Diffuse light and galaxy interactions in the core of nearby clusters

The kinematics of the diffuse light in the densest regions of the nearby clusters can be unmasked using the planetary nebulae (PNs) as probes of the stellar motions. The position-velocity diagrams around the brightest cluster galaxies (BCGs) identify the relative contributions from the outer halos and the intracluster light (ICL), defined as the light radiated by the stars floating in the cluster potential. The kinematics of the ICL can then be used to asses the dynamical status of the nearby cluster cores and to infer their formation histories. The cores of the Virgo and Coma are observed to be far from equilibrium, with mergers currently on-going, while the ICL properties in the Fornax and Hydra clusters show the presence of sub-components being accreted in their cores, but superposed to an otherwise relaxed population of stars. Finally the comparison of the observed ICL properties with those predicted from Lambda-CDM simulations indicates a qualitative agreement and provides insights on the ICL formation. Both observations and simulations indicate that BCG halos and ICL are physically distinct components, with the ``hotter" ICL dominating at large radial distances from the BCGs halos as the latter become progressively fainter.Comment: 14 pages, 5 figures. Invited review to appear in the proceedings of "Galaxies and their masks" eds. Block, D.L., Freeman, K.C. and Puerari, I., 2010, Springer (New York

Optical Spectra of SNR Candidates in NGC 300

We present moderate-resolution (<5A) long-slit optical spectra of 51 nebular objects in the nearby Sculptor Group galaxy NGC 300 obtained with the 2.3 meter Advanced Technology Telescope at Siding Spring Observatory, Australia. Adopting the criterion of [SII]/Ha>=0.4 to confirm supernova remnants (SNRs) from optical spectra, we find that of 28 objects previously proposed as SNRs from optical observations, 22 meet this criterion with six showing [SII]/Ha of less than 0.4. Of 27 objects suggested as SNRs from radio data, four are associated with the 28 previously proposed SNRs. Of these four, three (included in the 22 above) meet the criterion. In all, 22 of the 51 nebular objects meet the [SII]/Ha criterion as SNRs while the nature of the remaining 29 objects remains undetermined by these observations.Comment: Accepted for publication in Astrophysics & Space Scienc

Antihypertensive medication use and blood pressure control among treated older adults

The association of different antihypertensive regimens with blood pressure (BP) control is not well-described among community-dwelling older adults with low comorbidity. We examined antihypertensive use and BP control in 10 062 treated hypertensives from Australia and the United States (US) using baseline data from the ASPirin in Reducing Events in the Elderly (ASPREE) trial. Renin-angiotensin system (RAS) drugs were the most prevalently used antihypertensive in both countries (Australia: 81.7% of all regimens; US: 62.9% of all regimens; P P P P = .002; diuretic monotherapy: BP control = 45.2% vs 64.5%; P = .001; and RAS blocker/diuretic combo: BP control = 50.2% vs 65.6%; P = .001). Our findings highlight variation in antihypertensive use in older adults treated for hypertension, with implications for BP control. Differences in BP control that were observed may be influenced, in part, by reasons other than choice of specific regimens

Electroweak measurements in electron–positron collisions at w-boson-pair energies at lep

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