The Discovery of a Gravitationally Lensed Supernova Ia at Redshift 2.22

Rubin, D.,Hayden, B.,Huang, X.,Aldering, G.,Amanullah, R.,Barbary, K.,Boone, K.,Brodwin, M.,Deustua, S. E.,Dixon, S.,Eisenhardt, P.,Fruchter, A. S.,Gonzalez, A. H.,Goobar, A.,Gupta, R. R.,Hook, I.,Jee American Astronomical Society 2018 The Astrophysical journal Vol.866 No.1

DISCOVERY OF A STRONG LENSING GALAXY EMBEDDED IN A CLUSTER AT z = 1.62

WONG, KENNETH C.,TRAN, KIM-VY H.,SUYU, SHERRY H.,MOMCHEVA, IVELINA G.,BRAMMER, GABRIEL B.,BRODWIN, MARK,GONZALEZ, ANTHONY H.,HALKOLA, ALEKSI,KACPRZAK, GLENN G.,KOEKEMOER, ANTON M.,PAPOVICH, CASEY J.,R The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2

We identify a strong lensing galaxy in the cluster IRC 0218 that is spectroscopically confirmed to be at z = 1.62, making it the highest-redshift strong lens galaxy known. The lens is one of the two brightest cluster galaxies and lenses a background source galaxy into an arc and a counterimage. With Hubble Space Telescope (HST) grism and Keck/LRIS spectroscopy, we measure the source redshift to be $z_S=2.26$. Using HST imaging, we model the lens mass distribution with an elliptical power-law profile and account for the effects of the cluster halo and nearby galaxies. The Einstein radius is $^{\theta}E=0.38^{+0.02{\prime}{\prime}}_{-0.01}$ ($3.2^{+0.2}_{-0.1}kpc$) and the total enclosed mass is $M_{tot}(<^{\theta}_E)=1.8^{+0.2}_{-0.1}{\times}10^{11}M_{\odot}$. We estimate that the cluster environment contributes ~ 10% of this total mass. Assuming a Chabrier IMF, the dark matter fraction within $^{\theta}E$ is $f^{Chab}_{DM}=0.3^{+0.1}_{-0.3}$, while a Salpeter IMF is marginally inconsistent with the enclosed mass ($f^{Salp}_{DM}=-0.3^{+0.2}_{-0.5}$).

Baryon content of massive galaxy clusters at 0.57 < <i>z</i> < 1.33

Chiu, I.,Mohr, J.,McDonald, M.,Bocquet, S.,Ashby, M. L. N.,Bayliss, M.,Benson, B. A.,Bleem, L. E.,Brodwin, M.,Desai, S.,Dietrich, J. P.,Forman, W. R.,Gangkofner, C.,Gonzalez, A. H.,Hennig, C.,Liu, J. Oxford University Press 2016 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.455 No.1

GALAXY CLUSTERS DISCOVERED VIA THE SUNYAEV-ZEL'DOVICH EFFECT IN THE 2500-SQUARE-DEGREE SPT-SZ SURVEY

Bleem, L. E.,Stalder, B.,de Haan, T.,Aird, K. A.,Allen, S. W.,Applegate, D. E.,Ashby, M. L. N.,Bautz, M.,Bayliss, M.,Benson, B. A.,Bocquet, S.,Brodwin, M.,Carlstrom, J. E.,Chang, C. L.,Chiu, I.,Cho, H IOP Publishing 2015 The Astrophysical journal Supplement series Vol.216 No.2

<P>We present a catalog of galaxy clusters selected via their Sunyaev-Zel'dovich (SZ) effect signature from 2500 deg(2) of South Pole Telescope (SPT) data. This work represents the complete sample of clusters detected at high significance in the 2500 deg(2) SPT-SZ survey, which was completed in 2011. A total of 677 (409) cluster candidates are identified above a signal-to-noise threshold of xi = 4.5 (5.0). Ground-and space-based optical and near-infrared (NIR) imaging confirms overdensities of similarly colored galaxies in the direction of 516 (or 76%) of the xi > 4.5 candidates and 387 (or 95%) of the xi > 5 candidates; the measured purity is consistent with expectations from simulations. Of these confirmed clusters, 415 were first identified in SPT data, including 251 new discoveries reported in this work. We estimate photometric redshifts for all candidates with identified optical and/or NIR counterparts; we additionally report redshifts derived from spectroscopic observations for 141 of these systems. The mass threshold of the catalog is roughly independent of redshift above z similar to 0.25 leading to a sample of massive clusters that extends to high redshift. The median mass of the sample is M-500c(rho(crit)) similar to 3.5 x 10(14) M-circle dot h(70)(-1) 70, the median redshift is z(med) = 0.55, and the highest-redshift systems are at z > 1.4. The combination of large redshift extent, clean selection, and high typical mass makes this cluster sample of particular interest for cosmological analyses and studies of cluster formation and evolution.</P>

X-RAY CAVITIES IN A SAMPLE OF 83 SPT-SELECTED CLUSTERS OF GALAXIES: TRACING THE EVOLUTION OF AGN FEEDBACK IN CLUSTERS OF GALAXIES OUT TO<i>z</i>= 1.2

Hlavacek-Larrondo, J.,McDonald, M.,Benson, B. A.,Forman, W. R.,Allen, S. W.,Bleem, L. E.,Ashby, M. L. N.,Bocquet, S.,Brodwin, M.,Dietrich, J. P.,Jones, C.,Liu, J.,Reichardt, C. L.,Saliwanchik, B. R.,S IOP Publishing 2015 The Astrophysical journal Vol.805 No.1

<P>X-ray cavities are key tracers of mechanical (or radio mode) heating arising from the active galactic nuclei (AGNs) in brightest cluster galaxies (BCGs). We report on a survey for X-ray cavities in 83 massive, high-redshift (0.4 < z < 1.2) clusters of galaxies selected by their Sunyaev-Zel'dovich signature in the South Pole Telescope data. Based on Chandra X-ray images, we find a total of six clusters having symmetric pairs of surface brightness depressions consistent with the picture of radio jets inflating X-ray cavities in the intracluster medium (ICM). The majority of these detections are of relatively low significance and require deeper follow-up data in order to be confirmed. Further, this search will miss small (<10 kpc) X-ray cavities that are unresolved by Chandra at high (z greater than or similar to 5) redshift. Despite these limitations, our results suggest that the power generated by AGN feedback in BCGs has remained unchanged for over half of the age of the universe (>7 Gyr at z similar to 0.8). On average, the detected X-ray cavities have powers of (0.8-5) x 10(45) erg s(-1), enthalpies of (3-6) x 10(59) erg, and radii of similar to 17 kpc. Integrating over 7 Gyr, we find that the supermassive black holes in BCGs may have accreted 10(8) to several 10(9) M-circle dot of material to power these outflows. This level of accretion indicates that significant supermassive black hole growth may occur not only at early times, in the quasar era, but at late times as well. We also find that X-ray cavities at high redshift may inject an excess heat of 0.1-1.0 keV per particle into the hot ICM above and beyond the energy needed to offset cooling. Although this result needs to be confirmed, we note that the magnitude of excess heating is similar to the energy needed to preheat clusters, break self-similarity, and explain the excess entropy in hot atmospheres.</P>

Spectroscopic needs for imaging dark energy experiments

Newman, J.A.,Abate, A.,Abdalla, F.B.,Allam, S.,Allen, S.W.,Ansari, R.,Bailey, S.,Barkhouse, W.A.,Beers, T.C.,Blanton, M.R.,Brodwin, M.,Brownstein, J.R.,Brunner, R.J.,Carrasco Kind, M.,Cervantes-Cota, North-Holland 2015 Astroparticle physics Vol.63 No.-

Ongoing and near-future imaging-based dark energy experiments are critically dependent upon photometric redshifts (a.k.a. photo-z's): i.e., estimates of the redshifts of objects based only on flux information obtained through broad filters. Higher-quality, lower-scatter photo-z's will result in smaller random errors on cosmological parameters; while systematic errors in photometric redshift estimates, if not constrained, may dominate all other uncertainties from these experiments. The desired optimization and calibration is dependent upon spectroscopic measurements for secure redshift information; this is the key application of galaxy spectroscopy for imaging-based dark energy experiments. Hence, to achieve their full potential, imaging-based experiments will require large sets of objects with spectroscopically-determined redshifts, for two purposes:*Training: Objects with known redshift are needed to map out the relationship between object color and z (or, equivalently, to determine empirically-calibrated templates describing the rest-frame spectra of the full range of galaxies, which may be used to predict the color-z relation). The ultimate goal of training is to minimize each moment of the distribution of differences between photometric redshift estimates and the true redshifts of objects, making the relationship between them as tight as possible. The larger and more complete our ''training set'' of spectroscopic redshifts is, the smaller the RMS photo-z errors should be, increasing the constraining power of imaging experiments. Requirements: Spectroscopic redshift measurements for ~30,000 objects over >~15 widely-separated regions, each at least ~20arcmin in diameter, and reaching the faintest objects used in a given experiment, will likely be necessary if photometric redshifts are to be trained and calibrated with conventional techniques. Larger, more complete samples (i.e., with longer exposure times) can improve photo-z algorithms and reduce scatter further, enhancing the science return from planned experiments greatly (increasing the Dark Energy Task Force figure of merit by up to ~50%). Options: This spectroscopy will most efficiently be done by covering as much of the optical and near-infrared spectrum as possible at modestly high spectral resolution (λ/Δλ>~3000), while maximizing the telescope collecting area, field of view on the sky, and multiplexing of simultaneous spectra. The most efficient instrument for this would likely be either the proposed GMACS/MANIFEST spectrograph for the Giant Magellan Telescope or the OPTIMOS spectrograph for the European Extremely Large Telescope, depending on actual properties when built. The PFS spectrograph at Subaru would be next best and available considerably earlier, c. 2018; the proposed ngCFHT and SSST telescopes would have similar capabilities but start later. Other key options, in order of increasing total time required, are the WFOS spectrograph at TMT, MOONS at the VLT, and DESI at the Mayall 4m telescope (or the similar 4MOST and WEAVE projects); of these, only DESI, MOONS, and PFS are expected to be available before 2020. Table 2-3 of this white paper summarizes the observation time required at each facility for strawman training samples. To attain secure redshift measurements for a high fraction of targeted objects and cover the full redshift span of future experiments, additional near-infrared spectroscopy will also be required; this is best done from space, particularly with WFIRST-2.4 and JWST. Calibration: The first several moments of redshift distributions (the mean, RMS redshift dispersion, etc.), must be known to high accuracy for cosmological constraints not to be systematics-dominated (equivalently, the moments of the distribution of differences between photometric and true redshifts could be determined instead). The ultimate goal of calibration is to characterize these moments for every subsample used in analyses - i.e., to minimi