cross-correlations
Brownstein, Joel R.; Mandelbaum, Rachel; Singh, Sukhdeep
We present results from cross-correlating Planck cosmic microwave background (CMB) lensing maps with the Sloan Digital Sky Survey (SDSS) galaxy lensing shape catalogue and BOSS (Baryon Oscillation Spectroscopic Survey) galaxy catalogues. For galaxy position versus CMB lensing cross-correlations, we measure the convergence signal around the galaxie…