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…
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…
Measurements and simulation of Faraday rotation across the Coma radio relic
Vazza, F.; Bonafede, A.; Govoni, F. +5 more
The aim of this work is to probe the magnetic field properties in relics and infall regions of galaxy clusters using Faraday rotation measures. We present Very Large Array multifrequency observations of seven sources in the region south-west of the Coma cluster, where the infalling group NGC 4839 and the relic 1253+275 are located. The Faraday rot…
Constraints on decreases in η Carinae's mass-loss from 3D hydrodynamic simulations of its binary colliding winds
Gull, T. R.; Corcoran, M. F.; Madura, T. I. +6 more
Recent work suggests that the mass-loss rate of the primary star ηA in the massive colliding wind binary η Carinae dropped by a factor of 2-3 between 1999 and 2010. We present results from large- (±1545 au) and small- (±155 au) domain, 3D smoothed particle hydrodynamics (SPH) simulations of η Car's colliding winds for three ηA
Comprehensive study of a z = 2.35 DLA Galaxy: mass, metallicity, age, morphology and SFR from HST and VLT
Pettini, Max; Noterdaeme, Pasquier; Gallazzi, Anna +8 more
We present a detailed study of the emission from a z = 2.35 galaxy that causes damped Lyman α absorption in the spectrum of the background quasar (QSO), SDSS J2222-0946. We present the results of extensive analyses of the stellar continuum covering the rest frame optical-UV regime based on broad-band Hubble Space Telescope (HST) imaging, and of sp…
Evidence for a correlation between the sizes of quiescent galaxies and local environment to z ∼ 2
Grogin, Norman A.; Kocevski, Dale D.; Koekemoer, Anton M. +14 more
We present evidence for a strong relationship between galaxy size and environment for the quiescent population in the redshift range 1 < z < 2. Environments were measured using projected galaxy overdensities on a scale of 400 kpc, as determined from ∼96 000 K-band-selected galaxies from the UKIDSS Ultra Deep Survey (UDS). Sizes were determin…
Revealing the X-ray source in IRAS 13224-3809 through flux-dependent reverberation lags
Fabian, A. C.; Miniutti, G.; Uttley, P. +2 more
IRAS 13224-3809 was observed in 2011 for 500 ks with the XMM-Newton observatory. We detect highly significant X-ray lags between soft (0.3-1 keV) and hard (1.2-5 keV) energies. The hard band lags the soft at low frequencies (i.e. hard lag), while the opposite (i.e. soft lag) is observed at high frequencies. In this paper, we study the lag during f…
Constraints on dark energy with the LOSS SN Ia sample
Filippenko, Alexei V.; Li, Weidong; Ganeshalingam, Mohan
We present a cosmological analysis of the Lick Observatory Supernova Search (LOSS) Type Ia supernova (SN Ia) photometry sample introduced by Ganeshalingam et al. These supernovae (SNe) provide an effective anchor point to estimate cosmological parameters when combined with data sets at higher redshift. The data presented by Ganeshalingam et al. ha…