Afshordi et al. stack 193 X-ray emitting clusters to find a 9 sigma detection of the SZ effect in the WMAP 3-year data. They find that 32+/-10% of the baryons are not in the hot ICM.
Cattaneo & Treyssier perform detailed simulations of AGN feedback on cluster ICM and show that after an initial rapid accretion phase a stable solution is reached with a constant small accretion rate.
Hashimoto et al. analyze a sample of Chandra images of clusters using simple statistics to define morphology. They find that distorted and non-distorted clusters occupy different loci in the L-T plane but no correlation between morphology and luminosity or temperature.
Crowder & Cornish present their solution to the "cocktail party" problem of LISA analysis of Galactic binaries using a Blocked Annealing Metropolis-Hastings MCMC.
Riess et al. present new SNIa, 13 of which are at z>1, and conclude that the data are still consistent with w=-1 and rule out dw/dz>>1.
Borkin et al. use medical imaging technology for slicing 3D data cubes in an astronomical context as part of the Harvard AstroMed initiative.
Fusco-Femiano et al. argue that there really is a non-thermal excess from the Coma cluster.
Jonsson et al. calculate the effects of weak lensing on possible attempts to do cosmology useing GW detections of chirping black holes with EM counterparts (hence redshifts).
Nayakshin explains the variability of continuum and constancy of reflection components in AGN by arguing that disk coronal flares are likely to emit anisotropically.