Search Publications
Properties of gas clumps and gas clumping factor in the intra-cluster medium
Simionescu, A.; Eckert, D.; Ettori, S. +2 more
The spatial distribution of gas matter inside galaxy clusters is not completely smooth, but may host gas clumps associated with substructures. These overdense gas substructures are generally a source of unresolved bias of X-ray observations towards high-density gas, but their bright luminosity peaks may be resolved sources within the intra cluster…
Extreme-velocity quasar outflows and the role of X-ray shielding
Chartas, G.; Charlton, J.; Hamann, F. +5 more
Quasar accretion disc winds observed via broad absorption lines (BALs) in the UV produce strong continuous absorption in X-rays. The X-ray absorber is believed to serve critically as a radiative shield to keep the outflow ionizations low enough for radiative driving. However, previous studies have shown that `mini-BAL' and narrow absorption line (…
HERMES: unveiling obscured star formation - the far-infrared luminosity function of ultraviolet-selected galaxies at z ∼ 1.5
Aussel, H.; Rodighiero, G.; Ivison, R. J. +22 more
We study the far-infrared and sub-millimetre properties of a sample of ultraviolet (UV) selected galaxies at z ∼ 1.5. Using stacking at 250, 350 and 500 µm from Herschel Space Observatory Spectral and Photometric Imaging Receiver (SPIRE) imaging of the Cosmological Evolution Survey (COSMOS) field obtained within the Herschel Multi-tiered Ext…
Measuring the Rotational Periods of Isolated Magnetic White Dwarfs
Burleigh, Matthew R.; Marsh, Thomas R.; Knigge, Christian +2 more
We present time-series photometry of 30 isolated magnetic white dwarfs, surveyed with the Jacobus Kapteyn Telescope between 2002 August and 2003 May. We find that 9 were untestable due to varying comparison stars, but of the remaining 21, 5 (24%) are variable with reliably derived periods, while a further 9 (43%) are seen to vary during our study,…
Challenges to our understanding of radio relics: X-ray observations of the Toothbrush cluster
Croston, J. H.; van Weeren, R. J.; Brüggen, M. +3 more
The cluster 1RXS J0603.3+4214 is a merging galaxy cluster that hosts three radio relics and a giant radio halo. The northern relic, the Toothbrush, is 1.9 Mpc long and has an unusual linear morphology. According to simple diffusive shock acceleration theory, its radio spectral index indicates a Mach number of 3.3-4.6. Here, we present results from…
Structure of sunspot penumbral filaments: a remarkable uniformity of properties
Lagg, Andreas; Solanki, Sami K.; Tiwari, Sanjiv Kumar +1 more
Context. The sunspot penumbra comprises numerous thin, radially elongated filaments that are central for heat transport within the penumbra, but whose structure is still not clear.
Aims: We aim to investigate the fine-scale structure of these penumbral filaments.
Methods: We perform a depth-dependent inversion of spectropolarimetric data…
The Ultra-long GRB 111209A. II. Prompt to Afterglow and Afterglow Properties
Piro, L.; De Pasquale, M.; Klotz, A. +7 more
The "ultra-long" gamma-ray burst GRB 111209A at redshift z = 0.677 is the longest GRB ever observed thus far, with a rest frame prompt emission duration of ~4 hr. In order to explain the burst exceptional longevity, a low-metallicity blue supergiant progenitor was invoked. In this article we further constrain the phenomenology and progenitor prope…
The COS/UVES Absorption Survey of the Magellanic Stream. I. One-tenth Solar Abundances along the Body of the Stream
Richter, Philipp; Bland-Hawthorn, Joss; Fox, Andrew J. +5 more
The Magellanic Stream (MS) is a massive and extended tail of multi-phase gas stripped out of the Magellanic Clouds and interacting with the Galactic halo. In this first paper of an ongoing program to study the Stream in absorption, we present a chemical abundance analysis based on HST/COS and VLT/UVES spectra of four active galactic nuclei (RBS 14…
Energy Partition in Magnetic Reconnection in Earth's Magnetotail
Eastwood, J. P.; Lavraud, B.; Phan, T. D. +4 more
The partition of energy flux in magnetic reconnection is examined experimentally using Cluster satellite observations of collisionless reconnection in Earth’s magnetotail. In this plasma regime, the dominant component of the energy flux is ion enthalpy flux, with smaller contributions from the electron enthalpy and heat flux and the ion kinetic en…
Kronoseismology: Using Density Waves in Saturn's C Ring to Probe the Planet's Interior
Nicholson, P. D.; Hedman, M. M.
Saturn's C ring contains multiple spiral patterns that appear to be density waves driven by periodic gravitational perturbations. In other parts of Saturn's rings, such waves are generated by Lindblad resonances with Saturn's various moons, but most of the wave-like C-ring features are not situated near any strong resonance with any known moon. Us…