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We present the discovery of the most distant, dynamically relaxed cool core cluster, SPT-CL J2215-3537 (SPT2215) and its central brightest cluster galaxy (BCG) at z=1.16. Using new X-ray observations, we demonstrate that SPT2215 harbors a strong cool core, with a central cooling time of 200 Myr (at 10 kpc) and a maximal intracluster medium cooling rate of 1900+/-400 Msun/yr. This prodigious cooling may be responsible for fueling extended, star-forming filaments observed in Hubble Space Telescope imaging. Based on new spectrophotometric data, we detect bright [O II] emission in the BCG, implying an unobscured star formation rate (SFR) of 320^{+230}_{-140} Msun/yr. The detection of a weak radio source (2.0+/-0.8 mJy at 0.8 GHz) suggests ongoing feedback from an active galactic nucleus (AGN), though the implied jet power is less than half the cooling luminosity of the hot gas, consistent with cooling overpowering heating. The extreme cooling and SFR of SPT2215 is rare among known cool core clusters, and it is even more remarkable that we observe these at such high redshift, when most clusters are still dynamically disturbed. The high mass of this cluster, coupled with the fact that it is dynamically relaxed with a highly-isolated BCG, suggests that it is an exceptionally rare system that must have formed very rapidly in the early Universe. Combined with the high SFR, SPT2215 may be a high-z analog of the Phoenix cluster, potentially providing insight into the limits of AGN feedback and star formation in the most massive galaxies., 14 pages, 5 figures, 1 table. Accepted in ApJ

We present a multi-wavelength analysis of the galaxy cluster SPT-CL J0607-4448 (SPT0607), which is one of the most distant clusters discovered by the South Pole Telescope (SPT) at $z=1.4010\pm0.0028$. The high-redshift cluster shows clear signs of being relaxed with well-regulated feedback from the active galactic nucleus (AGN) in the brightest cluster galaxy (BCG). Using Chandra X-ray data, we construct thermodynamic profiles and determine the properties of the intracluster medium. The cool core nature of the cluster is supported by a centrally-peaked density profile and low central entropy ($K_0=18_{-9}^{+11}$ keV cm$^2$), which we estimate assuming an isothermal temperature profile due to the limited spectral information given the distance to the cluster. Using the density profile and gas cooling time inferred from the X-ray data, we find a mass cooling rate of $\dot{M}_\mathrm{cool}=100_{-60}^{+90}~M_\odot$ yr$^{-1}$. From optical spectroscopy and photometry around the [O II] emission line, we estimate that the BCG star formation rate is SFR$_\mathrm{[O~II]}=1.7_{-0.6}^{+1.0}~M_\odot$ yr$^{-1}$, roughly two orders of magnitude lower than the predicted mass cooling rate. In addition, using ATCA radio data at 2.1 GHz, we measure a radio jet power of $P_\mathrm{cav}=3.2_{-1.3}^{+2.1}\times10^{44}$ erg s$^{-1}$, which is consistent with the X-ray cooling luminosity ($L_\mathrm{cool}=1.9_{-0.5}^{+0.2}\times10^{44}$ erg s$^{-1}$ within $r_\mathrm{cool}=43$ kpc). These findings suggest that SPT0607 is a relaxed, cool core cluster with AGN-regulated cooling at an epoch shortly after cluster formation, implying that the balance between cooling and feedback can be reached quickly. We discuss implications for these findings on the evolution of AGN feedback in galaxy clusters., Comment: 13 pages, 5 figures, accepted for publication in ApJ

The Pelona-Orocopia-Rand Schist (PORS) of southern California and southwest Arizona are interpreted as Late Cretaceous correlatives of the Jurassic-Cretaceous Franciscan accretionary complex that were subducted and accreted beneath cratonal and Mesozoic magmatic rocks during flat-slab subduction of the Farallon oceanic lithosphere. The Orocopia Schist (OS) of southeast California and southwest Arizona occurs east of the San Andreas fault and represents the furthest inboard member of the 800 km PORS belt. While the bulk of the Orocopia Schist exposures occur within the core of the 230-km-long, NW-SE– to E-W–trending Chocolate Mountains Anticlinorium (CMA), recent discoveries at Cemetery Ridge and the Plomosa Mountains significantly increase the known areal distribution of the PORS in southwestern Arizona. These exposures occur 300 km inland of the present-day continental margin and up to 450 km inboard of the reconstructed position of the trench.The Orocopia Schist provides a unique opportunity to investigate the timing of the underplated schist and the metamorphic conditions the schist underwent during low-angle subduction. Previous work determined the evolution of the PORS by constraining the time between the youngest detrital U/Pb zircon ages and oldest 40Ar/39Ar metamorphic mineral cooling ages, thus determining the PORS “cycling interval”. However, the recent discovery of metamorphic zircon growth in samples from Cemetery Ridge and the Plomosa Mountains has permitted more direct estimates of the time of metamorphism that attended accretion of subducted sediment beneath cratonal southwestern Arizona.Here, we present U/Pb age data and chemical proxies for recrystallization (e.g., Th/U) from overgrowths upon detrital zircon grains from several different major exposures of Orocopia Schist. This study utilized cycle-by-cycle depth-profile laser-ablation split-stream ICP-MS methods to target

We present the analysis of deep X-ray observations of 10 massive galaxy clusters at redshifts $1.05 < z < 1.71$, with the primary goal of measuring the metallicity of the intracluster medium (ICM) at intermediate radii, to better constrain models of the metal enrichment of the intergalactic medium. The targets were selected from X-ray and Sunyaev-Zel'dovich (SZ) effect surveys, and observed with both the \textit{XMM-Newton} and \textit{Chandra} satellites. For each cluster, a precise gas mass profile was extracted, from which the value of $r_{500}$ could be estimated. This allows us to define consistent radial ranges over which the metallicity measurements can be compared. In general, the data are of sufficient quality to extract meaningful metallicity measurements in two radial bins, $r, Comment: 10 pages, 5 figures

Using stellar population synthesis models to infer star formation histories (SFHs), we analyse photometry and spectroscopy of a large sample of quiescent galaxies which are members of Sunyaev-Zel'dovich (SZ)-selected galaxy clusters across a wide range of redshifts. We calculate stellar masses and mass-weighted ages for 837 quiescent cluster members at 0.3 < z < 1.4 using rest-frame optical spectra and the Python-based Prospector framework, from 61 clusters in the SPT-GMOS Spectroscopic Survey (0.3 < z < 0.9) and 3 clusters in the SPT Hi-z cluster sample (1.25 < z < 1.4). We analyse spectra of subpopulations divided into bins of redshift, stellar mass, cluster mass, and velocity-radius phase-space location, as well as by creating composite spectra of quiescent member galaxies. We find that quiescent galaxies in our dataset sample a diversity of SFHs, with a median formation redshift (corresponding to the lookback time from the redshift of observation to when a galaxy forms 50% of its mass, t$_{50}$) of $z=2.8\pm0.5$, which is similar to or marginally higher than that of massive quiescent field and cluster galaxy studies. We also report median age-stellar mass relations for the full sample (age of the Universe at $t_{50}$ (Gyr) = $2.52 (\pm0.04) - 1.66 (\pm0.11)$ log$_{10}(M/10^{11} M\odot))$ and recover downsizing trends across stellar mass; we find that massive galaxies in our cluster sample form on aggregate $\sim0.75$ Gyr earlier than lower mass galaxies. We also find marginally steeper age-mass relations at high redshifts, and report a bigger difference in formation redshifts across stellar mass for fixed environment, relative to formation redshifts across environment for fixed stellar mass., 35 pages, 23 figures, 5 tables. Submitted to The Astrophysical Journal. Comments and feedback welcome

Parametric modeling of galaxy cluster density profiles from weak lensing observations leads to a mass bias, whose detailed understanding is critical in deriving accurate mass-observable relations for constraining cosmological models. Drawing from existing methods, we develop a robust framework for calculating this mass bias in one-parameter fits to simulations of dark matter halos. We show that our approach has the advantage of being independent of the absolute noise level, so that only the number of halos in a given simulation and the representativeness of the simulated halos for real clusters limit the accuracy of the bias estimation. While we model the bias as a log-normal distribution and the halos with a Navarro-Frenk-White profile, our method can be generalized to any bias distribution and parametric model of the radial mass distribution. We find that the log-normal assumption is not strictly valid in the presence of miscentring of halos. We investigate the use of cluster centers derived from weak lensing in the context of mass bias, and tentatively find that such centroids can yield sensible mass estimates if the convergence peak has a signal-to-noise ratio approximately greater than four. In this context we also find that the standard approach to estimating the positional uncertainty of weak lensing mass peaks using bootstrapping severely underestimates the true positional uncertainty for peaks with low signal-to-noise ratios. Though we determine the mass and redshift dependence of the bias distribution for a few experimental setups, our focus remains providing a general approach to computing such distributions., Comment: 19 pages, 12 fiures, 2 tables, submitted to MNRAS

We present the results of a joint analysis of $Chandra$ X-ray and South Pole Telescope (SPT) SZ observations targeting the first sample of galaxy clusters at $0.3 < z < 1.3$, selected to be the progenitors of well-studied nearby clusters based on their expected accretion rate. We develop a new procedure in order to tackle the analysis challenge that is estimating the intracluster medium (ICM) properties of low-mass and high-redshift clusters with ${\sim}150$ X-ray counts. One of the dominant sources of uncertainty on the ICM density profile estimated with a standard X-ray analysis with such shallow X-ray data is due to the systematic uncertainty associated with the ICM temperature obtained through the analysis of the background-dominated X-ray spectrum. We show that we can decrease the uncertainty on the density profile by a factor ${\sim}5$ with a joint deprojection of the X-ray surface brightness profile measured by $Chandra$ and the SZ integrated Compton parameter available in the SPT cluster catalog. We apply this technique to the whole sample of 67 clusters in order to track the evolution of the ICM core density during cluster growth. We confirm that the evolution of the gas density profile is well modeled by the combination of a fixed core and a self-similarly evolving non-cool core profile. We show that the fraction of cool-cores in this sample is remarkably stable with redshift although clusters have gained a factor ${\sim}4$ in total mass over the past ${\sim}9$ Gyr. This new sample combined with our new X-ray/SZ analysis procedure and extensive multi-wavelength data will allow us to address fundamental shortcomings in our current understanding of cluster formation and evolution at $z > 1$.

We present results from a 577 ks XMM-Newton observation of SPT-CL J0459-4947, the most distant cluster detected in the South Pole Telescope 2500 square degree (SPT-SZ) survey, and currently the most distant cluster discovered through its Sunyaev-Zel'dovich effect. The data confirm the cluster's high redshift, $z=1.71 \pm 0.02$, in agreement with earlier, less precise optical/IR photometric estimates. From the gas density profile, we estimate a characteristic mass of $M_{500}=(1.8 \pm 0.2) \times 10^{14}M_{Sun}$; cluster emission is detected above the background to a radius of $\sim 2.2 r_{500}$, or approximately the virial radius. The intracluster gas is characterized by an emission-weighted average temperature of $7.2 \pm 0.3$ keV and metallicity with respect to Solar of $0.37 \pm 0.08$. For the first time at such high redshift, this deep data set provides a measurement of metallicity outside the cluster center; at radii $r > 0.3 r_{500}$, we find it to be $0.33 \pm 0.17$, in good agreement with precise measurements at similar radii in the most nearby clusters, supporting an early enrichment scenario in which the bulk of the cluster gas is enriched to a universal metallicity prior to cluster formation, with little to no evolution thereafter. The leverage provided by the high redshift of this cluster tightens by a factor of 2 constraints on evolving metallicity models, when combined with previous measurements at lower redshifts., 12 pages, to be published in MNRAS

Full author list: L. E. Bleem, S. Bocquet, B. Stalder, M. D. Gladders, P. A. R. Ade, S. W. Allen, A. J. Anderson, J. Annis, M. L. N. Ashby, J. E. Austermann, S. Avila, J. S. Avva, M. Bayliss, J. A. Beall, K. Bechtol, A. N. Bender, B. A. Benson, E. Bertin, F. Bianchini, C. Blake, M. Brodwin, D. Brooks, E. Buckley-Geer, D. L. Burke, J. E. Carlstrom, A. Carnero Rosell, M. Carrasco Kind, J. Carretero, C. L. Chang, H. C. Chiang, R. Citron, C. Corbett Moran, M. Costanzi, T. M. Crawford, A. T. Crites, L. N. da Costa, T. de Haan, J. De Vicente, S. Desai, H. T. Diehl, J. P. Dietrich, M. A. Dobbs, T. F. Eifler, W. Everett, B. Flaugher, B. Floyd, J. Frieman, J. Gallicchio, J. García-Bellido, E. M. George, D. W. Gerdes, A. Gilbert, D. Gruen, R. A. Gruendl, J. Gschwend, N. Gupta, G. Gutierrez, N. W. Halverson, N. Harrington, J. W. Henning, C. Heymans, G. P. Holder, D. L. Hollowood, W. L. Holzapfel, K. Honscheid, J. D. Hrubes, N. Huang, J. Hubmayr, K. D. Irwin, D. J. James, T. Jeltema, S. Joudaki, G. Khullar, M. Klein, L. Knox, N. Kuropatkin, A. T. Lee, D. Li, C. Lidman, A. Lowitz, N. MacCrann, G. Mahler, M. A. G. Maia, J. L. Marshall, M. McDonald, J. J. McMahon, P. Melchior, F. Menanteau, S. S. Meyer, R. Miquel, L. M. Mocanu, J. J. Mohr, J. Montgomery, A. Nadolski, T. Natoli, J. P. Nibarger, G. Noble, V. Novosad, S. Padin, A. Palmese, D. Parkinson, S. Patil, F. Paz-Chinchón, A. A. Plazas, C. Pryke, N. S. Ramachandra, C. L. Reichardt, J. D. Remolina González, A. K. Romer, A. Roodman, J. E. Ruhl, E. S. Rykoff, B. R. Saliwanchik, E. Sanchez, A. Saro, J. T. Sayre, K. K. Schaffer, T. Schrabback, S. Serrano, K. Sharon, C. Sievers, G. Smecher, M. Smith, M. Soares-Santos, A. A. Stark, K. T. Story, E. Suchyta, G. Tarle, C. Tucker, K. Vanderlinde, T. Veach, J. D. Vieira, G. Wang, J. Weller, N. Whitehorn, W. L. K. Wu, V. Yefremenko, and Y. Zhang, We describe the observations and resultant galaxy cluster catalog from the 2770 deg2 SPTpol Extended Cluster Survey (SPT-ECS). Clusters are identified via the Sunyaev-Zel'dovich (SZ) effect and confirmed with a combination of archival and targeted follow-up data, making particular use of data from the Dark Energy Survey (DES). With incomplete follow-up we have confirmed as clusters 244 of 266 candidates at a detection significance ξ ≥ 5 and an additional 204 systems at 4 < ξ < 5. The confirmed sample has a median mass of M500c ~ 4.4 ¿ 1014 M☉ h70 -1 and a median redshift of z = 0.49, and we have identified 44 strong gravitational lenses in the sample thus far. Radio data are used to characterize contamination to the SZ signal; the median contamination for confirmed clusters is predicted to be ∼1% of the SZ signal at the ξ > 4 threshold, and 10% of their measured SZ flux. We associate SZ-selected clusters, from both SPT-ECS and the SPT-SZ survey, with clusters from the DES redMaPPer sample, and we find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets. Adopting a fixed Planck-like cosmology, we measure the optical richness-SZ mass (l - M) relation and find it to be 28% shallower than that from a weak-lensing analysis of the DES data-a difference significant at the 4σ level-with the relations intersecting at λ = 60. The SPT-ECS cluster sample will be particularly useful for studying the evolution of massive clusters and, in combination with DES lensing observations and the SPT-SZ cluster sample, will be an important component of future cosmological analyses., This work was performed in the context of the South Pole Telescope scientific program. SPT is supported by the National Science Foundation through grant PLR-1248097. Partial support is also provided by the NSF Physics Frontier Center grant PHY-0114422 to the Kavli Institute of Cosmological Physics at the University of Chicago, the Kavli Foundation, and the Gordon and Betty Moore Foundation grant GBMF 947 to the University of Chicago. This work is also supported by the U.S. Department of Energy. PISCO observations are supported by NSF AST-1814719. Work at Argonne National Lab is supported by UChicago Argonne LLC, operator of Argonne National Laboratory (Argonne). Argonne, a U.S. Department of Energy Office of Science Laboratory, is operated under contract No. DE-AC02- 06CH11357. We also acknowledge support from the Argonne Center for Nanoscale Materials. M.G. and L.B. acknowledge partial support from HST-GO-15307.001. B.B. is supported by the Fermi Research Alliance LLC under contract No. De-AC02- 07CH11359 with the U.S. Department of Energy. The CU Boulder group acknowledges support from NSF AST-0956135. The McGill authors acknowledge funding from the Natural Sciences and Engineering Research Council of Canada, Canadian Institute for Advanced Research, and the Fonds de Recherche du Québec Nature et technologies. The UCLA authors acknowledge support from NSF AST-1716965 and CSSI-1835865. The Stanford/SLAC group acknowledges support from the U.S. Department of Energy under contract No. DE-AC02-76SF00515. A.S. is supported by the ERC-StG “ClustersXCosmo” grant agreement 716762 and by the FARE-MIUR grant “ClustersXEuclid” R165SBKTMA. C.H. acknowledges support from the Max Planck Society and the Alexander von Humboldt Foundation, in the framework of the Max Planck-Humboldt Research Award endowed by the Federal Ministry of Education and Research, in addition to support from the European Research Council under grant No. 647112. S.J. acknowledges support from the Beecroft Trust and ERC 693024. T.S. acknowledges support from the German Federal Ministry of Economics and Technology (BMWi) provided through DLR under projects 50 OR 1610 and 50 OR 1803, as well as support from the Deutsche Forschungsgemeinschaft, DFG, under project SCHR 1400/3-1. The Melbourne authors acknowledge support from the Australian Research Council’s Discovery Projects scheme (DP150103208). The 2dFLenS survey is based on data acquired through the Australian Astronomical Observatory, under program A/2014B/008. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. Funding for the DES Projects has been provided by the U.S. Department of Energy, the U.S. National Science Foundation, the Ministry of Science and Education of Spain, the Science and Technology Facilities Council of the United Kingdom, the Higher Education Funding Council for England, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, the Kavli Institute of Cosmological Physics at the University of Chicago, the Center for Cosmology and Astro-Particle Physics at The Ohio State University, the Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University, Financiadora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência, Tecnologia e Inovação, the Deutsche Forschungsgemeinschaft, and the Collaborating Institutions in the Dark Energy Survey. The Collaborating Institutions are Argonne National Laboratory, the University of California at Santa Cruz, the University of Cambridge, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas-Madrid, the University of Chicago, University College London, the DES-Brazil Consortium, the University of Edinburgh, the Eidgenössische Technische Hochschule (ETH) Zürich, Fermi National Accelerator Laboratory, the University of Illinois at UrbanaChampaign, the Institut de Ciències de l’Espai (IEEC/CSIC), the Institut de Física d’Altes Energies, Lawrence Berkeley National Laboratory, the Ludwig-Maximilians Universität München and the associated Excellence Cluster Universe, the University of Michigan, the National Optical Astronomy Observatory, the University of Nottingham, The Ohio State University, the University of Pennsylvania, the University of Portsmouth, SLAC National Accelerator Laboratory, Stanford University, the University of Sussex, Texas A&M University, and the OzDES Membership Consortium. Based in part on observations at Cerro Tololo InterAmerican Observatory, National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. The DES data management system is supported by the National Science Foundation under grant Nos. AST-1138766 and AST-1536171. The DES participants from Spanish institutions are partially supported by MINECO under grants AYA2015-71825, ESP2015-66861, FPA2015-68048, SEV2016-0588, SEV-2016-0597, and MDM-2015-0509, some of which include ERDF funds from the European Union. IFAE is partially funded by the CERCA program of the Generalitat de Catalunya. Research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Program (FP7/2007- 2013), including ERC grant agreements 240672, 291329, and 306478. We acknowledge support from the Brazilian Instituto Nacional de Ciência e Tecnologia (INCT) e-Universe (CNPq grant 465376/2014-2). This manuscript has been authored by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Pan-STARRS1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, Johns Hopkins University, Durham University, the University of Edinburgh, the Queen’s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation grant No. AST1238877, the University of Maryland, Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation

We present a catalog of galaxy cluster candidates detected in 100 square degrees surveyed with the SPTpol receiver on the South Pole Telescope. The catalog contains 89 candidates detected with a signal-to-noise ratio greater than 4.6. The candidates are selected using the Sunyaev-Zel'dovich effect at 95 and 150 GHz. Using both space- and ground-based optical and infrared telescopes, we have confirmed 81 candidates as galaxy clusters. We use these follow-up images and archival images to estimate photometric redshifts for 66 galaxy clusters and spectroscopic observations to obtain redshifts for 13 systems. An additional 2 galaxy clusters are confirmed using the overdensity of near-infrared galaxies only, and are presented without redshifts. We find that 15 candidates (18% of the total sample) are at redshift of $z \geq 1.0$, with a maximum confirmed redshift of $z_{\rm{max}} = 1.38 \pm 0.10$. We expect this catalog to contain every galaxy cluster with $M_{500c} > 2.6 \times 10^{14} M_\odot h^{-1}_{70}$ and $z > 0.25$ in the survey area. The mass threshold is approximately constant above $z = 0.25$, and the complete catalog has a median mass of approximately $ M_{500c} = 2.7 \times 10^{14} M_\odot h^{-1}_{70}$. Compared to previous SPT works, the increased depth of the millimeter-wave data (11.2 and 6.5 $��$K-arcmin at 95 and 150 GHz, respectively) makes it possible to find more galaxy clusters at high redshift and lower mass., 21 pages, 7 figures, associated data available at http://pole.uchicago.edu/public/data/sptsz-clusters. V2 was accepted to the AJ, and includes minor changes requested by the reviewer

We present ~103 ks of Chandra observations of the galaxy cluster SPT-CLJ0528-5300 (SPT0528, z=0.768). This cluster harbors the most radio-loud (L_1.4GHz = 1.01 x 10^33 erg/s/Hz) central AGN of any cluster in the South Pole Telescope (SPT) SZ survey with available X-ray data. We find evidence of AGN-inflated cavities in the X-ray emission, which are consistent with the orientation of the jet direction revealed by ATCA radio data. The combined probability that two such depressions -- each at ~1.4-1.8sigma significance, oriented ~180 degrees apart and aligned with the jet axis -- would occur by chance is 0.1%. At >10^61 erg, the outburst in SPT0528 is among the most energetic known in the universe, and certainly the most powerful known at z>0.25. This work demonstrates that such powerful outbursts can be detected even in shallow X-ray exposures out to relatively high redshifts (z~0.8), providing an avenue for studying the evolution of extreme AGN feedback. The ratio of the cavity power (P_cav = 9.4+/-5.8 x 10^45 erg/s) to the cooling luminosity (L_cool = 1.5+/-0.5 x 10^44 erg/s) for SPT0528 is among the highest measured to date. If, in the future, additional systems are discovered at similar redshifts with equally high P_cav/L_cool ratios, it would imply that the feedback/cooling cycle was not as gentle at high redshifts as in the low-redshift universe., Comment: Accepted to ApJL. 8 pages, 5 figures

From e-commerce to command-and-control to situational awareness, organizations increasingly depend on web servers for mission-critical functionality. Distributed denial-of-service (DDoS) attacks put that functionality at risk. DDoS attacks pose an asymmetric threat; attackers with minimal resources can impact well-provisioned systems, and current best-of-breed commercial systems cannot counter zero-day algorithmic DDoS attacks. The NNBC Firewall is a practical DDoS solution. Operating on its own it can defend a site against both algorithmic and volumetric application-level DoS attacks. When used in conjunction with a commercial overlay network that provides a black list API, the NNBC can defeat bandwidth-consuming volumetric attacks. Central to the NNBC Firewall is the NEMESIS Non-Bayesian Classifier (NNBC), a sequential decision maker that uses temporal correlation between web requests and DoS events to classify clients as attacker vs. non-attacker. This allows the firewall to defend the web site against volumetric and algorithmic DoS attacks, including zero-day attacks that cannot be detected.

We present an analysis of the mass distribution inferred from strong lensing by SPT-CL J0356-5337, a cluster of galaxies at redshift z = 1.0359 revealed in the follow-up of the SPT-SZ clusters. The cluster has an Einstein radius of Erad=14 for a source at z = 3 and a mass within 500 kpc of M_500kpc = 4.0+-0.8x10^14Msol. Our spectroscopic identification of three multiply-imaged systems (z = 2.363, z = 2.364, and z = 3.048), combined with HST F606W-band imaging allows us to build a strong lensing model for this cluster with an rms of, 19 pages, 11 figures. Submitted to ApJ

Subjective judgments in software engineering tasks are of critical importance but can be difficult to study with conventional means. Medical imaging techniques hold the promise of relating cognition to physical activities and brain structures. In a controlled experiment involving 29 participants, we examine code comprehension, code review and prose review using functional magnetic resonance imaging. We find that the neural representations of programming languages vs. natural languages are distinct. We can classify which task a participant is under-taking based solely on brain activity (balanced accuracy 79%, p r = 0.99, p r = −0.44, p = 0.016) indicating that more skilled participants treat code and prose more similarly at a neural activation level.

From Abstract: "This publication attempts to diminish the incidence of stress corrosion failures by assembling the available practical measures to avoid or minimize the problem and present these measures in a form comprehensible to those persons responsible for the design, fabrication, and maintenance of new structures."