Galaxy kinematics and mass calibration in massive SZE-selected galaxy clusters to z = 1.3

The galaxy phase-space distribution in galaxy clusters provides insights into the formation and evolution of cluster galaxies, and it can also be used to measure cluster mass profiles. We present a dynamical study based on 3c3000 passive, non-emission-line cluster galaxies drawn from 110 galaxy clusters. The galaxy clusters were selected using the Sunyaev-Zel'dovich effect (SZE) in the 2500 deg2 South Pole Telescope (SPT)-SZ survey and cover the redshift range 0.2 < z < 1.3. We model the clusters using the Jeans equation, while adopting NFW mass profiles and a broad range of velocity dispersion anisotropy profiles. The data prefer velocity dispersion anisotropy profiles that are approximately isotropic near the centre and increasingly radial toward the cluster virial radius, and this is true for all redshifts and masses we study. The pseudo-phase-space density profile of the passive galaxies is consistent with expectations for dark matter particles and subhaloes from cosmological N-body simulations. The dynamical mass constraints are in good agreement with external mass estimates of the SPT cluster sample from either weak lensing, velocity dispersions, or X-ray YX measurements. However, the dynamical masses are lower (at the 2.2\u3c3 level) when compared to the mass calibration favoured when fitting the SPT cluster data to a \u39bcold dark matter model with external cosmological priors, including cosmic microwave background anisotropy data from Planck. The discrepancy grows with redshift, where in the highest redshift bin the ratio of dynamical to SPT + Planck masses is \u3b7 = 0.63^{+0.13}_{-0.08}\ub1 0.06 (statistical and systematic), corresponding to a 2.6\u3c3 discrepancy

Deep Chandra, HST-COS, and Megacam Observations of the Phoenix Cluster: Extreme Star Formation and AGN Feedback on Hundred Kiloparsec Scales

We present new ultraviolet, optical, and X-ray data on the Phoenix galaxy cluster (SPT-CLJ2344-4243). Deep optical imaging reveals previously undetected filaments of star formation, extending to radii of ~50–100 kpc in multiple directions. Combined UV-optical spectroscopy of the central galaxy reveals a massive (2 × 109 M⊙), young (~4.5 Myr) population of stars, consistent with a time-averaged star formation rate of 610 ± 50 M⊙ yr−1. We report a strong detection of O vi λλ1032,1038, which appears to originate primarily in shock-heated gas, but may contain a substantial contribution (>1000 M⊙ yr−1) from the cooling intracluster medium (ICM). We confirm the presence of deep X-ray cavities in the inner ~10 kpc, which are among the most extreme examples of radio-mode feedback detected to date, implying jet powers of 2–7 × 1045 erg s−1. We provide evidence that the active galactic nucleus inflating these cavities may have only recently transitioned from "quasar-mode" to "radio-mode," and may currently be insufficient to completely offset cooling. A model-subtracted residual X-ray image reveals evidence for prior episodes of strong radio-mode feedback at radii of ~100 kpc, with extended "ghost" cavities indicating a prior epoch of feedback roughly 100 Myr ago. This residual image also exhibits significant asymmetry in the inner ~200 kpc (0.15R500), reminiscent of infalling cool clouds, either due to minor mergers or fragmentation of the cooling ICM. Taken together, these data reveal a rapidly evolving cool core which is rich with structure (both spatially and in temperature), is subject to a variety of highly energetic processes, and yet is cooling rapidly and forming stars along thin, narrow filaments

From the Inside: The Meaning of Probation to Probationers

Beyond considerations of relative punitiveness, very little is known about how offenders understand the experience of serving a probation sentence. The current study surveyed offenders currently on probation to assess the extent to which they believed their sentence was rehabilitative, incapacitative, deserved, and a deterrent to future offending. Perceptions that probation served no purpose and that it represented a game of manipulation and impression management were also investigated. The results showed that most probationers believed that their sentence was a deterrent, and it was rehabilitative and deserved. They also felt that probation served multiple purposes, and a minority of respondents perceived that there was no point to being on probation. The implications of these findings are discussed

Spectroscopic Confirmation of Five Galaxy Clusters at z > 1.25 in the 2500 deg 2 SPT-SZ Survey

© 2018. The American Astronomical Society. All rights reserved.. We present spectroscopic confirmation of five galaxy clusters at 1.25 1.25 from three to eight, further demonstrating the efficacy of SZ selection for the highest redshift massive clusters and enabling detailed study of these systems