Tailed Radio Galaxies as Probes of Cluster Physics in the Square Kilometre Array Era

In recent years, the use of tailed radio galaxies as environmental probes has gained momentum as a method for galaxy cluster detection, examining the dynamics of individual clusters, measuring the density and velocity flows in the intra-cluster medium, and for probing cluster magnetic fields. To date instrumental limitations in terms of resolution and sensitivity have confined this research to the local (z < 0.7) Universe. The advent of SKA-1 surveys however will allow detection of well over 1 million tailed radio galaxies and their associated galaxy clusters out to redshifts of 2 or more. This is in fact ten times more than the current number of known clusters in the Universe. Such a substantial sample of tailed galaxies will provide an invaluable tool not only for detecting clusters, but also for characterizing their intra-cluster medium, magnetic fields and dynamical state as a function of cosmic time. In this paper we present an analysis of the usability of tailed radio galaxies as tracers of dense environments extrapolated from existing deep radio surveys such the Extended Chandra Deep Field-South.Comment: 4 pages, 2 figures, in URSI GASS (XXXIth) held 16-23 August 2014, Beijing, China. Published as AIP Conference Proceeding

Components of attentional bias for food cues among restrained eaters

Author version made available in accordance with the publisher's policy.The study aimed to investigate attentional bias for food cues among restrained eaters. In particular, the roles of speeded detection (enhanced orientation of attention toward food stimuli) and slowed disengagement (trouble disengaging attention from food stimuli) were examined. Participants were 78 female undergraduate students aged 18- 25 years, classified as restrained (N = 38) or unrestrained eaters (N = 40). Attentional bias was assessed by a visual search task which required participants to locate the position of an odd-one-out target word in a matrix of 19 distractor words. Restrained eaters were disproportionately faster than unrestrained eaters to detect a food word within a neutral matrix compared to a neutral word within a neutral distractor matrix. Restrained eaters were also disproportionately faster, rather than slower, than unrestrained eaters to detect a neutral word within a food matrix compared to a neutral word within a neutral distractor matrix. Thus restrained eaters show a heightened vigilance for food cues, but no slower disengagement from such cues

Unravelling the origin of large-scale magnetic fields in galaxy clusters and beyond through Faraday Rotation Measures with the SKA

We investigate the possibility for the SKA to detect and study the magnetic fields in galaxy clusters and in the less dense environments surrounding them using Faraday Rotation Measures. To this end, we produce 3-dimensional magnetic field models for galaxy clusters of different masses and in different stages of their evolution, and derive mock rotation measure observations of background radiogalaxies. According to our results, already in phase I, we will be able to infer the magnetic field properties in galaxy clusters as a function of the cluster mass, down to $10^{13}$ solar-masses. Moreover, using cosmological simulations to model the gas density, we have computed the expected rotation measure through shock-fronts that occur in the intra-cluster medium during cluster mergers. The enhancement in the rotation measure due to the density jump will permit to constraint the magnetic field strength and structure after the shock passage. SKA observations of polarised sources located behind galaxy clusters will answer several questions about the magnetic field strength and structure in galaxy clusters, and its evolution with cosmic time.Comment: 9 pages, 4 Figures, to appear as part of 'Cosmic Magnetism' in Proceedings 'Advancing Astrophysics with the SKA (AASKA14)', PoS(AASKA14