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Minor mergers have been proposed as the driving mechanism for the size growth of quiescent galaxies with decreasing redshift. The process whereby large star-forming galaxies quench and join the quiescent population at the large size end has also been suggested as an explanation for this size growth. Given the clear association of quenching with clusters, we explore this mechanism by studying the structural properties of 23 spectroscopically identified recently quenched (or 'post-starburst' (PSB)) cluster galaxies at z ∼ 1. Despite clear PSB spectral signatures implying rapid and violent quenching, 87 per cent of these galaxies have symmetric, undisturbed morphologies in the stellar continuum. Remarkably, they follow a mass–size relation lying midway between the star-forming and quiescent field relations, with sizes 0.1 dex smaller than z ∼ 1 star-forming galaxies at log(M */M⊙) = 10.5. This implies a rapid change in the light profile without directly effecting the stellar distribution, suggesting changes in the mass-to-light ratio gradients across the galaxy are responsible. We develop fading toy models to explore how star-forming galaxies move across the mass–size plane as their stellar populations fade to match those of the PSBs. 'Outside-in' fading has the potential to reproduce the contraction in size and increase in bulge-dominance observed between star-forming and PSB cluster galaxies. Since cluster PSBs lie on the large size end of the quiescent mass–size relation, and our previous work shows cluster galaxies are smaller than field galaxies, the sizes of quiescent galaxies must grow both from the quenching of star-forming galaxies and dry minor mergers. [ABSTRACT FROM AUTHOR]

Minor mergers are thought to be responsible for the size growth of quiescent field galaxies with decreasing redshift. We test this hypothesis using the cluster environment as a laboratory. Satellite galaxies in clusters move at high velocities, making mergers between them rare. The stellar mass–size relation in 10 clusters and in the field is measured and compared at |$z$| ∼ 1. Our cluster sample contains 344 spectroscopically confirmed cluster members with Gemini/Gemini Multi-Object Spectrographs and 182 confirmed with Hubble Space Telescope /Wide Field Camera 3 G141 grism spectroscopy. On average, quiescent and star-forming cluster galaxies are smaller than their field counterparts by (0.08 ± 0.04) and (0.07 ± 0.01) dex, respectively. These size offsets are consistent with the average sizes of quiescent and star-forming field galaxies between 1.2 ≤ |$z$| ≤ 1.5, implying the cluster environment has inhibited size growth between this period and |$z$| ∼ 1. The negligible differences measured between the |$z$| ∼ 0 field and cluster quiescent mass–size relations in other works imply that the average size of quiescent cluster galaxies must rise with decreasing redshift. Using a toy model, we show that the disappearance of the compact cluster galaxies might be explained if, on average, |${\sim }40{{\ \rm per\ cent}}$| of them merge with their brightest cluster galaxies (BCGs) and |${\sim }60{{\ \rm per\ cent}}$| are tidally destroyed into the intracluster light (ICL) between 0 ≤ |$z$| ≤ 1. This is in agreement with the observed stellar mass growth of BCGs between 0 ≤ |$z$| ≤ 1 and the observed ICL stellar mass fraction at |$z$| ∼ 0. Our results support minor mergers as the cause for the size growth in quiescent field galaxies, with cluster-specific processes responsible for the similarity between the field and cluster quiescent mass–size relations at low redshift. [ABSTRACT FROM AUTHOR]

Abstract: We present a study of the growth and reactivity of ultra-thin films of TiO2 grown on W(100). Three approaches to film growth are investigated, each resulting in films that show order in low-energy diffraction (LEED) and a low level of non-stoichiometry in X-ray photoelectron spectroscopy (XPS). H2O is used as a probe of the reactivity of the films, with changes in the Ti 2p and O 1s core levels being monitored by XPS. Evidence for the dissociation of H2O on the TiO2(110) ultra-thin film surface is adduced. These results are discussed with reference to related studies on native TiO2(110). [Copyright &y& Elsevier]

Intracluster light is thought to originate from stars that were ripped away from their parent galaxies by gravitational tides and galaxy interactions during the build up of the cluster. The stars from such interactions will accumulate over time, so semi-analytic models suggest that the abundance of intracluster stars is negligible in young proto-clusters at z ∼ 2 and grows to around a quarter of the stellar mass in the oldest, most mature clusters. In contrast to these theoretical expectations, we report on the detection of intracluster light within two proto-clusters at z = 2 using deep HST images. We use the colour of the intracluster light to estimate its mass-to-light ratio in annuli around the brightest cluster galaxies (BCG), up to a radius of 100 kpc. We find that 54 ± 5 per cent and 71 ± 3 per cent of the stellar mass in these regions is located more than 10 kpc away from the BCGs in the two proto-clusters. This low concentration is similar to BCGs in lower redshift clusters, and distinct from other massive proto-cluster galaxies. This suggests that intracluster stars are already present within the core 100 kpc of proto-clusters. We compare these observations to the Hydrangea hydrodynamical galaxy cluster simulations and find that intracluster stars are predicted to be a generic feature of group-sized haloes at z = 2. These intracluster stars will gradually move further away from the BCG as the proto-cluster assembles into a cluster. [ABSTRACT FROM AUTHOR]

Abstract: Local defects present in CeO2−x films result in a mixture of Ce3+ and Ce4+ oxidation states. Previous studies of the Ce 3d region with XPS have shown that depositing metal nanoparticles on ceria films causes further reduction, with an increase in Ce3+ concentration. Here, we compare the use of XPS and resonant photoemission spectroscopy (RESPES) to estimate the concentration of Ce3+ and Ce4+ in CeO2−x films grown on Pt (111), and the variation of this concentration as a function of Pd deposition. Due to the nature of the electronic structure of CeO2−x, resonant peaks are observed for the 4d–4f transitions when the photon energy matches the resonant energy; (hν=121.0eV) for Ce3+ and (hν=124.5eV) for Ce4+. This results in two discrete resonant photoemission peaks in valence band spectra. The ratio of the difference of these peaks with off-resonance scans gives an indication of the relative contribution of Ce3+. Results from RESPES indicate reduction of CeO2−x on deposition of Pd, confirming earlier findings from XPS studies. [Copyright &y& Elsevier]

Benign parotid tumours have historically often been managed surgically by superficial parotidectomy. While this approach usually gives a generous cuff of surrounding normal parotid tissue to increase tumour margins, it requires a much larger incision than the increasingly used extracapsular dissection ( ECD) technique. Furthermore, superficial parotidectomy can result in marked facial hollowing, Frey syndrome and an increased risk of both temporary and permanent facial nerve weakness. ECD has been popularised as a safe alternative to parotidectomy primarily for the removal of mobile, benign parotid tumours with safe outcomes and reduced risk to the facial nerve. In this article, we review the growing body of evidence for ECD and include our own experience confirming the move away from superficial parotidectomy in contemporary practice for the treatment of benign parotid tumours. [ABSTRACT FROM AUTHOR]