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Sample records for galaxy cluster surveys

  1. The APM Galaxy Survey - V. Catalogues of galaxy clusters

    NASA Astrophysics Data System (ADS)

    Dalton, G. B.; Maddox, S. J.; Sutherland, W. J.; Efstathiou, G.

    1997-08-01

    We describe the construction of catalogues of galaxy clusters from the APM Galaxy survey using an automated algorithm based on Abell-like selection criteria. We investigate the effects of varying several parameters in our selection algorithm, including the magnitude range and radius from the cluster centre used to estimate the cluster richnesses. We quantify the accuracy of the photometric distance estimates by comparing them with measured redshifts, and we investigate the stability and completeness of the resulting catalogues. We find that the angular correlation functions for different cluster catalogues are in good agreement with one another, and are also consistent with the observed amplitude of the spatial correlation function of rich clusters.

  2. ChaMP Serendipitous Galaxy Cluster Survey

    SciTech Connect

    Barkhouse, Wayne A.; Green, P.J.; Vikhlinin, A.; Kim, D.-W.; Perley, D.; Cameron, R.; Silverman, J.; Mossman, A.; Burenin, R.; Jannuzi, B.T.; Kim, M.; Smith, M.G.; Smith, R.C.; Tananbaum, H.; Wilkes, B.J.; /Harvard-Smithsonian Ctr. Astrophys. /UC, Berkeley, Astron. Dept. /SLAC /Garching, Max Planck Inst., MPE /Moscow, Space Res. Inst. /NOAO, Tucson /Cerro-Tololo InterAmerican Obs.

    2006-04-03

    We present a survey of serendipitous extended X-ray sources and optical cluster candidates from the Chandra Multi-wavelength Project (ChaMP). Our main goal is to make an unbiased comparison of X-ray and optical cluster detection methods. In 130 archival Chandra pointings covering 13 square degrees, we use a wavelet decomposition technique to detect 55 extended sources, of which 6 are nearby single galaxies. Our X-ray cluster catalog reaches a typical flux limit of about {approx} 10{sup -14} erg s{sup -1} cm{sup -2}, with a median cluster core radius of 21''. For 56 of the 130 X-ray fields, we use the ChaMP's deep NOAO/4m MOSAIC g', r', and i' imaging to independently detect cluster candidates using a Voronoi tessellation and percolation (VTP) method. Red-sequence filtering decreases the galaxy fore/background contamination and provides photometric redshifts to z {approx} 0.7. From the overlapping 6.1 square degree X-ray/optical imaging, we find 115 optical clusters (of which 11% are in the X-ray catalog) and 28 X-ray clusters (of which 46% are in the optical VTP catalog). The median redshift of the 13 X-ray/optical clusters is 0.41, and their median X-ray luminosity (0.5-2 keV) is L{sub X} = (2.65 {+-} 0.19) x 10{sup 43} ergs s{sup -1}. The clusters in our sample that are only detected in our optical data are poorer on average ({approx} 4{sigma}) than the X-ray/optically matched clusters, which may partially explain the difference in the detection fractions.

  3. LENSING NOISE IN MILLIMETER-WAVE GALAXY CLUSTER SURVEYS

    SciTech Connect

    Hezaveh, Yashar; Vanderlinde, Keith; Holder, Gilbert; De Haan, Tijmen

    2013-08-01

    We study the effects of gravitational lensing by galaxy clusters of the background of dusty star-forming galaxies (DSFGs) and the cosmic microwave background (CMB), and examine the implications for Sunyaev-Zel'dovich-based (SZ) galaxy cluster surveys. At the locations of galaxy clusters, gravitational lensing modifies the probability distribution of the background flux of the DSFGs as well as the CMB. We find that, in the case of a single-frequency 150 GHz survey, lensing of DSFGs leads both to a slight increase ({approx}10%) in detected cluster number counts (due to a {approx}50% increase in the variance of the DSFG background, and hence an increased Eddington bias) and a rare (occurring in {approx}2% of clusters) 'filling-in' of SZ cluster signals by bright strongly lensed background sources. Lensing of the CMB leads to a {approx}55% reduction in CMB power at the location of massive galaxy clusters in a spatially matched single-frequency filter, leading to a net decrease in detected cluster number counts. We find that the increase in DSFG power and decrease in CMB power due to lensing at cluster locations largely cancel, such that the net effect on cluster number counts for current SZ surveys is subdominant to Poisson errors.

  4. Clusters of Galaxies in the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Nichol, Robert C.

    I review here past and present research on clusters and groups of galaxies within the Sloan Digital Sky Survey (SDSS). I begin with a short review of the SDSS and efforts to find clusters of galaxies using both the photometric and spectroscopic SDSS data. In particular, I discuss the C4 algorithm, which is designed to search for clusters and groups within a seven-dimensional (7-D) data space, i.e., simultaneous clustering in both color and space. The C4 catalog has a well-quantified selection function based on mock SDSS galaxy catalogs constructed from the Hubble Volume simulation. These simulations indicate that the C4 catalog is >90% complete, with <10% contamination, for halos of M200 >1014 Modot at z<0.14. Furthermore, the observed summed r-band luminosity of C4 clusters is linearly related to M200, with <30% scatter at any given halo mass. I also briefly review the selection and observation of luminous red galaxies and demonstrate that these galaxies have a similar clustering strength as clusters and groups of galaxies. I outline a new collaboration planning to obtain redshifts for 10,000 luminous red galaxies at 0.4 clusters and groups of galaxies in the study of galaxy properties as a function of environment. In particular, I discuss the ``star formation rate-density'' and ``morphology-radius'' relations for the SDSS and note that both of these relationships have a critical density (or ``break'') at a projected local galaxy density of ˜1 h75-2 {Mpc-2 (or between 1 to 2 virial radii). One possible physical mechanism to explain this observed critical density is the stripping of warm gas from the halos of infalling spiral galaxies, thus leading to a slow strangulation of star formation in these galaxies. This scenario is consistent with the recent discovery (within the SDSS) of an excess of ``passive'' or ``anemic'' spiral galaxies located

  5. Galaxy Clusters and Properties in the CFHTLS/VIPERS Survey

    NASA Astrophysics Data System (ADS)

    Gallego Gallego, Sofia Carolina; Murphy, David; Hyazinth Puzia, Thomas

    2015-08-01

    We present our analysis of clusters in the CFHTLS Wide fields using a red-sequence based cluster finding code. The deep five-band photometry and panoramic coverage permits detection of galaxy clusters between z=0 and z~1 over 132 square degrees. We present a cluster catalogue and optical richness estimates as mass proxies, derived cluster properties from a novel template-fitting analysis and cluster redshift measurements utilizing data from the VLT/VIPERS spectroscopic survey.We complement our analysis with studies of mock cluster catalogues generated from N-body simulation lightcones featuring semi-analytic prescriptions of galaxy formation. These provide us with an insight into the performance of the cluster-finding technique, uncertainties in the derived properties of the detected cluster populations and an important comparison of the popular “lambda” optical richness estimator to known dark matter halo properties.This study serves as the perfect precursor to LSST-depth cluster science, providing an important input into how models describe the evolution of clusters and their members as a function of redshift and mass, and the role high-density environments play in galaxy evolution over half the Hubble time.

  6. Searching for galaxy clusters in the Kilo-Degree Survey

    NASA Astrophysics Data System (ADS)

    Radovich, M.; Puddu, E.; Bellagamba, F.; Roncarelli, M.; Moscardini, L.; Bardelli, S.; Grado, A.; Getman, F.; Maturi, M.; Huang, Z.; Napolitano, N.; McFarland, J.; Valentijn, E.; Bilicki, M.

    2017-02-01

    Aims: In this paper, we present the tools used to search for galaxy clusters in the Kilo Degree Survey (KiDS), and our first results. Methods: The cluster detection is based on an implementation of the optimal filtering technique that enables us to identify clusters as over-densities in the distribution of galaxies using their positions on the sky, magnitudes, and photometric redshifts. The contamination and completeness of the cluster catalog are derived using mock catalogs based on the data themselves. The optimal signal to noise threshold for the cluster detection is obtained by randomizing the galaxy positions and selecting the value that produces a contamination of less than 20%. Starting from a subset of clusters detected with high significance at low redshifts, we shift them to higher redshifts to estimate the completeness as a function of redshift: the average completeness is 85%. An estimate of the mass of the clusters is derived using the richness as a proxy. Results: We obtained 1858 candidate clusters with redshift 0 Survey (SDSS)-based cluster catalogs shows that we match more than 50% of the clusters (77% in the case of the redMaPPer catalog). We also cross-matched our cluster catalog with the Abell clusters, and clusters found by XMM and in the Planck-SZ survey; however, only a small number of them lie inside the KiDS area currently available. The catalog is available at http://kids.strw.leidenuniv.nl/DR2 and at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/598/A107

  7. SPATIAL ANISOTROPY OF GALAXY KINEMATICS IN SLOAN DIGITAL SKY SURVEY GALAXY CLUSTERS

    SciTech Connect

    Skielboe, Andreas; Wojtak, Radoslaw; Pedersen, Kristian; Rozo, Eduardo; Rykoff, Eli S.

    2012-10-10

    Measurements of galaxy cluster kinematics are important in understanding the dynamical state and evolution of clusters of galaxies, as well as constraining cosmological models. While it is well established that clusters exhibit non-spherical geometries, evident in the distribution of galaxies on the sky, azimuthal variations of galaxy kinematics within clusters have yet to be observed. Here we measure the azimuthal dependence of the line-of-sight velocity dispersion profile in a stacked sample of 1743 galaxy clusters from the Sloan Digital Sky Survey (SDSS). The clusters are drawn from the SDSS DR8 redMaPPer catalog. We find that the line-of-sight velocity dispersion of galaxies lying along the major axis of the central galaxy is larger than those that lie along the minor axis. This is the first observational detection of anisotropic kinematics of galaxies in clusters. We show that the result is consistent with predictions from numerical simulations. Furthermore, we find that the degree of projected anisotropy is strongly dependent on the line-of-sight orientation of the galaxy cluster, opening new possibilities for assessing systematics in optical cluster finding.

  8. Galaxy clustering with photometric surveys using PDF redshift information

    NASA Astrophysics Data System (ADS)

    Asorey, J.; Carrasco Kind, M.; Sevilla-Noarbe, I.; Brunner, R. J.; Thaler, J.

    2016-06-01

    Photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or colours, that are obtained through multiband imaging to produce a probability density function (PDF) for each galaxy in the map. We used simulated data to study the effect of using different photo-z estimators to assign galaxies to redshift bins in order to compare their effects on angular clustering and galaxy bias measurements. We found that if we use the entire PDF, rather than a single-point (mean or mode) estimate, the deviations are less biased, especially when using narrow redshift bins. When the redshift bin widths are Δz = 0.1, the use of the entire PDF reduces the typical measurement bias from 5 per cent, when using single point estimates, to 3 per cent.

  9. Galaxy clustering with photometric surveys using PDF redshift information

    DOE PAGES

    Asorey, J.; Carrasco Kind, M.; Sevilla-Noarbe, I.; ...

    2016-03-28

    Here, photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or colors, that are obtained through multi-band imaging to produce a probability density function (PDF) for each galaxy in the map. We used simulated data to study the effect of using different photo-z estimators to assign galaxies to redshift bins in order to compare their effects on angular clustering and galaxy bias measurements. We found that if we use the entire PDF, rather than a single-point (mean or mode) estimate, the deviations are less biased, especially when using narrow redshift bins. When the redshift bin widths aremore » $$\\Delta z=0.1$$, the use of the entire PDF reduces the typical measurement bias from 5%, when using single point estimates, to 3%.« less

  10. Galaxy clustering with photometric surveys using PDF redshift information

    SciTech Connect

    Asorey, J.; Carrasco Kind, M.; Sevilla-Noarbe, I.; Brunner, R. J.; Thaler, J.

    2016-03-28

    Here, photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or colors, that are obtained through multi-band imaging to produce a probability density function (PDF) for each galaxy in the map. We used simulated data to study the effect of using different photo-z estimators to assign galaxies to redshift bins in order to compare their effects on angular clustering and galaxy bias measurements. We found that if we use the entire PDF, rather than a single-point (mean or mode) estimate, the deviations are less biased, especially when using narrow redshift bins. When the redshift bin widths are $\\Delta z=0.1$, the use of the entire PDF reduces the typical measurement bias from 5%, when using single point estimates, to 3%.

  11. Strong Lens Models for Massive Galaxy Clusters in the Reionization Lensing Cluster Survey

    NASA Astrophysics Data System (ADS)

    Cerny, Catherine; Sharon, Keren; Coe, Dan A.; Paterno-Mahler, Rachel; Jones, Christine; Czakon, Nicole G.; Umetsu, Keiichi; Stark, Daniel; Bradley, Larry D.; Trenti, Michele; Johnson, Traci; Bradac, Marusa; Dawson, William; Rodney, Steven A.; Strolger, Louis-Gregory; RELICS Team

    2017-01-01

    We present strong lensing models for five galaxy clusters from the Planck SZ cluster catalog as a part of the Reionization Lensing Cluster Survey (RELICS), a program that seeks to constrain the galaxy luminosity function past z~9 by conducting a wide field survey of massive galaxy clusters with HST (GO-14096, PI: Coe). The strong gravitational lensing effects of these clusters significantly magnify background galaxies, which enhances our ability to discover the large numbers of high redshift galaxies at z~9-12 needed to create a representative sample. We use strong lensing models for these clusters to study their mass distribution and magnification, which allows us to quantify the lensing effect on the background galaxies. These models can then be utilized in the RELICS survey in order to identify high redshift galaxy candidates that may be lensed by the clusters. The intrinsic properties of these galaxy candidates can be derived by removing the lensing effect as predicted by our models, which will meet the science goals of the RELICS survey. We use HST WFC3 and ACS imaging to create lensing models for the clusters RXC J0142.9+4438, ACO-2537, ACO-2163, RXCJ2211.7-0349, and ACT-CLJ0102-49151.

  12. Distant Compact Clusters of Galaxies from the BMW survey

    NASA Astrophysics Data System (ADS)

    Dell'Antonio, Ian; Guzzo, Luigi; Longhetti, Marcella; Moretti, Alberto; Campana, Sergio; Lazzati, Davide; Panzera, Mariarosa; Tagliaferri, Gianpiero

    2002-02-01

    We propose to use SQIID to identify high-redshift clusters of galaxies from the BMW, an X-ray selected sample of serendipitously detected extended sources from the ROSAT HRI archive. The BMW survey is unique because of the superior angular resolution of the HRI. In fact, this is the only modern sample of distant clusters available that is not based on the low-resolution PSPC. Using 4m optical imaging, we have already identified several high-redshift clusters, two of which have z> 0.8, thus confirming the ability of the survey to peer efficiently into the z~ 1 regime, where only a handful of X-ray clusters are known. To test the evolution of the cluster abundance, we must increase the number of clusters known in this redshift regime. The BMW survey provides us with the only current opportunity to study compact clusters missing in all PSPC surveys. Because z~ 1 ellipticals have very red colors, K-band imaging is the most effective way of identifying these clusters. With SQIID, we also can obtain redshift estimates via the J-K red sequence. We propose near-IR imaging in J,H,K of 30 highest-z cluster candidates from the BMW survey, as indicated by their small size and low flux. This will allow efficient use of 8-meter spectroscopy to follow up the high-end tail of the redshift distribution.

  13. Hα star formation rates of z > 1 galaxy clusters in the IRAC shallow cluster survey

    SciTech Connect

    Zeimann, Gregory R.; Stanford, S. A.; Brodwin, Mark; Gonzalez, Anthony H.; Mancone, Conor; Snyder, Gregory F.; Stern, Daniel; Eisenhardt, Peter; Dey, Arjun; Moustakas, John

    2013-12-20

    We present Hubble Space Telescope near-IR spectroscopy for 18 galaxy clusters at 1.0 Cluster Survey. We use Wide Field Camera 3 grism data to spectroscopically identify Hα emitters in both the cores of galaxy clusters as well as in field galaxies. We find a large cluster-to-cluster scatter in the star formation rates within a projected radius of 500 kpc, and many of our clusters (∼60%) have significant levels of star formation within a projected radius of 200 kpc. A stacking analysis reveals that dust reddening in these star-forming galaxies is positively correlated with stellar mass and may be higher in the field than the cluster at a fixed stellar mass. This may indicate a lower amount of gas in star-forming cluster galaxies than in the field population. Also, Hα equivalent widths of star-forming galaxies in the cluster environment are still suppressed below the level of the field. This suppression is most significant for lower mass galaxies (log M {sub *} < 10.0 M {sub ☉}). We therefore conclude that environmental effects are still important at 1.0 galaxies in galaxy clusters with log M {sub *} ≲ 10.0 M {sub ☉}.

  14. A Snapshot Survey of The Most Massive Clusters of Galaxies

    NASA Astrophysics Data System (ADS)

    Ebeling, Harald

    2007-07-01

    We propose the continuation of our highly successful SNAPshot survey of a sample of 125 very X-ray luminous clusters in the redshift range 0.3-0.7. As demonstrated by the 25 snapshots obtained so far in Cycle14 and Cycle15 these systems frequently exhibit strong gravitational lensing as well as spectacular examples of violent galaxy interactions. The proposed observations will provide important constraints on the cluster mass distributions, the physical nature of galaxy-galaxy and galaxy-gas interactions in cluster cores, and a set of optically bright, lensed galaxies for further 8-10m spectroscopy. All of our primary science goals require only the detection and characterisation of high-surface-brightness features and are thus achievable even at the reduced sensitivity of WFPC2. Because of their high redshift and thus compact angular scale our target clusters are less adversely affected by the smaller field of view of WFPC2 than more nearby systems. Acknowledging the broad community interest in this sample we waive our data rights for these observations. Due to a clerical error at STScI our approved Cycle15 SNAP program was barred from execution for 3 months and only 6 observations have been performed to date - reinstating this SNAP at Cycle16 priority is of paramount importance to reach meaningful statistics.

  15. The Herschel Virgo Cluster Survey - VIII. The Bright Galaxy Sample

    NASA Astrophysics Data System (ADS)

    Davies, J. I.; Bianchi, S.; Cortese, L.; Auld, R.; Baes, M.; Bendo, G. J.; Boselli, A.; Ciesla, L.; Clemens, M.; Corbelli, E.; De Looze, I.; di Serego Alighieri, S.; Fritz, J.; Gavazzi, G.; Pappalardo, C.; Grossi, M.; Hunt, L. K.; Madden, S.; Magrini, L.; Pohlen, M.; Smith, M. W. L.; Verstappen, J.; Vlahakis, C.

    2012-02-01

    We describe the Herschel Virgo Cluster Survey and the first data that cover the complete survey area (four 4 × 4 deg2 regions). We use these data to measure and compare the global far-infrared properties of 78 optically bright galaxies that are selected at 500 μm and detected in all five far-infrared bands. We show that our measurements and calibration are broadly consistent with previous data obtained by the IRAS, ISO, Spitzer and Planck. We use SPIRE and PACS photometry data to produce 100-, 160-, 250-, 350- and 500-μm cluster luminosity distributions. These luminosity distributions are not power laws, but 'peaked', with small numbers of both faint and bright galaxies. We measure a cluster 100-500 μm far-infrared luminosity density of 1.6(7.0) ± 0.2 × 109 L⊙ Mpc-3. This compares to a cluster 0.4-2.5 μm optical luminosity density of 5.0(20.0) × 109 L⊙ Mpc-3, some 3.2(2.9) times larger than the far-infrared. A 'typical' photon originates from an optical depth of 0.4 ± 0.1. Most of our sample galaxies are well fitted by a single modified blackbody (β= 2), leading to a mean dust mass of log MDust= 7.31 M⊙ and temperature of 20.0 K. We also derive both stellar and atomic hydrogen masses from which we calculate mean values for the star-to-gas (atomic) and gas (atomic)-to-dust mass ratios of 15.1 and 58.2, respectively. Using our derived dust, atomic gas and stellar masses, we estimate cluster mass densities of 8.6(27.8) × 106, 4.6(13.9) × 108 and 7.8(29.7) × 109 M⊙ Mpc-3 for dust, atomic gas and stars, respectively. These values are higher than those derived for field galaxies by factors of 39(126), 6(18) and 34(129), respectively. In the above, the luminosity/mass densities are given using the whole sample with the values in brackets using just those galaxies that lie between 17 and 23 Mpc. We provide a data table of flux densities in all the Herschel bands for all 78 bright Virgo Cluster galaxies. Herschel is an ESA space observatory with science

  16. Super Star Clusters in Luminous Infrared Galaxies: the SUNBIRD Survey

    NASA Astrophysics Data System (ADS)

    Väisänen, P.; Randriamanakoto, Z.; Escala, A.; Kankare, E.; Kniazev, A.; Kotilainen, J. K.; Mattila, S.; Ramphul, R.; Ryder, S.; Tekola, A.

    2014-09-01

    We summarize recent results from an Adaptive Optics (AO) imaging survey of 40 Luminous IR Galaxies (LIRGs). We have constructed the first statistically significant sample of Luminosity Functions (LFs) of Super Star Clusters (SSCs) in the near-IR, and find evidence that the LF slopes in LIRGs are shallower than in more quiescent spiral galaxies. Distance and blending effects were investigated in detail paving the way for SSC studies further out than done previously. We have also correlated the luminosities of the brightest clusters with the star formation rates of the hosts and find that the characteristics of the relation suggest an underlying physical driver rather than solely a size-of-sample effect. Finally we present early results of using SSC age and mass properties to trace the histories of the target LIRG systems.

  17. Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Miller, Christopher J. Miller

    2012-03-01

    There are many examples of clustering in astronomy. Stars in our own galaxy are often seen as being gravitationally bound into tight globular or open clusters. The Solar System's Trojan asteroids cluster at the gravitational Langrangian in front of Jupiter’s orbit. On the largest of scales, we find gravitationally bound clusters of galaxies, the Virgo cluster (in the constellation of Virgo at a distance of ˜50 million light years) being a prime nearby example. The Virgo cluster subtends an angle of nearly 8◦ on the sky and is known to contain over a thousand member galaxies. Galaxy clusters play an important role in our understanding of theUniverse. Clusters exist at peaks in the three-dimensional large-scale matter density field. Their sky (2D) locations are easy to detect in astronomical imaging data and their mean galaxy redshifts (redshift is related to the third spatial dimension: distance) are often better (spectroscopically) and cheaper (photometrically) when compared with the entire galaxy population in large sky surveys. Photometric redshift (z) [Photometric techniques use the broad band filter magnitudes of a galaxy to estimate the redshift. Spectroscopic techniques use the galaxy spectra and emission/absorption line features to measure the redshift] determinations of galaxies within clusters are accurate to better than delta_z = 0.05 [7] and when studied as a cluster population, the central galaxies form a line in color-magnitude space (called the the E/S0 ridgeline and visible in Figure 16.3) that contains galaxies with similar stellar populations [15]. The shape of this E/S0 ridgeline enables astronomers to measure the cluster redshift to within delta_z = 0.01 [23]. The most accurate cluster redshift determinations come from spectroscopy of the member galaxies, where only a fraction of the members need to be spectroscopically observed [25,42] to get an accurate redshift to the whole system. If light traces mass in the Universe, then the locations

  18. The 2dF Galaxy Redshift Survey: luminosity dependence of galaxy clustering

    NASA Astrophysics Data System (ADS)

    Norberg, Peder; Baugh, Carlton M.; Hawkins, Ed; Maddox, Steve; Peacock, John A.; Cole, Shaun; Frenk, Carlos S.; Bland-Hawthorn, Joss; Bridges, Terry; Cannon, Russell; Colless, Matthew; Collins, Chris; Couch, Warrick; Dalton, Gavin; De Propris, Roberto; Driver, Simon P.; Efstathiou, George; Ellis, Richard S.; Glazebrook, Karl; Jackson, Carole; Lahav, Ofer; Lewis, Ian; Lumsden, Stuart; Madgwick, Darren; Peterson, Bruce A.; Sutherland, Will; Taylor, Keith

    2001-11-01

    We investigate the dependence of the strength of galaxy clustering on intrinsic luminosity using the Anglo-Australian two degree field galaxy redshift survey (2dFGRS). The 2dFGRS is over an order of magnitude larger than previous redshift surveys used to address this issue. We measure the projected two-point correlation function of galaxies in a series of volume-limited samples. The projected correlation function is free from any distortion of the clustering pattern induced by peculiar motions and is well described by a power law in pair separation over the range 0.1<(r/h-1Mpc)<10. The clustering of L*(MbJ-5log10h=-19.7) galaxies in real space is well-fitted by a correlation length r0=4.9+/-0.3h-1Mpc and power-law slope γ=1.71+/-0.06. The clustering amplitude increases slowly with absolute magnitude for galaxies fainter than M*, but rises more strongly at higher luminosities. At low luminosities, our results agree with measurements from the Southern Sky Redshift Survey 2 by Benoist et al. However, we find a weaker dependence of clustering strength on luminosity at the highest luminosities. The correlation function amplitude increases by a factor of 4.0 between MbJ-5log10h=-18 and -22.5, and the most luminous galaxies are 3.0 times more strongly clustered than L* galaxies. The power-law slope of the correlation function shows remarkably little variation for samples spanning a factor of 20 in luminosity. Our measurements are in very good agreement with the predictions of the hierarchical galaxy formation models of Benson et al.

  19. A faint galaxy redshift survey behind massive clusters

    SciTech Connect

    Frye, Brenda Louise

    1999-05-01

    This thesis is concerned with the gravitational lensing effect by massive galaxy clusters. We have explored a new technique for measuring galaxy masses and for detecting high-z galaxies by their optical colors. A redshift survey has been obtained at the Keck for a magnitude limited sample of objects (I<23) behind three clusters, A1689, A2390, and A2218 within a radius of 0.5M pc. For each cluster we see both a clear trend of increasing flux and redshift towards the center. This behavior is the result of image magnifications, such that at fixed redshift one sees further down the luminosity function. The gradient of this magnification is, unlike measurements of image distortion, sensitive to the mass profile, and found to depart strongly from a pure isothermal halo. We have found that V RI color selection can be used effectively as a discriminant for finding high-z galaxies behind clusters and present five 4.1 < z < 5.1 spectra which are of very high quality due to their high mean magnification of ~20, showing strong, visibly-saturated interstellar metal lines in some cases. We have also investigated the radio ring lens PKS 1830-211, locating the source and multiple images and detected molecular absorption at mm wavelengths. Broad molecular absorption of width 1/40kms is found toward the southwest component only, where surprisingly it does not reach the base of the continuum, which implies incomplete coverage of the SW component by molecular gas, despite the small projected size of the source, less than 1/8h pc at the absorption redshift.

  20. The XMM Cluster Survey: the halo occupation number of BOSS galaxies in X-ray clusters

    NASA Astrophysics Data System (ADS)

    Mehrtens, Nicola; Romer, A. Kathy; Nichol, Robert C.; Collins, Chris A.; Sahlén, Martin; Rooney, Philip J.; Mayers, Julian A.; Bermeo-Hernandez, A.; Bristow, Martyn; Capozzi, Diego; Christodoulou, L.; Comparat, Johan; Hilton, Matt; Hoyle, Ben; Kay, Scott T.; Liddle, Andrew R.; Mann, Robert G.; Masters, Karen; Miller, Christopher J.; Parejko, John K.; Prada, Francisco; Ross, Ashley J.; Schneider, Donald P.; Stott, John P.; Streblyanska, Alina; Viana, Pedro T. P.; White, Martin; Wilcox, Harry; Zehavi, Idit

    2016-12-01

    We present a direct measurement of the mean halo occupation distribution (HOD) of galaxies taken from the eleventh data release (DR11) of the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey (BOSS). The HOD of BOSS low-redshift (LOWZ: 0.2 < z < 0.4) and Constant-Mass (CMASS: 0.43 < z < 0.7) galaxies is inferred via their association with the dark matter haloes of 174 X-ray-selected galaxy clusters drawn from the XMM Cluster Survey (XCS). Halo masses are determined for each galaxy cluster based on X-ray temperature measurements, and range between log10(M180/M⊙) = 13 and 15. Our directly measured HODs are consistent with the HOD-model fits inferred via the galaxy-clustering analyses of Parejko et al. for the BOSS LOWZ sample and White et al. for the BOSS CMASS sample. Under the simplifying assumption that the other parameters that describe the HOD hold the values measured by these authors, we have determined a best-fitting alpha-index of 0.91 ± 0.08 and 1.27^{+0.03}_{-0.04} for the CMASS and LOWZ HOD, respectively. These alpha-index values are consistent with those measured by White et al. and Parejko et al. In summary, our study provides independent support for the HOD models assumed during the development of the BOSS mock-galaxy catalogues that have subsequently been used to derive BOSS cosmological constraints.

  1. THE IMACS CLUSTER BUILDING SURVEY. II. SPECTRAL EVOLUTION OF GALAXIES IN THE EPOCH OF CLUSTER ASSEMBLY

    SciTech Connect

    Dressler, Alan; Oemler, Augustus Jr.; Poggianti, Bianca M.; Vulcani, Benedetta; Gladders, Michael D.; Abramson, Louis

    2013-06-10

    The IMACS Cluster Building Survey (ICBS) provides spectra of {approx}2200 galaxies 0.31 < z < 0.54 in five rich clusters (R {approx}< 5 Mpc) and the field. Infalling, dynamically cold groups with tens of members account for approximately half of the supercluster population, contributing to a growth in cluster mass of {approx}100% by the present day. The ICBS spectra distinguish non-star-forming (PAS) and poststarburst (PSB) from star-forming galaxies-continuously star-forming (CSF) or starbursts (SBH or SBO), identified by anomalously strong H{delta} absorption or [O II] emission. For the infalling cluster groups and similar field groups, we find a correlation between PAS+PSB fraction and group mass, indicating substantial ''preprocessing'' through quenching mechanisms that can turn star-forming galaxies into passive galaxies without the unique environment of rich clusters. SBH + SBO starburst galaxies are common, and they maintain an approximately constant ratio (SBH+SBO)/CSF Almost-Equal-To 25% in all environments-from field, to groups, to rich clusters. Similarly, while PSB galaxies strongly favor denser environments, PSB/PAS Almost-Equal-To 10%-20% for all environments. This result, and their timescale {tau} {approx} 500 Myr, indicates that starbursts are not signatures of a quenching mechanism that produces the majority of passive galaxies. We suggest instead that starbursts and poststarbursts signal minor mergers and accretions, in star-forming and passive galaxies, respectively, and that the principal mechanisms for producing passive systems are (1) early major mergers, for elliptical galaxies, and (2) later, less violent processes-such as starvation and tidal stripping, for S0 galaxies.

  2. The ACS Fornax Cluster Survey. XII. Diffuse Star Clusters in Early-type Galaxies

    NASA Astrophysics Data System (ADS)

    Liu, Yiqing; Peng, Eric W.; Lim, Sungsoon; Jordán, Andrés; Blakeslee, John; Côté, Patrick; Ferrarese, Laura; Pattarakijwanich, Petchara

    2016-10-01

    Diffuse star clusters (DSCs) are old and dynamically hot stellar systems that have lower surface brightness and more extended morphology than globular clusters (GCs). Using the images from Hubble Space Telescope (HST)/ACS Fornax Cluster Survey, we find that 12 out of 43 early-type galaxies (ETGs) in the Fornax Cluster host significant numbers of DSCs. Together with literature data from the HST/ACS Virgo Cluster Survey, where 18 out of 100 ETGs were found to host DSCs, we systematically study the relationship of DSCs with GCs and their host galaxy environment. Two DSC hosts are post-merger galaxies, with most of the other hosts either having low mass or showing clear disk components. We find that while the number ratio of DSCs to GCs is nearly constant in massive galaxies, the DSC-to-GC ratio becomes systematically higher in lower-mass hosts. This suggests that DSCs may be more efficient at forming (or surviving) in low-density environments. DSC hosts are not special either in their position in the cluster or in the galactic color-magnitude diagram. Why some disk and low-mass galaxies host DSCs while others do not is still a puzzle, however. The mean ages of DSC hosts and nonhosts are similar at similar masses, implying that formation efficiency rather than survival is the reason behind different DSC number fractions in ETGs.

  3. VizieR Online Data Catalog: Galaxy clusters from the APM galaxy survey (Dalton+ 1997)

    NASA Astrophysics Data System (ADS)

    Dalton, G. B.; Maddox, S. J.; Sutherland, W. J.; Efstahiou, G.

    1997-10-01

    We describe the construction of catalogues of galaxy clusters from the APM Galaxy survey using an automated algorithm based on Abell-like selection criteria. We investigate the effects of varying several parameters in our selection algorithm, including the magnitude range and radius from the cluster centre used to estimate the cluster richnesses. We quantify the accuracy of the photometric distance estimates by comparing them with measured redshifts, and we investigate the stability and completeness of the resulting catalogues. We find that the angular correlation functions for different cluster catalogues are in good agreement with one another, and are also consistent with the observed amplitude of the spatial correlation function of rich clusters. (1 data file).

  4. The C4 clustering algorithm: Clusters of galaxies in the Sloan Digital Sky Survey

    SciTech Connect

    Miller, Christopher J.; Nichol, Robert; Reichart, Dan; Wechsler, Risa H.; Evrard, August; Annis, James; McKay, Timothy; Bahcall, Neta; Bernardi, Mariangela; Boehringer, Hans; Connolly, Andrew; Goto, Tomo; Kniazev, Alexie; Lamb, Donald; Postman, Marc; Schneider, Donald; Sheth, Ravi; Voges, Wolfgang; /Cerro-Tololo InterAmerican Obs. /Portsmouth U., ICG /North Carolina U. /Chicago U., Astron. Astrophys. Ctr. /Chicago U., EFI /Michigan U. /Fermilab /Princeton U. Observ. /Garching, Max Planck Inst., MPE /Pittsburgh U. /Tokyo U., ICRR /Baltimore, Space Telescope Sci. /Penn State U. /Chicago U. /Stavropol, Astrophys. Observ. /Heidelberg, Max Planck Inst. Astron. /INI, SAO

    2005-03-01

    We present the ''C4 Cluster Catalog'', a new sample of 748 clusters of galaxies identified in the spectroscopic sample of the Second Data Release (DR2) of the Sloan Digital Sky Survey (SDSS). The C4 cluster-finding algorithm identifies clusters as overdensities in a seven-dimensional position and color space, thus minimizing projection effects that have plagued previous optical cluster selection. The present C4 catalog covers {approx}2600 square degrees of sky and ranges in redshift from z = 0.02 to z = 0.17. The mean cluster membership is 36 galaxies (with redshifts) brighter than r = 17.7, but the catalog includes a range of systems, from groups containing 10 members to massive clusters with over 200 cluster members with redshifts. The catalog provides a large number of measured cluster properties including sky location, mean redshift, galaxy membership, summed r-band optical luminosity (L{sub r}), velocity dispersion, as well as quantitative measures of substructure and the surrounding large-scale environment. We use new, multi-color mock SDSS galaxy catalogs, empirically constructed from the {Lambda}CDM Hubble Volume (HV) Sky Survey output, to investigate the sensitivity of the C4 catalog to the various algorithm parameters (detection threshold, choice of passbands and search aperture), as well as to quantify the purity and completeness of the C4 cluster catalog. These mock catalogs indicate that the C4 catalog is {approx_equal}90% complete and 95% pure above M{sub 200} = 1 x 10{sup 14} h{sup -1}M{sub {circle_dot}} and within 0.03 {le} z {le} 0.12. Using the SDSS DR2 data, we show that the C4 algorithm finds 98% of X-ray identified clusters and 90% of Abell clusters within 0.03 {le} z {le} 0.12. Using the mock galaxy catalogs and the full HV dark matter simulations, we show that the L{sub r} of a cluster is a more robust estimator of the halo mass (M{sub 200}) than the galaxy line-of-sight velocity dispersion or the richness of the cluster. However, if we

  5. Sunyaev Zel'dovich galaxy cluster wide surveys for cosmology

    NASA Astrophysics Data System (ADS)

    Juin, J.-B.; Pires, S.; Yvon, D.; Refregier, A.; Yeche, C.; Moudden, Y.; Anthoine, S.; Pierpaoli, E.

    The observation of galaxy cluster population in milimeter wavelength through their Sunyaev Zel'dovich signal, both at low and high redshifts will provide the large sample needed to perform statistical studies of both intra-cluster physics and cosmology allowing a better understanding of universe dark-components: dark- matter density and dark-energy equation of state. Starting now, Olimpo, South Pole Telescope, Planck-HFI, APEX-SZ and Atacama Cosmology Telescope are world- class instruments dedicated to perform such surveys. After the technological challenge overcomed by state-of-art telescopes and bolometer camera, achievement of milimeter wide surveys need dedicated alogrithms to extract the SZ signal of galaxy cluster from foregrounds and backgrounds contaminants. This difficulty arise complex selection effects that have to be understood properly to allow optimal constraints calculation on physical models. Presented results are a summary of both articles: Pires et al. 2006 and Juin et al. 2007 published in Astronomy and Astrophics. In the first paper we present an efficient detection pipeline to extract SZ signal of galaxy clusters from multi-band millimeter maps. The pipeline core is an Independant Component Analysis algorithm that will isolate SZ signal from other physical contaminants (CMB anisotropies, galactic dust and SCUBA-like point sources) considered as statistically independant physical signals. While ICA algorithm is able to efficiently separate SZ signal from the mixture of physical signals, noise still remains in the SZ recovered map implying the necessity of a denoising step after the ICA. We used different classical filters (gaussian, wiener) and a state-of-art non-linear multi-scale entropy filtering, ME-FDR, with false-detection rate automatized threshold choice in each scale. This non-linear filtering showed to be an efficient method to avoid false detections of point sources that could have succeed the ICA selection and show up in the

  6. Joint analysis of galaxy-galaxy lensing and galaxy clustering: Methodology and forecasts for Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Park, Y.; Krause, E.; Dodelson, S.; Jain, B.; Amara, A.; Becker, M. R.; Bridle, S. L.; Clampitt, J.; Crocce, M.; Fosalba, P.; Gaztanaga, E.; Honscheid, K.; Rozo, E.; Sobreira, F.; Sánchez, C.; Wechsler, R. H.; Abbott, T.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Fausti Neto, A.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; James, D. J.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Roe, N.; Romer, A. K.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Soares-Santos, M.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Vikram, V.; Walker, A. R.; Weller, J.; Zuntz, J.; DES Collaboration

    2016-09-01

    The joint analysis of galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth function of large-scale structure. Anticipating a near future application of this analysis to Dark Energy Survey (DES) measurements of galaxy positions and shapes, we develop a practical approach to modeling the assumptions and systematic effects affecting the joint analysis of small-scale galaxy-galaxy lensing and large-scale galaxy clustering. Introducing parameters that characterize the halo occupation distribution (HOD), photometric redshift uncertainties, and shear measurement errors, we study how external priors on different subsets of these parameters affect our growth constraints. Degeneracies within the HOD model, as well as between the HOD and the growth function, are identified as the dominant source of complication, with other systematic effects being subdominant. The impact of HOD parameters and their degeneracies necessitate the detailed joint modeling of the galaxy sample that we employ. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the Universe, conservatively/optimistically constraining the growth function to 7.9%/4.8% with its first-year data that cover over 1000 square degrees, and to 3.9%/2.3% with its full five-year data that will survey 5000 square degrees, including both statistical and systematic uncertainties.

  7. Joint analysis of galaxy-galaxy lensing and galaxy clustering: Methodology and forecasts for Dark Energy Survey

    SciTech Connect

    Park, Y.; Krause, E.; Dodelson, S.; Jain, B.; Amara, A.; Becker, M. R.; Bridle, S. L.; Clampitt, J.; Crocce, M.; Fosalba, P.; Gaztanaga, E.; Honscheid, K.; Rozo, E.; Sobreira, F.; Sánchez, C.; Wechsler, R. H.; Abbott, T.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Fausti Neto, A.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; James, D. J.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Roe, N.; Romer, A. K.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Soares-Santos, M.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Vikram, V.; Walker, A. R.; Weller, J.; Zuntz, J.

    2016-09-30

    Here, the joint analysis of galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth function of large-scale structure. Anticipating a near future application of this analysis to Dark Energy Survey (DES) measurements of galaxy positions and shapes, we develop a practical approach to modeling the assumptions and systematic effects affecting the joint analysis of small-scale galaxy-galaxy lensing and large-scale galaxy clustering. Introducing parameters that characterize the halo occupation distribution (HOD), photometric redshift uncertainties, and shear measurement errors, we study how external priors on different subsets of these parameters affect our growth constraints. Degeneracies within the HOD model, as well as between the HOD and the growth function, are identified as the dominant source of complication, with other systematic effects being subdominant. The impact of HOD parameters and their degeneracies necessitate the detailed joint modeling of the galaxy sample that we employ. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the Universe, conservatively/optimistically constraining the growth function to 7.9%/4.8% with its first-year data that cover over 1000 square degrees, and to 3.9%/2.3% with its full five-year data that will survey 5000 square degrees, including both statistical and systematic uncertainties.

  8. Joint analysis of galaxy-galaxy lensing and galaxy clustering: Methodology and forecasts for Dark Energy Survey

    DOE PAGES

    Park, Y.; Krause, E.; Dodelson, S.; ...

    2016-09-30

    Here, the joint analysis of galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth function of large-scale structure. Anticipating a near future application of this analysis to Dark Energy Survey (DES) measurements of galaxy positions and shapes, we develop a practical approach to modeling the assumptions and systematic effects affecting the joint analysis of small-scale galaxy-galaxy lensing and large-scale galaxy clustering. Introducing parameters that characterize the halo occupation distribution (HOD), photometric redshift uncertainties, and shear measurement errors, we study how external priors on different subsets of these parameters affect our growth constraints. Degeneracies within the HODmore » model, as well as between the HOD and the growth function, are identified as the dominant source of complication, with other systematic effects being subdominant. The impact of HOD parameters and their degeneracies necessitate the detailed joint modeling of the galaxy sample that we employ. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the Universe, conservatively/optimistically constraining the growth function to 7.9%/4.8% with its first-year data that cover over 1000 square degrees, and to 3.9%/2.3% with its full five-year data that will survey 5000 square degrees, including both statistical and systematic uncertainties.« less

  9. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    SciTech Connect

    Melchior, P.; Suchyta, E.; Huff, E.; Hirsch, M.; Kacprzak, T.; Rykoff, E.; Gruen, D.; Armstrong, R.; Bacon, D.; Bechtol, K.; Bernstein, G. M.; Bridle, S.; Clampitt, J.; Honscheid, K.; Jain, B.; Jouvel, S.; Krause, E.; Lin, H.; MacCrann, N.; Patton, K.; Plazas, A.; Rowe, B.; Vikram, V.; Wilcox, H.; Young, J.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Allam, S. S.; Banerji, M.; Bernstein, J. P.; Bernstein, R. A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Castander, F. J.; da Costa, L. N.; Cunha, C. E.; Depoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Evrard, A. E.; Neto, A. F.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Frieman, J. A.; Gaztanaga, E.; Gerdes, D.; Gruendl, R. A.; Gutierrez, G. R.; Jarvis, M.; Karliner, I.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marriner, J.; Marshall, J. L.; Merritt, K. W.; Miller, C. J.; Miquel, R.; Mohr, J.; Neilsen, E.; Nichol, R. C.; Nord, B. D.; Reil, K.; Roe, N. A.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B. X.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, C.; Soares-Santos, M.; Swanson, M. E. C.; Sypniewski, A. J.; Tarle, G.; Thaler, J.; Thomas, D.; Tucker, D. L.; Walker, A.; Wechsler, R.; Weller, J.; Wester, W.

    2015-03-31

    We measure the weak-lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey. This pathfinder study is meant to 1) validate the DECam imager for the task of measuring weak-lensing shapes, and 2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, PSF modeling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well-behaved, but the modeling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting NFW profiles to the clusters in this study, we determine weak-lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak-lensing mass, and richness. In addition, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1 degree (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

  10. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    SciTech Connect

    Melchior, P.; Suchyta, E.; Huff, E.; Hirsch, M.; Kacprzak, T.; Rykoff, E.; Gruen, D.; Armstrong, R.; Bacon, D.; Bechtol, K.; Bernstein, G. M.; Bridle, S.; Clampitt, J.; Honscheid, K.; Jain, B.; Jouvel, S.; Krause, E.; Lin, H.; MacCrann, N.; Patton, K.; Plazas, A.; Rowe, B.; Vikram, V.; Wilcox, H.; Young, J.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Allam, S. S.; Banerji, M.; Bernstein, J. P.; Bernstein, R. A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Castander, F. J.; da Costa, L. N.; Cunha, C. E.; Depoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Evrard, A. E.; Neto, A. F.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Frieman, J. A.; Gaztanaga, E.; Gerdes, D.; Gruendl, R. A.; Gutierrez, G. R.; Jarvis, M.; Karliner, I.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marriner, J.; Marshall, J. L.; Merritt, K. W.; Miller, C. J.; Miquel, R.; Mohr, J.; Neilsen, E.; Nichol, R. C.; Nord, B. D.; Reil, K.; Roe, N. A.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B. X.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, C.; Soares-Santos, M.; Swanson, M. E. C.; Sypniewski, A. J.; Tarle, G.; Thaler, J.; Thomas, D.; Tucker, D. L.; Walker, A.; Wechsler, R.; Weller, J.; Wester, W.

    2015-03-31

    We measure the weak lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey (DES). This pathfinder study is meant to (1) validate the Dark Energy Camera (DECam) imager for the task of measuring weak lensing shapes, and (2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, point spread function (PSF) modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting Navarro-Frenk-White profiles to the clusters in this study, we determine weak lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak lensing mass, and richness. In addition, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1. (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

  11. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    DOE PAGES

    Melchior, P.; Suchyta, E.; Huff, E.; ...

    2015-03-31

    We measure the weak-lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey. This pathfinder study is meant to 1) validate the DECam imager for the task of measuring weak-lensing shapes, and 2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, PSF modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Sciencemore » Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well-behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting NFW profiles to the clusters in this study, we determine weak-lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak-lensing mass, and richness. Additionally, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1degree (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.« less

  12. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    SciTech Connect

    Melchior, P.; Suchyta, E.; Huff, E.; Hirsch, M.; Kacprzak, T.; Rykoff, E.; Gruen, D.; Armstrong, R.; Bacon, D.; Bechtol, K.; Bernstein, G. M.; Bridle, S.; Clampitt, J.; Honscheid, K.; Jain, B.; Jouvel, S.; Krause, E.; Lin, H.; MacCrann, N.; Patton, K.; Plazas, A.; Rowe, B.; Vikram, V.; Wilcox, H.; Young, J.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Allam, S. S.; Banerji, M.; Bernstein, J. P.; Bernstein, R. A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Castander, F. J.; da Costa, L. N.; Cunha, C. E.; Depoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Evrard, A. E.; Neto, A. F.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Frieman, J. A.; Gaztanaga, E.; Gerdes, D.; Gruendl, R. A.; Gutierrez, G. R.; Jarvis, M.; Karliner, I.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marriner, J.; Marshall, J. L.; Merritt, K. W.; Miller, C. J.; Miquel, R.; Mohr, J.; Neilsen, E.; Nichol, R. C.; Nord, B. D.; Reil, K.; Roe, N. A.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B. X.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, C.; Soares-Santos, M.; Swanson, M. E. C.; Sypniewski, A. J.; Tarle, G.; Thaler, J.; Thomas, D.; Tucker, D. L.; Walker, A.; Wechsler, R.; Weller, J.; Wester, W.

    2015-03-31

    We measure the weak-lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey. This pathfinder study is meant to 1) validate the DECam imager for the task of measuring weak-lensing shapes, and 2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, PSF modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well-behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting NFW profiles to the clusters in this study, we determine weak-lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak-lensing mass, and richness. Additionally, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1degree (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

  13. A 1400-MHz survey of 1478 Abell clusters of galaxies

    NASA Technical Reports Server (NTRS)

    Owen, F. N.; White, R. A.; Hilldrup, K. C.; Hanisch, R. J.

    1982-01-01

    Observations of 1478 Abell clusters of galaxies with the NRAO 91-m telescope at 1400 MHz are reported. The measured beam shape was deconvolved from the measured source Gaussian fits in order to estimate the source size and position angle. All detected sources within 0.5 corrected Abell cluster radii are listed, including the cluster number, richness class, distance class, magnitude of the tenth brightest galaxy, redshift estimate, corrected cluster radius in arcmin, right ascension and error, declination and error, total flux density and error, and angular structure for each source.

  14. A New Galaxy Cluster Survey For The Northern Sky

    NASA Astrophysics Data System (ADS)

    Gal, R. R.; et al.

    We present a new galaxy cluster catalog constructed from the Digitized Second Palomar Observatory Sky Survey. Our objectively defined catalog covers the entire Northern sky at |b|>30°, and contains nearly 20,000 cluster candidates with photometric redshifts and richnesses. Extensive simulations are used to establish contamination rates and our selection function. We also present some initial work on cluster mass estimation directly from our plate photometry. bibitem Borgani, S., Girardi, M., Carlberg, R. G., Yee, H. K. C., & Ellingson, E. 1999, apj, 527, 561 bibitem Djorgovski, S. G., Odewahn, S. C., Gal, R. R., Brunner, R., de Carvalho, R. R., Longo, G. & Scaramella, R. 1999, American Astronomical Society Meeting, 194, 0414 bibitem Gal, R. R., de Carvalho, R. R., Odewahn, S. C., Djorgovski, S. G., Mahabal, A., Brunner, R. J. & Lopes, P. 2003, AJ, in press bibitem Kim, R. S. J. 2001, Ph.D. Thesis, Princeton bibitem Paolillo, M., Andreon, S., Longo, G., Puddu, E., Gal, R. R., Scaramella, R., Djorgovski, S. G., & de Carvalho, R. 2001, aa, 367, 59 bibitem Postman, M., Lauer, T. R., Oegerle, W., & Donahue, M. 2002, apj, 579, 93 bibitem Struble, M. F. & Rood, H. J. 1999, apjs, 125, 35

  15. The Herschel Virgo Cluster Survey - XII. FIR properties of optically selected Virgo cluster galaxies

    NASA Astrophysics Data System (ADS)

    Auld, R.; Bianchi, S.; Smith, M. W. L.; Davies, J. I.; Bendo, G. J.; di Serego, S. Alighieri; Cortese, L.; Baes, M.; Bomans, D. J.; Boquien, M.; Boselli, A.; Ciesla, L.; Clemens, M.; Corbelli, E.; De Looze, I.; Fritz, J.; Gavazzi, G.; Pappalardo, C.; Grossi, M.; Hunt, L. K.; Madden, S.; Magrini, L.; Pohlen, M.; Verstappen, J.; Vlahakis, C.; Xilouris, E. M.; Zibetti, S.

    2013-01-01

    The Herschel Virgo Cluster Survey (HeViCS) is the deepest, confusion-limited survey of the Virgo Cluster at far-infrared (FIR) wavelengths. The entire survey at full depth covers ˜55 deg2 in five bands (100-500 μm), encompassing the areas around the central dominant elliptical galaxies (M87, M86 and M49) and extends as far as the NW cloud, the W cloud and the Southern extension. The survey extends beyond this region with lower sensitivity so that the total area covered is 84 deg2. In this paper we describe the data, the data acquisition techniques and present the detection rates of the optically selected Virgo Cluster Catalogue (VCC). We detect 254 (34 per cent) of 750 VCC galaxies found within the survey boundary in at least one band and 171 galaxies are detected in all five bands. For the remainder of the galaxies we have measured strict upper limits for their FIR emission. The population of detected galaxies contains early as well as late types although the latter dominate the detection statistics. We have modelled 168 galaxies, showing no evidence of a strong synchrotron component in their FIR spectra, using a single-temperature modified blackbody spectrum with a fixed emissivity index (β = 2). A study of the χ2 distribution indicates that this model is not appropriate in all cases, and this is supported by the FIR colours which indicate a spread in β = 1-2. Statistical comparison of the dust mass and temperature distributions from 140 galaxies with χ2d.o.f. = 3 < 7.8 (95 per cent confidence level) shows that late types have typically colder, more massive dust reservoirs; the early-type dust masses have a mean of log[/M⊙] = 6.3 ± 0.3, while for late types log[/M⊙] = 7.1 ± 0.1. The late-type dust temperatures have a mean of = 19.4 ± 0.2 K, while for the early types, = 21.1 ± 0.8 K. Late-type galaxies in the cluster exhibit slightly lower dust masses than those in the field, but the cluster environment seems to have little effect on

  16. The Wide-Field Nearby Galaxy-Cluster Survey (WINGS) and Its Extension OMEGAWINGS

    NASA Astrophysics Data System (ADS)

    Poggianti, B. M.; Fasano, G.; Bettoni, D.; Cava, A.; Couch, W.; D'Onofrio, M.; Dressler, A.; Fritz, J.; Kjaergaard, P.; Gullieuszik, M.; Moles, M.; Moretti, A.; Omizzolo, A.; Paccagnella, A.; Varela, J.; Vulcani, B.

    WINGS is a wide-field multi-wavelength survey of 76 X-ray selected clusters at low redshift. The WINGS database has been used for a variety of cluster and cluster galaxy studies, investigating galaxy star formation, morphologies, structure, stellar mass functions and other properties. We present the recent wider-field extension of WINGS, OMEGAWINGS, conducted with OmegaCAM@VST and AAOmega@AAT. We show two of our latest results regarding jellyfish galaxies and galaxy sizes. OMEGAWINGS has allowed the first systematic search of galaxies with signs of ongoing ram pressure stripping (jellyfishes), yielding a catalog of ˜ 240 galaxies in 41 clusters. We discuss the first results obtained from this sample and the prospects for integral field data. Finally, we summarize our results regarding the discovery of compact massive galaxies at low redshift, their properties, dependence on environment and the implications for the evolution of galaxy sizes from high- to low-z.

  17. The richness dependence of galaxy cluster correlations: results from a redshift survey of rich APM clusters

    NASA Astrophysics Data System (ADS)

    Croft, R. A. C.; Dalton, G. B.; Efstathiou, G.; Sutherland, W. J.; Maddox, S. J.

    1997-10-01

    We analyse the spatial clustering properties of a new catalogue of very rich galaxy clusters with newly measured redshifts selected from the APM Galaxy Survey. These clusters are of comparable richness and space density to Abell richness class≯1 clusters, but selected using an objective algorithm from a catalogue demonstrably free of artificial inhomogeneities. Evaluation of the two-point correlation function xi_cc(r) for the full sample and for richer subsamples reveals that the correlation amplitude is consistent with that measured for lower richness APM clusters and X-ray selected clusters. We apply a maximum likelihood estimator to find the best-fitting slope and amplitude of a power-law fit to xi_cc(r), and to estimate the correlation length r_0 [the value of r at which xi_cc(r) is equal to unity]. For clusters with a mean space density of 1.6x10^-6 h^3 Mpc^-3 (equivalent to the space density of Abell richness≯2 clusters), we find r_0=21.3^+11.1_-9.3 h^-1 Mpc (95 per cent confidence limits). This is consistent with the weak richness dependence of xi_cc(r) expected in Gaussian models of structure formation. In particular, the amplitude of xi_cc(r) at all richnesses matches that of xi_cc(r) for clusters selected in N-body simulations of a low-density cold dark matter model.

  18. THE STELLAR MASS GROWTH OF BRIGHTEST CLUSTER GALAXIES IN THE IRAC SHALLOW CLUSTER SURVEY

    SciTech Connect

    Lin, Yen-Ting; Brodwin, Mark; Gonzalez, Anthony H.; Bode, Paul; Eisenhardt, Peter R. M.; Stanford, S. A.; Vikhlinin, Alexey

    2013-07-01

    The details of the stellar mass assembly of brightest cluster galaxies (BCGs) remain an unresolved problem in galaxy formation. We have developed a novel approach that allows us to construct a sample of clusters that form an evolutionary sequence, and have applied it to the Spitzer IRAC Shallow Cluster Survey (ISCS) to examine the evolution of BCGs in progenitors of present-day clusters with mass of (2.5-4.5) Multiplication-Sign 10{sup 14} M{sub Sun }. We follow the cluster mass growth history extracted from a high resolution cosmological simulation, and then use an empirical method that infers the cluster mass based on the ranking of cluster luminosity to select high-z clusters of appropriate mass from ISCS to be progenitors of the given set of z = 0 clusters. We find that, between z = 1.5 and 0.5, the BCGs have grown in stellar mass by a factor of 2.3, which is well-matched by the predictions from a state-of-the-art semi-analytic model. Below z = 0.5 we see hints of differences in behavior between the model and observation.

  19. THE XMM CLUSTER SURVEY: THE STELLAR MASS ASSEMBLY OF FOSSIL GALAXIES

    SciTech Connect

    Harrison, Craig D.; Miller, Christopher J.; Richards, Joseph W.; Deadman, Paul-James; Lloyd-Davies, E. J.; Kathy Romer, A.; Mehrtens, Nicola; Liddle, Andrew R.; Hoyle, Ben; Hilton, Matt; Stott, John P.; Capozzi, Diego; Collins, Chris A.; Sahlen, Martin; Stanford, S. Adam; Viana, Pedro T. P.

    2012-06-10

    This paper presents both the result of a search for fossil systems (FSs) within the XMM Cluster Survey and the Sloan Digital Sky Survey and the results of a study of the stellar mass assembly and stellar populations of their fossil galaxies. In total, 17 groups and clusters are identified at z < 0.25 with large magnitude gaps between the first and fourth brightest galaxies. All the information necessary to classify these systems as fossils is provided. For both groups and clusters, the total and fractional luminosity of the brightest galaxy is positively correlated with the magnitude gap. The brightest galaxies in FSs (called fossil galaxies) have stellar populations and star formation histories which are similar to normal brightest cluster galaxies (BCGs). However, at fixed group/cluster mass, the stellar masses of the fossil galaxies are larger compared to normal BCGs, a fact that holds true over a wide range of group/cluster masses. Moreover, the fossil galaxies are found to contain a significant fraction of the total optical luminosity of the group/cluster within 0.5 R{sub 200}, as much as 85%, compared to the non-fossils, which can have as little as 10%. Our results suggest that FSs formed early and in the highest density regions of the universe and that fossil galaxies represent the end products of galaxy mergers in groups and clusters.

  20. The VIMOS VLT Deep Survey: Clustering and the Role of Environment in Galaxy Evolution

    NASA Astrophysics Data System (ADS)

    Le Fèvre, O.; Cucciati, O.; Guzzo, L.; Ilbert, O.; Iovino, A.; Marinoni, C.; Meneux, B.; Paltani, S.; Pollo, A.; Bottini, D.; Garilli, B.; Le Brun, V.; Maccagni, D.; Picat, J. P.; Scaramella, R.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnaboldi, M.; Arnouts, S.; Bardelli, S.; Bolzonella, M.; Cappi, A.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Franzetti, P.; Gavignaud, I.; McCracken, H. J.; Marano, B.; Mazure, A.; Merighi, R.; Pellò, R.; Pozzetti, L.; Radovich, M.; Zamorani, G.; Zucca, E.; Bondi, M.; Bongiorno, A.; Busarello, G.; de La Torre, S.; Gregorini, L.; Lamareille, F.; Mathez, G.; Mellier, Y.; Merluzzi, P.; Ripepi, V.; Rizzo, D.

    2007-12-01

    We present results from the VIMOS VLT Deep Survey on the influence of large scale structures on the evolution of galaxies. The large volume and 11564 galaxies with measured spectroscopic redshifts in the ``First Epoch'' survey enables to study galaxy evolution as a function of local galaxy density and galaxy luminosity or type. We find that the clustering of galaxies is strongly dependent on galaxy types at all redshifts probed, with early spectral type galaxies always more clustered than late-type or irregular galaxies up to z≃1.5. The more luminous galaxies with M_B ≥ -20 are also more strongly clustered than fainter galaxies at all epochs probed up to z≃1.5. From the 3D galaxy density field computed using spectroscopic redshifts, we find a strong evolution of the color-density relation which flattens out with increasing redshifts, with red and blue galaxies becoming equally likely to be found in high density regions probed by the VVDS. At high redshifts 3 ≤ z ≤ 4, we find that the progenitors of the most massive galaxies are more numerous and concentrating more luminosity density than galaxies previously measured at these epochs.

  1. The XMM Cluster Survey: A Massive Galaxy Cluster at z = 1.45

    SciTech Connect

    Stanford, S A; Romer, A K; Sabirli, K; Davidson, M; Hilton, M; Viana, P P; Collins, C A; Kay, S T; Liddle, A R; Mann, R G; Miller, C J; Nichol, R C; West, M J; Conselice, C J; Spinrad, H; Stern, D; Bundy, K

    2006-05-24

    We report the discovery of XMMXCS J2215.9-1738, a massive galaxy cluster at z = 1.45, which was found in the XMM Cluster Survey. The cluster candidate was initially identified as an extended X-ray source in archival XMM data. Optical spectroscopy shows that 6 galaxies within a {approx}60 arcsec diameter region lie at z = 1.45 {+-} 0.01. Model fits to the X-ray spectra of the extended emission yield kT = 7.4{sub -1.8}{sup +2.7} keV (90% confidence); if there is an undetected central X-ray point source then kT = 6.5{sub -1.8}{sup +2.6} keV. The bolometric X-ray luminosity is L{sub x} = 4.4{sub -0.6}{sup +0.8} x 10{sup 44} ergs s{sup -1} over a 2 Mpc radial region. The measured T{sub x}, which is the highest for any known cluster at z > 1, suggests that this cluster is relatively massive for such a high redshift. The redshift of XMMXCS J2215.9-1738 is the highest currently known for a spectroscopically-confirmed cluster of galaxies.

  2. The Herschel Virgo Cluster Survey. XVIII. Star-forming dwarf galaxies in a cluster environment

    NASA Astrophysics Data System (ADS)

    Grossi, M.; Hunt, L. K.; Madden, S. C.; Hughes, T. M.; Auld, R.; Baes, M.; Bendo, G. J.; Bianchi, S.; Bizzocchi, L.; Boquien, M.; Boselli, A.; Clemens, M.; Corbelli, E.; Cortese, L.; Davies, J.; De Looze, I.; di Serego Alighieri, S.; Fritz, J.; Pappalardo, C.; Pierini, D.; Rémy-Ruyer, A.; Smith, M. W. L.; Verstappen, J.; Viaene, S.; Vlahakis, C.

    2015-02-01

    To assess the effects of the cluster environment on the different components of the interstellar medium, we analyse the far-infrared (FIR) and submillimetre (submm) properties of a sample of star-forming dwarf galaxies detected by the Herschel Virgo Cluster Survey (HeViCS). We determine dust masses and dust temperatures by fitting a modified black body function to the spectral energy distributions (SEDs). Stellar and gas masses, star formation rates (SFRs), and metallicities are obtained from the analysis of a set of ancillary data. Dust is detected in 49 out of a total 140 optically identified dwarfs covered by the HeViCS field; considering only dwarfs brighter than mB = 18 mag, this gives a detection rate of 43%. After evaluating different emissivity indices, we find that the FIR-submm SEDs are best-fit by β = 1.5, with a median dust temperature Td = 22.4 K. Assuming β = 1.5, 67% of the 23 galaxies detected in all five Herschel bands show emission at 500 μm in excess of the modified black-body model. The fraction of galaxies with a submillimetre excess decreases for lower values of β, while a similarly high fraction (54%) is found if a β-free SED modelling is applied. The excess is inversely correlated with SFR and stellar masses. To study the variations in the global properties of our sample that come from environmental effects, we compare the Virgo dwarfs to other Herschel surveys,such as the Key Insights into Nearby Galaxies: Far-Infrared Survey with Herschel (KINGFISH), the Dwarf Galaxy Survey (DGS), and the HeViCS Bright Galaxy Catalogue (BGC). We explore the relations between stellar mass and Hi fraction, specific star formation rate, dust fraction, gas-to-dust ratio over a wide range of stellar masses (from 107 to 1011 M⊙) for both dwarfs and spirals. Highly Hi-deficient Virgo dwarf galaxies are mostly characterised by quenched star formation activity and lower dust fractions giving hints for dust stripping in cluster dwarfs. However, to explain the

  3. SUPERDENSE MASSIVE GALAXIES IN THE ESO DISTANT CLUSTER SURVEY (EDisCS)

    SciTech Connect

    Valentinuzzi, T.; D'onofrio, M.; Vulcani, B.; Poggianti, B. M.; Fritz, J.; Moretti, A.; Saglia, R. P.; Aragon-Salamanca, A.; Simard, L.; Sanchez-Blazquez, P.; Cava, A.; Couch, W. J.

    2010-09-20

    We find a significant number of massive and compact galaxies in clusters from the ESO Distant Clusters Survey (EDisCS) at 0.4 < z < 1. They have similar stellar masses, ages, sizes, and axial ratios to local z {approx} 0.04 compact galaxies in WIde field Nearby Galaxy clusters Survey (WINGS) clusters, and to z = 1.4-2 massive and passive galaxies found in the general field. If non-brightest cluster galaxies of all densities, morphologies, and spectral types are considered, the median size of EDisCS galaxies is only a factor 1.18 smaller than in WINGS. We show that for morphologically selected samples, the morphological evolution taking place in a significant fraction of galaxies during the last Gyr may introduce an apparent, spurious evolution of size with redshift, which is actually due to intrinsic differences in the selected samples. We conclude that the median mass-size relation of cluster galaxies does not evolve significantly from z {approx} 0.7 to z {approx} 0.04. In contrast, the masses and sizes of BCGs and galaxies with M {sub *}>4 x 10{sup 11} M {sub sun} have significantly increased by a factor of 2 and 4, respectively, confirming the results of a number of recent works on the subject. Our findings show that progenitor bias effects play an important role in the size-growth paradigm of massive and passive galaxies.

  4. The Herschel Virgo Cluster Survey . VII. Dust in cluster dwarf elliptical galaxies

    NASA Astrophysics Data System (ADS)

    De Looze, I.; Baes, M.; Zibetti, S.; Fritz, J.; Cortese, L.; Davies, J. I.; Verstappen, J.; Bendo, G. J.; Bianchi, S.; Clemens, M.; Bomans, D. J.; Boselli, A.; Corbelli, E.; Dariush, A.; di Serego Alighieri, S.; Fadda, D.; Garcia-Appadoo, D. A.; Gavazzi, G.; Giovanardi, C.; Grossi, M.; Hughes, T. M.; Hunt, L. K.; Jones, A. P.; Madden, S.; Pierini, D.; Pohlen, M.; Sabatini, S.; Smith, M. W. L.; Vlahakis, C.; Xilouris, E. M.

    2010-07-01

    We use the science demonstration phase data of the Herschel Virgo Cluster Survey to search for dust emission of early-type dwarf galaxies in the central regions of the Virgo cluster as an alternative way of identifying the interstellar medium. We present the first possible far-infrared detection of cluster early-type dwarf galaxies: VCC 781 and VCC 951 are detected at the 10σ level in the SPIRE 250 μm image. Both detected galaxies have dust masses of the order of 105 M_⊙ and average dust temperatures ≈20 K. The detection rate (less than 1%) is quite high compared to the 1.7% detection rate for Hi emission, considering that dwarfs in the central regions are more Hi deficient. We conclude that the removal of interstellar dust from dwarf galaxies resulting from ram pressure stripping, harassment, or tidal effects must be as efficient as the removal of interstellar gas. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  5. The VIRMOS-VLT Deep Survey: the Last 10 Billion Years of Evolution of Galaxy Clustering

    NASA Astrophysics Data System (ADS)

    Pollo, A.; Guzzo, L.; Le Fèvre, O.; Meneux, B.; Cappi, A.; McCracken, H. J.; Iovino, A.; Marinoni, C.; Bottini, D.; Garilli, B.; Le Brun, V. L.; Maccagni, D.; Picat, J. P.; Scaramella, R.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnouts, S.; Bardelli, S.; Bolzonella, M.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Franzetti, P.; Gavignaud, I.; Ilbert, O.; Marano, B.; Mazure, A.; Merighi, R.; Paltani, S.; Pellò, R.; Pozzetti, L.; Radovich, M.; Zamorani, G.; Zucca, E.; Bondi, M.; Bongiorno, A.; Brinchmann, J.; Cucciati, O.; de la Torre, S.; Lamareille, F.; Mellier, Y.; Merluzzi, P.; Temporin, S.; Vergani, D.; Walcher, C. J.

    2007-12-01

    We discuss the evolution of clustering of galaxies in the Universe from the present epoch back to z ˜ 2, using the first-epoch data from the VIMOS-VLT Deep Survey (VVDS). We present the evolution of the projected two-point correlation function of galaxies for the global galaxy population, as well as its dependence on galaxy intrinsic luminosities and spectral types. While we do not find strong variations of the correlation function parameters with redshift for the global galaxy population, the clustering of objects with different intrinsic luminosities evolved significantly during last 8-10 billion years. Our findings indicate that bright galaxies in the past traced higher density peaks than they do now and that the shape of the correlation function of most luminous galaxies is different from observed for their local counterparts, which is a supporting evidence of a non-trivial evolution of the galaxy vs. dark matter bias.

  6. SPT-GMOS: A Gemini/GMOS-South Spectroscopic survey of galaxy clusters in the SPT-SZ survey

    DOE PAGES

    Bayliss, M. B.; Ruel, J.; Stubbs, C. W.; ...

    2016-11-01

    Here, we present the results of SPT-GMOS, a spectroscopic survey with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. The targets of SPT-GMOS are galaxy clusters identified in the SPT-SZ survey, a millimeter-wave survey of 2500 deg2 of the southern sky using the South Pole Telescope (SPT). Multi-object spectroscopic observations of 62 SPT-selected galaxy clusters were performed between 2011 January and 2015 December, yielding spectra with radial velocity measurements for 2595 sources. We identify 2243 of these sources as galaxies, and 352 as stars. Of the galaxies, we identify 1579 as members of SPT-SZ galaxy clusters. The primary goal ofmore » these observations was to obtain spectra of cluster member galaxies to estimate cluster redshifts and velocity dispersions. We describe the full spectroscopic data set and resulting data products, including galaxy redshifts, cluster redshifts, and velocity dispersions, and measurements of several well-known spectral indices for each galaxy: the equivalent width, W, of [O II] λλ3727, 3729 and H-δ, and the 4000 Å break strength, D4000. We use the spectral indices to classify galaxies by spectral type (i.e., passive, post-starburst, star-forming), and we match the spectra against photometric catalogs to characterize spectroscopically observed cluster members as a function of brightness (relative to m*). Lastly, we report several new measurements of redshifts for ten bright, strongly lensed background galaxies in the cores of eight galaxy clusters. Combining the SPT-GMOS data set with previous spectroscopic follow-up of SPT-SZ galaxy clusters results in spectroscopic measurements for >100 clusters, or ~20% of the full SPT-SZ sample.« less

  7. SPT-GMOS: A Gemini/GMOS-South Spectroscopic survey of galaxy clusters in the SPT-SZ survey

    SciTech Connect

    Bayliss, M. B.; Ruel, J.; Stubbs, C. W.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Benson, B. A.; Bleem, L. E.; Bocquet, S.; Carlstrom, J. E.; Chang, C. L.

    2016-11-01

    Here, we present the results of SPT-GMOS, a spectroscopic survey with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. The targets of SPT-GMOS are galaxy clusters identified in the SPT-SZ survey, a millimeter-wave survey of 2500 deg2 of the southern sky using the South Pole Telescope (SPT). Multi-object spectroscopic observations of 62 SPT-selected galaxy clusters were performed between 2011 January and 2015 December, yielding spectra with radial velocity measurements for 2595 sources. We identify 2243 of these sources as galaxies, and 352 as stars. Of the galaxies, we identify 1579 as members of SPT-SZ galaxy clusters. The primary goal of these observations was to obtain spectra of cluster member galaxies to estimate cluster redshifts and velocity dispersions. We describe the full spectroscopic data set and resulting data products, including galaxy redshifts, cluster redshifts, and velocity dispersions, and measurements of several well-known spectral indices for each galaxy: the equivalent width, W, of [O II] λλ3727, 3729 and H-δ, and the 4000 Å break strength, D4000. We use the spectral indices to classify galaxies by spectral type (i.e., passive, post-starburst, star-forming), and we match the spectra against photometric catalogs to characterize spectroscopically observed cluster members as a function of brightness (relative to m*). Lastly, we report several new measurements of redshifts for ten bright, strongly lensed background galaxies in the cores of eight galaxy clusters. Combining the SPT-GMOS data set with previous spectroscopic follow-up of SPT-SZ galaxy clusters results in spectroscopic measurements for >100 clusters, or ~20% of the full SPT-SZ sample.

  8. SPT-GMOS: A Gemini/GMOS-South Spectroscopic Survey of Galaxy Clusters in the SPT-SZ Survey

    NASA Astrophysics Data System (ADS)

    Bayliss, M. B.; Ruel, J.; Stubbs, C. W.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Benson, B. A.; Bleem, L. E.; Bocquet, S.; Brodwin, M.; Capasso, R.; Carlstrom, J. E.; Chang, C. L.; Chiu, I.; Cho, H.-M.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Desai, S.; Dietrich, J. P.; Dobbs, M. A.; Doucouliagos, A. N.; Foley, R. J.; Forman, W. R.; Garmire, G. P.; George, E. M.; Gladders, M. D.; Gonzalez, A. H.; Gupta, N.; Halverson, N. W.; Hlavacek-Larrondo, J.; Hoekstra, H.; Holder, G. P.; Holzapfel, W. L.; Hou, Z.; Hrubes, J. D.; Huang, N.; Jones, C.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; von der Linden, A.; Luong-Van, D.; Mantz, A.; Marrone, D. P.; McDonald, M.; McMahon, J. J.; Meyer, S. S.; Mocanu, L. M.; Mohr, J. J.; Murray, S. S.; Padin, S.; Pryke, C.; Rapetti, D.; Reichardt, C. L.; Rest, A.; Ruhl, J. E.; Saliwanchik, B. R.; Saro, A.; Sayre, J. T.; Schaffer, K. K.; Schrabback, T.; Shirokoff, E.; Song, J.; Spieler, H. G.; Stalder, B.; Stanford, S. A.; Staniszewski, Z.; Stark, A. A.; Story, K. T.; Vanderlinde, K.; Vieira, J. D.; Vikhlinin, A.; Williamson, R.; Zenteno, A.

    2016-11-01

    We present the results of SPT-GMOS, a spectroscopic survey with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. The targets of SPT-GMOS are galaxy clusters identified in the SPT-SZ survey, a millimeter-wave survey of 2500 deg2 of the southern sky using the South Pole Telescope (SPT). Multi-object spectroscopic observations of 62 SPT-selected galaxy clusters were performed between 2011 January and 2015 December, yielding spectra with radial velocity measurements for 2595 sources. We identify 2243 of these sources as galaxies, and 352 as stars. Of the galaxies, we identify 1579 as members of SPT-SZ galaxy clusters. The primary goal of these observations was to obtain spectra of cluster member galaxies to estimate cluster redshifts and velocity dispersions. We describe the full spectroscopic data set and resulting data products, including galaxy redshifts, cluster redshifts, and velocity dispersions, and measurements of several well-known spectral indices for each galaxy: the equivalent width, W, of [O ii] λλ3727, 3729 and H-δ, and the 4000 Å break strength, D4000. We use the spectral indices to classify galaxies by spectral type (i.e., passive, post-starburst, star-forming), and we match the spectra against photometric catalogs to characterize spectroscopically observed cluster members as a function of brightness (relative to m ⋆). Finally, we report several new measurements of redshifts for ten bright, strongly lensed background galaxies in the cores of eight galaxy clusters. Combining the SPT-GMOS data set with previous spectroscopic follow-up of SPT-SZ galaxy clusters results in spectroscopic measurements for >100 clusters, or ∼20% of the full SPT-SZ sample.

  9. A VIRUS-P Survey of Galaxy Clusters to Find Faint Lyα-emitting Galaxies

    NASA Astrophysics Data System (ADS)

    McLinden, Emily; Finkelstein, S. L.; Siana, B. D.; Alavi, A.

    2014-01-01

    The VIRUS-P instrument on the 2.7m telescope at the McDonald Observatory was originally built as a prototype of the larger VIRUS instrument that will be used for HETDEX. We demonstrate that this multi-fiber, optical integral field unit spectrograph can be efficiently used to detect faint Lyα-emitting galaxies (LAEs) at intermediate redshift (z = 2-3) with the aid of gravitational lensing from galaxy clusters. The bulk z=2-3 LAEs to date have been discovered with narrowband imaging campaigns, which are highly efficient only at selecting L > L_star galaxies and only over a narrow redshift slice. By making use of gravitational lensing, however, we are able to observe intrinsically very faint galaxies that only appear to have brightnesses ≥ L_star. Gravitationally lensed faint LAEs, such as our sample from VIRUS-P, allow us to go fainter than existing narrowband surveys and therefore allow for better constraints at the faint end of the Lyα luminosity function at these intermediate redshifts.

  10. Cosmology from large scale galaxy clustering and galaxy-galaxy lensing with Dark Energy Survey Science Verification data

    DOE PAGES

    Kwan, J.

    2016-10-05

    Here, we present cosmological constraints from the Dark Energy Survey (DES) using a combined analysis of angular clustering of red galaxies and their cross-correlation with weak gravitational lensing of background galaxies. We use a 139 square degree contiguous patch of DES data from the Science Verification (SV) period of observations. Using large scale measurements, we constrain the matter density of the Universe as Ωm = 0.31 ± 0.09 and the clustering amplitude of the matter power spectrum as σ8 = 0.74 ± 0.13 after marginalizing over seven nuisance parameters and three additional cosmological parameters. This translates into S8 Ξ σ8more » (Ωm/0.3)0.16 = 0.74 ± 0.12 for our fiducial lens redshift bin at 0.35 < z < 0.5, while S8 = 0.78 ± 0.09 using two bins over the range 0.2 < z < 0.5. We study the robustness of the results under changes in the data vectors, modelling and systematics treatment, including photometric redshift and shear calibration uncertainties, and find consistency in the derived cosmological parameters. We show that our results are consistent with previous cosmological analyses from DES and other data sets and conclude with a joint analysis of DES angular clustering and galaxy-galaxy lensing with Planck CMB data, Baryon Accoustic Oscillations and Supernova type Ia measurements.« less

  11. Cosmology from large-scale galaxy clustering and galaxy-galaxy lensing with Dark Energy Survey Science Verification data

    NASA Astrophysics Data System (ADS)

    Kwan, J.; Sánchez, C.; Clampitt, J.; Blazek, J.; Crocce, M.; Jain, B.; Zuntz, J.; Amara, A.; Becker, M. R.; Bernstein, G. M.; Bonnett, C.; DeRose, J.; Dodelson, S.; Eifler, T. F.; Gaztanaga, E.; Giannantonio, T.; Gruen, D.; Hartley, W. G.; Kacprzak, T.; Kirk, D.; Krause, E.; MacCrann, N.; Miquel, R.; Park, Y.; Ross, A. J.; Rozo, E.; Rykoff, E. S.; Sheldon, E.; Troxel, M. A.; Wechsler, R. H.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Carrasco Kind, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D. W.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Jarvis, M.; Kuehn, K.; Lahav, O.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Martini, P.; Melchior, P.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.; Walker, A. R.; DES Collaboration

    2017-02-01

    We present cosmological constraints from the Dark Energy Survey (DES) using a combined analysis of angular clustering of red galaxies and their cross-correlation with weak gravitational lensing of background galaxies. We use a 139 deg2 contiguous patch of DES data from the Science Verification (SV) period of observations. Using large-scale measurements, we constrain the matter density of the Universe as Ωm = 0.31 ± 0.09 and the clustering amplitude of the matter power spectrum as σ8 = 0.74 ± 0.13 after marginalizing over seven nuisance parameters and three additional cosmological parameters. This translates into S8 ≡ σ8(Ωm/0.3)0.16 = 0.74 ± 0.12 for our fiducial lens redshift bin at 0.35 < z < 0.5, while S8 = 0.78 ± 0.09 using two bins over the range 0.2 < z < 0.5. We study the robustness of the results under changes in the data vectors, modelling and systematics treatment, including photometric redshift and shear calibration uncertainties, and find consistency in the derived cosmological parameters. We show that our results are consistent with previous cosmological analyses from DES and other data sets and conclude with a joint analysis of DES angular clustering and galaxy-galaxy lensing with Planck Cosmic Microwave Background data, baryon accoustic oscillations and Supernova Type Ia measurements.

  12. The Richness Dependence of Galaxy Cluster Correlations: Results From A Redshift Survey Of Rich APM Clusters

    NASA Technical Reports Server (NTRS)

    Croft, R. A. C.; Dalton, G. B.; Efstathiou, G.; Sutherland, W. J.; Maddox, S. J.

    1997-01-01

    We analyze the spatial clustering properties of a new catalog of very rich galaxy clusters selected from the APM Galaxy Survey. These clusters are of comparable richness and space density to Abell Richness Class greater than or equal to 1 clusters, but selected using an objective algorithm from a catalog demonstrably free of artificial inhomogeneities. Evaluation of the two-point correlation function xi(sub cc)(r) for the full sample and for richer subsamples reveals that the correlation amplitude is consistent with that measured for lower richness APM clusters and X-ray selected clusters. We apply a maximum likelihood estimator to find the best fitting slope and amplitude of a power law fit to x(sub cc)(r), and to estimate the correlation length r(sub 0) (the value of r at which xi(sub cc)(r) is equal to unity). For clusters with a mean space density of 1.6 x 10(exp -6) h(exp 3) MpC(exp -3) (equivalent to the space density of Abell Richness greater than or equal to 2 clusters), we find r(sub 0) = 21.3(+11.1/-9.3) h(exp -1) Mpc (95% confidence limits). This is consistent with the weak richness dependence of xi(sub cc)(r) expected in Gaussian models of structure formation. In particular, the amplitude of xi(sub cc)(r) at all richnesses matches that of xi(sub cc)(r) for clusters selected in N-Body simulations of a low density Cold Dark Matter model.

  13. The 2dF Galaxy Redshift Survey: the clustering of galaxy groups

    NASA Astrophysics Data System (ADS)

    Padilla, Nelson D.; Baugh, Carlton M.; Eke, Vincent R.; Norberg, Peder; Cole, Shaun; Frenk, Carlos S.; Croton, Darren J.; Baldry, Ivan K.; Bland-Hawthorn, Joss; Bridges, Terry; Cannon, Russell; Colless, Matthew; Collins, Chris; Couch, Warrick; Dalton, Gavin; De Propris, Roberto; Driver, Simon P.; Efstathiou, George; Ellis, Richard S.; Glazebrook, Karl; Jackson, Carole; Lahav, Ofer; Lewis, Ian; Lumsden, Stuart; Maddox, Steve; Madgwick, Darren; Peacock, John A.; Peterson, Bruce A.; Sutherland, Will; Taylor, Keith

    2004-07-01

    We measure the clustering of galaxy groups in the 2dFGRS Percolation-Inferred Galaxy Group (2PIGG) catalogue. The 2PIGG sample has 28 877 groups with at least two members. The clustering amplitude of the full 2PIGG catalogue is weaker than that of 2dFGRS galaxies, in agreement with theoretical predictions. We have subdivided the 2PIGG catalogue into samples that span a factor of ~ 25 in median total luminosity. Our correlation function measurements span an unprecedented range of clustering strengths, connecting the regimes probed by groups fainter than L* galaxies and rich clusters. There is a steady increase in clustering strength with group luminosity; the most luminous groups are 10 times more strongly clustered than the full 2PIGG catalogue. We demonstrate that the 2PIGG results are in very good agreement with the clustering of groups expected in the ΛCDM model.

  14. The Herschel Fornax Cluster Survey - I. The bright galaxy sample

    NASA Astrophysics Data System (ADS)

    Davies, J. I.; Bianchi, S.; Baes, M.; Boselli, A.; Ciesla, L.; Clemens, M.; Davis, T. A.; De Looze, I.; di Serego Alighieri, S.; Fuller, C.; Fritz, J.; Hunt, L. K.; Serra, P.; Smith, M. W. L.; Verstappen, J.; Vlahakis, C.; Xilouris, E. M.; Bomans, D.; Hughes, T.; Garcia-Appadoo, D.; Madden, S.

    2013-01-01

    We present Herschel Space Telescope observations of the nearby Fornax cluster at 100, 160, 250, 350 and 500 μm with a spatial resolution of 7-36 arcsec (10 arcsec ≈ 1 kpc at dFornax = 17.9 Mpc). We define a sample of 11 bright galaxies, selected at 500 μm, that can be directly compared with our past work on the Virgo cluster. We check and compare our results with previous observations made by IRAS and Planck, finding good agreement. The far-infrared luminosity density is higher, by about a factor of 3, in Fornax compared to Virgo, consistent with the higher number density of galaxies. The 100 μm (42.5-122.5 μm) luminosity is two orders of magnitude larger in Fornax than in the local field as measured by IRAS. We calculate stellar (L0.4-2.5) and far-infrared (L100-500) luminosities for each galaxy and use these to estimate a mean optical depth of τ = 0.4 ± 0.1 - the same value as we previously found for Virgo cluster galaxies. For 10 of the 11 galaxies (NGC 1399 excepted), we fit a modified blackbody curve (β = 2.0) to our observed flux densities to derive dust masses and temperatures of 106.54-8.35 M⊙ and T =14.6-24.2 K, respectively, values comparable to those found for Virgo. The derived stars-to-gas(atomic) and gas(atomic)-to-dust ratios vary from 1.1-67.6 to 9.8-436.5, respectively, again broadly consistent with values for Virgo. Fornax is a mass overdensity in stars and dust of about 120 when compared to the local field (30 for Virgo). Fornax and Virgo are both a factor of 6 lower overdensities in gas(atomic) than in stars and dust indicating loss of gas, but not dust and stars, in the cluster environment. We consider in more detail two of the sample galaxies. As the brightest source in either Fornax or Virgo, NGC 1365 is also detected by Planck. The Planck data fit the PACS/SPIRE spectral energy distribution out to 1382 μm with no evidence of other sources of emission (`spinning dust', free-free, synchrotron). At the opposite end of the scale, NGC

  15. The WARPS survey for faint clusters of galaxies

    NASA Technical Reports Server (NTRS)

    Jones, L. R.; Scharf, C. A.; Perlman, E.; Ebeling, H.; Wegner, G.; Malkan, M.

    1996-01-01

    The wide angle Rosat pointed survey (WARPS) of clusters is based on the Rosat position sensitive proportional counter (PSPC) archive of pointed observations. It includes extended X-ray sources and point-like X-ray sources with non-stellar optical counterparts. It was designed to minimize the selection effects while covering a large area of the sky. The purposes of the survey were to measure the low luminosity, high redshift, X-ray luminosity function of clusters and groups and to investigate cluster morphologies and unusual systems.

  16. The Herschel Virgo Cluster Survey - XIV. Transition-type dwarf galaxies in the Virgo cluster

    NASA Astrophysics Data System (ADS)

    De Looze, Ilse; Baes, Maarten; Boselli, Alessandro; Cortese, Luca; Fritz, Jacopo; Auld, Robbie; Bendo, George J.; Bianchi, Simone; Boquien, Médéric; Clemens, Marcel; Ciesla, Laure; Davies, Jonathan; di Serego Alighieri, Sperello; Grossi, Marco; Jones, Anthony; Madden, Suzanne C.; Pappalardo, Ciro; Pierini, Daniele; Smith, Matthew W. L.; Verstappen, Joris; Vlahakis, Catherine; Zibetti, Stefano

    2013-12-01

    We use dust scaling relations to investigate the hypothesis that Virgo cluster transition-type dwarfs are infalling star-forming field galaxies, which is argued based on their optical features (e.g. discs, spiral arms and bars) and kinematic properties similar to late-type galaxies. After their infall, environmental effects gradually transform them into early-type galaxies through the removal of their interstellar medium and quenching of all star formation activity. In this paper, we aim to verify whether this hypothesis holds using far-infrared diagnostics based on Herschel observations of the Virgo cluster taken as part of the Herschel Virgo Cluster Survey. We select transition-type objects in the nearest cluster, Virgo, based on spectral diagnostics indicative for their residual or ongoing star formation. We detect dust (Md ˜ 105-6 M⊙) in 36 per cent of the transition-type dwarfs located on the high end of the stellar mass distribution. This suggests that the dust reservoirs present in non-detections fall just below the Herschel detection limit (≲1.1 × 105 M⊙). Dust scaling relations support the hypothesis of a transformation between infalling late-type galaxies to quiescent low-mass spheroids governed by environmental effects, with dust-to-stellar mass fractions for transition-type dwarfs in between values characteristic for late-type objects and the lower dust fractions observed in early-type galaxies. Several transition-type dwarfs demonstrate blue central cores, hinting at the radially outside-in removal of gas and quenching of star formation activity. The fact that dust is also confined to the inner regions suggests that metals are stripped in the outer regions along with the gas. In the scenario of most dust being stripped from the galaxy along with the gas, we argue that the ejected metals by transition-type dwarfs significantly contribute to the enrichment of the intracluster medium over the lifetime of the Virgo cluster. The accretion of gas

  17. THE CLUSTERING CHARACTERISTICS OF H I-SELECTED GALAXIES FROM THE 40% ALFALFA SURVEY

    SciTech Connect

    Martin, Ann M.; Giovanelli, Riccardo; Haynes, Martha P.; Guzzo, Luigi E-mail: riccardo@astro.cornell.edu E-mail: luigi.guzzo@brera.inaf.it

    2012-05-01

    The 40% Arecibo Legacy Fast ALFA survey catalog ({alpha}.40) of {approx}10,150 H I-selected galaxies is used to analyze the clustering properties of gas-rich galaxies. By employing the Landy-Szalay estimator and a full covariance analysis for the two-point galaxy-galaxy correlation function, we obtain the real-space correlation function and model it as a power law, {xi}(r) = (r/r{sub 0}){sup -{gamma}}, on scales <10 h{sup -1} Mpc. As the largest sample of blindly H I-selected galaxies to date, {alpha}.40 provides detailed understanding of the clustering of this population. We find {gamma} = 1.51 {+-} 0.09 and r{sub 0} = 3.3 + 0.3, -0.2 h{sup -1} Mpc, reinforcing the understanding that gas-rich galaxies represent the most weakly clustered galaxy population known; we also observe a departure from a pure power-law shape at intermediate scales, as predicted in {Lambda}CDM halo occupation distribution models. Furthermore, we measure the bias parameter for the {alpha}.40 galaxy sample and find that H I galaxies are severely antibiased on small scales, but only weakly antibiased on large scales. The robust measurement of the correlation function for gas-rich galaxies obtained via the {alpha}.40 sample constrains models of the distribution of H I in simulated galaxies, and will be employed to better understand the role of gas in environmentally dependent galaxy evolution.

  18. The REFLEX II galaxy cluster survey: power spectrum analysis

    NASA Astrophysics Data System (ADS)

    Balaguera-Antolínez, A.; Sánchez, Ariel G.; Böhringer, H.; Collins, C.; Guzzo, L.; Phleps, S.

    2011-05-01

    We present the power spectrum of galaxy clusters measured from the new ROSAT-ESO Flux-Limited X-Ray (REFLEX II) galaxy cluster catalogue. This new sample extends the flux limit of the original REFLEX catalogue to 1.8 × 10-12 erg s-1 cm-2, yielding a total of 911 clusters with ≥94 per cent completeness in redshift follow-up. The analysis of the data is improved by creating a set of 100 REFLEX II-catalogue-like mock galaxy cluster catalogues built from a suite of large-volume Λ cold dark matter (ΛCDM) N-body simulations (L-BASICC II). The measured power spectrum is in agreement with the predictions from a ΛCDM cosmological model. The measurements show the expected increase in the amplitude of the power spectrum with increasing X-ray luminosity. On large scales, we show that the shape of the measured power spectrum is compatible with a scale-independent bias and provide a model for the amplitude that allows us to connect our measurements with a cosmological model. By implementing a luminosity-dependent power-spectrum estimator, we observe that the power spectrum measured from the REFLEX II sample is weakly affected by flux-selection effects. The shape of the measured power spectrum is compatible with a featureless power spectrum on scales k > 0.01 h Mpc-1 and hence no statistically significant signal of baryonic acoustic oscillations can be detected. We show that the measured REFLEX II power spectrum displays signatures of non-linear evolution.

  19. MEASURING THE ULTIMATE HALO MASS OF GALAXY CLUSTERS: REDSHIFTS AND MASS PROFILES FROM THE HECTOSPEC CLUSTER SURVEY (HeCS)

    SciTech Connect

    Rines, Kenneth; Geller, Margaret J.; Kurtz, Michael J.; Diaferio, Antonaldo E-mail: diaferio@ph.unito.it

    2013-04-10

    The infall regions of galaxy clusters represent the largest gravitationally bound structures in a {Lambda}CDM universe. Measuring cluster mass profiles into the infall regions provides an estimate of the ultimate mass of these halos. We use the caustic technique to measure cluster mass profiles from galaxy redshifts obtained with the Hectospec Cluster Survey (HeCS), an extensive spectroscopic survey of galaxy clusters with MMT/Hectospec. We survey 58 clusters selected by X-ray flux at 0.1 < z < 0.3. The survey includes 22,680 unique MMT/Hectospec redshifts for individual galaxies; 10,145 of these galaxies are cluster members. For each cluster, we acquired high signal-to-noise spectra for {approx}200 cluster members and a comparable number of foreground/background galaxies. The cluster members trace out infall patterns around the clusters. The members define a very narrow red sequence. We demonstrate that the determination of velocity dispersion is insensitive to the inclusion of bluer members (a small fraction of the cluster population). We apply the caustic technique to define membership and estimate the mass profiles to large radii. The ultimate halo mass of clusters (the mass that remains bound in the far future of a {Lambda}CDM universe) is on average (1.99 {+-} 0.11)M{sub 200}, a new observational cosmological test in essential agreement with simulations. Summed profiles binned in M{sub 200} and in L{sub X} demonstrate that the predicted Navarro-Frenk-White form of the density profile is a remarkably good representation of the data in agreement with weak lensing results extending to large radius. The concentration of these summed profiles is also consistent with theoretical predictions.

  20. The SCUBA-2 Cosmology Legacy Survey: the clustering of submillimetre galaxies in the UKIDSS UDS field

    NASA Astrophysics Data System (ADS)

    Wilkinson, Aaron; Almaini, Omar; Chen, Chian-Chou; Smail, Ian; Arumugam, Vinodiran; Blain, Andrew; Chapin, Edward L.; Chapman, Scott C.; Conselice, Christopher J.; Cowley, William I.; Dunlop, James S.; Farrah, Duncan; Geach, James; Hartley, William G.; Ivison, Rob J.; Maltby, David T.; Michałowski, Michał J.; Mortlock, Alice; Scott, Douglas; Simpson, Chris; Simpson, James M.; van der Werf, Paul; Wild, Vivienne

    2017-01-01

    Submillimetre galaxies (SMGs) are among the most luminous dusty galaxies in the Universe, but their true nature remains unclear; are SMGs the progenitors of the massive elliptical galaxies we see in the local Universe, or are they just a short-lived phase among more typical star-forming galaxies? To explore this problem further, we investigate the clustering of SMGs identified in the SCUBA-2 Cosmology Legacy Survey. We use a catalogue of submillimetre (850 μm) source identifications derived using a combination of radio counterparts and colour/infrared selection to analyse a sample of 610 SMG counterparts in the United Kingdom Infrared Telescope (UKIRT) Infrared Deep Survey (UKIDSS) Ultra Deep Survey (UDS), making this the largest high-redshift sample of these galaxies to date. Using angular cross-correlation techniques, we estimate the halo masses for this large sample of SMGs and compare them with passive and star-forming galaxies selected in the same field. We find that SMGs, on average, occupy high-mass dark matter haloes (Mhalo > 1013 M⊙) at redshifts z > 2.5, consistent with being the progenitors of massive quiescent galaxies in present-day galaxy clusters. We also find evidence of downsizing, in which SMG activity shifts to lower mass haloes at lower redshifts. In terms of their clustering and halo masses, SMGs appear to be consistent with other star-forming galaxies at a given redshift.

  1. The 3XMM/SDSS Stripe 82 Galaxy Cluster Survey. I. Cluster catalogue and discovery of two merging cluster candidates

    NASA Astrophysics Data System (ADS)

    Takey, A.; Durret, F.; Mahmoud, E.; Ali, G. B.

    2016-10-01

    We present a galaxy cluster survey based on XMM-Newton observations that are located in Stripe 82 of the Sloan Digital Sky Survey (SDSS). The survey covers an area of 11.25 deg2. The X-ray cluster candidates were selected as serendipitously extended detected sources from the third XMM-Newton serendipitous source catalogue (3XMM-DR5). A cross-correlation of the candidate list that comprises 94 objects with recently published X-ray and optically selected cluster catalogues provided optical confirmations and redshift estimates for about half of the candidate sample. We present a catalogue of X-ray cluster candidates previously known in X-ray and/or optical bands from the matched catalogues or NED. The catalogue consists of 54 systems with redshift measurements in the range of 0.05-1.19 with a median of 0.36. Of these, 45 clusters have spectroscopic confirmations as stated in the matched catalogues. We spectroscopically confirmed another 6 clusters from the available spectroscopic redshifts in the SDSS-DR12. The cluster catalogue includes 17 newly X-ray discovered clusters, while the remainder were detected in previous XMM-Newton and/or ROSAT cluster surveys. Based on the available redshifts and fluxes given in the 3XMM-DR5 catalogue, we estimated the X-ray luminosities and masses for the cluster sample. We also present the list of the remaining X-ray cluster candidates (40 objects) that have no redshift information yet in the literature. Of these candidates, 25 sources are considered as distant cluster candidates beyond a redshift of 0.6. We also searched for galaxy cluster mergers in our cluster sample and found two strong candidates for newly discovered cluster mergers at redshifts of 0.11 and 0.26. The X-ray and optical properties of these systems are presented. Tables A.1, C.1, and C.2 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/594/A32

  2. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: anisotropic galaxy clustering in Fourier space

    NASA Astrophysics Data System (ADS)

    Beutler, Florian; Seo, Hee-Jong; Saito, Shun; Chuang, Chia-Hsun; Cuesta, Antonio J.; Eisenstein, Daniel J.; Gil-Marín, Héctor; Grieb, Jan Niklas; Hand, Nick; Kitaura, Francisco-Shu; Modi, Chirag; Nichol, Robert C.; Olmstead, Matthew D.; Percival, Will J.; Prada, Francisco; Sánchez, Ariel G.; Rodriguez-Torres, Sergio; Ross, Ashley J.; Ross, Nicholas P.; Schneider, Donald P.; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magaña, Mariana

    2017-04-01

    We investigate the anisotropic clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 12 sample, which consists of 1198 006 galaxies in the redshift range 0.2 < z < 0.75 and a sky coverage of 10 252 deg2. We analyse this data set in Fourier space, using the power-spectrum multipoles to measure redshift-space distortions simultaneously with the Alcock-Paczynski effect and the baryon acoustic oscillation scale. We include the power-spectrum monopole, quadrupole and hexadecapole in our analysis and compare our measurements with a perturbation-theory-based model, while properly accounting for the survey window function. To evaluate the reliability of our analysis pipeline, we participate in a mock challenge, which results in systematic uncertainties significantly smaller than the statistical uncertainties. While the high-redshift constraint on fσ8 at zeff = 0.61 indicates a small (∼1.4σ) deviation from the prediction of the Planck ΛCDM (Λ cold dark matter) model, the low-redshift constraint is in good agreement with Planck ΛCDM. This paper is part of a set that analyses the final galaxy clustering data set from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. to produce the final cosmological constraints from BOSS.

  3. Searching for Galaxy Clusters in the VST-KiDS Survey

    NASA Astrophysics Data System (ADS)

    Radovich, M.; Puddu, E.; Bellagamba, F.; Moscardini, L.; Roncarelli, M.; Getman, F.; Grado, A.

    We present the methods and first results of the search for galaxy clusters in the Kilo Degree Survey (KiDS). The adopted algorithm and the criterium for selecting the member galaxies are illustrated. Here we report the preliminary results obtained over a small area (7 deg2), and the comparison of our cluster candidates with those found in the RedMapper and SZ Planck catalogues; the analysis to a larger area (148 deg2) is currently in progress. By the KiDS cluster search, we expect to increase the completeness of the clusters catalogue to z = 0.6-0.7 compared to RedMapper.

  4. Cosmology from large scale galaxy clustering and galaxy-galaxy lensing with Dark Energy Survey Science Verification data

    SciTech Connect

    Kwan, J.

    2016-10-05

    Here, we present cosmological constraints from the Dark Energy Survey (DES) using a combined analysis of angular clustering of red galaxies and their cross-correlation with weak gravitational lensing of background galaxies. We use a 139 square degree contiguous patch of DES data from the Science Verification (SV) period of observations. Using large scale measurements, we constrain the matter density of the Universe as Ωm = 0.31 ± 0.09 and the clustering amplitude of the matter power spectrum as σ8 = 0.74 ± 0.13 after marginalizing over seven nuisance parameters and three additional cosmological parameters. This translates into S8 Ξ σ8m/0.3)0.16 = 0.74 ± 0.12 for our fiducial lens redshift bin at 0.35 < z < 0.5, while S8 = 0.78 ± 0.09 using two bins over the range 0.2 < z < 0.5. We study the robustness of the results under changes in the data vectors, modelling and systematics treatment, including photometric redshift and shear calibration uncertainties, and find consistency in the derived cosmological parameters. We show that our results are consistent with previous cosmological analyses from DES and other data sets and conclude with a joint analysis of DES angular clustering and galaxy-galaxy lensing with Planck CMB data, Baryon Accoustic Oscillations and Supernova type Ia measurements.

  5. Brightest Cluster Galaxy Identification

    NASA Astrophysics Data System (ADS)

    Leisman, Luke; Haarsma, D. B.; Sebald, D. A.; ACCEPT Team

    2011-01-01

    Brightest cluster galaxies (BCGs) play an important role in several fields of astronomical research. The literature includes many different methods and criteria for identifying the BCG in the cluster, such as choosing the brightest galaxy, the galaxy nearest the X-ray peak, or the galaxy with the most extended profile. Here we examine a sample of 75 clusters from the Archive of Chandra Cluster Entropy Profile Tables (ACCEPT) and the Sloan Digital Sky Survey (SDSS), measuring masked magnitudes and profiles for BCG candidates in each cluster. We first identified galaxies by hand; in 15% of clusters at least one team member selected a different galaxy than the others.We also applied 6 other identification methods to the ACCEPT sample; in 30% of clusters at least one of these methods selected a different galaxy than the other methods. We then developed an algorithm that weighs brightness, profile, and proximity to the X-ray peak and centroid. This algorithm incorporates the advantages of by-hand identification (weighing multiple properties) and automated selection (repeatable and consistent). The BCG population chosen by the algorithm is more uniform in its properties than populations selected by other methods, particularly in the relation between absolute magnitude (a proxy for galaxy mass) and average gas temperature (a proxy for cluster mass). This work supported by a Barry M. Goldwater Scholarship and a Sid Jansma Summer Research Fellowship.

  6. COMPARING DENSE GALAXY CLUSTER REDSHIFT SURVEYS WITH WEAK-LENSING MAPS

    SciTech Connect

    Hwang, Ho Seong; Geller, Margaret J.; Zahid, H. Jabran; Diaferio, Antonaldo; Rines, Kenneth J. E-mail: mgeller@cfa.harvard.edu E-mail: diaferio@ph.unito.it

    2014-12-20

    We use dense redshift surveys of nine galaxy clusters at z ∼ 0.2 to compare the galaxy distribution in each system with the projected matter distribution from weak lensing. By combining 2087 new MMT/Hectospec redshifts and the data in the literature, we construct spectroscopic samples within the region of weak-lensing maps of high (70%-89%) and uniform completeness. With these dense redshift surveys, we construct galaxy number density maps using several galaxy subsamples. The shape of the main cluster concentration in the weak-lensing maps is similar to the global morphology of the number density maps based on cluster members alone, mainly dominated by red members. We cross-correlate the galaxy number density maps with the weak-lensing maps. The cross-correlation signal when we include foreground and background galaxies at 0.5z {sub cl} < z < 2z {sub cl} is 10%-23% larger than for cluster members alone at the cluster virial radius. The excess can be as high as 30% depending on the cluster. Cross-correlating the galaxy number density and weak-lensing maps suggests that superimposed structures close to the cluster in redshift space contribute more significantly to the excess cross-correlation signal than unrelated large-scale structure along the line of sight. Interestingly, the weak-lensing mass profiles are not well constrained for the clusters with the largest cross-correlation signal excesses (>20% for A383, A689, and A750). The fractional excess in the cross-correlation signal including foreground and background structures could be a useful proxy for assessing the reliability of weak-lensing cluster mass estimates.

  7. The CfA-Rosat Survey of Distant Clusters of Galaxies

    NASA Technical Reports Server (NTRS)

    McNamara, Brian

    1998-01-01

    We (Vikhlinin, McNamara, Forman, Jones, Hornstrup, Quintana) have completed a new survey of distant clusters of galaxies, which we use to to study cluster evolution over cosmological timescales. The clusters were identified as extended X-ray sources in 650 ROSAT PSPC images of high Galactic latitude fields. Our catalog of approximately 230 extended X-ray sources covers 160 square degrees on the sky. Ours is the largest of the several ROSAT serendipitous cluster surveys in progress (e.g. SHARC, Rosati, WARPS etc.). Using V,R,I imagery obtained at several observatories, we find that greater than 90% of the X-ray sources are associated with distant clusters of galaxies. We have obtained spectroscopic redshifts for nearly 80 clusters in our catalog, and we have measured photometric redshifts for the remaining clusters. Our sample contains more than 20 clusters at z > 0.5. I will discuss the logN-logS relationship for our clusters. Because our large survey area, we are able to confirm the evolution of the most luminous distant clusters first seen in the Einstein Extended Medium Sensitivity Survey. In addition, I will discuss the relationships between optical richness, core radius, and X-ray luminosity for distant, X-ray-selected clusters.

  8. Investigating the Cores of Early-Type Galaxies Using the ACS Virgo and Fornax Cluster Surveys

    NASA Astrophysics Data System (ADS)

    Glass, Lisa; Ferrarese, L.; Côté, P.; Jordán, A.; Peng, E.; Blakeslee, J.; Chen, C.; Infante, L.; Mei, S.; Tonry, J.; West, M. J.

    2011-01-01

    Understanding the processes that shape and influence the centers of galaxies is crucial to understanding galaxies as a whole. In particular, data suggests nuclear star clusters are three times more common than previously thought and there is evidence to suggest that they may be the low-mass analogues to the supermassive black holes found in more luminous galaxies. My research focuses on the cores of early-type galaxies and how they relate, influence, and respond to processes occurring in the rest of the galaxy. I will present new results from the ACS Virgo and Fornax Cluster Surveys that shed light on these questions. The authors gratefully acknowledge support from NSERC though the Discovery and Postgraduate Scholarship programs, as well as from the University of Victoria through their fellowship program.

  9. The evolution of active galactic nuclei in clusters of galaxies from the Dark Energy Survey

    SciTech Connect

    Bufanda, E.; Hollowood, D.; Jeltema, T. E.; Rykoff, E. S.; Rozo, E.; Martini, P.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Banerji, M.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Evrard, A. E.; Fausti Neto, A.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Melchior, P.; Miquel, R.; Mohr, J. J.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Rooney, P.; Sanchez, E.; Santiago, B.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.; Tucker, D. L.; Walker, A. R.

    2016-12-13

    The correlation between active galactic nuclei (AGN) and environment provides important clues to AGN fueling and the relationship of black hole growth to galaxy evolution. In this paper, we analyze the fraction of galaxies in clusters hosting AGN as a function of redshift and cluster richness for X-ray detected AGN associated with clusters of galaxies in Dark Energy Survey (DES) Science Verification data. The present sample includes 33 AGN with L_X > 1043 ergs s-1 in non-central, host galaxies with luminosity greater than 0.5 L* from a total sample of 432 clusters in the redshift range of 0.1cluster members has a strong positive correlation with redshift such that the AGN fraction increases by a factor of ~8 from low to high redshift, and the fraction of cluster galaxies hosting AGN at high redshifts is greater than the low-redshift fraction at 3.6 sigma. In particular, the AGN fraction increases steeply at the highest redshifts in our sample at z>0.7. This result is in good agreement with previous work and parallels the increase in star formation in cluster galaxies over the same redshift range. However, the AGN fraction in clusters is observed to have no significant correlation with cluster mass. Future analyses with DES Year 1 through Year 3 data will be able to clarify whether AGN activity is correlated to cluster mass and will tightly constrain the relationship between cluster AGN populations and redshift.

  10. The evolution of active galactic nuclei in clusters of galaxies from the Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Bufanda, E.; Hollowood, D.; Jeltema, T. E.; Rykoff, E. S.; Rozo, E.; Martini, P.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Banerji, M.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Evrard, A. E.; Fausti Neto, A.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Melchior, P.; Miquel, R.; Mohr, J. J.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Rooney, P.; Sanchez, E.; Santiago, B.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.; Tucker, D. L.; Walker, A. R.; DES Collaboration

    2017-03-01

    The correlation between active galactic nuclei (AGNs) and environment provides important clues to AGN fuelling and the relationship of black hole growth to galaxy evolution. In this paper, we analyse the fraction of galaxies in clusters hosting AGN as a function of redshift and cluster richness for X-ray-detected AGN associated with clusters of galaxies in Dark Energy Survey (DES) Science Verification data. The present sample includes 33 AGNs with LX > 1043 erg s-1 in non-central, host galaxies with luminosity greater than 0.5L* from a total sample of 432 clusters in the redshift range of 0.1 < z < 0.95. Analysis of the present sample reveals that the AGN fraction in red-sequence cluster members has a strong positive correlation with redshift such that the AGN fraction increases by a factor of ∼8 from low to high redshift, and the fraction of cluster galaxies hosting AGN at high redshifts is greater than the low-redshift fraction at 3.6σ. In particular, the AGN fraction increases steeply at the highest redshifts in our sample at z > 0.7. This result is in good agreement with previous work and parallels the increase in star formation in cluster galaxies over the same redshift range. However, the AGN fraction in clusters is observed to have no significant correlation with cluster mass. Future analyses with DES Year 1 through Year 3 data will be able to clarify whether AGN activity is correlated to cluster mass and will tightly constrain the relationship between cluster AGN populations and redshift.

  11. Galaxy Clusters to z <= 1 from the Oxford Dartmouth Thirty Degree Survey

    NASA Astrophysics Data System (ADS)

    Hammell, Molly; Wegner, Gary; Moustakas, Leonidas; Allen, Paul; Dalton, Gavin; Olding, Edward

    2003-05-01

    The properties of galaxy clusters in the local universe have been fairly well determined in the past few decades, and wide field surveys in the near infrared are converging on a statistically significant sample of high redshift clusters. These catalogs may soon allow discrimination between the competing models of galaxy formation and evolution [1]. The Oxford-Dartmouth Thirty Degree Survey (ODT) will span four widely separated 3° × 3° fields, to B < 26 in UBVRi'Z with an extension in the near-infrared to K < 19. With more than half of the survey completed, this deep, wide-area, multi-color dataset has yielded a large sample of K-selected clusters to probe the formation and evolution history of galaxies in dense environments. An exploration of cluster color-magnitude slopes and intercepts [2], luminosity functions [3], and morphological distributions [4, 5] should constrain the relative dominance of star formation rates and merger events on cluster galaxy evolution. Here, we present our cluster-finding method and preliminary results.

  12. THE ACS FORNAX CLUSTER SURVEY. VI. THE NUCLEI OF EARLY-TYPE GALAXIES IN THE FORNAX CLUSTER

    SciTech Connect

    Turner, Monica L.; Cote, Patrick; Ferrarese, Laura; Blakeslee, John P.; Jordan, Andres; Mei, Simona; Peng, Eric W.; West, Michael J.

    2012-11-15

    The Advanced Camera for Surveys (ACS) Fornax Cluster Survey is a Hubble Space Telescope program to image 43 early-type galaxies in the Fornax cluster, using the F475W and F850LP bandpasses of the ACS. We employ both one-dimensional and two-dimensional techniques to characterize the properties of the stellar nuclei in these galaxies, defined as the central 'luminosity excesses', relative to a Sersic model fitted to the underlying host. We find 72% {+-} 13% of our sample (31 galaxies) to be nucleated, with only three of the nuclei offset by more than 0.''5 from their galaxy photocenter, and with the majority of nuclei having colors bluer than their hosts. The nuclei are observed to be larger, and brighter, than typical Fornax globular clusters and to follow different structural scaling relations. A comparison of our results to those from the ACS Virgo Cluster Survey reveals striking similarities in the properties of the nuclei belonging to these different environments. We briefly review a variety of proposed formation models and conclude that, for the low-mass galaxies in our sample, the most important mechanism for nucleus growth is probably infall of star clusters through dynamical friction, while for higher mass galaxies, gas accretion triggered by mergers, accretions, and tidal torques is likely to dominate, with the relative importance of these two processes varying smoothly as a function of galaxy mass. Some intermediate-mass galaxies in our sample show a complexity in their inner structure that may be the signature of the 'hybrid nuclei' that arose through parallel formation channels.

  13. The 2dF galaxy redshift survey: clustering properties of radio galaxies

    NASA Astrophysics Data System (ADS)

    Magliocchetti, Manuela; Maddox, Steve J.; Hawkins, Ed; Peacock, John A.; Bland-Hawthorn, Joss; Bridges, Terry; Cannon, Russell; Cole, Shaun; Colless, Matthew; Collins, Chris; Couch, Warrick; Dalton, Gavin; de Propris, Roberto; Driver, Simon P.; Efstathiou, George; Ellis, Richard S.; Frenk, Carlos S.; Glazebrook, Karl; Jackson, Carole A.; Jones, Bryn; Lahav, Ofer; Lewis, Ian; Lumsden, Stuart; Norberg, Peder; Peterson, Bruce A.; Sutherland, Will; Taylor, Keith; 2dFGRS Team

    2004-06-01

    The clustering properties of local, S1.4 GHz>= 1 mJy, radio sources are investigated for a sample of 820 objects drawn from the joint use of the Faint Images of the Radio Sky at 20 cm (FIRST) and 2dF Galaxy Redshift surveys. To this aim, we present 271 new bJ<= 19.45 spectroscopic counterparts of FIRST radio sources to be added to those already introduced in our previous paper. The two-point correlation function for the local radio population is found to be entirely consistent with estimates obtained for the whole sample of 2dFGRS galaxies. From measurements of the redshift-space correlation function ξ(s) we derive a redshift-space clustering length s0= 10.7+0.8-0.7 Mpc, while from the projected correlation function Ξ(rT) we estimate the parameters of the real-space correlation function ξ(r) = (r/r0)-γ, r0= 6.7+0.9-1.1 Mpc and γ= 1.6 +/- 0.1, where h= 0.7 is assumed. Different results are instead obtained if we only consider sources that present signatures of active galactic nucleus (AGN) activity in their spectra. These objects are shown to be very strongly correlated, with r0= 10.9+1.0-1.2 Mpc and γ= 2 +/- 0.1, a steeper slope than has been claimed in other recent works. No difference is found in the clustering properties of radio-AGNs of different radio luminosity. Comparisons with models for ξ(r) show that AGN-fuelled sources reside in dark matter haloes more massive than ~1013.4 Msolar, higher than the corresponding figure for radio-quiet quasi-stellar objects. This value can be converted into a minimum black hole mass associated with radio-loud, AGN-fuelled objects of MminBH~ 109 Msolar. The above results then suggest - at least for relatively faint radio objects - the existence of a threshold black hole mass associated with the onset of significant radio activity such as that of radio-loud AGNs; however, once the activity is triggered, there appears to be no evidence for a connection between black hole mass and level of radio output.

  14. Virtual Sky Surveys and Multi-wavelength Investigations of Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Nord, Brian D.

    2010-12-01

    The advent of large and overlapping sky surveys brings promise of a new era in the study of galaxy clusters and dark energy. Clusters have been used for decades as faithful buoys of space-time, tracing cosmic evolution through their matter content and spatial distribution. High-fidelity tracking relies on a robust connection between observable cluster signatures and the underlying dark matter content, which is otherwise invisible. Until now, clusters have been mostly viewed through independent signals in distinct wavebands. The next era of cluster cosmology may be led by multi-variate, cross-waveband detections and analyses of clusters, where different facets of clusters can be cross-correlated to develop a more complete, unified picture of cluster populations. To these ends, in this dissertation, I perform multi-variate analyses of galaxy cluster populations and develop a simulated sky survey, with which to prepare for the next generation of multi-wavelength cluster observations. First, in a new multi-variate framework, I quantify the effects of observational biases on measures of the cluster distribution function and on cosmological constraints derived from X-ray cluster populations. I also demonstrate the indispensability of the multi-variate approach in measuring the evolution of X-ray galaxy clusters; without it, we find that the combination of scatter, intrinsic correlation and irrevocable survey flux limits substantially confuses any measure of redshift evolution. Next, I construct the Millennium Gas Simulation-Virtual Sky Survey (MGSVSS), a multi-wavelength mock sky derived from an N-body gas-dynamic simulation. The MGSVSS contains both sub-mm and optical wavelength sky signals to redshift, z = 1., in a 5 x 5deg2 field of view, with O (103) halos, O (104) optically selected clusters, and O (102) clusters selected via the Sunyaev-Zel'dovich (SZ) signature. The SZ sky also includes a minimal level of sky and instrumental noise, which nearly mimics that of

  15. Cool Core Bias in Sunyaev-Zel’dovich Galaxy Cluster Surveys

    DOE PAGES

    Lin, Henry W.; McDonald, Michael; Benson, Bradford; ...

    2015-03-18

    Sunyaev-Zeldovich (SZ) surveys find massive clusters of galaxies by measuring the inverse Compton scattering of cosmic microwave background off of intra-cluster gas. The cluster selection function from such surveys is expected to be nearly independent of redshift and cluster astrophysics. In this work, we estimate the effect on the observed SZ signal of centrally-peaked gas density profiles (cool cores) and radio emission from the brightest cluster galaxy (BCG) by creating mock observations of a sample of clusters that span the observed range of classical cooling rates and radio luminosities. For each cluster, we make simulated SZ observations by the Southmore » Pole Telescope and characterize the cluster selection function, but note that our results are broadly applicable to other SZ surveys. We find that the inclusion of a cool core can cause a change in the measured SPT significance of a cluster between 0.01%–10% at z > 0.3, increasing with cuspiness of the cool core and angular size on the sky of the cluster (i.e., decreasing redshift, increasing mass). We provide quantitative estimates of the bias in the SZ signal as a function of a gas density cuspiness parameter, redshift, mass, and the 1.4 GHz radio luminosity of the central AGN. Based on this work, we estimate that, for the Phoenix cluster (one of the strongest cool cores known), the presence of a cool core is biasing the SZ significance high by ~6%. The ubiquity of radio galaxies at the centers of cool core clusters will offset the cool core bias to varying degrees« less

  16. Cool Core Bias in Sunyaev-Zel’dovich Galaxy Cluster Surveys

    SciTech Connect

    Lin, Henry W.; McDonald, Michael; Benson, Bradford; Miller, Eric

    2015-03-18

    Sunyaev-Zeldovich (SZ) surveys find massive clusters of galaxies by measuring the inverse Compton scattering of cosmic microwave background off of intra-cluster gas. The cluster selection function from such surveys is expected to be nearly independent of redshift and cluster astrophysics. In this work, we estimate the effect on the observed SZ signal of centrally-peaked gas density profiles (cool cores) and radio emission from the brightest cluster galaxy (BCG) by creating mock observations of a sample of clusters that span the observed range of classical cooling rates and radio luminosities. For each cluster, we make simulated SZ observations by the South Pole Telescope and characterize the cluster selection function, but note that our results are broadly applicable to other SZ surveys. We find that the inclusion of a cool core can cause a change in the measured SPT significance of a cluster between 0.01%–10% at z > 0.3, increasing with cuspiness of the cool core and angular size on the sky of the cluster (i.e., decreasing redshift, increasing mass). We provide quantitative estimates of the bias in the SZ signal as a function of a gas density cuspiness parameter, redshift, mass, and the 1.4 GHz radio luminosity of the central AGN. Based on this work, we estimate that, for the Phoenix cluster (one of the strongest cool cores known), the presence of a cool core is biasing the SZ significance high by ~6%. The ubiquity of radio galaxies at the centers of cool core clusters will offset the cool core bias to varying degrees

  17. The dynamics of z ~ 1 clusters of galaxies from the GCLASS survey

    NASA Astrophysics Data System (ADS)

    Biviano, A.; van der Burg, R. F. J.; Muzzin, A.; Sartoris, B.; Wilson, G.; Yee, H. K. C.

    2016-10-01

    Context. The dynamics of clusters of galaxies and its evolution provide information on their formation and growth, on the nature of dark matter and on the evolution of the baryonic components. Poor observational constraints exist so far on the dynamics of clusters at redshift z > 0.8. Aims: We aim to constrain the internal dynamics of clusters of galaxies at redshift z ~ 1, namely their mass profile M(r), velocity anisotropy profile β(r), and pseudo-phase-space density profiles Q(r) and Qr(r), obtained from the ratio between the mass density profile and the third power of the (total and, respectively, radial) velocity dispersion profiles of cluster galaxies. Methods: We used the spectroscopic and photometric data-set of 10 clusters at 0.87 < z < 1.34 from the Gemini Cluster Astrophysics Spectroscopic Survey (GCLASS). We determined the individual cluster masses from their velocity dispersions, then stack the clusters in projected phase-space. We investigated the internal dynamics of this stack cluster, using the spatial and velocity distribution of its member galaxies. We determined the stack cluster M(r) using the MAMPOSSt method, and its β(r) by direct inversion of the Jeans equation. The procedures used to determine the two aforementioned profiles also allowed us to determine Q(r) and Qr(r). Results: Several M(r) models are statistically acceptable for the stack cluster (Burkert, Einasto, Hernquist, NFW). The stack cluster total mass concentration, c ≡ r200/r-2 = 4.0-0.6+1.0, is in agreement with theoretical expectations. The total mass distribution is less concentrated than both the cluster stellar-mass and the cluster galaxies distributions. The stack cluster β(r) indicates that galaxy orbits are isotropic near the cluster center and become increasingly radially elongated with increasing cluster-centric distance. Passive and star-forming galaxies have similar β(r). The observed β(r) is similar to that of dark matter particles in simulated cosmological

  18. Redshift-Distance Survey of Early-Type Galaxies. I. The ENEARc Cluster Sample

    NASA Astrophysics Data System (ADS)

    Bernardi, M.; Alonso, M. V.; da Costa, L. N.; Willmer, C. N. A.; Wegner, G.; Pellegrini, P. S.; Rité, C.; Maia, M. A. G.

    2002-06-01

    This paper presents data on the ENEARc subsample of the larger ENEAR survey of nearby early-type galaxies. The ENEARc galaxies belong to clusters and were specifically chosen to be used for the construction of a Dn-σ template. The ENEARc sample includes new measurements of spectroscopic and photometric parameters (redshift, velocity dispersion, line index Mg2, and the angular diameter dn), as well as data from the literature. New spectroscopic data are given for 229 cluster early-type galaxies, and new photometry is presented for 348 objects. Repeat and overlap observations with external data sets are used to construct a final merged catalog consisting of 640 early-type galaxies in 28 clusters. Objective criteria, based on catalogs of groups of galaxies derived from complete redshift surveys of the nearby universe, are used to assign galaxies to clusters. In a companion paper, these data are used to construct the template Dn-σ distance relation for early-type galaxies, which has been used to estimate galaxy distances and derive peculiar velocities for the ENEAR all-sky sample. Based on observations at Complejo Astronomico El Leoncito, operated under agreement between the Consejo Nacional de Investigaciones Científicas de la República Argentina and the National Universities of La Plata, Córdoba, and San Juan; Cerro Tololo Inter-American Observatory, National Optical Astronomical Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation; the European Southern Observatory (ESO), partially under the ESO-ON agreement; the Fred Lawrence Whipple Observatory; the Observatório do Pico dos Dias, operated by the Laboratório Nacional de Astrofísica and the MDM Observatory at Kitt Peak.

  19. The 2dF Galaxy Redshift Survey: correlation with the ROSAT-ESO flux-limited X-ray galaxy cluster survey

    NASA Astrophysics Data System (ADS)

    Hilton, Matt; Collins, Chris; De Propris, Roberto; Baldry, Ivan K.; Baugh, Carlton M.; Bland-Hawthorn, Joss; Bridges, Terry; Cannon, Russell; Cole, Shaun; Colless, Matthew; Couch, Warrick J.; Dalton, Gavin B.; Driver, Simon P.; Efstathiou, George; Ellis, Richard S.; Frenk, Carlos S.; Glazebrook, Karl; Jackson, Carole A.; Lahav, Ofer; Lewis, Ian; Lumsden, Stuart; Maddox, Steve J.; Madgwick, Darren; Norberg, Peder; Peacock, John A.; Peterson, Bruce A.; Sutherland, Will; Taylor, Keith

    2005-10-01

    The ROSAT-European Southern Observatory (ESO) flux-limited X-ray (REFLEX) galaxy cluster survey and the Two-degree Field Galaxy Redshift Survey (2dFGRS), respectively, comprise the largest, homogeneous X-ray selected cluster catalogue and completed galaxy redshift survey. In this work, we combine these two outstanding data sets in order to study the effect of the large-scale cluster environment, as traced by X-ray luminosity, on the properties of the cluster member galaxies. We measure the LX-σr relation from the correlated data set and find it to be consistent with recent results found in the literature. Using a sample of 19 clusters with LX>= 0.36 × 1044 erg s-1 in the 0.1-2.4 keV band, and 49 clusters with lower X-ray luminosity, we find that the fraction of early spectral type (η<=-1.4), passively evolving galaxies is significantly higher in the high-LX sample within R200. We extend the investigation to include composite bJ cluster luminosity functions, and find that the characteristic magnitude of the Schechter-function fit to the early-type luminosity function is fainter for the high-LX sample compared to the low-LX sample (ΔM*= 0.58 +/- 0.14). This seems to be driven by a deficit of such galaxies with MbJ~-21. In contrast, we find no significant differences between the luminosity functions of star-forming, late-type galaxies. We believe these results are consistent with a scenario in which the high-LX clusters are more dynamically evolved systems than the low-LX clusters.

  20. A DEEP, WIDE-FIELD H{alpha} SURVEY OF NEARBY CLUSTERS OF GALAXIES: DATA

    SciTech Connect

    Sakai, Shoko; Kennicutt, Robert C. Jr.; Moss, Chris

    2012-04-01

    We present the results of a wide-field H{alpha} imaging survey of eight nearby (z = 0.02-0.03) Abell clusters. We have measured H{alpha} fluxes and equivalent widths for 465 galaxies, of which 360 are new detections. The survey was designed to obtain complete emission-line-selected inventories of star-forming galaxies in the inner regions of these clusters, extending to star formation rates below 0.1 M{sub Sun} yr{sup -1}. This paper describes the observations, data processing, and source identification procedures, and presents an H{alpha} and R-band catalog of detected cluster members and other candidates. Future papers in the series will use these data to study the completeness of spectroscopically based star formation surveys, and to quantify the effects of cluster environment on the present-day populations of star-forming galaxies. The data will also provide a valuable foundation for imaging surveys of redshifted H{alpha} emission in more distant clusters.

  1. X-ray survey of galaxy clusters in the SDSS Stripe 82 region

    NASA Astrophysics Data System (ADS)

    Durret, Florence; Takey, Ali

    2016-07-01

    We conducted a survey of galaxy clusters detected from XMM-Newton observations covering an area of 11.25 deg^2 in the Stripe 82 region of the Sloan Digital Sky Survey (SDSS). We found 94 X-ray cluster candidates from the third XMM-Newton serendipitous source catalogue (3XMM-DR5) and correlated this list with recently published X-ray and optically selected cluster catalogues to obtain optical confirmations and redshifts (between 0.05 and 1.19, with a median of 0.36) for 54 galaxy groups/clusters. Of these, 17 are newly X-ray discovered clusters and 45 systems with spectroscopic confirmations. Among the remaining candidates, 25 sources are distant cluster candidates (beyond a redshift of 0.6). We will present preliminary results on the X-ray and optical properties of these clusters: luminosities and temperatures of the X-ray gas, and optical properties of the galaxies (morphology, luminosity functions).

  2. Galaxy Clustering in the Completed SDSS Redshift Survey: The Dependence on Color and Luminosity

    NASA Astrophysics Data System (ADS)

    Zehavi, Idit; Zheng, Zheng; Weinberg, David H.; Blanton, Michael R.; Bahcall, Neta A.; Berlind, Andreas A.; Brinkmann, Jon; Frieman, Joshua A.; Gunn, James E.; Lupton, Robert H.; Nichol, Robert C.; Percival, Will J.; Schneider, Donald P.; Skibba, Ramin A.; Strauss, Michael A.; Tegmark, Max; York, Donald G.

    2011-07-01

    We measure the luminosity and color dependence of galaxy clustering in the largest-ever galaxy redshift survey, the main galaxy sample of the Sloan Digital Sky Survey Seventh Data Release. We focus on the projected correlation function wp (rp ) of volume-limited samples, extracted from the parent sample of ~700,000 galaxies over 8000 deg2, extending up to redshift of 0.25. We interpret our measurements using halo occupation distribution (HOD) modeling assuming a ΛCDM cosmology (inflationary cold dark matter with a cosmological constant). The amplitude of wp (rp ) grows slowly with luminosity for L < L * and increases sharply at higher luminosities, with a large-scale bias factor b(> L) × (σ8/0.8) = 1.06 + 0.21(L/L *)1.12, where L is the sample luminosity threshold. At fixed luminosity, redder galaxies exhibit a higher amplitude and steeper correlation function, a steady trend that runs through the "blue cloud" and "green valley" and continues across the "red sequence." The cross-correlation of red and blue galaxies is close to the geometric mean of their autocorrelations, dropping slightly below at rp < 1 h -1 Mpc. The luminosity trends for the red and blue galaxy populations separately are strikingly different. Blue galaxies show a slow but steady increase of clustering strength with luminosity, with nearly constant shape of wp (rp ). The large-scale clustering of red galaxies shows little luminosity dependence until a sharp increase at L > 4 L *, but the lowest luminosity red galaxies (0.04-0.25 L *) show very strong clustering on small scales (rp < 2 h -1 Mpc). Most of the observed trends can be naturally understood within the ΛCDM+HOD framework. The growth of wp (rp ) for higher luminosity galaxies reflects an overall shift in the mass scale of their host dark matter halos, in particular an increase in the minimum host halo mass M min. The mass at which a halo has, on average, one satellite galaxy brighter than L is M 1 ≈ 17 M min(L) over most of the

  3. Constraining galaxy cluster temperatures and redshifts with eROSITA survey data

    NASA Astrophysics Data System (ADS)

    Borm, K.; Reiprich, T. H.; Mohammed, I.; Lovisari, L.

    2014-07-01

    Context. The nature of dark energy is imprinted in the large-scale structure of the Universe and thus in the mass and redshift distribution of galaxy clusters. The upcoming eROSITA instrument will exploit this method of probing dark energy by detecting ~100 000 clusters of galaxies in X-rays. Aims: For a precise cosmological analysis the various galaxy cluster properties need to be measured with high precision and accuracy. To predict these characteristics of eROSITA galaxy clusters and to optimise optical follow-up observations, we estimate the precision and the accuracy with which eROSITA will be able to determine galaxy cluster temperatures and redshifts from X-ray spectra. Additionally, we present the total number of clusters for which these two properties will be available from the eROSITA survey directly. Methods: We simulate the spectra of galaxy clusters for a variety of different cluster masses and redshifts while taking into account the X-ray background as well as the instrumental response. An emission model is then fit to these spectra to recover the cluster temperature and redshift. The number of clusters with precise properties is then based on the convolution of the above fit results with the galaxy cluster mass function and an assumed eROSITA selection function. Results: During its four years of all-sky surveys, eROSITA will determine cluster temperatures with relative uncertainties of ΔT/T ≲ 10% at the 68%-confidence level for clusters up to redshifts of z ~ 0.16 which corresponds to ~1670 new clusters with precise properties. Redshift information itself will become available with a precision of Δz/ (1 + z) ≲ 10% for clusters up to z ~ 0.45. Additionally, we estimate how the number of clusters with precise properties increases with a deepening of the exposure. For the above clusters, the fraction of catastrophic failures in the fit is below 20% and in most cases it is even much smaller. Furthermore, the biases in the best-fit temperatures as

  4. CLUSTER LENSING PROFILES DERIVED FROM A REDSHIFT ENHANCEMENT OF MAGNIFIED BOSS-SURVEY GALAXIES

    SciTech Connect

    Coupon, Jean; Umetsu, Keiichi; Broadhurst, Tom

    2013-07-20

    We report the first detection of a redshift-depth enhancement of background galaxies magnified by foreground clusters. Using 300,000 BOSS survey galaxies with accurate spectroscopic redshifts, we measure their mean redshift depth behind four large samples of optically selected clusters from the Sloan Digital Sky Survey (SDSS) surveys, totaling 5000-15,000 clusters. A clear trend of increasing mean redshift toward the cluster centers is found, averaged over each of the four cluster samples. In addition, we find similar but noisier behavior for an independent X-ray sample of 158 clusters lying in the foreground of the current BOSS sky area. By adopting the mass-richness relationships appropriate for each survey, we compare our results with theoretical predictions for each of the four SDSS cluster catalogs. The radial form of this redshift enhancement is well fitted by a richness-to-mass weighted composite Navarro-Frenk-White profile with an effective mass ranging between M{sub 200} {approx} 1.4-1.8 Multiplication-Sign 10{sup 14} M{sub Sun} for the optically detected cluster samples, and M{sub 200} {approx} 5.0 Multiplication-Sign 10{sup 14} M{sub Sun} for the X-ray sample. This lensing detection helps to establish the credibility of these SDSS cluster surveys, and provides a normalization for their respective mass-richness relations. In the context of the upcoming bigBOSS, Subaru Prime Focus Spectrograph, and EUCLID-NISP spectroscopic surveys, this method represents an independent means of deriving the masses of cluster samples for examining the cosmological evolution, and provides a relatively clean consistency check of weak-lensing measurements, free from the systematic limitations of shear calibration.

  5. Evolution of Group Galaxies from the First Red-Sequence Cluster Survey

    NASA Astrophysics Data System (ADS)

    Li, I. H.; Yee, H. K. C.; Hsieh, B. C.; Gladders, M.

    2012-04-01

    We study the evolution of the red-galaxy fraction (f red) in 905 galaxy groups with 0.15 <= z < 0.52. The galaxy groups are identified by the "probability friends-of-friends" algorithm from the first Red-Sequence Cluster Survey (RCS1) photometric-redshift sample. There is a high degree of uniformity in the properties of the red sequence of the group galaxies, indicating that the luminous red-sequence galaxies in the groups are already in place by z ~ 0.5 and that they have a formation epoch of z >~ 2. In general, groups at lower redshifts exhibit larger f red than those at higher redshifts, showing a group Butcher-Oemler effect. We investigate the evolution of f red by examining its dependence on four parameters, one of which can be classified as intrinsic and three of which can be classified as environmental: galaxy stellar mass (M *), total group stellar mass (M *, grp, a proxy for group halo mass), normalized group-centric radius (r grp), and local galaxy density (Σ5). We find that M * is the dominant parameter such that there is a strong correlation between f red and galaxy stellar mass. Furthermore, the dependence of f red on the environmental parameters is also a strong function of M *. Massive galaxies (M * >~ 1011 M ⊙) show little dependence of f red on r grp, M *, grp, and Σ5 over the redshift range. The dependence of f red on these parameters is primarily seen for galaxies with lower masses, especially for M * <~ 1010.6 M ⊙. We observe an apparent "group down-sizing" effect, in that galaxies in lower-mass halos, after controlling for galaxy stellar mass, have lower f red. We find a dependence of f red on both r grp and Σ5 after the other parameters are controlled. At a fixed r grp, there is a significant dependence of f red on Σ5, while r grp gradients of f red are seen for galaxies in similar Σ5 regions. This indicates that galaxy group environment has a residual effect over that of local galaxy density (or vice versa), and both parameters need

  6. GEMINI SPECTROSCOPIC SURVEY OF YOUNG STAR CLUSTERS IN MERGING/INTERACTING GALAXIES. IV. STEPHAN's QUINTET

    SciTech Connect

    Trancho, Gelys; Konstantopoulos, Iraklis S.; Mullan, Brendan; Charlton, Jane C.; Bastian, Nate; Fedotov, Konstantin; Gallagher, Sarah

    2012-04-01

    We present a spectroscopic survey of 21 young massive clusters and complexes and one tidal dwarf galaxy (TDG) candidate in Stephan's Quintet, an interacting compact group of galaxies. All of the selected targets lie outside the main galaxies of the system and are associated with tidal debris. We find clusters with ages between a few and 125 Myr and confirm the ages estimated through Hubble Space Telescope photometry by Fedotov et al., as well as their modeled interaction history of the Quintet. Many of the clusters are found to be relatively long-lived, given their spectrosopically derived ages, while their high masses suggest that they will likely evolve to eventually become intergalactic clusters. One cluster, T118, is particularly interesting, given its age ({approx}125 Myr), high mass ({approx}2 Multiplication-Sign 10{sup 6} M{sub Sun }), and position in the extreme outer end of the young tidal tail. This cluster appears to be quite extended (R{sub eff} {approx} 12-15 pc) compared to clusters observed in galaxy disks (R{sub eff} {approx} 3-4 pc), which confirms an effect we previously found in the tidal tails of NGC 3256, where clusters are similarly extended. We find that star and cluster formation can proceed at a continuous pace for at least {approx}150 Myr within the tidal debris of interacting galaxies. The spectrum of the TDG candidate is dominated by a young population ({approx}7 Myr), and, assuming a single age for the entire region, has a mass of at least 10{sup 6} M{sub Sun }.

  7. WINGS: a WIde-field Nearby Galaxy-cluster Survey. I. Optical imaging

    NASA Astrophysics Data System (ADS)

    Fasano, G.; Marmo, C.; Varela, J.; D'Onofrio, M.; Poggianti, B. M.; Moles, M.; Pignatelli, E.; Bettoni, D.; Kjærgaard, P.; Rizzi, L.; Couch, W. J.; Dressler, A.

    2006-01-01

    This is the first paper of a series that will present data and scientific results from the WINGS project, a wide-field, multiwavelength imaging and spectroscopic survey of galaxies in 77 nearby clusters. The sample was extracted from the ROSAT catalogs of X-Ray emitting clusters, with constraints on the redshift (0.04< z<0.07) and distance from the galactic plane ({\\vert}b{\\vert}≥ 20 deg). The global goal of the WINGS project is the systematic study of the local cosmic variance of the cluster population and of the properties of cluster galaxies as a function of cluster properties and local environment. This data collection will allow the definition of a local, "zero-point" reference against which to gauge the cosmic evolution when compared to more distant clusters. The core of the project consists of wide-field optical imaging of the selected clusters in the B and V bands. We have also completed a multi-fiber, medium-resolution spectroscopic survey for 51 of the clusters in the master sample. The imaging and spectroscopy data were collected using, respectively, the WFC@INT and WYFFOS@WHT in the northern hemisphere, and the WFI@MPG and 2dF@AAT in the southern hemisphere. In addition, a NIR (J, K) survey of ˜50 clusters and an Hα+U survey of some 10 clusters are presently ongoing with the WFCAM@UKIRT and WFC@INT, respectively, while a very-wide-field optical survey has also been programmed with OmegaCam@VST. In this paper we briefly outline the global objectives and the main characteristics of the WINGS project. Moreover, the observing strategy and the data reduction of the optical imaging survey (WINGS-OPT) are presented. We have achieved a photometric accuracy of ˜0.025 mag, reaching completeness to V˜ 23.5. Field size and resolution (FWHM) span the absolute intervals (1.6-2.7) Mpc and (0.7-1.7) kpc, respectively, depending on the redshift and on the seeing. This allows the planned studies to obtain a valuable description of the local properties of clusters

  8. The colour-magnitude relation of elliptical and lenticular galaxies in the ESO Distant Cluster Survey

    NASA Astrophysics Data System (ADS)

    Jaffé, Yara L.; Aragón-Salamanca, Alfonso; De Lucia, Gabriella; Jablonka, Pascale; Rudnick, Gregory; Saglia, Roberto; Zaritsky, Dennis

    2011-01-01

    In this paper we study the colour-magnitude relation (CMR) for a sample of 172 morphologically classified elliptical and S0 cluster galaxies from the ESO Distant Cluster Survey (EDisCS) at 0.4 ≲z≲ 0.8. The intrinsic colour scatter about the CMR is very small (<σint>= 0.076) in rest-frame U-V. However, there is a small minority of faint early-type galaxies (7 per cent) that are significantly bluer than the CMR. We observe no significant dependence of σint with redshift or cluster velocity dispersion. Because our sample is strictly morphologically selected, this implies that by the time cluster elliptical and S0 galaxies achieve their morphology, the vast majority have already joined the red sequence. The only exception seems to be the very small fraction of faint blue early types. Assuming that the intrinsic colour scatter is due to differences in stellar population ages, we estimate the galaxy formation redshift zF of each cluster and find that zF does not depend on the cluster velocity dispersion. However, zF increases weakly with cluster redshift within the EDisCS sample. This trend becomes very clear when higher redshift clusters from the literature are included. This suggests that, at any given redshift, in order to have a population of fully formed ellipticals and S0s they needed to have formed most of their stars ≃2-4 Gyr prior to observation. That does not mean that all early-type galaxies in all clusters formed at these high redshifts. It means that the ones we see already having early-type morphologies also have reasonably old stellar populations. This is partly a manifestation of the `progenitor bias', but also a consequence of the fact that the vast majority of the early-type galaxies in clusters (in particular the massive galaxies) were already red (i.e. already had old stellar populations) by the time they achieved their morphology. Elliptical and S0 galaxies exhibit very similar colour scatter, implying similar stellar population ages. The

  9. Spectral analysis of the Stromlo-APM Survey - II. Galaxy luminosity function and clustering by spectral type

    NASA Astrophysics Data System (ADS)

    Loveday, J.; Tresse, L.; Maddox, S.

    1999-11-01

    We study the luminosity function and clustering properties of subsamples of local galaxies selected from the Stromlo-APM Survey by the rest-frame equivalent widths of their Hα and [Oii] emission lines. The bJ luminosity function of star-forming galaxies has a significantly steeper faint-end slope than that for quiescent galaxies: the majority of sub-L* galaxies are currently undergoing significant star formation. Emission-line galaxies are less strongly clustered, both amongst themselves and with the general galaxy population, than are quiescent galaxies. Thus as well as being less luminous, star-forming galaxies also inhabit lower density regions of the Universe than quiescent galaxies.

  10. Clustering properties of luminous red galaxies with the Sloan Digital Sky Survey imaging data

    NASA Astrophysics Data System (ADS)

    Padmanabhan, Nikhil

    We study the 3D spatial clustering properties of luminous red galaxies in the Sloan Digital Sky Survey (SDSS) imaging data, and discuss their cosmological implications. The need to control systematics leads us to propose a new algorithm to photometrically calibrate wide-field imaging surveys. Applying this to the SDSS, we achieve a 1% relative photometric calibration over 8500 square degrees, an improvement of a factor of ~2 over current calibrations. We then calibrate distances, derived from only the SDSS imaging data, to a class of galaxies with very regular colours, the luminous red galaxies (LRGs). Measuring their 2-point correlation function allows us to detect the non-random clustering of galaxies on gigaparsec scales for the first time. We also detect the imprint of acoustic oscillations in the plasma of the early Universe on the clustering of the LRGs. We finally discuss cross-correlating the LRGs with the cosmic microwave background, detecting the integrated Sachs-Wolfe effect and providing further evidence for a late-time acceleration in the expansion of the Universe.

  11. THE MASSIVE AND DISTANT CLUSTERS OF WISE SURVEY. II. INITIAL SPECTROSCOPIC CONFIRMATION OF z ∼ 1 GALAXY CLUSTERS SELECTED FROM 10,000 deg{sup 2}

    SciTech Connect

    Stanford, S. A.; Gonzalez, Anthony H.; Gettings, Daniel P.; Brodwin, Mark; Eisenhardt, Peter R. M.; Stern, Daniel; Wylezalek, Dominika

    2014-08-01

    We present optical and infrared imaging and optical spectroscopy of galaxy clusters which were identified as part of an all-sky search for high-redshift galaxy clusters, the Massive and Distant Clusters of WISE Survey (MaDCoWS). The initial phase of MaDCoWS combined infrared data from the all-sky data release of the Wide-field Infrared Survey Explorer (WISE) with optical data from the Sloan Digital Sky Survey to select probable z ∼ 1 clusters of galaxies over an area of 10,000 deg{sup 2}. Our spectroscopy confirms 19 new clusters at 0.7 < z < 1.3, half of which are at z > 1, demonstrating the viability of using WISE to identify high-redshift galaxy clusters. The next phase of MaDCoWS will use the greater depth of the AllWISE data release to identify even higher redshift cluster candidates.

  12. Cosmology from large-scale galaxy clustering and galaxy–galaxy lensing with Dark Energy Survey Science Verification data

    SciTech Connect

    Kwan, J.; Sánchez, C.; Clampitt, J.; Blazek, J.; Crocce, M.; Jain, B.; Zuntz, J.; Amara, A.; Becker, M. R.; Bernstein, G. M.; Bonnett, C.; DeRose, J.; Dodelson, S.; Eifler, T. F.; Gaztanaga, E.; Giannantonio, T.; Gruen, D.; Hartley, W. G.; Kacprzak, T.; Kirk, D.; Krause, E.; MacCrann, N.; Miquel, R.; Park, Y.; Ross, A. J.; Rozo, E.; Rykoff, E. S.; Sheldon, E.; Troxel, M. A.; Wechsler, R. H.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Carrasco Kind, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D. W.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Jarvis, M.; Kuehn, K.; Lahav, O.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Martini, P.; Melchior, P.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.; Walker, A. R.

    2016-10-05

    We present cosmological constraints from the Dark Energy Survey (DES) using a combined analysis of angular clustering of red galaxies and their cross-correlation with weak gravitational lensing of background galaxies. We use a 139 square degree contiguous patch of DES data from the Science Verification (SV) period of observations. Using large scale measurements, we constrain the matter density of the Universe as $\\Omega_m = 0.31 \\pm 0.09$ and the clustering amplitude of the matter power spectrum as $\\sigma_8 = 0.74 +\\pm 0.13$ after marginalizing over seven nuisance parameters and three additional cosmological parameters. This translates into $S_8$ = $\\sigma_8(\\Omega_m/0.3)^{0.16} = 0.74 \\pm 0.12$ for our fiducial lens redshift bin at 0.35 < z < 0.5, while $S_8 = 0.78 \\pm 0.09$ using two bins over the range 0.2 < z < 0.5. We study the robustness of the results under changes in the data vectors, modelling and systematics treatment, including photometric redshift and shear calibration uncertainties, and find consistency in the derived cosmological parameters. We show that our results are consistent with previous cosmological analyses from DES and other data sets and conclude with a joint analysis of DES angular clustering and galaxy-galaxy lensing with Planck CMB data, Baryon Accoustic Oscillations and Supernova type Ia measurements.

  13. Percolation galaxy groups and clusters in the sdss redshift survey: identification, catalogs, and the multiplicity function

    SciTech Connect

    Berlind, Andreas A.; Frieman, Joshua A.; Weinberg, David H.; Blanton, Michael R.; Warren, Michael S.; Abazajian, Kevork; Scranton, Ryan; Hogg, David W.; Scoccimarro, Roman; Bahcall, Neta A.; Brinkmann, J.; Gott, J.Richard, III; Kleinman, S.J.; Krzesinski, J.; Lee, Brian C.; Miller, Christopher J.; Nitta, Atsuko; Schneider, Donald P.; Tucker, Douglas L.; Zehavi, Idit; /CCPP, New York /Chicago U., Astron. Astrophys. Ctr. /Ohio State U., Dept. Astron. /Los Alamos /Pittsburgh U. /Princeton U. /Subaru Telescope /Apache Point Observ. /Mt. Suhora Observ., Cracow /LBL, Berkeley /Cerro-Tololo InterAmerican Obs. /Penn State U., Astron. Astrophys. /Fermilab /Arizona U., Astron. Dept. - Steward Observ. /Case Western Reserve U.

    2006-01-01

    We identify galaxy groups and clusters in volume-limited samples of the SDSS redshift survey, using a redshift-space friends-of-friends algorithm. We optimize the friends-of-friends linking lengths to recover galaxy systems that occupy the same dark matter halos, using a set of mock catalogs created by populating halos of N-body simulations with galaxies. Extensive tests with these mock catalogs show that no combination of perpendicular and line-of-sight linking lengths is able to yield groups and clusters that simultaneously recover the true halo multiplicity function, projected size distribution, and velocity dispersion. We adopt a linking length combination that yields, for galaxy groups with ten or more members: a group multiplicity function that is unbiased with respect to the true halo multiplicity function; an unbiased median relation between the multiplicities of groups and their associated halos; a spurious group fraction of less than {approx}1%; a halo completeness of more than {approx}97%; the correct projected size distribution as a function of multiplicity; and a velocity dispersion distribution that is {approx}20% too low at all multiplicities. These results hold over a range of mock catalogs that use different input recipes of populating halos with galaxies. We apply our group-finding algorithm to the SDSS data and obtain three group and cluster catalogs for three volume-limited samples that cover 3495.1 square degrees on the sky. We correct for incompleteness caused by fiber collisions and survey edges, and obtain measurements of the group multiplicity function, with errors calculated from realistic mock catalogs. These multiplicity function measurements provide a key constraint on the relation between galaxy populations and dark matter halos.

  14. Gravitational redshift of galaxies in clusters from the sloan digital sky survey and the Baryon Oscillation spectroscopic survey.

    PubMed

    Sadeh, Iftach; Feng, Low Lerh; Lahav, Ofer

    2015-02-20

    The gravitational redshift effect allows one to directly probe the gravitational potential in clusters of galaxies. Following up on Wojtak et al. [Nature (London) 477, 567 (2011)], we present a new measurement. We take advantage of new data from the tenth data release of the Sloan Digital Sky Survey and the Baryon Oscillation Spectroscopic Survey. We compare the spectroscopic redshift of the brightest cluster galaxies (BCGs) with that of galaxies at the outskirts of clusters, using a sample with an average cluster mass of 1014M⊙. We find that these galaxies have an average relative redshift of -11  km/s compared with that of BCGs, with a standard deviation of +7 and -5  km/s. Our measurement is consistent with that of Wojtak et al. [Nature (London) 477, 567 (2011)]. However, our derived standard deviation is larger, as we take into account various systematic effects, beyond the size of the data set. The result is in good agreement with the predictions from general relativity.

  15. THE ACS VIRGO CLUSTER SURVEY. XVII. THE SPATIAL ALIGNMENT OF GLOBULAR CLUSTER SYSTEMS WITH EARLY-TYPE HOST GALAXIES

    SciTech Connect

    Wang Qiushi; Peng, Eric W.; Blakeslee, John P.; Cote, Patrick; Ferrarese, Laura; Jordan, Andres; Mei, Simona; West, Michael J.

    2013-06-01

    We study the azimuthal distribution of globular clusters (GCs) in early-type galaxies and compare them to their host galaxies using data from the ACS Virgo Cluster Survey. We find that in host galaxies with visible elongation ({epsilon} > 0.2) and intermediate to high luminosities (M{sub z} < -19), the GCs are preferentially aligned along the major axis of the stellar light. The red (metal-rich) GC subpopulations show strong alignment with the major axis of the host galaxy, which supports the notion that these GCs are associated with metal-rich field stars. The metal-rich GCs in lenticular galaxies show signs of being more strongly associated with disks rather than bulges. Surprisingly, we also find that the blue (metal-poor) GCs can also show the same correlation. If the metal-poor GCs are part of the early formation of the halo and built up through mergers, then our results support a picture where halo formation and merging occur anisotropically, and that the present-day major axis is an indicator of the preferred merging axis.

  16. The Next Generation Virgo Cluster Survey. XXII. Shell Feature Early-type Dwarf Galaxies in the Virgo Cluster

    NASA Astrophysics Data System (ADS)

    Paudel, Sanjaya; Smith, Rory; Duc, Pierre-Alain; Côté, Patrick; Cuillandre, Jean-Charles; Ferrarese, Laura; Blakeslee, John P.; Boselli, Alessandro; Cantiello, Michele; Gwyn, S. D. J.; Guhathakurta, Puragra; Mei, Simona; Mihos, J. Christopher; Peng, Eric W.; Powalka, Mathieu; Sánchez-Janssen, Rúben; Toloba, Elisa; Zhang, Hongxin

    2017-01-01

    The Next Generation Virgo Cluster Survey is a deep (with a 2σ detection limit μg = 29 mag arcsec‑2 in the g-band) optical panchromatic survey targeting the Virgo cluster from its core to virial radius, for a total areal coverage of 104 square degrees. As such, the survey is well suited for the study of galaxies’ outskirts, haloes, and low surface brightness features that arise from dynamical interactions within the cluster environment. We report the discovery of extremely faint (μg > 25 mag arcsec‑2) shells in three Virgo cluster early-type dwarf galaxies: VCC 1361, VCC 1447, and VCC 1668. Among them, VCC 1447 has an absolute magnitude Mg = ‑11.71 mag and is the least massive galaxy with a shell system discovered to date. We present a detailed study of these low surface brightness features. We detect between three and four shells in each of our galaxies. Within the uncertainties, we find no evidence of a color difference between the galaxy main body and shell features. The observed arcs of the shells are located up to several effective radii of the galaxies. We further explore the origin of these low surface brightness features with the help of idealized numerical simulations. We find that a near equal mass merger is best able to reproduce the main properties of the shells, including their quite symmetric appearance and their alignment along the major axis of the galaxy. The simulations provide support for a formation scenario in which a recent merger, between two near-equal mass, gas-free dwarf galaxies, forms the observed shell systems. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada–France–Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l’Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.

  17. STAR FORMATION AND UV COLORS OF THE BRIGHTEST CLUSTER GALAXIES IN THE REPRESENTATIVE XMM-NEWTON CLUSTER STRUCTURE SURVEY

    SciTech Connect

    Donahue, Megan; Bruch, Seth; Wang, Emily; Voit, G. Mark; Hicks, Amalia K.; Haarsma, Deborah B.; Croston, Judith H.; Pratt, Gabriel W.; O'Connell, Robert W.

    2010-06-01

    We present UV broadband photometry and optical emission-line measurements for a sample of 32 brightest cluster galaxies (BCGs) in clusters of the Representative XMM-Newton Cluster Structure Survey (REXCESS) with z = 0.06-0.18. The REXCESS clusters, chosen to study scaling relations in clusters of galaxies, have X-ray measurements of high quality. The trends of star formation and BCG colors with BCG and host properties can be investigated with this sample. The UV photometry comes from the XMM-Newton Optical Monitor, supplemented by existing archival Galaxy Evolution Explorer photometry. We detected H{alpha} and forbidden line emission in seven (22%) of these BCGs, in optical spectra obtained using the Southern Astrophysical Research Goodman spectrograph. All of these emission-line BCGs occupy clusters classified as cool cores (CCs) based on the central cooling time in the cluster core, for an emission-line incidence rate of 70% for BCGs in REXCESS CC clusters. Significant correlations between the H{alpha} equivalent widths, excess UV production in the BCG, and the presence of dense, X-ray bright intracluster gas with a short cooling time are seen, including the fact that all of the H{alpha} emitters inhabit systems with short central cooling times and high central intracluster medium densities. Estimates of the star formation rates based on H{alpha} and UV excesses are consistent with each other in these seven systems, ranging from 0.1to8 solar masses per year. The incidence of emission-line BCGs in the REXCESS sample is intermediate, somewhat lower than in other X-ray-selected samples ({approx}35%), and somewhat higher than but statistically consistent with optically selected, slightly lower redshift BCG samples ({approx}10%-15%). The UV-optical colors (UVW1 - R {approx}4.7 {+-} 0.3) of REXCESS BCGs without strong optical emission lines are consistent with those predicted from templates and observations of ellipticals dominated by old stellar populations. We see no

  18. WEAK LENSING MEASUREMENT OF GALAXY CLUSTERS IN THE CFHTLS-WIDE SURVEY

    SciTech Connect

    Shan Huanyuan; Tao Charling; Kneib, Jean-Paul; Jauzac, Mathilde; Limousin, Marceau; Fan Zuhui; Massey, Richard; Rhodes, Jason; Thanjavur, Karun; McCracken, Henry J.

    2012-03-20

    We present the first weak gravitational lensing analysis of the completed Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). We study the 64 deg{sup 2} W1 field, the largest of the CFHTLS-Wide survey fields, and present the largest contiguous weak lensing convergence 'mass map' yet made. 2.66 million galaxy shapes are measured, using the Kaiser Squires and Broadhurst Method (KSB) pipeline verified against high-resolution Hubble Space Telescope imaging that covers part of the CFHTLS. Our i'-band measurements are also consistent with an analysis of independent r'-band imaging. The reconstructed lensing convergence map contains 301 peaks with signal-to-noise ratio {nu} > 3.5, consistent with predictions of a {Lambda}CDM model. Of these peaks, 126 lie within 3.'0 of a brightest central galaxy identified from multicolor optical imaging in an independent, red sequence survey. We also identify seven counterparts for massive clusters previously seen in X-ray emission within 6 deg{sup 2} XMM-LSS survey. With photometric redshift estimates for the source galaxies, we use a tomographic lensing method to fit the redshift and mass of each convergence peak. Matching these to the optical observations, we confirm 85 groups/clusters with {chi}{sup 2}{sub reduced} < 3.0, at a mean redshift (z{sub c} ) = 0.36 and velocity dispersion ({sigma}{sub c}) = 658.8 km s{sup -1}. Future surveys, such as DES, LSST, KDUST, and EUCLID, will be able to apply these techniques to map clusters in much larger volumes and thus tightly constrain cosmological models.

  19. Weak Lensing Measurement of Galaxy Clusters in the CFHTLS-Wide Survey

    NASA Astrophysics Data System (ADS)

    Shan, HuanYuan; Kneib, Jean-Paul; Tao, Charling; Fan, Zuhui; Jauzac, Mathilde; Limousin, Marceau; Massey, Richard; Rhodes, Jason; Thanjavur, Karun; McCracken, Henry J.

    2012-03-01

    We present the first weak gravitational lensing analysis of the completed Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). We study the 64 deg2 W1 field, the largest of the CFHTLS-Wide survey fields, and present the largest contiguous weak lensing convergence "mass map" yet made. 2.66 million galaxy shapes are measured, using the Kaiser Squires and Broadhurst Method (KSB) pipeline verified against high-resolution Hubble Space Telescope imaging that covers part of the CFHTLS. Our i'-band measurements are also consistent with an analysis of independent r'-band imaging. The reconstructed lensing convergence map contains 301 peaks with signal-to-noise ratio ν > 3.5, consistent with predictions of a ΛCDM model. Of these peaks, 126 lie within 3farcm0 of a brightest central galaxy identified from multicolor optical imaging in an independent, red sequence survey. We also identify seven counterparts for massive clusters previously seen in X-ray emission within 6 deg2 XMM-LSS survey. With photometric redshift estimates for the source galaxies, we use a tomographic lensing method to fit the redshift and mass of each convergence peak. Matching these to the optical observations, we confirm 85 groups/clusters with χ2 reduced < 3.0, at a mean redshift langzc rang = 0.36 and velocity dispersion langσ c rang = 658.8 km s-1. Future surveys, such as DES, LSST, KDUST, and EUCLID, will be able to apply these techniques to map clusters in much larger volumes and thus tightly constrain cosmological models.

  20. The Herschel Virgo Cluster Survey. XIII. Dust in early-type galaxies

    NASA Astrophysics Data System (ADS)

    di Serego Alighieri, S.; Bianchi, S.; Pappalardo, C.; Zibetti, S.; Auld, R.; Baes, M.; Bendo, G.; Corbelli, E.; Davies, J. I.; Davis, T.; De Looze, I.; Fritz, J.; Gavazzi, G.; Giovanardi, C.; Grossi, M.; Hunt, L. K.; Magrini, L.; Pierini, D.; Xilouris, E. M.

    2013-04-01

    Aims: We study the dust content of a large optical input sample of 910 early-type galaxies (ETG) in the Virgo cluster, also extending to the dwarf ETG, and examine the results in relation to those on the other cold ISM components. Methods: We have searched for far-infrared emission in all galaxies in the input sample using the 250 μm image of the Herschel Virgo Cluster Survey (HeViCS). This image covers a large fraction of the cluster with an area of ~55 square degrees. For the detected ETG we measured fluxes in five bands from 100 to 500 μm, and estimated the dust mass and temperature with modified black-body fits. Results: Dust is detected above the completeness limit of 25.4 mJy at 250 μm in 46 ETG, 43 of which are in the optically complete part of the input sample. In addition, dust is present at fainter levels in another six ETG. We detect dust in the four ETG with synchrotron emission, including M 87. Dust appears to be much more concentrated than stars and more luminous ETG have higher dust temperatures. Considering only the optically complete input sample and correcting for the contamination by background galaxies, dust detection rates down to the 25.4 mJy limit are 17% for ellipticals, about 40% for lenticulars (S0 + S0a), and around 3% for dwarf ETG. Dust mass does not correlate clearly with stellar mass and is often much greater than expected for a passive galaxy in a closed-box model. The dust-to-stars mass ratio anticorrelates with galaxy luminosity, and for some dwarf ETG reaches values as high as for dusty late-type galaxies. In the Virgo cluster slow rotators appear more likely to contain dust than fast ones. Comparing the dust results with those on Hi there are only eight ETG detected both in dust and in Hi in the HeViCS area; 39 have dust but only an upper limit on Hi, and eight have Hi but only an upper limit on dust. The locations of these galaxies in the cluster are different, with the dusty ETG concentrated in the densest regions, while the

  1. EVOLUTION OF GROUP GALAXIES FROM THE FIRST RED-SEQUENCE CLUSTER SURVEY

    SciTech Connect

    Li, I. H.; Yee, H. K. C.; Hsieh, B. C.; Gladders, M. E-mail: hyee@astro.utoronto.ca E-mail: gladders@oddjob.uchicago.edu

    2012-04-20

    We study the evolution of the red-galaxy fraction (f{sub red}) in 905 galaxy groups with 0.15 {<=} z < 0.52. The galaxy groups are identified by the 'probability friends-of-friends' algorithm from the first Red-Sequence Cluster Survey (RCS1) photometric-redshift sample. There is a high degree of uniformity in the properties of the red sequence of the group galaxies, indicating that the luminous red-sequence galaxies in the groups are already in place by z {approx} 0.5 and that they have a formation epoch of z {approx}> 2. In general, groups at lower redshifts exhibit larger f{sub red} than those at higher redshifts, showing a group Butcher-Oemler effect. We investigate the evolution of f{sub red} by examining its dependence on four parameters, one of which can be classified as intrinsic and three of which can be classified as environmental: galaxy stellar mass (M{sub *}), total group stellar mass (M{sub *,grp}, a proxy for group halo mass), normalized group-centric radius (r{sub grp}), and local galaxy density ({Sigma}{sub 5}). We find that M{sub *} is the dominant parameter such that there is a strong correlation between f{sub red} and galaxy stellar mass. Furthermore, the dependence of f{sub red} on the environmental parameters is also a strong function of M{sub *}. Massive galaxies (M{sub *} {approx}> 10{sup 11} M{sub Sun }) show little dependence of f{sub red} on r{sub grp}, M{sub *,grp}, and {Sigma}{sub 5} over the redshift range. The dependence of f{sub red} on these parameters is primarily seen for galaxies with lower masses, especially for M{sub *} {approx}< 10{sup 10.6} M{sub Sun }. We observe an apparent 'group down-sizing' effect, in that galaxies in lower-mass halos, after controlling for galaxy stellar mass, have lower f{sub red}. We find a dependence of f{sub red} on both r{sub grp} and {Sigma}{sub 5} after the other parameters are controlled. At a fixed r{sub grp}, there is a significant dependence of f{sub red} on {Sigma}{sub 5}, while r{sub grp

  2. The SUNBIRD survey: characterizing the super star cluster populations of intensely star-forming galaxies

    NASA Astrophysics Data System (ADS)

    Randriamanakoto, Zara; Väisänen, Petri

    2017-03-01

    Super star clusters (SSCs) represent the youngest and most massive form of known gravitationally bound star clusters in the Universe. They are born abundantly in environments that trigger strong and violent star formation. We investigate the properties of these massive SSCs in a sample of 42 nearby starbursts and luminous infrared galaxies. The targets form the sample of the SUperNovae and starBursts in the InfraReD (SUNBIRD) survey that were imaged using near-infrared (NIR) K-band adaptive optics mounted on the Gemini/NIRI and the VLT/NaCo instruments. Results from i) the fitted power-laws to the SSC K-band luminosity functions, ii) the NIR brightest star cluster magnitude - star formation rate (SFR) relation and iii) the star cluster age and mass distributions have shown the importance of studying SSC host galaxies with high SFR levels to determine the role of the galactic environments in the star cluster formation, evolution and disruption mechanisms.

  3. A Photometric redshift galaxy catalog from the Red-Sequence Cluster Survey

    SciTech Connect

    Hsieh, Bau-Ching; Yee, H.K.C.; Lin, H.; Gladders, M.D.; /Carnegie Inst. Observ.

    2005-02-01

    The Red-Sequence Cluster Survey (RCS) provides a large and deep photometric catalog of galaxies in the z' and R{sub c} bands for 90 square degrees of sky, and supplemental V and B data have been obtained for 33.6 deg{sup 2}. They compile a photometric redshift catalog from these 4-band data by utilizing the empirical quadratic polynomial photometric redshift fitting technique in combination with CNOC2 and GOODS/HDF-N redshift data. The training set includes 4924 spectral redshifts. The resulting catalog contains more than one million galaxies with photometric redshifts < 1.5 and R{sub c} < 24, giving an rms scatter {delta}({Delta}z) < 0.06 within the redshift range 0.2 < z < 0.5 and {sigma}({Delta}z) < 0.11 for galaxies at 0.0 < z < 1.5. They describe the empirical quadratic polynomial photometric redshift fitting technique which they use to determine the relation between red-shift and photometry. A kd-tree algorithm is used to divide up the sample to improve the accuracy of the catalog. They also present a method for estimating the photometric redshift error for individual galaxies. They show that the redshift distribution of the sample is in excellent agreement with smaller and much deeper photometric and spectroscopic redshift surveys.

  4. The XMM Cluster Survey: the interplay between the brightest cluster galaxy and the intracluster medium via AGN feedback

    NASA Astrophysics Data System (ADS)

    Stott, John P.; Hickox, Ryan C.; Edge, Alastair C.; Collins, Chris A.; Hilton, Matt; Harrison, Craig D.; Romer, A. Kathy; Rooney, Philip J.; Kay, Scott T.; Miller, Christopher J.; Sahlén, Martin; Lloyd-Davies, Ed J.; Mehrtens, Nicola; Hoyle, Ben; Liddle, Andrew R.; Viana, Pedro T. P.; McCarthy, Ian G.; Schaye, Joop; Booth, C. M.

    2012-05-01

    Using a sample of 123 X-ray clusters and groups drawn from the XMM Cluster Survey first data release, we investigate the interplay between the brightest cluster galaxy (BCG), its black hole and the intracluster/group medium (ICM). It appears that for groups and clusters with a BCG likely to host significant active galactic nuclei (AGN) feedback, gas cooling dominates in those with TX > 2 keV while AGN feedback dominates below. This may be understood through the subunity exponent found in the scaling relation we derive between the BCG mass and cluster mass over the halo mass range 1013 < M500 < 1015 M⊙ and the lack of correlation between radio luminosity and cluster mass, such that BCG AGN in groups can have relatively more energetic influence on the ICM. The LX-TX relation for systems with the most massive BCGs, or those with BCGs co-located with the peak of the ICM emission, is steeper than that for those with the least massive and most offset, which instead follows self-similarity. This is evidence that a combination of central gas cooling and powerful, well fuelled AGN causes the departure of the ICM from pure gravitational heating, with the steepened relation crossing self-similarity at TX= 2 keV. Importantly, regardless of their black hole mass, BCGs are more likely to host radio-loud AGN if they are in a massive cluster (TX≳ 2 keV) and again co-located with an effective fuel supply of dense, cooling gas. This demonstrates that the most massive black holes appear to know more about their host cluster than they do about their host galaxy. The results lead us to propose a physically motivated, empirical definition of 'cluster' and 'group', delineated at 2 keV.

  5. One survey to find them all: detecting and studying galaxy clusters from infancy to maturity with Subaru HyperSuprimeCam Survey

    NASA Astrophysics Data System (ADS)

    Lin, Yen-Ting; HSC Collaboration

    2017-01-01

    With its unprecedented combination of depth and area, the Subaru HSC survey opens up a unique window to probe the formation and evolution of galaxy clusters from infancy (proto-clusters) to maturity based on one single dataset. Furthermore, the superb imaging quality and the combination of broad and narrow band filters offer several complementary ways in detecting clusters, including total-mass selection (via weak shear), red sequence selection, and concentration of line-emitting galaxies (for clusters at z>1). I will present the efforts of the HSC cluster working group in detecting clusters and proto-clusters, and the studies of galaxy population evolution in clusters. In particular, for the latter topic, I will summarize results based on the Camira cluster sample (Oguri et al.), which is constructed from concentrations of red galaxies in multi-color space. Using cross correlation techniques, we have examined the stellar mass assembly history of brightest cluster galaxies, inferred the details of dynamical friction and mechanisms of quenching of star formation from the radial profile of quiescent galaxies, quantified the evolution of stellar mass function of both red and blue galaxies, and made the first measurement of the radio luminosity function of radio-loud galaxies in clusters out to z~1.

  6. WINGS: A WIde-field Nearby Galaxy-cluster Survey. II. Deep optical photometry of 77 nearby clusters

    NASA Astrophysics Data System (ADS)

    Varela, J.; D'Onofrio, M.; Marmo, C.; Fasano, G.; Bettoni, D.; Cava, A.; Couch, W. J.; Dressler, A.; Kjærgaard, P.; Moles, M.; Pignatelli, E.; Poggianti, B. M.; Valentinuzzi, T.

    2009-04-01

    Context: This is the second paper of a series devoted to the WIde Field Nearby Galaxy-cluster Survey (WINGS). WINGS is a long term project which is gathering wide-field, multi-band imaging and spectroscopy of galaxies in a complete sample of 77 X-ray selected, nearby clusters (0.04 < z < 0.07) located far from the galactic plane (|b|≥ 20°). The main goal of this project is to establish a local reference for evolutionary studies of galaxies and galaxy clusters. Aims: This paper presents the optical (B,V) photometric catalogs of the WINGS sample and describes the procedures followed to construct them. We have paid special care to correctly treat the large extended galaxies (which includes the brightest cluster galaxies) and the reduction of the influence of the bright halos of very bright stars. Methods: We have constructed photometric catalogs based on wide-field images in B and V bands using SExtractor. Photometry has been performed on images in which large galaxies and halos of bright stars were removed after modeling them with elliptical isophotes. Results: We publish deep optical photometric catalogs (90% complete at V ~ 21.7, which translates to ˜ M^*_V+6 at mean redshift), giving positions, geometrical parameters, and several total and aperture magnitudes for all the objects detected. For each field we have produced three catalogs containing galaxies, stars and objects of “unknown” classification (~6%). From simulations we found that the uncertainty of our photometry is quite dependent of the light profile of the objects with stars having the most robust photometry and de Vaucouleurs profiles showing higher uncertainties and also an additional bias of ~-0.2^m. The star/galaxy classification of the bright objects (V < 20) was checked visually making negligible the fraction of misclassified objects. For fainter objects, we found that simulations do not provide reliable estimates of the possible misclassification and therefore we have compared our data

  7. Observation of the Coma cluster of galaxies with ROSAT during the all-sky survey

    NASA Technical Reports Server (NTRS)

    Briel, U. G.; Henry, J. P.; Boehringer, H.

    1992-01-01

    The Coma cluster of galaxies was observed with the position sensitive proportional counter (PSPC) during the ROSAT all sky survey. We find evidence for substructure in this cluster. Diffuse X-ray emission is detected from the regions of the NGC 4839 and 4911 subgroups at 6 percent and 1 percent of the total cluster emission respectively. There may be emission associated with the NGC 4874 and 4889 subgroups as well. The NGC 4839 group appears to be in the process of merging with the cluster. These X-ray data show that at least some of the groups previously found in projection are in fact physical objects possessing potential wells deep enough to trap their own X-ray gas. Because of the unlimited field of view of the all sky survey and the low background of the PSPC, we were able to measure the azimuthally averaged surface brightness of Coma out to approximately 100 arcmin, twice as far as was previously possible. Given the validity of our mass models, these new X-ray data imply that within 5/h(50) Mpc the binding mass of the Coma cluster is 1.8 +/- 0.6 x 10 exp 15/h(50) solar mass, and the fraction of cluster mass contained in hot gas is 0.30 +/- 0.14h(50) exp -3/2. Furthermore, the binding mass is more centrally concentrated than is the X-ray gas.

  8. The WARPS Survey - VIII. Evolution of the galaxy cluster X-ray Luminosity Function

    NASA Astrophysics Data System (ADS)

    Koens, L. A.; Maughan, B. J.; Jones, L. R.; Ebeling, H.; Horner, D. J.; Perlman, E. S.; Phillipps, S.; Scharf, C. A.

    2013-11-01

    We present measurements of the galaxy cluster X-ray Luminosity Function (XLF) from the Wide Angle ROSAT Pointed Survey (WARPS) and quantify its evolution. WARPS is a serendipitous survey of the central region of ROSAT pointed observations and was carried out in two phases (WARPS-I and WARPS-II). The results here are based on a final sample of 124 clusters, complete above a flux limit of 6.5 × 10-14 erg cm-2 s-1, with members out to redshift z ˜ 1.05, and a sky coverage of 70.9 deg2. We find significant evidence for negative evolution of the XLF, which complements the majority of X-ray cluster surveys. To quantify the suggested evolution, we perform a maximum likelihood analysis and conclude that the evolution is driven by a decreasing number density of high-luminosity clusters with redshift, while the bulk of the cluster population remains nearly unchanged out to redshift z ≈ 1.1, as expected in a low-density universe. The results are found to be insensitive to a variety of sources of systematic uncertainty that affect the measurement of the XLF and determination of the survey selection function. We perform a Bayesian analysis of the XLF to fully account for uncertainties in the local XLF on the measured evolution, and find that the detected evolution remains significant at the 95 per cent level. We observe a significant excess of clusters in the WARPS at 0.1 < z < 0.3 and LX ≈ 2 × 1043 erg s-1 compared with the reference low-redshift XLF, or our Bayesian fit to the WARPS data. We find that the excess cannot be explained by sample variance, or Eddington bias, and is unlikely to be due to problems with the survey selection function.

  9. Galaxy cluster's rotation

    NASA Astrophysics Data System (ADS)

    Manolopoulou, M.; Plionis, M.

    2017-03-01

    We study the possible rotation of cluster galaxies, developing, testing, and applying a novel algorithm which identifies rotation, if such does exist, as well as its rotational centre, its axis orientation, rotational velocity amplitude, and, finally, the clockwise or counterclockwise direction of rotation on the plane of the sky. To validate our algorithms we construct realistic Monte Carlo mock rotating clusters and confirm that our method provides robust indications of rotation. We then apply our methodology on a sample of Abell clusters with z ≲ 0.1 with member galaxies selected from the Sloan Digital Sky Survey DR10 spectroscopic data base. After excluding a number of substructured clusters, which could provide erroneous indications of rotation, and taking into account the expected fraction of misidentified coherent substructure velocities for rotation, provided by our Monte Carlo simulation analysis, we find that ∼23 per cent of our clusters are rotating under a set of strict criteria. Loosening the strictness of the criteria, on the expense of introducing spurious rotation indications, we find this fraction increasing to ∼28 per cent. We correlate our rotation indicators with the cluster dynamical state, provided either by their Bautz-Morgan type or by their X-ray isophotal shape and find for those clusters showing rotation within 1.5 h^{-1}_{70} Mpc that the significance of their rotation is related to the dynamically younger phases of cluster formation but after the initial anisotropic accretion and merging has been completed. Finally, finding rotational modes in galaxy clusters could lead to the necessity of correcting the dynamical cluster mass calculations.

  10. THE DEEP2 GALAXY REDSHIFT SURVEY: CLUSTERING DEPENDENCE ON GALAXY STELLAR MASS AND STAR FORMATION RATE AT z {approx} 1

    SciTech Connect

    Mostek, Nick; Coil, Alison L.; Cooper, Michael; Davis, Marc; Newman, Jeffrey A.; Weiner, Benjamin J.

    2013-04-10

    We present DEEP2 galaxy clustering measurements at z {approx} 1 as a function of stellar mass, star formation rate (SFR), and specific SFR (sSFR). We find a strong positive correlation between stellar mass and clustering amplitude on 1-10 h {sup -1} Mpc scales for blue, star-forming galaxies with 9.5 < log(M{sub *}/M{sub Sun }) < 11 and no dependence for red, quiescent galaxies with 10.5 < log(M{sub *}/M{sub Sun }) < 11.5. Using recently re-calibrated DEEP2 SFRs from restframe B-band magnitude and optical colors, we find that within the blue galaxy population at z {approx} 1 the clustering amplitude increases strongly with increasing SFR and decreasing sSFR. For red galaxies there is no significant correlation between clustering amplitude and either SFR or sSFR. Blue galaxies with high SFR or low sSFR are as clustered on large scales as red galaxies. We find that the clustering trend observed with SFR can be explained mostly, but not entirely, by the correlation between stellar mass and clustering amplitude for blue galaxies. We also show that galaxies above the star-forming 'main sequence' are less clustered than galaxies below the main sequence, at a given stellar mass. These results are not consistent with the high-sSFR population being dominated by major mergers. We also measure the clustering amplitude on small scales ({<=}0.3 h {sup -1} Mpc) and find an enhanced clustering signal relative to the best-fit large-scale power law for red galaxies with high stellar mass, blue galaxies with high SFR, and both red and blue galaxies with high sSFR. The increased small-scale clustering for galaxies with high sSFRs is likely linked to triggered star formation in interacting galaxies. These measurements provide strong constraints on galaxy evolution and halo occupation distribution models at z {approx} 1.

  11. The VLT LBG Redshift Survey - I. Clustering and dynamics of ≈1000 galaxies at z≈ 3

    NASA Astrophysics Data System (ADS)

    Bielby, R. M.; Shanks, T.; Weilbacher, P. M.; Infante, L.; Crighton, N. H. M.; Bornancini, C.; Bouché, N.; Héraudeau, P.; Lambas, D. G.; Lowenthal, J.; Minniti, D.; Padilla, N.; Petitjean, P.; Theuns, T.

    2011-06-01

    We present the initial imaging and spectroscopic data acquired as part of the Very Large Telescope (VLT) VIMOS Lyman-break galaxy Survey. UBR (or UBVI) imaging covers five ≈36 × 36 arcmin2 fields centred on bright z > 3 quasi-stellar objects (QSOs), allowing ≈21 000 2 < z < 3.5 galaxy candidates to be selected using the Lyman-break technique. We performed spectroscopic follow-up using VLT VIMOS, measuring redshifts for 1020 z > 2 Lyman-break galaxies and 10 z > 2 QSOs from a total of 19 VIMOS pointings. From the galaxy spectra, we observe a 625 ± 510 km s-1 velocity offset between the interstellar absorption and Lyman α emission-line redshifts, consistent with previous results. Using the photometric and spectroscopic catalogues, we have analysed the galaxy clustering at z≈ 3. The angular correlation function, w(θ), is well fitted by a double power law with clustering scalelength, r0= 3.19+0.32-0.54 h-1 Mpc and slope γ= 2.45 for r < 1 h-1 Mpc and r0= 4.37+0.43-0.55 h-1 Mpc with γ= 1.61 ± 0.15 at larger scales. Using the redshift sample we estimate the semiprojected correlation function, wp(σ), and, for a γ= 1.8 power law, find r0= 3.67+0.23-0.24 h-1 Mpc for the VLT sample and r0= 3.98+0.14-0.15 h-1 Mpc for a combined VLT+Keck sample. From ξ(s) and ξ(σ, π), and assuming the above ξ(r) models, we find that the combined VLT and Keck surveys require a galaxy pairwise velocity dispersion of ≈700 km s-1, higher than ≈400 km s-1 assumed by previous authors. We also measure a value for the gravitational growth rate parameter of β(z= 3) = 0.48 ± 0.17, again higher than that previously found and implying a low value for the bias of b= 2.06+1.1-0.5. This value is consistent with the galaxy clustering amplitude which gives b= 2.22 ± 0.16, assuming the standard cosmology, implying that the evolution of the gravitational growth rate is also consistent with Einstein gravity. Finally, we have compared our Lyman-break galaxy clustering amplitudes with

  12. Radio AGN in 13,240 galaxy clusters from the Sloan Digital Sky Survey

    SciTech Connect

    Croft, S; de Vries, W; Becker, R

    2007-05-30

    We correlate the positions of 13,240 Brightest Cluster Galaxies (BCGs) with 0.1 {le} z {le} 0.3 from the maxBCG catalog with radio sources from the FIRST survey to study the sizes and distributions of radio AGN in galaxy clusters. We find that 19.7% of our BCGs are radio-loud, and this fraction depends on the stellar mass of the BCG, and to a lesser extent on the richness of the parent cluster (in the sense of increasing radio loudness with increasing mass). The intrinsic size of the radio emission associated with the BCGs peaks at 55 kpc, with a tail extending to 200 kpc. The radio power of the extended sources places them on the divide between FR I and FR II type sources, while sources compact in the radio tend to be somewhat less radio-luminous. We also detect an excess of radio sources associated with the cluster, instead of with the BCG itself, extending out to {approx} 1.4 kpc.

  13. WINGS: a WIde-field nearby Galaxy-cluster survey. III. Deep near-infrared photometry of 28 nearby clusters

    NASA Astrophysics Data System (ADS)

    Valentinuzzi, T.; Woods, D.; Fasano, G.; Riello, M.; D'Onofrio, M.; Varela, J.; Bettoni, D.; Cava, A.; Couch, W. J.; Dressler, A.; Fritz, J.; Moles, M.; Omizzolo, A.; Poggianti, B. M.; Kjærgaard, P.

    2009-07-01

    Context: This is the third paper in a series devoted to the WIde-field Nearby Galaxy-cluster Survey (WINGS). WINGS is a long-term project aimed at gathering wide-field, multiband imaging and spectroscopy of galaxies in a complete sample of 77 X-ray selected, nearby clusters (0.04galaxies and galaxy clusters. Aims: This paper presents the near-infrared (J,K) photometric catalogs of 28 clusters of the WINGS sample and describes the procedures followed to construct them. Methods: The raw data has been reduced at CASU and special care has been devoted to the final coadding, drizzling technique, astrometric solution, and magnitude calibration for the WFCAM pipeline-processed data. We constructed the photometric catalogs based on the final calibrated, coadded mosaics (≈0.79 deg^2) in J (19 clusters) and K (27 clusters) bands. A customized interactive pipeline was used to clean the catalogs and to make mock images for photometric errors and completeness estimates. Results: We provide deep near-infrared photometric catalogs (90% complete in detection rate at total magnitudes J≈ 20.5, K≈ 19.4, and in classification rate at J≈19.5 and K≈ 18.5), giving positions, geometrical parameters, total and aperture magnitudes for all detected sources. For each field we classify the detected sources as stars, galaxies, and objects of “unknown” nature. Based on observations taken at the United Kingdom Infra-Red Telescope, operated by the Joint Astronomy Centre on behalf of the Science and Technology Facilities Council of the UK. J and K photometric catalogs are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/501/851

  14. Galaxy populations in the 26 most massive galaxy clusters in the South Pole Telescope SPT-SZ survey

    NASA Astrophysics Data System (ADS)

    Zenteno, A.; Mohr, J. J.; Desai, S.; Stalder, B.; Saro, A.; Dietrich, J. P.; Bayliss, M.; Bocquet, S.; Chiu, I.; Gonzalez, A. H.; Gangkofner, C.; Gupta, N.; Hlavacek-Larrondo, J.; McDonald, M.; Reichardt, C.; Rest, A.

    2016-10-01

    We present a study of the optical properties of the 26 most massive galaxy clusters within the South Pole Telescope Sunyaev-Zel'dovich (SPT-SZ) 2500 deg2 survey spanning the redshift range 0.10 < z < 1.13. We measure the radial profiles, the luminosity functions (LFs), and the halo occupation numbers (HONs) using optical data of typical depth m* + 2. The stacked radial profiles are consistent with a Navarro-Frenk-White profile of concentration 2.84^{+0.40}_{-0.37} for the red sequence (RS) and 2.36^{+0.38}_{-0.35} for the total population. Stacking the data in multiple redshift bins shows slight redshift evolution in the concentration when both the total population is used, and when only RS galaxies are used (at 2.1σ and 2.8σ, respectively). The stacked LF shows a faint end slope α = -1.06^{+0.04}_{-0.03} for the total and α = -0.80^{+0.04}_{-0.03} for the RS population. The redshift evolution of m* is consistent with a passively evolving composite stellar population (CSP) model. Adopting the CSP model predictions, we explore the redshift evolution of the Schechter parameters α and φ*. We find α for the total population to be consistent with no evolution (0.3σ), and mildly significant evidence of evolution for the red galaxies (1.1-2.1σ). The data show that the density φ*/E2(z) decreases with redshift, in tension with the self-similar expectation at a 2.4σ level for the total population. The measured HON-mass relation has a lower normalization than previous low redshift studies. Finally, our data support HON redshift evolution at a 2.1σ level, with clusters at higher redshift containing fewer galaxies than their low-z counterparts.

  15. The Herschel Virgo Cluster Survey. IV. Resolved dust analysis of spiral galaxies

    NASA Astrophysics Data System (ADS)

    Smith, M. W. L.; Vlahakis, C.; Baes, M.; Bendo, G. J.; Bianchi, S.; Bomans, D. J.; Boselli, A.; Clemens, M.; Corbelli, E.; Cortese, L.; Dariush, A.; Davies, J. I.; De Looze, I.; di Serego Alighieri, S.; Fadda, D.; Fritz, J.; Garcia-Appadoo, D. A.; Gavazzi, G.; Giovanardi, C.; Grossi, M.; Hughes, T. M.; Hunt, L. K.; Jones, A. P.; Madden, S.; Pierini, D.; Pohlen, M.; Sabatini, S.; Verstappen, J.; Xilouris, E. M.; Zibetti, S.

    2010-07-01

    We present a resolved dust analysis of three of the largest angular size spiral galaxies, NGC 4501 and NGC 4567/8, in the Herschel Virgo Cluster Survey (HeViCS) science demonstration field. Herschel has unprecedented spatial resolution at far-infrared wavelengths and with the PACS and SPIRE instruments samples both sides of the peak in the far infrared spectral energy distribution (SED). We present maps of dust temperature, dust mass, and gas-to-dust ratio, produced by fitting modified black bodies to the SED for each pixel. We find that the distribution of dust temperature in both systems is in the range ~19-22 K and peaks away from the centres of the galaxies. The distribution of dust mass in both systems is symmetrical and exhibits a single peak coincident with the galaxy centres. This Letter provides a first insight into the future analysis possible with a large sample of resolved galaxies to be observed by Herschel. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  16. The SUNBIRD survey: characterizing the super star cluster populations of intensely star-forming galaxies

    NASA Astrophysics Data System (ADS)

    Randriamanakoto, Zara; Vaisanen, Petri; Escala, Andres

    2015-08-01

    This work investigates properties of young, massive and dense star clusters in a sample of 42 nearby starbursts and LIRGs with an average distance of 80 Mpc. The targets form the sample of the SUperNovae and starBursts in the InfraReD (SUNBIRD) survey that were imaged using near-infrared K-band adaptive optics mounted on the Gemini/NIRI and the VLT/NaCo instruments.We fitted power-laws to the SSC K-band luminosity functions and found index values ranging between 1.5 and 2.4 with a median value of α ˜ 1.86±0.24. This is shallower than the average of ≈ 2.4 associated with normal spiral galaxies indicating that SSCs hosted by star-forming galaxies are disrupted in a way depending on their mass or environment. Using simulations we found that blending effects are not significant for targets closer than ≈100Mpc. We also established the first ever near-infrared (NIR) brightest star cluster magnitude - star formation rate (SFR) relation. The correlation has a steeper slope compared to the one with optical data at lower SFRs which could indicate a simple statistical effect, though we argue that a physical truncation of the mass distribution at high masses would better explain the tight scatter of the observed relation.Finally, we combined new NIR imaging of seven LIRG targets with their optical HST archival data to derive the age, mass, and extinction distributions of optically-selected SSC candidates. Apart from having a high mass range of 10^4 - 10^8 M⊙, more than a quarter of the cluster population is younger than 30 Myr. We also derived the cluster initial mass functions and found that at least in one of the LIRGs, a mass-dependent disruption mechanism is responsible for the deficiency in low-mass star clusters. The cluster formation efficiencies Γ = 10 - 23 %, on the other hand, support the arguments that highly-pressurized environments favor SF in bound star clusters.This work has shown the importance of studying SSC host galaxies with high SFR levels to

  17. THE ACS NEARBY GALAXY SURVEY TREASURY. X. QUANTIFYING THE STAR CLUSTER FORMATION EFFICIENCY OF NEARBY DWARF GALAXIES

    SciTech Connect

    Cook, David O.; Dale, Daniel A.; Seth, Anil C.; Johnson, L. Clifton; Weisz, Daniel R.; Fouesneau, Morgan; Dalcanton, Julianne J.; Olsen, Knut A. G.; Engelbracht, Charles W.

    2012-06-01

    We study the relationship between the field star formation and cluster formation properties in a large sample of nearby dwarf galaxies. We use optical data from the Hubble Space Telescope and from ground-based telescopes to derive the ages and masses of the young (t{sub age} {approx}< 100 Myr) cluster sample. Our data provide the first constraints on two proposed relationships between the star formation rate (SFR) of galaxies and the properties of their cluster systems in the low SFR regime. The data show broad agreement with these relationships, but significant galaxy-to-galaxy scatter exists. In part, this scatter can be accounted for by simulating the small number of clusters detected from stochastically sampling the cluster mass function. However, this stochasticity does not fully account for the observed scatter in our data, suggesting that there may be true variations in the fraction of stars formed in clusters in dwarf galaxies. Comparison of the cluster formation and the brightest cluster in our sample galaxies also provide constraints on cluster destruction models.

  18. Cosmological constraints from galaxy clusters in the 2500 square-degree SPT-SZ survey

    DOE PAGES

    Haan, T. de; Benson, B. A.; Bleem, L. E.; ...

    2016-11-18

    Here, we present cosmological parameter constraints obtained from galaxy clusters identified by their Sunyaev–Zel’dovich effect signature in the 2500 square-degree South Pole Telescope Sunyaev Zel’dovich (SPT-SZ) survey. We consider the 377 cluster candidates identified atmore » $$z\\gt 0.25$$ with a detection significance greater than five, corresponding to the 95% purity threshold for the survey. We compute constraints on cosmological models using the measured cluster abundance as a function of mass and redshift. We include additional constraints from multi-wavelength observations, including Chandra X-ray data for 82 clusters and a weak lensing-based prior on the normalization of the mass-observable scaling relations. Assuming a spatially flat ΛCDM cosmology, we combine the cluster data with a prior on H (0) and find $${\\sigma }_{8}=0.784\\pm 0.039$$ and $${{\\rm{\\Omega }}}_{m}=0.289\\pm 0.042$$, with the parameter combination $${\\sigma }_{8}{({{\\rm{\\Omega }}}_{m}/0.27)}^{0.3}=0.797\\pm 0.031$$. These results are in good agreement with constraints from the cosmic microwave background (CMB) from SPT, WMAP, and Planck, as well as with constraints from other cluster data sets. We also consider several extensions to ΛCDM, including models in which the equation of state of dark energy w, the species-summed neutrino mass, and/or the effective number of relativistic species ($${N}_{\\mathrm{eff}}$$) are free parameters. When combined with constraints from the Planck CMB, H (0), baryon acoustic oscillation, and SNe, adding the SPT cluster data improves the w constraint by 14%, to $$w=-1.023\\pm 0.042$$.« less

  19. Cosmological constraints from galaxy clusters in the 2500 square-degree SPT-SZ survey

    SciTech Connect

    Haan, T. de; Benson, B. A.; Bleem, L. E.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Bayliss, M.; Bocquet, S.; Brodwin, M.; Carlstrom, J. E.; Chang, C. L.; Chiu, I.; Cho, H-M.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; Desai, S.; Dietrich, J. P.; Dobbs, M. A.; Doucouliagos, A. N.; Foley, R. J.; Forman, W. R.; Garmire, G. P.; George, E. M.; Gladders, M. D.; Gonzalez, A. H.; Gupta, N.; Halverson, N. W.; Hlavacek-Larrondo, J.; Hoekstra, H.; Holder, G. P.; Holzapfel, W. L.; Hou, Z.; Hrubes, J. D.; Huang, N.; Jones, C.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Linden, A. von der; Luong-Van, D.; Mantz, A.; Marrone, D. P.; McDonald, M.; McMahon, J. J.; Meyer, S. S.; Mocanu, L. M.; Mohr, J. J.; Murray, S. S.; Padin, S.; Pryke, C.; Rapetti, D.; Reichardt, C. L.; Rest, A.; Ruel, J.; Ruhl, J. E.; Saliwanchik, B. R.; Saro, A.; Sayre, J. T.; Schaffer, K. K.; Schrabback, T.; Shirokoff, E.; Song, J.; Spieler, H. G.; Stalder, B.; Stanford, S. A.; Staniszewski, Z.; Stark, A. A.; Story, K. T.; Stubbs, C. W.; Vanderlinde, K.; Vieira, J. D.; Vikhlinin, A.; Williamson, R.; Zenteno, A.

    2016-11-18

    Here, we present cosmological parameter constraints obtained from galaxy clusters identified by their Sunyaev–Zel’dovich effect signature in the 2500 square-degree South Pole Telescope Sunyaev Zel’dovich (SPT-SZ) survey. We consider the 377 cluster candidates identified at $z\\gt 0.25$ with a detection significance greater than five, corresponding to the 95% purity threshold for the survey. We compute constraints on cosmological models using the measured cluster abundance as a function of mass and redshift. We include additional constraints from multi-wavelength observations, including Chandra X-ray data for 82 clusters and a weak lensing-based prior on the normalization of the mass-observable scaling relations. Assuming a spatially flat ΛCDM cosmology, we combine the cluster data with a prior on H (0) and find ${\\sigma }_{8}=0.784\\pm 0.039$ and ${{\\rm{\\Omega }}}_{m}=0.289\\pm 0.042$, with the parameter combination ${\\sigma }_{8}{({{\\rm{\\Omega }}}_{m}/0.27)}^{0.3}=0.797\\pm 0.031$. These results are in good agreement with constraints from the cosmic microwave background (CMB) from SPT, WMAP, and Planck, as well as with constraints from other cluster data sets. We also consider several extensions to ΛCDM, including models in which the equation of state of dark energy w, the species-summed neutrino mass, and/or the effective number of relativistic species (${N}_{\\mathrm{eff}}$) are free parameters. When combined with constraints from the Planck CMB, H (0), baryon acoustic oscillation, and SNe, adding the SPT cluster data improves the w constraint by 14%, to $w=-1.023\\pm 0.042$.

  20. Cosmological Constraints from Galaxy Clusters in the 2500 Square-degree SPT-SZ Survey

    NASA Astrophysics Data System (ADS)

    de Haan, T.; Benson, B. A.; Bleem, L. E.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Bayliss, M.; Bocquet, S.; Brodwin, M.; Carlstrom, J. E.; Chang, C. L.; Chiu, I.; Cho, H.-M.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; Desai, S.; Dietrich, J. P.; Dobbs, M. A.; Doucouliagos, A. N.; Foley, R. J.; Forman, W. R.; Garmire, G. P.; George, E. M.; Gladders, M. D.; Gonzalez, A. H.; Gupta, N.; Halverson, N. W.; Hlavacek-Larrondo, J.; Hoekstra, H.; Holder, G. P.; Holzapfel, W. L.; Hou, Z.; Hrubes, J. D.; Huang, N.; Jones, C.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; von der Linden, A.; Luong-Van, D.; Mantz, A.; Marrone, D. P.; McDonald, M.; McMahon, J. J.; Meyer, S. S.; Mocanu, L. M.; Mohr, J. J.; Murray, S. S.; Padin, S.; Pryke, C.; Rapetti, D.; Reichardt, C. L.; Rest, A.; Ruel, J.; Ruhl, J. E.; Saliwanchik, B. R.; Saro, A.; Sayre, J. T.; Schaffer, K. K.; Schrabback, T.; Shirokoff, E.; Song, J.; Spieler, H. G.; Stalder, B.; Stanford, S. A.; Staniszewski, Z.; Stark, A. A.; Story, K. T.; Stubbs, C. W.; Vanderlinde, K.; Vieira, J. D.; Vikhlinin, A.; Williamson, R.; Zenteno, A.

    2016-11-01

    We present cosmological parameter constraints obtained from galaxy clusters identified by their Sunyaev-Zel’dovich effect signature in the 2500 square-degree South Pole Telescope Sunyaev Zel’dovich (SPT-SZ) survey. We consider the 377 cluster candidates identified at z\\gt 0.25 with a detection significance greater than five, corresponding to the 95% purity threshold for the survey. We compute constraints on cosmological models using the measured cluster abundance as a function of mass and redshift. We include additional constraints from multi-wavelength observations, including Chandra X-ray data for 82 clusters and a weak lensing-based prior on the normalization of the mass-observable scaling relations. Assuming a spatially flat ΛCDM cosmology, we combine the cluster data with a prior on H 0 and find {σ }8=0.784+/- 0.039 and {{{Ω }}}m=0.289+/- 0.042, with the parameter combination {σ }8{({{{Ω }}}m/0.27)}0.3=0.797+/- 0.031. These results are in good agreement with constraints from the cosmic microwave background (CMB) from SPT, WMAP, and Planck, as well as with constraints from other cluster data sets. We also consider several extensions to ΛCDM, including models in which the equation of state of dark energy w, the species-summed neutrino mass, and/or the effective number of relativistic species ({N}{eff}) are free parameters. When combined with constraints from the Planck CMB, H 0, baryon acoustic oscillation, and SNe, adding the SPT cluster data improves the w constraint by 14%, to w=-1.023+/- 0.042.

  1. The zCOSMOS-Bright survey: the clustering of early and late galaxy morphological types since z≃ 1

    NASA Astrophysics Data System (ADS)

    de la Torre, S.; Le Fèvre, O.; Porciani, C.; Guzzo, L.; Meneux, B.; Abbas, U.; Tasca, L.; Carollo, C. M.; Contini, T.; Kneib, J.-P.; Lilly, S. J.; Mainieri, V.; Renzini, A.; Scodeggio, M.; Zamorani, G.; Bardelli, S.; Bolzonella, M.; Bongiorno, A.; Caputi, K.; Coppa, G.; Cucciati, O.; de Ravel, L.; Franzetti, P.; Garilli, B.; Halliday, C.; Iovino, A.; Kampczyk, P.; Knobel, C.; Koekemoer, A. M.; Kovač, K.; Lamareille, F.; Le Borgne, J.-F.; Le Brun, V.; Maier, C.; Mignoli, M.; Pelló, R.; Peng, Y.; Perez-Montero, E.; Ricciardelli, E.; Silverman, J.; Tanaka, M.; Tresse, L.; Vergani, D.; Zucca, E.; Bottini, D.; Cappi, A.; Cassata, P.; Cimatti, A.; Leauthaud, A.; Maccagni, D.; Marinoni, C.; McCracken, H. J.; Memeo, P.; Oesch, P.; Pozzetti, L.; Scaramella, R.

    2011-04-01

    We measure the spatial clustering of galaxies as a function of their morphological type at z≃ 0.8, for the first time in a deep redshift survey with full morphological information. This is obtained by combining high-resolution Hubble Space Telescope imaging and Very Large Telescope spectroscopy for about 8500 galaxies to ? with accurate spectroscopic redshifts from the zCOSMOS-Bright redshift survey. At this epoch, early-type galaxies already show a significantly stronger clustering than late-type galaxies on all probed scales. A comparison to the Sloan Digital Sky Survey Data at z≃ 0.1 shows that the relative clustering strength between early and late morphological classes tends to increase with cosmic time at small separations, while on large scales it shows no significant evolution since z≃ 0.8. This suggests that most early-type galaxies had already formed in intermediate and dense environments at this epoch. Our results are consistent with a picture in which the relative clustering of different morphological types between z≃ 1 and 0 reflects the evolving role of environment in the morphological transformation of galaxies, on top of a global evolution driven by mass.

  2. CLUSTERING OF SLOAN DIGITAL SKY SURVEY III PHOTOMETRIC LUMINOUS GALAXIES: THE MEASUREMENT, SYSTEMATICS, AND COSMOLOGICAL IMPLICATIONS

    SciTech Connect

    Ho, Shirley; White, Martin; Schlegel, David J.; Seljak, Uros; Reid, Beth; Cuesta, Antonio; Padmanabhan, Nikhil; Seo, Hee-Jong; De Putter, Roland; Ross, Ashley J.; Percival, Will J.; Saito, Shun; Schlafly, Eddie; Hernandez-Monteagudo, Carlos; Sanchez, Ariel G.; Blanton, Michael; Skibba, Ramin; Schneider, Don; Mena, Olga; Viel, Matteo; and others

    2012-12-10

    The Sloan Digital Sky Survey (SDSS) surveyed 14,555 deg{sup 2}, and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross et al. This data set spans 11,000 deg{sup 2} and probes a volume of 3 h {sup -3} Gpc{sup 3}, making it the largest volume ever used for galaxy clustering measurements. We describe in detail the construction of the survey window function and various systematics affecting our measurement. With such a large volume, high-precision cosmological constraints can be obtained given careful control and understanding of the observational systematics. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. In this paper, we measure the angular clustering using an optimal quadratic estimator at four redshift slices with an accuracy of {approx}15%, with a bin size of {delta}{sub l} = 10 on scales of the baryon acoustic oscillations (BAOs; at l {approx} 40-400). We also apply corrections to the power spectra due to systematics and derive cosmological constraints using the full shape of the power spectra. For a flat {Lambda}CDM model, when combined with cosmic microwave background Wilkinson Microwave Anisotropy Probe 7 (WMAP7) and H{sub 0} constraints from using 600 Cepheids observed by Wide Field Camera 3 (WFC3; HST), we find {Omega}{sub {Lambda}} = 0.73 {+-} 0.019 and H{sub 0} to be 70.5 {+-} 1.6 s{sup -1} Mpc{sup -1} km. For an open {Lambda}CDM model, when combined with WMAP7 + HST, we find {Omega}{sub K} = 0.0035 {+-} 0.0054, improved over WMAP7+HST alone by 40%. For a wCDM model, when combined with WMAP7+HST+SN, we find w = -1.071 {+-} 0.078, and H{sub 0} to be 71.3 {+-} 1.7 s{sup -1} Mpc{sup -1} km, which is competitive with the latest large-scale structure constraints from large spectroscopic

  3. Clustering of Sloan Digital Sky Survey III Photometric Luminous Galaxies: The Measurement, Systematics, and Cosmological Implications

    NASA Astrophysics Data System (ADS)

    Ho, Shirley; Cuesta, Antonio; Seo, Hee-Jong; de Putter, Roland; Ross, Ashley J.; White, Martin; Padmanabhan, Nikhil; Saito, Shun; Schlegel, David J.; Schlafly, Eddie; Seljak, Uros; Hernández-Monteagudo, Carlos; Sánchez, Ariel G.; Percival, Will J.; Blanton, Michael; Skibba, Ramin; Schneider, Don; Reid, Beth; Mena, Olga; Viel, Matteo; Eisenstein, Daniel J.; Prada, Francisco; Weaver, Benjamin A.; Bahcall, Neta; Bizyaev, Dimitry; Brewinton, Howard; Brinkman, Jon; Nicolaci da Costa, Luiz; Gott, John R.; Malanushenko, Elena; Malanushenko, Viktor; Nichol, Bob; Oravetz, Daniel; Pan, Kaike; Palanque-Delabrouille, Nathalie; Ross, Nicholas P.; Simmons, Audrey; de Simoni, Fernando; Snedden, Stephanie; Yeche, Christophe

    2012-12-01

    The Sloan Digital Sky Survey (SDSS) surveyed 14,555 deg2, and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross et al. This data set spans 11,000 deg2 and probes a volume of 3 h -3 Gpc3, making it the largest volume ever used for galaxy clustering measurements. We describe in detail the construction of the survey window function and various systematics affecting our measurement. With such a large volume, high-precision cosmological constraints can be obtained given careful control and understanding of the observational systematics. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. In this paper, we measure the angular clustering using an optimal quadratic estimator at four redshift slices with an accuracy of ~15%, with a bin size of δ l = 10 on scales of the baryon acoustic oscillations (BAOs; at l ~ 40-400). We also apply corrections to the power spectra due to systematics and derive cosmological constraints using the full shape of the power spectra. For a flat ΛCDM model, when combined with cosmic microwave background Wilkinson Microwave Anisotropy Probe 7 (WMAP7) and H 0 constraints from using 600 Cepheids observed by Wide Field Camera 3 (WFC3; HST), we find ΩΛ = 0.73 ± 0.019 and H 0 to be 70.5 ± 1.6 s-1 Mpc-1 km. For an open ΛCDM model, when combined with WMAP7 + HST, we find Ω K = 0.0035 ± 0.0054, improved over WMAP7+HST alone by 40%. For a wCDM model, when combined with WMAP7+HST+SN, we find w = -1.071 ± 0.078, and H 0 to be 71.3 ± 1.7 s-1 Mpc-1 km, which is competitive with the latest large-scale structure constraints from large spectroscopic surveys such as the SDSS Data Release 7 (DR7) and WiggleZ. We also find that systematic-corrected power spectra give consistent

  4. X-ray selected galaxy clusters in the Pan-STARRS Medium Deep Survey

    NASA Astrophysics Data System (ADS)

    Ebeling, H.; Edge, A. C.; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Huber, M. E.; Kaiser, N.; Price, P. A.; Tonry, J. L.

    2013-06-01

    We present the results of a pilot study for the extended Massive Cluster Survey (eMACS), a comprehensive search for distant, X-ray luminous galaxy clusters at z > 0.5. Our pilot study applies the eMACS concept to the 71 deg2 area extended by the 10 fields of the Pan-STARRS1 (PS1) Medium Deep Survey (MDS). Candidate clusters are identified by visual inspection of PS1 images in the g, r, i and z bands in a 5 × 5 arcmin2 region around X-ray sources detected in the ROSAT All-Sky Survey (RASS). To test and optimize the eMACS X-ray selection criteria, our pilot study uses the largest possible RASS data base, i.e. all RASS sources listed in the Bright and Faint Source Catalogues (BSC and FSC) that fall within the MDS footprint. We apply no additional constraints regarding X-ray flux, spectral hardness ratio or photon statistics and lower the redshift threshold to z > 0.3 to extend the probed luminosity range to poorer systems. Scrutiny of PS1/MDS images for 41 BSC and 200 FSC sources combined with dedicated spectroscopic follow-up observations results in a sample of 11 clusters with estimated or spectroscopic redshifts of z > 0.3. In order to assess and quantify the degree of point source contamination of the observed RASS fluxes, we examine archival Chandra data obtained in targeted and serendipitous observations of six of the 11 clusters found. As expected, the diffuse emission from all six systems is contaminated by point sources to some degree, and for half of them active galactic nucleus emission dominates. X-ray follow-up observations will thus be crucial in order to establish robust cluster luminosities for eMACS clusters. Although the small number of distant X-ray luminous clusters in the MDS does not allow us to make firm predictions for the over 20 000 deg2 of extragalactic sky covered by eMACS, the identification of two extremely promising eMACS cluster candidates at z ≳ 0.6 (both yet to be observed with Chandra) in such a small solid angle is encouraging

  5. VizieR Online Data Catalog: Fornax Cluster Spectroscopic Survey 2MASS galaxies (Morris+ 2007)

    NASA Astrophysics Data System (ADS)

    Morris, R. A. H.; Phillipps, S.; Jones, J. B.; Drinkwater, M. J.; Gregg, M. D.; Couch, W. J.; Parker, Q. A.; Smith, R. M.

    2007-09-01

    We present two tables, the results of matching the Fornax Cluster Spectroscopic Survey (FCSS) both with the 2MASS extended source catalogue (XSC) and the 2MASS point source catalogue (PSC, Cat. II/246). The 2MASS 2nd release data described in Jarrett et al. (2000AJ....119.2498J) is used in this paper. xsc-fcss.dat contains 114 extended objects in a circle of radius 1degree centred on NGC1399, 84 are matched in the FCSS itself using a positional error of 3", 28 are in the brighter FLAIR sample of Drinkwater et al. (2001ApJ...548L.139D) and two are 15th magnitude galaxies in the Ferguson (1989AJ.....98..367F, Cat. ) Fornax Cluster Catalogue (FCC). psc-fcss.dat contains objects that are in the 2MASS PSC and also in the FCSS again using a positional error of 3". Objects with cz of less than 900km/s are removed as are objects which are also in the extended sample above to leave a sample of 228 confirmed galaxies. (2 data files).

  6. The Role of Environment in Shaping Galaxy Evolution at High Redshift: Insights from the SpARCS Cluster Survey

    NASA Astrophysics Data System (ADS)

    Wilson, Gillian

    2015-08-01

    Between z = 2 and z = 1, the main progenitors of present-day massive clusters undergo rapid collapse, and cluster members transform from active star-forming to quiescent galaxies. The SpARCS survey is one of the largest surveys designed to detect clusters of galaxies at z> 1, and has discovered hundreds of Spitzer IR-selected clusters.I will present results from GCLASS, a 25-night Gemini/GMOS spectroscopic follow-up survey of ten of the most massive SpARCS clusters at z~1, and explain what we are learning about quenching and stellar mass assembly of galaxies in these, the densest of environments, relative to the field population. I will explain how predictions and observations of the stellar mass growth of Brightest Cluster Galaxies, previously controversially divergent, are now coming into agreement, and discuss the evidence for the relative importance of mergers versus in-situ star formation in driving this stellar mass growth as a function of redshift.I will also present a sample of newly-confirmed clusters at z~2 for which we have HST spectroscopy and imaging, and have been targeting with Keck/MOSFIRE. I will conclude by discussing GOGREEN and DEEPDRILL, two new large surveys approved by Gemini & Spitzer, designed to study the effects of environment at lower stellar mass and at higher redshift, respectively. Collectively, these powerful new surveys are beginning to allow us to place constraints on the location and timescale of quenching and, in concert with both hydro-simulations and semi-analytic models, identify the complex role of environment in shaping galaxy evolution over cosmic time.

  7. The extended ROSAT-ESO flux limited X-ray galaxy cluster survey (REFLEX II) II. Construction and properties of the survey

    NASA Astrophysics Data System (ADS)

    Böhringer, H.; Chon, G.; Collins, C. A.; Guzzo, L.; Nowak, N.; Bobrovskyi, S.

    2013-07-01

    Context. Galaxy clusters provide unique laboratories to study astrophysical processes on large scales and are important probes for cosmology. X-ray observations are currently the best means of detecting and characterizing galaxy clusters. Therefore X-ray surveys for galaxy clusters are one of the best ways to obtain a statistical census of the galaxy cluster population. Aims: In this paper we describe the construction of the REFLEX II galaxy cluster survey based on the southern part of the ROSAT All-Sky Survey. REFLEX II extends the REFLEX I survey by a factor of about two down to a flux limit of 1.8 × 10-12 erg s cm (0.1-2.4 keV). Methods: We describe the determination of the X-ray parameters, the process of X-ray source identification, and the construction of the survey selection function. Results: The REFLEX II cluster sample comprises currently 915 objects. A standard selection function is derived for a lower source count limit of 20 photons in addition to the flux limit. The median redshift of the sample is z = 0.102. Internal consistency checks and the comparison to several other galaxy cluster surveys imply that REFLEX II is better than 90% complete with a contamination less than 10%. Conclusions: With this publication we give a comprehensive statistical description of the REFLEX II survey and provide all the complementary information necessary for a proper modeling of the survey for astrophysical and cosmological applications. Based on observations at the European Southern Observatory La Silla, ChileFull Tables 2 and 3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/555/A30

  8. The SLUGGS survey: the globular cluster systems of three early-type galaxies using wide-field imaging

    NASA Astrophysics Data System (ADS)

    Kartha, Sreeja S.; Forbes, Duncan A.; Spitler, Lee R.; Romanowsky, Aaron J.; Arnold, Jacob A.; Brodie, Jean P.

    2014-01-01

    We present the results from a wide-field imaging study of globular cluster (GC) systems in three early-type galaxies. Combinations of Subaru/Suprime-Cam, Canada-France-Hawaii Telescope/MegaCam and Hubble Space Telescope/Wide Field Planetary Camera 2/Advanced Camera for Surveys data were used to determine the GC system properties of three highly flattened galaxies NGC 720, NGC 1023 and NGC 2768. This work is the first investigation of the GC system in NGC 720 and NGC 2768 to very large galactocentric radius (˜100 kpc). The three galaxies have clear blue and red GC subpopulations. The radial surface densities of the GC systems are fitted with Sérsic profiles, and detected out to 15, 8 and 10 galaxy effective radii, respectively. The total number of GCs and specific frequency are determined for each GC system. The ellipticity of the red subpopulation is in better agreement with the host galaxy properties than is the blue subpopulation, supporting the traditional view that metal-rich GCs are closely associated with the bulk of their host galaxies' field stars, while metal-poor GCs reflect a distinct stellar halo. With the addition of another 37 literature studied galaxies, we present a new correlation of GC system extent with host galaxy effective radius. We find a dependence of the relative fraction of blue to red GCs on host galaxy environmental density for lenticular galaxies (but not for elliptical or spiral galaxies). We propose that tidal interactions between galaxies in cluster environments might be the reason behind the observed trend for lenticular galaxies.

  9. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: single-probe measurements from CMASS anisotropic galaxy clustering

    NASA Astrophysics Data System (ADS)

    Chuang, Chia-Hsun; Prada, Francisco; Pellejero-Ibanez, Marcos; Beutler, Florian; Cuesta, Antonio J.; Eisenstein, Daniel J.; Escoffier, Stephanie; Ho, Shirley; Kitaura, Francisco-Shu; Kneib, Jean-Paul; Manera, Marc; Nuza, Sebastián E.; Rodríguez-Torres, Sergio; Ross, Ashley; Rubiño-Martín, J. A.; Samushia, Lado; Schlegel, David J.; Schneider, Donald P.; Wang, Yuting; Weaver, Benjamin A.; Zhao, Gongbo; Brownstein, Joel R.; Dawson, Kyle S.; Maraston, Claudia; Olmstead, Matthew D.; Thomas, Daniel

    2016-10-01

    With the largest spectroscopic galaxy survey volume drawn from the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), we can extract cosmological constraints from the measurements of redshift and geometric distortions at quasi-linear scales (e.g. above 50 h-1 Mpc). We analyse the broad-range shape of the monopole and quadrupole correlation functions of the BOSS Data Release 12 (DR12) CMASS galaxy sample, at the effective redshift z = 0.59, to obtain constraints on the Hubble expansion rate H(z), the angular- diameter distance DA(z), the normalized growth rate f(z)σ8(z), and the physical matter density Ωm h2. We obtain robust measurements by including a polynomial as the model for the systematic errors, and find it works very well against the systematic effects, e.g. ones induced by stars and seeing. We provide accurate measurements {DA(0.59)rs,fid/rs, H(0.59)rs/rs,fid, f(0.59)σ8(0.59), Ωm h2} = {1427 ± 26 Mpc, 97.3 ± 3.3 km s-1 Mpc-1, 0.488 ± 0.060, 0.135 ± 0.016}, where rs is the comoving sound horizon at the drag epoch and rs,fid = 147.66 Mpc is the sound scale of the fiducial cosmology used in this study. The parameters which are not well constrained by our galaxy clustering analysis are marginalized over with wide flat priors. Since no priors from other data sets, e.g. cosmic microwave background (CMB), are adopted and no dark energy models are assumed, our results from BOSS CMASS galaxy clustering alone may be combined with other data sets, i.e. CMB, SNe, lensing or other galaxy clustering data to constrain the parameters of a given cosmological model. The uncertainty on the dark energy equation of state parameter, w, from CMB+CMASS is about 8 per cent. The uncertainty on the curvature fraction, Ωk, is 0.3 per cent. We do not find deviation from flat ΛCDM.

  10. Dynamics of cD Clusters of Galaxies. 4; Conclusion of a Survey of 25 Abell Clusters

    NASA Technical Reports Server (NTRS)

    Oegerle, William R.; Hill, John M.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    We present the final results of a spectroscopic study of a sample of cD galaxy clusters. The goal of this program has been to study the dynamics of the clusters, with emphasis on determining the nature and frequency of cD galaxies with peculiar velocities. Redshifts measured with the MX Spectrometer have been combined with those obtained from the literature to obtain typically 50 - 150 observed velocities in each of 25 galaxy clusters containing a central cD galaxy. We present a dynamical analysis of the final 11 clusters to be observed in this sample. All 25 clusters are analyzed in a uniform manner to test for the presence of substructure, and to determine peculiar velocities and their statistical significance for the central cD galaxy. These peculiar velocities were used to determine whether or not the central cD galaxy is at rest in the cluster potential well. We find that 30 - 50% of the clusters in our sample possess significant subclustering (depending on the cluster radius used in the analysis), which is in agreement with other studies of non-cD clusters. Hence, the dynamical state of cD clusters is not different than other present-day clusters. After careful study, four of the clusters appear to have a cD galaxy with a significant peculiar velocity. Dressler-Shectman tests indicate that three of these four clusters have statistically significant substructure within 1.5/h(sub 75) Mpc of the cluster center. The dispersion 75 of the cD peculiar velocities is 164 +41/-34 km/s around the mean cluster velocity. This represents a significant detection of peculiar cD velocities, but at a level which is far below the mean velocity dispersion for this sample of clusters. The picture that emerges is one in which cD galaxies are nearly at rest with respect to the cluster potential well, but have small residual velocities due to subcluster mergers.

  11. The VIMOS-VLT Deep Survey. The evolution of galaxy clustering per spectral type to z ≃ 1.5

    NASA Astrophysics Data System (ADS)

    Meneux, B.; Le Fèvre, O.; Guzzo, L.; Pollo, A.; Cappi, A.; Ilbert, O.; Iovino, A.; Marinoni, C.; McCracken, H. J.; Bottini, D.; Garilli, B.; Le Brun, V.; Maccagni, D.; Picat, J. P.; Scaramella, R.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnouts, S.; Arnaboldi, M.; Bardelli, S.; Bolzonella, M.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Franzetti, P.; Gavignaud, I.; Marano, B.; Mazure, A.; Merighi, R.; Paltani, S.; Pellò, R.; Pozzetti, L.; Radovich, M.; Zamorani, G.; Zucca, E.; Bondi, M.; Bongiorno, A.; Busarello, G.; Cucciati, O.; Gregorini, L.; Lamareille, F.; Mathez, G.; Mellier, Y.; Merluzzi, P.; Ripepi, V.; Rizzo, D.

    2006-06-01

    We measure the evolution of clustering for galaxies with different spectral types from 6495 galaxies with 17.5 ≤ IAB ≤ 24 and measured spectroscopic redshifts in the first epoch VIMOS-VLT Deep Survey (VVDS). We divide our sample into four classes, based on the fit of well-defined galaxy spectral energy distributions on observed multi-color data. We measure the projected correlation function w_p(r_p) and estimate the best-fit parameters for a power-law real-space correlation function ξ(r) = (r/r_0)-γ. We find the clustering of early-spectral-type galaxies to be markedly stronger than that of late-type galaxies at all redshifts up to z≃1.2. At z˜ 0.8 , early-type galaxies display a correlation length r_0=4.8 ±0.9 h-1 Mpc, while late types have r_0=2.5 ± 0.4 h-1 Mpc. For the latest class of star-forming blue galaxies, we are able to push our clustering measurement to an effective redshift z˜ 1.4, for luminous galaxies (M_B(AB)≃ -21). The clustering of these objects increases up to r_0=3.42 ± 0.7 h-1 Mpc for z=[1.2,2.0]. The relative bias between early- and late-type galaxies within our magnitude-limited survey remains approximately constant with b=1.6 ± 0.3 from z=0 to z=1.2. This result is in agrement with the local findings and fairly robust against different way of classifying red and blue galaxies. When compared to the expected linear growth of mass fluctuations, a natural interpretation of these observations is that: (a) the assembly of massive early type galaxies is already mostly complete in the densest dark matter halos at z≃1; (b) luminous late-type galaxies are located in higher-density, more clustered regions of the Universe at z≃1.5 than their local low luminous counterpart, indicating that star formation activity is progressively increasing, going back in time, in the higher-density peaks that today are mostly dominated by old galaxies.

  12. HOMOGENEOUS UGRIZ PHOTOMETRY FOR ACS VIRGO CLUSTER SURVEY GALAXIES: A NON-PARAMETRIC ANALYSIS FROM SDSS IMAGING

    SciTech Connect

    Chen, Chin-Wei; Cote, Patrick; Ferrarese, Laura; West, Andrew A.; Peng, Eric W.

    2010-11-15

    We present photometric and structural parameters for 100 ACS Virgo Cluster Survey (ACSVCS) galaxies based on homogeneous, multi-wavelength (ugriz), wide-field SDSS (DR5) imaging. These early-type galaxies, which trace out the red sequence in the Virgo Cluster, span a factor of nearly {approx}10{sup 3} in g-band luminosity. We describe an automated pipeline that generates background-subtracted mosaic images, masks field sources and measures mean shapes, total magnitudes, effective radii, and effective surface brightnesses using a model-independent approach. A parametric analysis of the surface brightness profiles is also carried out to obtain Sersic-based structural parameters and mean galaxy colors. We compare the galaxy parameters to those in the literature, including those from the ACSVCS, finding good agreement in most cases, although the sizes of the brightest, and most extended, galaxies are found to be most uncertain and model dependent. Our photometry provides an external measurement of the random errors on total magnitudes from the widely used Virgo Cluster Catalog, which we estimate to be {sigma}(B{sub T}){approx} 0.13 mag for the brightest galaxies, rising to {approx} 0.3 mag for galaxies at the faint end of our sample (B{sub T} {approx} 16). The distribution of axial ratios of low-mass ('dwarf') galaxies bears a strong resemblance to the one observed for the higher-mass ('giant') galaxies. The global structural parameters for the full galaxy sample-profile shape, effective radius, and mean surface brightness-are found to vary smoothly and systematically as a function of luminosity, with unmistakable evidence for changes in structural homology along the red sequence. As noted in previous studies, the ugriz galaxy colors show a nonlinear but smooth variation over a {approx}7 mag range in absolute magnitude, with an enhanced scatter for the faintest systems that is likely the signature of their more diverse star formation histories.

  13. Homogeneous UGRIZ Photometry for ACS Virgo Cluster Survey Galaxies: A Non-parametric Analysis from SDSS Imaging

    NASA Astrophysics Data System (ADS)

    Chen, Chin-Wei; Côté, Patrick; West, Andrew A.; Peng, Eric W.; Ferrarese, Laura

    2010-11-01

    We present photometric and structural parameters for 100 ACS Virgo Cluster Survey (ACSVCS) galaxies based on homogeneous, multi-wavelength (ugriz), wide-field SDSS (DR5) imaging. These early-type galaxies, which trace out the red sequence in the Virgo Cluster, span a factor of nearly ~103 in g-band luminosity. We describe an automated pipeline that generates background-subtracted mosaic images, masks field sources and measures mean shapes, total magnitudes, effective radii, and effective surface brightnesses using a model-independent approach. A parametric analysis of the surface brightness profiles is also carried out to obtain Sérsic-based structural parameters and mean galaxy colors. We compare the galaxy parameters to those in the literature, including those from the ACSVCS, finding good agreement in most cases, although the sizes of the brightest, and most extended, galaxies are found to be most uncertain and model dependent. Our photometry provides an external measurement of the random errors on total magnitudes from the widely used Virgo Cluster Catalog, which we estimate to be σ(BT )≈ 0.13 mag for the brightest galaxies, rising to ≈ 0.3 mag for galaxies at the faint end of our sample (BT ≈ 16). The distribution of axial ratios of low-mass ("dwarf") galaxies bears a strong resemblance to the one observed for the higher-mass ("giant") galaxies. The global structural parameters for the full galaxy sample—profile shape, effective radius, and mean surface brightness—are found to vary smoothly and systematically as a function of luminosity, with unmistakable evidence for changes in structural homology along the red sequence. As noted in previous studies, the ugriz galaxy colors show a nonlinear but smooth variation over a ~7 mag range in absolute magnitude, with an enhanced scatter for the faintest systems that is likely the signature of their more diverse star formation histories.

  14. Color and magnitude dependence of galaxy clustering

    NASA Astrophysics Data System (ADS)

    Müller, Volker

    2016-10-01

    A quantitative study of the clustering properties of galaxies in the cosmic web as a function of absolute magnitude and colour is presented using the SDSS Data Release 7 galaxy redshift survey. We compare our results with mock galaxy samples obtained with four different semi-analytical models of galaxy formation imposed on the merger trees of the Millenium simulation.

  15. Clusters of Galaxies

    NASA Astrophysics Data System (ADS)

    Huchtmeier, W. K.; Richter, O. G.; Materne, J.

    1981-09-01

    The large-scale structure of the universe is dominated by clustering. Most galaxies seem to be members of pairs, groups, clusters, and superclusters. To that degree we are able to recognize a hierarchical structure of the universe. Our local group of galaxies (LG) is centred on two large spiral galaxies: the Andromeda nebula and our own galaxy. Three sr:naller galaxies - like M 33 - and at least 23 dwarf galaxies (KraanKorteweg and Tammann, 1979, Astronomische Nachrichten, 300, 181) can be found in the evironment of these two large galaxies. Neighbouring groups have comparable sizes (about 1 Mpc in extent) and comparable numbers of bright members. Small dwarf galaxies cannot at present be observed at great distances.

  16. THE SLOAN DIGITAL SKY SURVEY CO-ADD: CROSS-CORRELATION WEAK LENSING AND TOMOGRAPHY OF GALAXY CLUSTERS

    SciTech Connect

    Simet, Melanie; Dodelson, Scott; Kubo, Jeffrey M.; Annis, James T.; Hao Jiangang; Johnston, David; Lin, Huan; Soares-Santos, Marcelle; Reis, Ribamar R. R.; Seo, Hee-Jong

    2012-04-01

    The shapes of distant galaxies are sheared by intervening galaxy clusters. We examine this effect in Stripe 82, a 275 deg{sup 2} region observed multiple times in the Sloan Digital Sky Survey (SDSS) and co-added to achieve greater depth. We obtain a mass-richness calibration that is similar to other SDSS analyses, demonstrating that the co-addition process did not adversely affect the lensing signal. We also propose a new parameterization of the effect of tomography on the cluster lensing signal which does not require binning in redshift, and we show that using this parameterization we can detect tomography for stacked clusters at varying redshifts. Finally, due to the sensitivity of the tomographic detection to accurately marginalize over the effect of the cluster mass, we show that tomography at low redshift (where dependence on exact cosmological models is weak) can be used to constrain mass profiles in clusters.

  17. The SLUGGS Survey: A Catalog of Over 4000 Globular Cluster Radial Velocities in 27 Nearby Early-type Galaxies

    NASA Astrophysics Data System (ADS)

    Forbes, Duncan A.; Alabi, Adebusola; Brodie, Jean P.; Romanowsky, Aaron J.; Strader, Jay; Foster, Caroline; Usher, Christopher; Spitler, Lee; Bellstedt, Sabine; Pastorello, Nicola; Villaume, Alexa; Wasserman, Asher; Pota, Vincenzo

    2017-03-01

    Here, we present positions and radial velocities for over 4000 globular clusters (GCs) in 27 nearby early-type galaxies from the SLUGGS survey. The SLUGGS survey is designed to be representative of elliptical and lenticular galaxies in the stellar mass range 10 < log {M}* /M ⊙ < 11.7. The data have been obtained over many years, mostly using the very stable multi-object spectrograph DEIMOS on the Keck II 10 m telescope. Radial velocities are measured using the calcium triplet lines, with a velocity accuracy of ±10–15 km s‑1. We use phase space diagrams (i.e., velocity–position diagrams) to identify contaminants such as foreground stars and background galaxies, and to show that the contribution of GCs from neighboring galaxies is generally insignificant. Likely ultra-compact dwarfs are tabulated separately. We find that the mean velocity of the GC system is close to that of the host galaxy systemic velocity, indicating that the GC system is in overall dynamical equilibrium within the galaxy potential. We also find that the GC system velocity dispersion scales with host galaxy stellar mass, in a similar manner to the Faber–Jackson relation for the stellar velocity dispersion. Publication of these GC radial velocity catalogs should enable further studies in many areas, such as GC system substructure, kinematics, and host galaxy mass measurements.

  18. The XXL Survey. X. K-band luminosity - weak-lensing mass relation for groups and clusters of galaxies

    NASA Astrophysics Data System (ADS)

    Ziparo, F.; Smith, G. P.; Mulroy, S. L.; Lieu, M.; Willis, J. P.; Hudelot, P.; McGee, S. L.; Fotopoulou, S.; Lidman, C.; Lavoie, S.; Pierre, M.; Adami, C.; Chiappetti, L.; Clerc, N.; Giles, P.; Maughan, B.; Pacaud, F.; Sadibekova, T.

    2016-06-01

    Galaxy clusters and groups are important cosmological probes and giant cosmic laboratories for studying galaxy evolution. Much effort has been devoted to understanding how and when baryonic matter cools at the centre of potential wells. However, a clear picture of the efficiency with which baryons are converted into stars is still missing. We present the K-band luminosity-halo mass relation, LK,500-M500,WL, for a subsample of 20 of the 100 brightest clusters in the XXL Survey observed with WIRCam at the Canada-France-Hawaii Telescope (CFHT). For the first time, we have measured this relation via weak-lensing analysis down to M500,WL = 3.5 × 1013 M⊙. This allows us to investigate whether the slope of the LK-M relation is different for groups and clusters, as seen in other works. The clusters in our sample span a wide range in mass, M500,WL = 0.35-12.10 × 1014 M⊙, at 0 < z < 0.6. The K-band luminosity scales as log 10(LK,500/ 1012 L⊙) ∝ βlog 10(M500,WL/ 1014 M⊙) with β = 0.85+0.35-0.27 and an intrinsic scatter of σlnLK|M = 0.37+0.19-0.17. Combining our sample with some clusters in the Local Cluster Substructure Survey (LoCuSS) present in the literature, we obtain a slope of 1.05+0.16-0.14 and an intrinsic scatter of 0.14+0.09-0.07. The flattening in the LK-M seen in previous works is not seen here and might be a result of a bias in the mass measurement due to assumptions on the dynamical state of the systems. We also study the richness-mass relation and find that group-sized halos have more galaxies per unit halo mass than massive clusters. However, the brightest cluster galaxy (BCG) in low-mass systems contributes a greater fraction to the total cluster light than BCGs do in massive clusters; the luminosity gap between the two brightest galaxies is more prominent for group-sized halos. This result is a natural outcome of the hierarchical growth of structures, where massive galaxies form and gain mass within low-mass groups and are ultimately accreted

  19. Constraining neutrino properties with a Euclid-like galaxy cluster survey

    SciTech Connect

    Cerbolini, M. Costanzi Alunno; Sartoris, B.; Borgani, S.; Xia, Jun-Qing; Biviano, A.; Viel, M. E-mail: sartoris@oats.inaf.it E-mail: borgani@oats.inaf.it E-mail: biviano@oats.inaf.it

    2013-06-01

    We perform a forecast analysis on how well a Euclid-like photometric galaxy cluster survey will constrain the total neutrino mass and effective number of neutrino species. We base our analysis on the Monte Carlo Markov Chains technique by combining information from cluster number counts and cluster power spectrum. We find that combining cluster data with Cosmic Microwave Background (CMB) measurements from Planck improves by more than an order of magnitude the constraint on neutrino masses compared to each probe used independently. For the ΛCDM+m{sub ν} model the 2σ upper limit on total neutrino mass shifts from Σm{sub ν} < 0.35 eV using cluster data alone to Σm{sub ν} < 0.031 eV when combined with Planck data. When a non-standard scenario with N{sub eff}≠3.046 number of neutrino species is considered, we estimate an upper limit of N{sub eff} < 3.14 (95%CL), while the bounds on neutrino mass are relaxed to Σm{sub ν} < 0.040 eV. This accuracy would be sufficient for a 2σ detection of neutrino mass even in the minimal normal hierarchy scenario (Σm{sub ν} ≅ 0.05 eV). In addition to the extended ΛCDM+m{sub ν}+N{sub eff} model we also consider scenarios with a constant dark energy equation of state and a non-vanishing curvature. When these models are considered the error on Σm{sub ν} is only slightly affected, while there is a larger impact of the order of ∼ 15% and ∼ 20% respectively on the 2σ error bar of N{sub eff} with respect to the standard case. To assess the effect of an uncertain knowledge of the relation between cluster mass and optical richness, we also treat the ΛCDM+m{sub ν}+N{sub eff} case with free nuisance parameters, which parameterize the uncertainties on the cluster mass determination. Adopting the over-conservative assumption of no prior knowledge on the nuisance parameter the loss of information from cluster number counts leads to a large degradation of neutrino constraints. In particular, the upper bounds for Σm{sub

  20. Galaxy evolution in clusters since z~1

    NASA Astrophysics Data System (ADS)

    Aragon-Salamanca, Alfonso

    2010-09-01

    Galaxy clusters provide some of the most extreme environments in which galaxies evolve, making them excellent laboratories to study the age old question of "nature" vs. "nurture" in galaxy evolution. Here I review some of the key observational results obtained during the last decade on the evolution of the morphology, structure, dynamics, star-formation history and stellar populations of cluster galaxies since the time when the universe was half its present age. Many of the results presented here have been obtained within the ESO Distant Cluster Survey (EDisCS) and Space Telescope A901/02 Galaxy Evolution Survey (STAGES) collaborations.

  1. Galaxy Evolution in Clusters Since z ~ 1

    NASA Astrophysics Data System (ADS)

    Aragón-Salamanca, A.

    Galaxy clusters provide some of the most extreme environments in which galaxies evolve, making them excellent laboratories to study the age old question of "nature" vs. "nurture" in galaxy evolution. Here I review some of the key observational results obtained during the last decade on the evolution of the morphology, structure, dynamics, star-formation history and stellar populations of cluster galaxies since the time when the Universe was half its present age. Many of the results presented here have been obtained within the ESO Distant Cluster Survey (EDisCS) and Space Telescope A901/02 Galaxy Evolution Survey (STAGES) collaborations.

  2. ACS Nearby Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Dalcanton, Julianne

    2006-07-01

    Existing HST observations of nearby galaxies comprise a sparse and highly non-uniform archive, making comprehensive comparative studies among galaxies essentially impossible. We propose to secure HST's lasting impact on the study of nearby galaxies by undertaking a systematic, complete, and carefully crafted imaging survey of ALL galaxies in the Local Universe outside the Local Group. The resulting images will allow unprecedented measurements of: {1} the star formation history {SFH} of a >100 Mpc^3 volume of the Universe with a time resolution of Delta[log{t}]=0.25; {2} correlations between spatially resolved SFHs and environment; {3} the structure and properties of thick disks and stellar halos; and {4} the color distributions, sizes, and specific frequencies of globular and disk clusters as a function of galaxy mass and environment. To reach these goals, we will use a combination of wide-field tiling and pointed deep imaging to obtain uniform data on all 72 galaxies within a volume-limited sample extending to 3.5 Mpc, with an extension to the M81 group. For each galaxy, the wide-field imaging will cover out to 1.5 times the optical radius and will reach photometric depths of at least 2 magnitudes below the tip of the red giant branch throughout the limits of the survey volume. One additional deep pointing per galaxy will reach SNR 10 for red clump stars, sufficient to recover the ancient SFH from the color-magnitude diagram. This proposal will produce photometric information for 100 million stars {comparable to the number in the SDSS survey} and uniform multi-color images of half a square degree of sky. The resulting archive will establish the fundamental optical database for nearby galaxies, in preparation for the shift of high-resolution imaging to the near-infrared.

  3. The Massive and Distant Clusters of WISE Survey (MaDCoWS): Stellar mass fractions in a sample of infrared-selected galaxy clusters at z~1

    NASA Astrophysics Data System (ADS)

    Decker, Bandon; Brodwin, Mark

    2017-01-01

    Galaxy clusters are the largest gravitationally bound objects in the universe. In addition to being interesting objects in their own right, they are excellent laboratories in which to study galaxy evolution and the properties and abundance of galaxy clusters provide important tests for cosmology. The Massive and Distant Clusters of WISE Survey (MaDCoWS) is a high-redshift (z~1) survey that selects galaxy clusters in the infrared over nearly the full extragalactic sky using the Wide-field Infrared Survey Explorer (WISE) AllWISE data release. We have measured Sunyaev-Zel'dovich (SZ) masses for twelve of the MaDCoWS clusters lying in the range 0.9 < z <1.3 using the Combined Array for Research in Millimeter-wave Astronomy (CARMA) and used follow-up Spitzer/IRAC rest-frame near-infrared observations to measure the stellar mass of these clusters. With these data, we have measured the stellar mass fraction, f_star, and it's relation to total mass for a sample of infrared-selected clusters at z~1. We repeated our analysis of stellar mass fraction on a sample of SZ-selected clusters from the South Pole Telescope (SPT)-SZ survey that lie in a comparable range of mass and redshift to our MaDCoWS clusters to compare the selection methods. We found no significant difference in the trend of stellar mass fraction-to-total mass between infrared and radio selections. Comparing to similar measurements in the local Universe, we find no evidence of strong evolution in the trend over the last 8 Gyr.

  4. Spectroscopic Confirmation of a Massive Red-sequence Selected Galaxy Cluster at Z=1.34 in the SpARCS-South Cluster Survey

    NASA Technical Reports Server (NTRS)

    Wilson, Gillian; Demarco, Ricardo; Muzzin, Adam; Yee, H.K.C.; Lacy, Mark; Surace, Jason; Gilbank, David; Blindert, Kris; Hoekstra, Henk; Majumdar, Subhabrata; Gardner, Jonathan P; Gladders, Michael D.; Lonsdale, Carol

    2008-01-01

    The Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a z'-passband imaging survey, consisting of deep (z' approx. 24 AB) observations made from both hemispheres using the CFHT 3.6m and CTIO 4m telescopes. The survey was designed with the primary aim of detecting galaxy clusters at z > 1. In tandem with pre-existing 3.6 micron observations from the Spitzer Space Telescope SWIRE Legacy Survey, SpARCS detects clusters using an infrared adaptation of the two-filter red-sequence cluster technique. The total effective area of the SpARCS cluster survey is 41.9 sq deg. In this paper, we provide an overview of the 13.6 sq deg Southern CTIO/MOSAICII observations. The 28.3 sq deg Northern CFHT/MegaCam observations are summarized in a companion paper by Muzzin et al. (2008a). In this paper, we also report spectroscopic confirmation of SpARCS J003550-431224, a very rich galaxy cluster at z = 1.335, discovered in the ELAIS-S1 field. To date, this is the highest spectroscopically confirmed redshift for a galaxy cluster discovered using the red-sequence technique. Based on nine confirmed members, SpARCS J003550-431224 has a preliminary velocity dispersion of 1050+/-230 km/s. With its proven capability for efficient cluster detection, SpARCS is a demonstration that we have entered an era of large, homogeneously-selected z > 1 cluster surveys.

  5. Optical spectroscopy and velocity dispersions of galaxy clusters from the SPT-SZ survey

    SciTech Connect

    Ruel, J.; Bayliss, M.; Bazin, G.; Bocquet, S.; Brodwin, M.; Foley, R. J.; Stalder, B.; Ashby, M. L. N.; Aird, K. A.; Armstrong, R.; Bautz, M.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T.; Chapman, S. C.; Cho, H. M.; Clocchiatti, A.; and others

    2014-09-01

    We present optical spectroscopy of galaxies in clusters detected through the Sunyaev-Zel'dovich (SZ) effect with the South Pole Telescope (SPT). We report our own measurements of 61 spectroscopic cluster redshifts, and 48 velocity dispersions each calculated with more than 15 member galaxies. This catalog also includes 19 dispersions of SPT-observed clusters previously reported in the literature. The majority of the clusters in this paper are SPT-discovered; of these, most have been previously reported in other SPT cluster catalogs, and five are reported here as SPT discoveries for the first time. By performing a resampling analysis of galaxy velocities, we find that unbiased velocity dispersions can be obtained from a relatively small number of member galaxies (≲ 30), but with increased systematic scatter. We use this analysis to determine statistical confidence intervals that include the effect of membership selection. We fit scaling relations between the observed cluster velocity dispersions and mass estimates from SZ and X-ray observables. In both cases, the results are consistent with the scaling relation between velocity dispersion and mass expected from dark-matter simulations. We measure a ∼30% log-normal scatter in dispersion at fixed mass, and a ∼10% offset in the normalization of the dispersion-mass relation when compared to the expectation from simulations, which is within the expected level of systematic uncertainty.

  6. Coma cluster of galaxies

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Atlas Image mosaic, covering 34' x 34' on the sky, of the Coma cluster, aka Abell 1656. This is a particularly rich cluster of individual galaxies (over 1000 members), most prominently the two giant ellipticals, NGC 4874 (right) and NGC 4889 (left). The remaining members are mostly smaller ellipticals, but spiral galaxies are also evident in the 2MASS image. The cluster is seen toward the constellation Coma Berenices, but is actually at a distance of about 100 Mpc (330 million light years, or a redshift of 0.023) from us. At this distance, the cluster is in what is known as the 'Hubble flow,' or the overall expansion of the Universe. As such, astronomers can measure the Hubble Constant, or the universal expansion rate, based on the distance to this cluster. Large, rich clusters, such as Coma, allow astronomers to measure the 'missing mass,' i.e., the matter in the cluster that we cannot see, since it gravitationally influences the motions of the member galaxies within the cluster. The near-infrared maps the overall luminous mass content of the member galaxies, since the light at these wavelengths is dominated by the more numerous older stellar populations. Galaxies, as seen by 2MASS, look fairly smooth and homogeneous, as can be seen from the Hubble 'tuning fork' diagram of near-infrared galaxy morphology. Image mosaic by S. Van Dyk (IPAC).

  7. THE EVOLUTION OF DUSTY STAR FORMATION IN GALAXY CLUSTERS TO z = 1: SPITZER INFRARED OBSERVATIONS OF THE FIRST RED-SEQUENCE CLUSTER SURVEY

    SciTech Connect

    Webb, T. M. A.; O'Donnell, D.; Coppin, Kristen; Faloon, Ashley; Geach, James E.; Noble, Allison; Yee, H. K. C.; Gilbank, David; Ellingson, Erica; Gladders, Mike; Muzzin, Adam; Wilson, Gillian; Yan, Renbin

    2013-10-01

    We present the results of an infrared (IR) study of high-redshift galaxy clusters with the MIPS camera on board the Spitzer Space Telescope. We have assembled a sample of 42 clusters from the Red-Sequence Cluster Survey-1 over the redshift range 0.3 < z < 1.0 and spanning an approximate range in mass of 10{sup 14-15} M {sub ☉}. We statistically measure the number of IR-luminous galaxies in clusters above a fixed inferred IR luminosity of 2 × 10{sup 11} M {sub ☉}, assuming a star forming galaxy template, per unit cluster mass and find it increases to higher redshift. Fitting a simple power-law we measure evolution of (1 + z){sup 5.1±1.9} over the range 0.3 < z < 1.0. These results are tied to the adoption of a single star forming galaxy template; the presence of active galactic nuclei, and an evolution in their relative contribution to the mid-IR galaxy emission, will alter the overall number counts per cluster and their rate of evolution. Under the star formation assumption we infer the approximate total star formation rate per unit cluster mass (ΣSFR/M {sub cluster}). The evolution is similar, with ΣSFR/M {sub cluster} ∼ (1 + z){sup 5.4±1.9}. We show that this can be accounted for by the evolution of the IR-bright field population over the same redshift range; that is, the evolution can be attributed entirely to the change in the in-falling field galaxy population. We show that the ΣSFR/M {sub cluster} (binned over all redshift) decreases with increasing cluster mass with a slope (ΣSFR/M{sub cluster}∼M{sub cluster}{sup -1.5±0.4}) consistent with the dependence of the stellar-to-total mass per unit cluster mass seen locally. The inferred star formation seen here could produce ∼5%-10% of the total stellar mass in massive clusters at z = 0, but we cannot constrain the descendant population, nor how rapidly the star-formation must shut-down once the galaxies have entered the cluster environment. Finally, we show a clear decrease in the number of IR

  8. THE MASSIVE AND DISTANT CLUSTERS OF WISE SURVEY: MOO J1142+1527, A 10{sup 15}M{sub ⊙} GALAXY CLUSTER AT z = 1.19

    SciTech Connect

    Gonzalez, Anthony H.; Gettings, Daniel P.; Decker, Bandon; Brodwin, Mark; Eisenhardt, Peter R. M.; Stern, Daniel; Marrone, Daniel P.; Greer, Christopher H.; Stanford, S. A.; Wylezalek, Dominika; Aldering, Greg; Boone, Kyle; Fagrelius, Parker; Hayden, Brian; Abdulla, Zubair; Carlstrom, John; Leitch, Erik M.; Lin, Yen-Ting; Mantz, Adam B.; Muchovej, Stephen; and others

    2015-10-20

    We present confirmation of the cluster MOO J1142+1527, a massive galaxy cluster discovered as part of the Massive and Distant Clusters of WISE Survey. The cluster is confirmed to lie at z = 1.19, and using the Combined Array for Research in Millimeter-wave Astronomy we robustly detect the Sunyaev–Zel’dovich (SZ) decrement at 13.2σ. The SZ data imply a mass of M{sub 200m} = (1.1 ± 0.2) × 10{sup 15}M{sub ⊙}, making MOO J1142+1527 the most massive galaxy cluster known at z > 1.15 and the second most massive cluster known at z > 1. For a standard ΛCDM cosmology it is further expected to be one of the ∼5 most massive clusters expected to exist at z ≥ 1.19 over the entire sky. Our ongoing Spitzer program targeting ∼1750 additional candidate clusters will identify comparably rich galaxy clusters over the full extragalactic sky.

  9. A Measurement of the Rate of Type Ia Supernovae in Galaxy Clusters from the SDSS-II Supernova Survey

    SciTech Connect

    Dilday, Benjamin; Bassett, Bruce; Becker, Andrew; Bender, Ralf; Castander, Francisco; Cinabro, David; Frieman, Joshua A.; Galbany, Lluis; Garnavich, Peter; Goobar, Ariel; Hopp, Ulrich; /Munich, Tech. U. /Munich U. Observ. /Tokyo U.

    2010-03-01

    We present measurements of the Type Ia supernova (SN) rate in galaxy clusters based on data from the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. The cluster SN Ia rate is determined from 9 SN events in a set of 71 C4 clusters at z {le} 0.17 and 27 SN events in 492 maxBCG clusters at 0.1 {le} z {le} 0.3. We find values for the cluster SN Ia rate of (0.37{sub -0.12-0.01}{sup +0.17+0.01}) SNur h{sup 2} and (0.55{sub -0.11-0.01}{sup +0.13+0.02}) SNur h{sup 2} (SNux = 10{sup -12}L{sub x{circle_dot}}{sup -1} yr{sup -1}) in C4 and maxBCG clusters, respectively, where the quoted errors are statistical and systematic, respectively. The SN rate for early-type galaxies is found to be (0.31{sub -0.12-0.01}{sup +0.18+0.01}) SNur h{sup 2} and (0.49{sub -0.11-0.01}{sup +0.15+0.02}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The SN rate for the brightest cluster galaxies (BCG) is found to be (2.04{sub -1.11-0.04}{sup +1.99+0.07}) SNur h{sup 2} and (0.36{sub -0.30-0.01}{sup +0.84+0.01}) SNur h{sup 2} in C4 and maxBCG clusters, respectively. The ratio of the SN Ia rate in cluster early-type galaxies to that of the SN Ia rate in field early-type galaxies is 1.94{sub -0.91-0.015}{sup +1.31+0.043} and 3.02{sub -1.03-0.048}{sup +1.31+0.062}, for C4 and maxBCG clusters, respectively. The SN rate in galaxy clusters as a function of redshift, which probes the late time SN Ia delay distribution, shows only weak dependence on redshift. Combining our current measurements with previous measurements, we fit the cluster SN Ia rate data to a linear function of redshift, and find r{sub L} = [(0.49{sub -0.14}{sup +0.15}) + (0.91{sub -0.81}{sup +0.85}) x z] SNuB h{sup 2}. A comparison of the radial distribution of SNe in cluster to field early-type galaxies shows possible evidence for an enhancement of the SN rate in the cores of cluster early-type galaxies. With an observation of at most 3 hostless, intra-cluster SNe Ia, we estimate the fraction of cluster SNe that are

  10. A MEASUREMENT OF THE RATE OF TYPE Ia SUPERNOVAE IN GALAXY CLUSTERS FROM THE SDSS-II SUPERNOVA SURVEY

    SciTech Connect

    Dilday, Benjamin; Jha, Saurabh W.; Bassett, Bruce; Becker, Andrew; Bender, Ralf; Hopp, Ulrich; Castander, Francisco; Cinabro, David; Frieman, Joshua A.; Galbany, LluIs; Miquel, Ramon; Garnavich, Peter; Goobar, Ariel; Ihara, Yutaka; Kessler, Richard; Lampeitl, Hubert; Nichol, Robert C.; Marriner, John; Molla, Mercedes

    2010-06-01

    We present measurements of the Type Ia supernova (SN) rate in galaxy clusters based on data from the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey. The cluster SN Ia rate is determined from 9 SN events in a set of 71 C4 clusters at z {<=} 0.17 and 27 SN events in 492 maxBCG clusters at 0.1 {<=} z {<=} 0.3. We find values for the cluster SN Ia rate of (0.37{sup +0.17+0.01} {sub -0.12-0.01}) SNur h {sup 2} and (0.55{sup +0.13+0.02} {sub -0.11-0.01}) SNur h {sup 2} (SNux = 10{sup -12} L {sup -1} {sub xsun} yr{sup -1}) in C4 and maxBCG clusters, respectively, where the quoted errors are statistical and systematic, respectively. The SN rate for early-type galaxies is found to be (0.31{sup +0.18+0.01} {sub -0.12-0.01}) SNur h {sup 2} and (0.49{sup +0.15+0.02} {sub -0.11-0.01}) SNur h {sup 2} in C4 and maxBCG clusters, respectively. The SN rate for the brightest cluster galaxies (BCG) is found to be (2.04{sup +1.99+0.07} {sub -1.11-0.04}) SNur h {sup 2} and (0.36{sup +0.84+0.01} {sub -0.30-0.01}) SNur h {sup 2} in C4 and maxBCG clusters, respectively. The ratio of the SN Ia rate in cluster early-type galaxies to that of the SN Ia rate in field early-type galaxies is 1.94{sup +1.31+0.043} {sub -0.91-0.015} and 3.02{sup +1.31+0.062} {sub -1.03-0.048}, for C4 and maxBCG clusters, respectively. The SN rate in galaxy clusters as a function of redshift, which probes the late time SN Ia delay distribution, shows only weak dependence on redshift. Combining our current measurements with previous measurements, we fit the cluster SN Ia rate data to a linear function of redshift, and find r{sub L} = [(0.49{sup +0.15} {sub -0.14})+(0.91{sup +0.85} {sub -0.81}) x z] SNuB h {sup 2}. A comparison of the radial distribution of SNe in cluster to field early-type galaxies shows possible evidence for an enhancement of the SN rate in the cores of cluster early-type galaxies. With an observation of at most three hostless, intra-cluster SNe Ia, we estimate the fraction of cluster SNe

  11. Galaxies in X-ray Selected Clusters and Groups in Dark Energy Survey Data: Stellar Mass Growth of Bright Central Galaxies Since z~1.2

    DOE PAGES

    Zhang, Y.; Miller, C.; McKay, T.; ...

    2016-01-10

    Using the science verification data of the Dark Energy Survey for a new sample of 106 X-ray selected clusters and groups, we study the stellar mass growth of bright central galaxies (BCGs) since redshift z ~ 1.2. Compared with the expectation in a semi-analytical model applied to the Millennium Simulation, the observed BCGs become under-massive/under-luminous with decreasing redshift. We incorporate the uncertainties associated with cluster mass, redshift, and BCG stellar mass measurements into analysis of a redshift-dependent BCG-cluster mass relation.

  12. The VIMOS VLT deep survey. The evolution of galaxy clustering to z ≃ 2 from first epoch observations

    NASA Astrophysics Data System (ADS)

    Le Fèvre, O.; Guzzo, L.; Meneux, B.; Pollo, A.; Cappi, A.; Colombi, S.; Iovino, A.; Marinoni, C.; McCracken, H. J.; Scaramella, R.; Bottini, D.; Garilli, B.; Le Brun, V.; Maccagni, D.; Picat, J. P.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnaboldi, M.; Arnouts, S.; Bardelli, S.; Blaizot, J.; Bolzonella, M.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Franzetti, P.; Gavignaud, I.; Ilbert, O.; Marano, B.; Mathez, G.; Mazure, A.; Merighi, R.; Paltani, S.; Pellò, R.; Pozzetti, L.; Radovich, M.; Zamorani, G.; Zucca, E.; Bondi, M.; Bongiorno, A.; Busarello, G.; Lamareille, F.; Mellier, Y.; Merluzzi, P.; Ripepi, V.; Rizzo, D.

    2005-09-01

    This paper presents the evolution of the clustering of the main population of galaxies from z≃2 to z=0.2, from the first epoch VIMOS VLT Deep Survey (VVDS), a magnitude limited sample with 17.5 ≤ IAB ≤ 24. The sample allows a direct estimate of evolution from within the same survey over the time base sampled. We have computed the correlation functions ξ(r_p,π) and w_p(r_p), and the correlation length r_0(z), for the VVDS-02h and VVDS-CDFS fields, for a total of 7155 galaxies in a 0.61 deg2 area. We find that the correlation length in this sample slightly increases from z=0.5 to z=1.1, with r_0(z)=2.2{-}2.9 h-1 Mpc (comoving), for galaxies comparable in luminosity to the local 2dFGRS and SDSS samples, indicating that the amplitude of the correlation function was ≃2.5 times lower at z≃1 than observed locally. The correlation length in our lowest redshift bin z=[0.2, 0.5] is r_0=2.2 h-1 Mpc, lower than for any other population at the same redshift, indicating the low clustering of very low luminosity galaxies, 1.5 mag fainter than in the 2dFGRS or SDSS. The correlation length increases to r_0˜3.6 h-1 Mpc at higher redshifts z=[1.3, 2.1], as we are observing increasingly brighter galaxies, comparable to galaxies with MB_{AB}=-20.5 locally. We compare our measurement to the DEEP2 measurements in the range z=[0.7, 1.35] (Coil et al. 2004, ApJ, in press) and find comparable results when applying the same magnitude and color selection criteria as in their survey. The slowly varying clustering of VVDS galaxies as redshift increases is markedly different from the predicted evolution of the clustering of dark matter, indicating that bright galaxies traced higher density peaks when the large scale structures were emerging from the dark matter distribution 9-10 billion years ago, being supporting evidence for a strong evolution of the galaxy vs. dark matter bias.

  13. Giant galaxies and their globular cluster populations: Analysis and results from a wide-field imaging survey and archive

    NASA Astrophysics Data System (ADS)

    Young, Michael D.

    The globular cluster (GC) systems of giant galaxies are valuable and intriguing tools for a number of reasons, both in terms of the properties of the overall system as well as the properties of the individual GCs that make up the system. GCs are old: their ages range from a few Gyrs up to 12 Gyrs, and they apparently form during galaxy mergers and major star formation events. The ensemble properties (including the color, metallicity, and spatial distributions) of the GC system constrain theoretical models of galaxy formation. For several years we have been carrying out a wide-field imaging survey of the GC populations of a sample of giant spiral, S0, and elliptical galaxies with distances of 10 - 30 Mpc. In this dissertation I present results and analysis of the GC systems of eight giant galaxies, representing a significant addition to the survey dataset. I also describe how the survey data and metadata was collected, homogenized, and ingested into a custom database and archive, and how a web portal was created to disseminate the survey products to the wider scientific community. I have developed and tested a probability factor to quantify the likelihood that a given GC candidate is in actuality a GC. I explored enhanced statistical methods to detect subpopulations in GC systems, and found that six of the GC systems in our survey presented with three GC subpopulations. I explored how the spatial and azimuthal distributions of these subpopulations differ in each host galaxy. I have supplemented our survey results with select GC system studies from the literature, and tested how different host galaxy properties correlate with the total number of globular clusters in a given system, finding that the combination of the dynamical mass of the galaxy and the K-band luminosity of the galaxy offered the best correlation with the number of GCs. Lastly, I applied this combination of predictors to a published catalog of GC system studies and found that the predictions were in

  14. Candidate Clusters of Galaxies at z > 1.3 Identified in the Spitzer South Pole Telescope Deep Field Survey

    NASA Astrophysics Data System (ADS)

    Rettura, A.; Martinez-Manso, J.; Stern, D.; Mei, S.; Ashby, M. L. N.; Brodwin, M.; Gettings, D.; Gonzalez, A. H.; Stanford, S. A.; Bartlett, J. G.

    2014-12-01

    We present 279 galaxy cluster candidates at z > 1.3 selected from the 94 deg2 Spitzer South Pole Telescope Deep Field (SSDF) survey. We use a simple algorithm to select candidate high-redshift clusters of galaxies based on Spitzer/IRAC mid-infrared data combined with shallow all-sky optical data. We identify distant cluster candidates adopting an overdensity threshold that results in a high purity (80%) cluster sample based on tests in the Spitzer Deep, Wide-Field Survey of the Boötes field. Our simple algorithm detects all three 1.4 < z <= 1.75 X-ray detected clusters in the Boötes field. The uniqueness of the SSDF survey resides not just in its area, one of the largest contiguous extragalactic fields observed with Spitzer, but also in its deep, multi-wavelength coverage by the South Pole Telescope (SPT), Herschel/SPIRE, and XMM-Newton. This rich data set will allow direct or stacked measurements of Sunyaev-Zel'dovich effect decrements or X-ray masses for many of the SSDF clusters presented here, and enable a systematic study of the most distant clusters on an unprecedented scale. We measure the angular correlation function of our sample and find that these candidates show strong clustering. Employing the COSMOS/UltraVista photometric catalog in order to infer the redshift distribution of our cluster selection, we find that these clusters have a comoving number density nc = (0.7+6.3-0.6) × 10-7 h3 {Mpc}-3 and a spatial clustering correlation scale length r 0 = (32 ± 7) h -1 Mpc. Assuming our sample is comprised of dark matter halos above a characteristic minimum mass, M min, we derive that at z = 1.5 these clusters reside in halos larger than Mmin = 1.5+0.9-0.7 × 1014 h-1 M⊙ . We find that the mean mass of our cluster sample is equal to Mmean = 1.9+1.0-0.8 × 1014 h-1 M⊙ ; thus, our sample contains the progenitors of present-day massive galaxy clusters.

  15. CANDIDATE CLUSTERS OF GALAXIES AT z > 1.3 IDENTIFIED IN THE SPITZER SOUTH POLE TELESCOPE DEEP FIELD SURVEY

    SciTech Connect

    Rettura, A.; Stern, D.; Martinez-Manso, J.; Gettings, D.; Gonzalez, A. H.; Mei, S.; Ashby, M. L. N.; Brodwin, M.; Stanford, S. A.; Bartlett, J. G.

    2014-12-20

    We present 279 galaxy cluster candidates at z > 1.3 selected from the 94 deg{sup 2} Spitzer South Pole Telescope Deep Field (SSDF) survey. We use a simple algorithm to select candidate high-redshift clusters of galaxies based on Spitzer/IRAC mid-infrared data combined with shallow all-sky optical data. We identify distant cluster candidates adopting an overdensity threshold that results in a high purity (80%) cluster sample based on tests in the Spitzer Deep, Wide-Field Survey of the Boötes field. Our simple algorithm detects all three 1.4 < z ≤ 1.75 X-ray detected clusters in the Boötes field. The uniqueness of the SSDF survey resides not just in its area, one of the largest contiguous extragalactic fields observed with Spitzer, but also in its deep, multi-wavelength coverage by the South Pole Telescope (SPT), Herschel/SPIRE, and XMM-Newton. This rich data set will allow direct or stacked measurements of Sunyaev-Zel'dovich effect decrements or X-ray masses for many of the SSDF clusters presented here, and enable a systematic study of the most distant clusters on an unprecedented scale. We measure the angular correlation function of our sample and find that these candidates show strong clustering. Employing the COSMOS/UltraVista photometric catalog in order to infer the redshift distribution of our cluster selection, we find that these clusters have a comoving number density n{sub c}=(0.7{sub −0.6}{sup +6.3})×10{sup −7} h{sup 3} Mpc{sup −3} and a spatial clustering correlation scale length r {sub 0} = (32 ± 7) h {sup –1} Mpc. Assuming our sample is comprised of dark matter halos above a characteristic minimum mass, M {sub min}, we derive that at z = 1.5 these clusters reside in halos larger than M{sub min}=1.5{sub −0.7}{sup +0.9}×10{sup 14} h{sup −1} M{sub ⊙}. We find that the mean mass of our cluster sample is equal to M{sub mean}=1.9{sub −0.8}{sup +1.0}×10{sup 14} h{sup −1} M{sub ⊙}; thus, our sample contains the progenitors of

  16. Combining Galaxy-Galaxy Lensing and Galaxy Clustering

    SciTech Connect

    Park, Youngsoo; Krause, Elisabeth; Dodelson, Scott; Jain, Bhuvnesh; Amara, Adam; Becker, Matt; Bridle, Sarah; Clampitt, Joseph; Crocce, Martin; Honscheid, Klaus; Gaztanaga, Enrique; Sanchez, Carles; Wechsler, Risa

    2015-01-01

    Combining galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth rate of large scale structure, a quantity that will shed light on the mechanism driving the acceleration of the Universe. The Dark Energy Survey (DES) is a prime candidate for such an analysis, with its measurements of both the distribution of galaxies on the sky and the tangential shears of background galaxies induced by these foreground lenses. By constructing an end-to-end analysis that combines large-scale galaxy clustering and small-scale galaxy-galaxy lensing, we also forecast the potential of a combined probes analysis on DES datasets. In particular, we develop a practical approach to a DES combined probes analysis by jointly modeling the assumptions and systematics affecting the different components of the data vector, employing a shared halo model, HOD parametrization, photometric redshift errors, and shear measurement errors. Furthermore, we study the effect of external priors on different subsets of these parameters. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the universe, conservatively/ optimistically constraining the growth function to 8%/4.9% with its first-year data covering 1000 square degrees, and to 4%/2.3% with its full five-year data covering 5000 square degrees.

  17. The SCUBA-2 cosmology legacy survey: Ultraluminous star-forming galaxies in a z = 1.6 cluster

    SciTech Connect

    Smail, Ian; Swinbank, A. M.; Danielson, A. L. R.; Edge, A. C.; Simpson, J. M.; Geach, J. E.; Tadaki, K.; Arumugam, V.; Dunlop, J. S.; Ivison, R. J.; Hartley, W.; Almaini, O.; Conselice, C.; Bremer, M. N.; Chapin, E.; Chapman, S. C.; Scott, D.; Simpson, C. J.; Karim, A.; Kodama, T.; and others

    2014-02-10

    We analyze new SCUBA-2 submillimeter and archival SPIRE far-infrared imaging of a z = 1.62 cluster, Cl 0218.3–0510, which lies in the UKIRT Infrared Deep Sky Survey/Ultra-Deep Survey field of the SCUBA-2 Cosmology Legacy Survey. Combining these tracers of obscured star-formation activity with the extensive photometric and spectroscopic information available for this field, we identify 31 far-infrared/submillimeter-detected probable cluster members with bolometric luminosities ≳10{sup 12} L {sub ☉} and show that by virtue of their dust content and activity, these represent some of the reddest and brightest galaxies in this structure. We exploit ALMA submillimeter continuum observations, which cover one of these sources, to confirm the identification of a SCUBA-2-detected ultraluminous star-forming galaxy in this structure. Integrating the total star-formation activity in the central region of the structure, we estimate that it is an order of magnitude higher (in a mass-normalized sense) than clusters at z ∼ 0.5-1. However, we also find that the most active cluster members do not reside in the densest regions of the structure, which instead host a population of passive and massive, red galaxies. We suggest that while the passive and active populations have comparable near-infrared luminosities at z = 1.6, M{sub H} ∼ –23, the subsequent stronger fading of the more active galaxies means that they will evolve into passive systems at the present day that are less luminous than the descendants of those galaxies that were already passive at z ∼ 1.6 (M{sub H} ∼ –20.5 and M{sub H} ∼ –21.5, respectively, at z ∼ 0). We conclude that the massive galaxy population in the dense cores of present-day clusters were already in place at z = 1.6 and that in Cl 0218.3–0510 we are seeing continuing infall of less extreme, but still ultraluminous, star-forming galaxies onto a pre-existing structure.

  18. Herschel-Astrophysical Terahertz Large Area Survey: detection of a far-infrared population around galaxy clusters

    NASA Astrophysics Data System (ADS)

    Coppin, K. E. K.; Geach, J. E.; Smail, Ian; Dunne, L.; Edge, A. C.; Ivison, R. J.; Maddox, S.; Auld, R.; Baes, M.; Buttiglione, S.; Cava, A.; Clements, D. L.; Cooray, A.; Dariush, A.; de Zotti, G.; Dye, S.; Eales, S.; Fritz, J.; Hopwood, R.; Ibar, E.; Jarvis, M.; Michałowski, M. J.; Murphy, D. N. A.; Negrello, M.; Pascale, E.; Pohlen, M.; Rigby, E.; Rodighiero, G.; Scott, D.; Serjeant, S.; Smith, D. J. B.; Temi, P.; van der Werf, P.

    2011-09-01

    We report the detection of a significant excess in the surface density of far-infrared sources from the Herschel-Astrophysical Terahertz Large Area Survey within ˜1 Mpc of the centres of 66 optically selected clusters of galaxies in the Sloan Digital Sky Survey with ˜ 0.25. From the analysis of the multiwavelength properties of their counterparts we conclude that the far-infrared emission is associated with dust-obscured star formation and/or active galactic nuclei (AGN) within galaxies in the clusters themselves. The excess reaches a maximum at a radius of ˜0.8 Mpc, where we find 1.0 ± 0.3 S250 > 34 mJy sources on average per cluster above what would be expected for random field locations. If the far-infrared emission is dominated by star formation (as opposed to AGN) then this corresponds to an average star formation rate of ˜7 M⊙ yr-1 per cluster in sources with LIR > 5 × 1010 L⊙. Although lensed sources make a negligible contribution to the excess signal, a fraction of the sources around the clusters could be gravitationally lensed, and we have identified a sample of potential cases of cluster-lensed Herschel sources that could be targeted in follow-up studies. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  19. PROSPECTS FOR MEASURING THE RELATIVE VELOCITIES OF GALAXY CLUSTERS IN PHOTOMETRIC SURVEYS USING THE KINETIC SUNYAEV-ZEL'DOVICH EFFECT

    SciTech Connect

    Keisler, Ryan; Schmidt, Fabian E-mail: fabians@astro.princeton.edu

    2013-03-10

    We consider the prospects for measuring the pairwise kinetic Sunyaev-Zel'dovich (kSZ) signal from galaxy clusters discovered in large photometric surveys such as the Dark Energy Survey (DES). We project that the DES cluster sample will, in conjunction with existing mm-wave data from the South Pole Telescope (SPT), yield a detection of the pairwise kSZ signal at the 8{sigma}-13{sigma} level, with sensitivity peaking for clusters separated by {approx}100 Mpc distances. A next-generation version of SPT would allow for a 18{sigma}-30{sigma} detection and would be limited by variance from the kSZ signal itself and the residual thermal Sunyaev-Zel'dovich (tSZ) signal. Throughout our analysis, we assume photometric redshift errors that wash out the signal for clusters separated by {approx}<50 Mpc; a spectroscopic survey of the DES sample would recover this signal and allow for a 26{sigma}-43{sigma} detection, and would again be limited by kSZ/tSZ variance. Assuming a standard model of structure formation, these high-precision measurements of the pairwise kSZ signal will yield detailed information on the gas content of the galaxy clusters. Alternatively, if the gas can be sufficiently characterized by other means (e.g., using tSZ, X-ray, or weak lensing), then the relative velocities of the galaxy clusters can be isolated, thereby providing a precision measurement of gravity on 100 Mpc scales. We briefly consider the utility of these measurements for constraining theories of modified gravity.

  20. Combining cluster number counts and galaxy clustering

    NASA Astrophysics Data System (ADS)

    Lacasa, Fabien; Rosenfeld, Rogerio

    2016-08-01

    The abundance of clusters and the clustering of galaxies are two of the important cosmological probes for current and future large scale surveys of galaxies, such as the Dark Energy Survey. In order to combine them one has to account for the fact that they are not independent quantities, since they probe the same density field. It is important to develop a good understanding of their correlation in order to extract parameter constraints. We present a detailed modelling of the joint covariance matrix between cluster number counts and the galaxy angular power spectrum. We employ the framework of the halo model complemented by a Halo Occupation Distribution model (HOD). We demonstrate the importance of accounting for non-Gaussianity to produce accurate covariance predictions. Indeed, we show that the non-Gaussian covariance becomes dominant at small scales, low redshifts or high cluster masses. We discuss in particular the case of the super-sample covariance (SSC), including the effects of galaxy shot-noise, halo second order bias and non-local bias. We demonstrate that the SSC obeys mathematical inequalities and positivity. Using the joint covariance matrix and a Fisher matrix methodology, we examine the prospects of combining these two probes to constrain cosmological and HOD parameters. We find that the combination indeed results in noticeably better constraints, with improvements of order 20% on cosmological parameters compared to the best single probe, and even greater improvement on HOD parameters, with reduction of error bars by a factor 1.4-4.8. This happens in particular because the cross-covariance introduces a synergy between the probes on small scales. We conclude that accounting for non-Gaussian effects is required for the joint analysis of these observables in galaxy surveys.

  1. Clusters of galaxies

    NASA Astrophysics Data System (ADS)

    Vikhlinin, A. A.; Kravtsov, A. V.; Markevich, M. L.; Sunyaev, R. A.; Churazov, E. M.

    2014-04-01

    Galaxy clusters are formed via nonlinear growth of primordial density fluctuations and are the most massive gravitationally bound objects in the present Universe. Their number density at different epochs and their properties depend strongly on the properties of dark matter and dark energy, making clusters a powerful tool for observational cosmology. Observations of the hot gas filling the gravitational potential well of a cluster allows studying gasdynamic and plasma effects and the effect of supermassive black holes on the heating and cooling of gas on cluster scales. The work of Yakov Borisovich Zeldovich has had a profound impact on virtually all cosmological and astrophysical studies of galaxy clusters, introducing concepts such as the Harrison-Zeldovich spectrum, the Zeldovich approximation, baryon acoustic peaks, and the Sunyaev-Zeldovich effect. Here, we review the most basic properties of clusters and their role in modern astrophysics and cosmology.

  2. The Herschel Virgo Cluster Survey. V. Star-forming dwarf galaxies - dust in metal-poor environments

    NASA Astrophysics Data System (ADS)

    Grossi, M.; Hunt, L. K.; Madden, S.; Vlahakis, C.; Bomans, D. J.; Baes, M.; Bendo, G. J.; Bianchi, S.; Boselli, A.; Clemens, M.; Corbelli, E.; Cortese, L.; Dariush, A.; Davies, J. I.; De Looze, I.; di Serego Alighieri, S.; Fadda, D.; Fritz, J.; Garcia-Appadoo, D. A.; Gavazzi, G.; Giovanardi, C.; Hughes, T. M.; Jones, A. P.; Pierini, D.; Pohlen, M.; Sabatini, S.; Smith, M. W. L.; Verstappen, J.; Xilouris, E. M.; Zibetti, S.

    2010-07-01

    We present the dust properties of a small sample of Virgo cluster dwarf galaxies drawn from the science demonstration phase data set of the Herschel Virgo Cluster Survey. These galaxies have low metallicities (7.8 < 12 + log(O/H) < 8.3) and star-formation rates ≲10-1 M⊙ yr-1. We measure the spectral energy distribution (SED) from 100 to 500 μm and derive dust temperatures and dust masses. The SEDs are fitted by a cool component of temperature T ≲ 20 K, implying dust masses around 105 M⊙ and dust-to-gas ratios D within the range 10-3-10-2. The completion of the full survey will yield a larger set of galaxies, which will provide more stringent constraints on the dust content of star-forming dwarf galaxies. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  3. A large Hα survey of star formation in relaxed and merging galaxy cluster environments at z ∼ 0.15-0.3

    NASA Astrophysics Data System (ADS)

    Stroe, Andra; Sobral, David; Paulino-Afonso, Ana; Alegre, Lara; Calhau, João; Santos, Sergio; van Weeren, Reinout

    2017-03-01

    We present the first results from the largest Hα survey of star formation and active galactic nucleus activity in galaxy clusters. Using nine different narrow-band filters, we select >3000 Hα emitters within 19 clusters and their larger scale environment over a total volume of 1.3 × 105 Mpc3. The sample includes both relaxed and merging clusters, covering the 0.15-0.31 redshift range and spanning from 5 × 1014 to 30 × 1014 M⊙. We find that the Hα luminosity function for merging clusters has a higher characteristic density ϕ* compared to relaxed clusters. ϕ* drops from cluster core to cluster outskirts for both merging and relaxed clusters, with the merging cluster values ∼0.3 dex higher at each projected radius. The characteristic luminosity L* drops over the 0.5-2.0 Mpc distance from the cluster centre for merging clusters and increases for relaxed objects. Among disturbed objects, clusters hosting large-scale shock waves (traced by radio relics) are overdense in Hα emitters compared to those with turbulence in their intracluster medium (traced by radio haloes). We speculate that the increase in star formation activity in disturbed, young, massive galaxy clusters can be triggered by interactions between gas-rich galaxies, shocks and/or the intracluster medium, as well as accretion of filaments and galaxy groups. Our results indicate that disturbed clusters represent vastly different environments for galaxy evolution compared to relaxed clusters or average field environments.

  4. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: combining correlated Gaussian posterior distributions

    NASA Astrophysics Data System (ADS)

    Sánchez, Ariel G.; Grieb, Jan Niklas; Salazar-Albornoz, Salvador; Alam, Shadab; Beutler, Florian; Ross, Ashley J.; Brownstein, Joel R.; Chuang, Chia-Hsun; Cuesta, Antonio J.; Eisenstein, Daniel J.; Kitaura, Francisco-Shu; Percival, Will J.; Prada, Francisco; Rodríguez-Torres, Sergio; Seo, Hee-Jong; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magaña, Mariana; Vazquez, Jose A.; Zhao, Gong-Bo

    2017-01-01

    The cosmological information contained in anisotropic galaxy clustering measurements can often be compressed into a small number of parameters whose posterior distribution is well described by a Gaussian. We present a general methodology to combine these estimates into a single set of consensus constraints that encode the total information of the individual measurements, taking into account the full covariance between the different methods. We illustrate this technique by applying it to combine the results obtained from different clustering analyses, including measurements of the signature of baryon acoustic oscillations and redshift-space distortions, based on a set of mock catalogues of the final SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). Our results show that the region of the parameter space allowed by the consensus constraints is smaller than that of the individual methods, highlighting the importance of performing multiple analyses on galaxy surveys even when the measurements are highly correlated. This paper is part of a set that analyses the final galaxy clustering data set from BOSS. The methodology presented here is used in Alam et al. to produce the final cosmological constraints from BOSS.

  5. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: combining correlated Gaussian posterior distributions

    SciTech Connect

    Sánchez, Ariel G.; Grieb, Jan Niklas; Salazar-Albornoz, Salvador; Alam, Shadab; Beutler, Florian; Ross, Ashley J.; Brownstein, Joel R.; Chuang, Chia-Hsun; Cuesta, Antonio J.; Eisenstein, Daniel J.; Kitaura, Francisco-Shu; Percival, Will J.; Prada, Francisco; Rodríguez-Torres, Sergio; Seo, Hee-Jong; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magaña, Mariana; Vazquez, Jose A.; Zhao, Gong-Bo

    2016-09-30

    The cosmological information contained in anisotropic galaxy clustering measurements can often be compressed into a small number of parameters whose posterior distribution is well described by a Gaussian. Here, we present a general methodology to combine these estimates into a single set of consensus constraints that encode the total information of the individual measurements, taking into account the full covariance between the different methods. We also illustrate this technique by applying it to combine the results obtained from different clustering analyses, including measurements of the signature of baryon acoustic oscillations and redshift-space distortions, based on a set of mock catalogues of the final SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). Our results show that the region of the parameter space allowed by the consensus constraints is smaller than that of the individual methods, highlighting the importance of performing multiple analyses on galaxy surveys even when the measurements are highly correlated. Our paper is part of a set that analyses the final galaxy clustering data set from BOSS. The methodology presented here is used in Alam et al. to produce the final cosmological constraints from BOSS.

  6. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: combining correlated Gaussian posterior distributions

    DOE PAGES

    Sánchez, Ariel G.; Grieb, Jan Niklas; Salazar-Albornoz, Salvador; ...

    2016-09-30

    The cosmological information contained in anisotropic galaxy clustering measurements can often be compressed into a small number of parameters whose posterior distribution is well described by a Gaussian. Here, we present a general methodology to combine these estimates into a single set of consensus constraints that encode the total information of the individual measurements, taking into account the full covariance between the different methods. We also illustrate this technique by applying it to combine the results obtained from different clustering analyses, including measurements of the signature of baryon acoustic oscillations and redshift-space distortions, based on a set of mock cataloguesmore » of the final SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS). Our results show that the region of the parameter space allowed by the consensus constraints is smaller than that of the individual methods, highlighting the importance of performing multiple analyses on galaxy surveys even when the measurements are highly correlated. Our paper is part of a set that analyses the final galaxy clustering data set from BOSS. The methodology presented here is used in Alam et al. to produce the final cosmological constraints from BOSS.« less

  7. The VLT LBG Redshift Survey - III. The clustering and dynamics of Lyman-break galaxies at z ˜ 3

    NASA Astrophysics Data System (ADS)

    Bielby, R.; Hill, M. D.; Shanks, T.; Crighton, N. H. M.; Infante, L.; Bornancini, C. G.; Francke, H.; Héraudeau, P.; Lambas, D. G.; Metcalfe, N.; Minniti, D.; Padilla, N.; Theuns, T.; Tummuangpak, P.; Weilbacher, P.

    2013-03-01

    We present a catalogue of 2135 galaxy redshifts from the VLT LBG Redshift Survey (VLRS), a spectroscopic survey of z ≈ 3 galaxies in wide fields centred on background quasi-stellar objects. We have used deep optical imaging to select galaxies via the Lyman-break technique. Spectroscopy of the Lyman-break galaxies (LBGs) was then made using the Very Large Telescope (VLT) Visible Multi-Object Spectrograph (VIMOS) instrument, giving a mean redshift of z = 2.79. We analyse the clustering properties of the VLRS sample and also of the VLRS sample combined with the smaller area Keck-based survey of Steidel et al. From the semiprojected correlation function, wp(σ), for the VLRS and combined surveys, we find that the results are well fit with a single power-law model, with clustering scale lengths of r0 = 3.46 ± 0.41 and 3.83 ± 0.24 h-1 Mpc, respectively. We note that the corresponding combined ξ(r) slope is flatter than for local galaxies at γ = 1.5-1.6 rather than γ = 1.8. This flat slope is confirmed by the z-space correlation function, ξ(s), and in the range 10 < s < 100 h-1 Mpc the VLRS shows an ≈2.5σ excess over the Λ cold dark matter (ΛCDM) linear prediction. This excess may be consistent with recent evidence for non-Gaussianity in clustering results at z ≈ 1. We then analyse the LBG z-space distortions using the 2D correlation function, ξ(σ, π), finding for the combined sample a large-scale infall parameter of β = 0.38 ± 0.19 and a velocity dispersion of sqrt{< w_z^2rangle }=420^{+140}_{-160} km s^{-1}. Based on our measured β, we are able to determine the gravitational growth rate, finding a value of f(z = 3) = 0.99 ± 0.50 (or fσ8 = 0.26 ± 0.13), which is the highest redshift measurement of the growth rate via galaxy clustering and is consistent with ΛCDM. Finally, we constrain the mean halo mass for the LBG population, finding that the VLRS and combined sample suggest mean halo masses of log(MDM/M⊙) = 11.57 ± 0.15 and 11.73 ± 0

  8. Spitzer/IRAC Imaging of Exceptionally Bright Cluster-Lensed Submillimeter Galaxies Discovered by the Herschel Lensing Survey

    NASA Astrophysics Data System (ADS)

    Egami, Eiichi; Ebeling, Harald; Rawle, Timothy; Clement, Benjamin; Walth, Gregory; Pereira, Maria; Richard, Johan; Kneib, Jean-Paul

    2012-12-01

    Over the last few years, discoveries of exceptionally bright (e.g., observed S_peak > 100 mJy in the Herschel/SPIRE bands) gravitationally lensed submillimeter galaxies (SMGs) have generated great excitement. This is because these gravitationally lensed SMGs are so bright that they enable us to perform a variety of follow-up observations using a suite of observing facilities in the submillimeter, millimeter, and radio now available on the ground. Using Herschel, our team has been conducting a survey of such bright lensed galaxies in the fields of massive galaxy clusters: ``The Herschel Lensing Survey (HLS)'' (PI: Egami; 419 hours). This large Herschel program targets a total of 581 X-ray/SZ-selected massive clusters, and is currently 80% complete. Cluster lenses are often more powerful than galaxy lenses, producing larger magnifications. For example, typical magnification factors for galaxy-lensed Herschel sources are x10 or less while cluster-lensed systems can often produce magnification factors of x20-30 and even above x100. Cluster lenses will therefore allow us to detect and study intrinsically less-luminous and/or more distant sources with the ability to provide a view of finer-scale (i.e., sub-kpc) structures. Here, we propose to conduct Spitzer/IRAC imaging of 56 bright lensed SMG candidates we have identified in the ~470 HLS cluster fields observed so far. The main scientific goal is twofold: (1) to locate the underlying stellar component, and (2) to study its properties (e.g., stellar mass, specific star-formation rate) by constraining the rest-frame near-infrared SED and comparing with the Herschel and other submillimeter/millimeter data (e.g., SMA, PdB, ALMA, etc.). These rare bright lensed SMGs will allow us to probe the population of heavily dust-obscured vigorously star-forming galaxies at high redshift (z>1), which is thought to play an important role in the cosmic star-formation history of the Universe and yet has been difficult to study due to the

  9. Spiral galaxies in clusters. III. Gas-rich galaxies in the Pegasus I cluster of galaxies

    SciTech Connect

    Bothun, G.D.; Schommer, R.A.; Sullivan, W.T. III

    1982-05-01

    We report the results of a 21-cm and optical survey of disk galaxies in the vicinity of the Pegasus I cluster of galaxies. The color--gas content relation (log(M/sub H//L/sub B/) vs (B-V)/sup T//sub 0/ ) for this particular cluster reveals the presence of a substantial number of blue, gas-rich galaxies. With few exceptions, the disk systems in Pegasus I retain large amounts of neutral hydrogen despite their presence in a cluster. This directly shows that environmental processes have not yet removed substantial amounts of gas from these disk galaxies. We conclude that the environment has had little or no observable effect upon the evolution of disk galaxies in Pegasus I. The overall properties of the Pegasus I spirals are consistent with the suggestion that this cluster is now at an early stage in its evolution.

  10. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: mock galaxy catalogues for the BOSS Final Data Release

    NASA Astrophysics Data System (ADS)

    Kitaura, Francisco-Shu; Rodríguez-Torres, Sergio; Chuang, Chia-Hsun; Zhao, Cheng; Prada, Francisco; Gil-Marín, Héctor; Guo, Hong; Yepes, Gustavo; Klypin, Anatoly; Scóccola, Claudia G.; Tinker, Jeremy; McBride, Cameron; Reid, Beth; Sánchez, Ariel G.; Salazar-Albornoz, Salvador; Grieb, Jan Niklas; Vargas-Magana, Mariana; Cuesta, Antonio J.; Neyrinck, Mark; Beutler, Florian; Comparat, Johan; Percival, Will J.; Ross, Ashley

    2016-03-01

    We reproduce the galaxy clustering catalogue from the SDSS-III Baryon Oscillation Spectroscopic Survey Final Data Release (BOSS DR11&DR12) with high fidelity on all relevant scales in order to allow a robust analysis of baryon acoustic oscillations and redshift space distortions. We have generated (6000) 12 288 MultiDark PATCHY BOSS (DR11) DR12 light cones corresponding to an effective volume of ˜192 000 [h-1 Gpc]3 (the largest ever simulated volume), including cosmic evolution in the redshift range from 0.15 to 0.75. The mocks have been calibrated using a reference galaxy catalogue based on the halo abundance matching modelling of the BOSS DR11&DR12 galaxy clustering data and on the data themselves. The production follows three steps. First, we apply the PATCHY code to generate a dark matter field and an object distribution including non-linear stochastic galaxy bias. Secondly, we run the halo/stellar distribution reconstruction HADRON code to assign masses to the various objects. This step uses the mass distribution as a function of local density and non-local indicators (i.e. tidal field tensor eigenvalues and relative halo exclusion separation for massive objects) from the reference simulation applied to the corresponding patchy dark matter and galaxy distribution. Finally, we apply the SUGAR code to build the light cones. The resulting MultiDarkPATCHY mock light cones reproduce the number density, selection function, survey geometry, and in general within 1σ, for arbitrary stellar mass bins, the power spectrum up to k = 0.3 h Mpc-1, the two-point correlation functions down to a few Mpc scales, and the three-point statistics of the BOSS DR11&DR12 galaxy samples.

  11. Cosmology with clustering anisotropies: disentangling dynamic and geometric distortions in galaxy redshift surveys

    NASA Astrophysics Data System (ADS)

    Marulli, Federico; Bianchi, Davide; Branchini, Enzo; Guzzo, Luigi; Moscardini, Lauro; Angulo, Raul E.

    2012-11-01

    We investigate the impact of different observational effects affecting a precise and accurate measurement of the growth rate of fluctuations from the anisotropy of clustering in galaxy redshift surveys. We focus here on redshift measurement errors, on the reconstruction of the underlying real-space clustering and, most importantly, on the apparent degeneracy existing with the geometrical distortions induced by the cosmology-dependent conversion of redshifts into distances. We use a suite of mock catalogues extracted from large N-body simulations, focusing on the analysis of intermediate, mildly non-linear scales (r < 50 h-1 Mpc) and apply the standard 'dispersion model' to fit the anisotropy of the observed correlation function ξ(r⊥, r∥) . We first verify that redshift errors up to δz ˜ 0.2 per cent (i.e. σz ˜ 0.002 at z = 1) have a negligible impact on the precision with which the specific growth rate β can be measured. Larger redshift errors introduce a positive systematic error, which can be alleviated by adopting a Gaussian distribution function of pairwise velocities. This is, in any case, smaller than the systematic error of up to 10 per cent due to the limitations of the dispersion model, which is studied in a separate paper. We then show that 50 per cent of the statistical error budget on β depends on the deprojection procedure through which the real-space correlation function, needed for the modelling process, is obtained. Finally, we demonstrate that the degeneracy with geometric distortions can in fact be circumvented. This is obtained through a modified version of the Alcock-Paczynski test in redshift space, which successfully recovers the correct cosmology by searching for the solution that optimizes the description of dynamical redshift distortions. For a flat cosmology, we obtain largely independent, robust constraints on β and on the mass density parameter, ΩM. In a volume of 2.4 (h-1 Gpc)3, the correct ΩM is obtained with ˜12 per

  12. The SDSS-IV Extended Baryon Oscillation Spectroscopic Survey: The Clustering of Luminous Red Galaxies Using Photometric Redshifts

    NASA Astrophysics Data System (ADS)

    Prakash, Abhishek; SDSS-IV/eBOSS

    2017-01-01

    SDSS-IV/eBOSS survey will allow a ˜1% measurement of the Baryon Acoustic Oscillation (BAO) scale and a 4.0%Redshift Space Distortion (RSD) measurement using a relatively uniform set of luminous, early-type galaxies in the redshift range 0.6 < z < 1. In this talk, I will present the 3D real space clustering of a sample of ~600,000 LRGs measured by the SDSS/eBOSS, using photometric redshifts. These galaxies have accurate photometric redshifts with an average error of z = 0.028. These LRGs range from redshift z = 0.6 to 1.0 over 10,000 deg2 of the sky, making it the largest volume ever used for galaxy clustering measurements. We measure the angular clusteringpower spectrum in different redshift slices and use well-calibrated redshift distributions to combine these into a high precision 3D real space clustering. i will present an evidence for BAO in the 2-point correlation function. The detection of BAO also allows the measurement of the comoving distance to z = 1.0. Traditionally, spectroscopic redshifts are used to estimate distances to the galaxies and, in turn, to measuregalaxy clustering. However, acquiring spectroscopic redshifts is a time consuming and expensive process even with modern multi-fiber spectrographs. Although photometric redshifts are less accurate, they are signicantly easier to obtain, and for a constant amount of time, one can image both wider areas and deeper volumes than would be possible with spectroscopy, allowing one to probe both larger scales and larger volumes. The ability to make precise clustering measurements with photometric data has been well demonstrated by Padmanabhan et al. (2007).

  13. Dust in galaxy clusters

    NASA Astrophysics Data System (ADS)

    Polikarpova, O. L.; Shchekinov, Yu. A.

    2017-02-01

    The conditions for the destruction of dust in hot gas in galaxy clusters are investigated. It is argued that extinction measurements can be subject to selection effects, hindering their use in obtaining trustworthy estimates of dust masses in clusters. It is shown, in particular, that the ratio of the dust mass to the extinction M d / S d increases as dust grains are disrupted, due to the rapid destruction of small grains. Over long times, this ratio can asymptotically reach values a factor of three higher than the mean value in the interstellar medium in the Galaxy. This lowers dust-mass estimates based on measurements of extinction in galaxy clusters. The characteristic lifetime of dust in hot cluster gas is determined by its possible thermal isolation by the denser medium of gas fragments within which the dust is ejected from galaxies, and can reach 100-300 million years, depending on the kinematics and morphology of the fragments. As a result, the mass fraction of dust in hot cluster gas can reach 1-3% of the Galactic value. Over its lifetime, dust can also be manifest through its far-infrared emission. The emission characteristics of the dust change as it is disrupted, and the ratio of the fluxes at 350 and 850 μm can increase appreciably. This can potentially serve as an indicator of the state of the dust and ambient gas.

  14. Galaxy clustering on large scales.

    PubMed Central

    Efstathiou, G

    1993-01-01

    I describe some recent observations of large-scale structure in the galaxy distribution. The best constraints come from two-dimensional galaxy surveys and studies of angular correlation functions. Results from galaxy redshift surveys are much less precise but are consistent with the angular correlations, provided the distortions in mapping between real-space and redshift-space are relatively weak. The galaxy two-point correlation function, rich-cluster two-point correlation function, and galaxy-cluster cross-correlation function are all well described on large scales ( greater, similar 20h-1 Mpc, where the Hubble constant, H0 = 100h km.s-1.Mpc; 1 pc = 3.09 x 10(16) m) by the power spectrum of an initially scale-invariant, adiabatic, cold-dark-matter Universe with Gamma = Omegah approximately 0.2. I discuss how this fits in with the Cosmic Background Explorer (COBE) satellite detection of large-scale anisotropies in the microwave background radiation and other measures of large-scale structure in the Universe. PMID:11607400

  15. Surveying Galaxy Proto-clusters in Emission: A Large-scale Structure at z = 2.44 and the Outlook for HETDEX

    NASA Astrophysics Data System (ADS)

    Chiang, Yi-Kuan; Overzier, Roderik A.; Gebhardt, Karl; Finkelstein, Steven L.; Chiang, Chi-Ting; Hill, Gary J.; Blanc, Guillermo A.; Drory, Niv; Chonis, Taylor S.; Zeimann, Gregory R.; Hagen, Alex; Schneider, Donald P.; Jogee, Shardha; Ciardullo, Robin; Gronwall, Caryl

    2015-07-01

    Galaxy proto-clusters at z≳ 2 provide a direct probe of the rapid mass assembly and galaxy growth of present-day massive clusters. Because of the need for precise galaxy redshifts for density mapping and the prevalence of star formation before quenching, nearly all the proto-clusters known to date were confirmed by spectroscopy of galaxies with strong emission lines. Therefore, large emission-line galaxy surveys provide an efficient way to identify proto-clusters directly. Here we report the discovery of a large-scale structure at z = 2.44 in the Hobby Eberly Telescope Dark Energy Experiment (HETDEX) Pilot Survey. On a scale of a few tens of Mpc comoving, this structure shows a complex overdensity of Lyα emitters (LAE), which coincides with broadband selected galaxies in the COSMOS/UltraVISTA photometric and zCOSMOS spectroscopic catalogs, as well as overdensities of intergalactic gas revealed in the Lyα absorption maps of Lee et al. We construct mock LAE catalogs to predict the cosmic evolution of this structure. We find that such an overdensity should have already broken away from the Hubble flow, and part of the structure will collapse to form a galaxy cluster with {10}14.5+/- 0.4 {M}⊙ by z = 0. The structure contains a higher median stellar mass of broadband selected galaxies, a boost of extended Lyα nebulae, and a marginal excess of active galactic nuclei relative to the field, supporting a scenario of accelerated galaxy evolution in cluster progenitors. Based on the correlation between galaxy overdensity and the z = 0 descendant halo mass calibrated in the simulation, we predict that several hundred 1.9\\lt z\\lt 3.5 proto-clusters with z = 0 mass of \\gt {10}14.5 {M}⊙ will be discovered in the 8.5 Gpc3 of space surveyed by the HETDEX.

  16. The ROSAT-ESO flux limited X-ray galaxy cluster survey (REFLEX II). I. Newly identified X-ray luminous clusters at z ≥ 0.2

    NASA Astrophysics Data System (ADS)

    Chon, G.; Böhringer, H.

    2012-02-01

    We report 19 intermediate redshift clusters newly detected in the ROSAT All-Sky survey that are spectroscopically confirmed. They form a part of 911 objects in the REFLEX II cluster catalogue with a limiting flux of 1.8 × 10-12 erg/s/cm2 in the 0.1-2.4 keV ROSAT band at redshift z ≥ 0.2. In addition we report three clusters from the REFLEX III supplementary catalogue, which contains objects below the REFLEX II flux limit but satisfies the redshift constraint above. These clusters are spectroscopically followed-up by our ESO NTT-EFOSC2 campaigns for the redshift measurement. We describe our observing and data reduction methods. We show how X-ray properties such as spectral hardness ratio and source extent can be used as important diagnostics in selecting galaxy cluster candidates. Physical properties of the clusters are subsequently calculated from the X-ray observations. This sample contains the high mass and intermediate-redshift galaxy clusters for astrophysical and cosmological applications. Based on the data obtained at the European Southern Observatory, La Silla, Chile.

  17. THE XMM CLUSTER SURVEY: THE BUILD-UP OF STELLAR MASS IN BRIGHTEST CLUSTER GALAXIES AT HIGH REDSHIFT

    SciTech Connect

    Stott, J. P.; Collins, C. A.; Hilton, M.; Capozzi, D.; Sahlen, M.; Lloyd-Davies, E.; Hosmer, M.; Liddle, A. R.; Mehrtens, N.; Romer, A. K.; Miller, C. J.; Stanford, S. A.; Viana, P. T. P.; Davidson, M.; Hoyle, B.; Kay, S. T.; Nichol, R. C.

    2010-07-20

    We present deep J- and K{sub s} -band photometry of 20 high redshift galaxy clusters between z = 0.8 and1.5, 19 of which are observed with the MOIRCS instrument on the Subaru telescope. By using near-infrared light as a proxy for stellar mass we find the surprising result that the average stellar mass of Brightest Cluster Galaxies (BCGs) has remained constant at {approx}9 x 10{sup 11} M {sub sun} since z {approx} 1.5. We investigate the effect on this result of differing star formation histories generated by three well-known and independent stellar population codes and find it to be robust for reasonable, physically motivated choices of age and metallicity. By performing Monte Carlo simulations we find that the result is unaffected by any correlation between BCG mass and cluster mass in either the observed or model clusters. The large stellar masses imply that the assemblage of these galaxies took place at the same time as the initial burst of star formation. This result leads us to conclude that dry merging has had little effect on the average stellar mass of BCGs over the last 9-10 Gyr in stark contrast to the predictions of semi-analytic models, based on the hierarchical merging of dark matter halos, which predict a more protracted mass build-up over a Hubble time. However, we discuss that there is potential for reconciliation between observation and theory if there is a significant growth of material in the intracluster light over the same period.

  18. Galaxy evolution in clusters since z=1

    NASA Astrophysics Data System (ADS)

    Aragón-Salamanca, A.

    2011-11-01

    It is now 30 years since Alan Dressler published his seminal paper onthe morphology-density relation. Although there is still much to learnon the effect of the environment on galaxy evolution, extensive progress has been made since then both observationally and theoretically.Galaxy clusters provide some of the most extreme environments in which galaxies evolve, making them excellent laboratories to study the age old question of "nature'' vs. "nurture'' in galaxy evolution. Here I review some of the key observational results obtained during the last decade on the evolution of the morphology, structure, dynamics, star-formation history and stellar populations of cluster galaxies since the time when the universe was half its present age.Many of the results presented here have been obtainedwithin the ESO Distant Cluster Survey (EDisCS) and Space Telescope A901/02 Galaxy Evolution Survey (STAGES) collaborations.

  19. Galaxy Cluster Smashes Distance Record

    NASA Astrophysics Data System (ADS)

    2009-10-01

    he most distant galaxy cluster yet has been discovered by combining data from NASA's Chandra X-ray Observatory and optical and infrared telescopes. The cluster is located about 10.2 billion light years away, and is observed as it was when the Universe was only about a quarter of its present age. The galaxy cluster, known as JKCS041, beats the previous record holder by about a billion light years. Galaxy clusters are the largest gravitationally bound objects in the Universe. Finding such a large structure at this very early epoch can reveal important information about how the Universe evolved at this crucial stage. JKCS041 is found at the cusp of when scientists think galaxy clusters can exist in the early Universe based on how long it should take for them to assemble. Therefore, studying its characteristics - such as composition, mass, and temperature - will reveal more about how the Universe took shape. "This object is close to the distance limit expected for a galaxy cluster," said Stefano Andreon of the National Institute for Astrophysics (INAF) in Milan, Italy. "We don't think gravity can work fast enough to make galaxy clusters much earlier." Distant galaxy clusters are often detected first with optical and infrared observations that reveal their component galaxies dominated by old, red stars. JKCS041 was originally detected in 2006 in a survey from the United Kingdom Infrared Telescope (UKIRT). The distance to the cluster was then determined from optical and infrared observations from UKIRT, the Canada-France-Hawaii telescope in Hawaii and NASA's Spitzer Space Telescope. Infrared observations are important because the optical light from the galaxies at large distances is shifted into infrared wavelengths because of the expansion of the universe. The Chandra data were the final - but crucial - piece of evidence as they showed that JKCS041 was, indeed, a genuine galaxy cluster. The extended X-ray emission seen by Chandra shows that hot gas has been detected

  20. The Cosmic Large-Scale Structure in X-rays (CLASSIX) Cluster Survey. I. Probing galaxy cluster magnetic fields with line of sight rotation measures

    NASA Astrophysics Data System (ADS)

    Böhringer, Hans; Chon, Gayoung; Kronberg, Philipp P.

    2016-11-01

    To search for a signature of an intracluster magnetic field, we compare measurements of Faraday rotation of polarised extragalactic radio sources in the line of sight of galaxy clusters with those outside. To this end, we correlated a catalogue of 1383 rotation measures of extragalactic polarised radio sources with galaxy clusters from the CLASSIX survey (combining REFLEX II and NORAS II) detected by their X-ray emission in the ROSAT All-Sky Survey. The survey covers 8.25 ster of the sky at | bII | ≥ 20°. We compared the rotation measures in the line of sight of clusters within their projected radii of r500 with those outside and found a significant excess of the dispersion of the rotation measures in the cluster regions. Since the observed rotation measure is the result of Faraday rotation in several presumably uncorrelated magnetised cells of the intracluster medium, the observations correspond to quantities averaged over several magnetic field directions and strengths. Therefore the interesting quantity is the dispersion or standard deviation of the rotation measure for an ensemble of clusters. In the analysis of the observations we found a standard deviation of the rotation measure inside r500 of about 120 (± 21) rad m-2. This compares to about 56 (± 8) rad m-2 outside. Correcting for the effect of the Galaxy with the mean rotation measure in a region of 10 deg radius in the outskirts of the clusters does not change the outcome quoted above. We show that the most X-ray luminous and thus most massive clusters contribute most to the observed excess rotation measure. Modelling the electron density distribution in the intracluster medium with a self-similar model based on the REXCESS Survey, we found that the dispersion of the rotation measure increases with the column density, and we deduce a magnetic field value of about 2-6 (l/ 10 kpc)- 1/2μG assuming a constant magnetic field strength, where l is the size of the coherently magnetised intracluster medium

  1. Clusters of Galaxies in Infrared Domain

    NASA Astrophysics Data System (ADS)

    Wszołek, B.

    2008-12-01

    Far infrared emission (FIR) of the sky is generally thought to originate mainly in cold dust grains distributed in space. The FIR emission of galaxy clusters may be considered therefore as a tracer of the dust constituent of the intracluster medium. The presence of dust distributed in the intergalactic medium of galaxy clusters is of considerable interest for several studies. Based on IRAS and COBE/DIRBE sky surveys we found excess FIR emission from the sky area occupied by galaxy cluster ZW5897. Very good positional and extensional coincidence between infrared source and ZW5897 may suggest intracluster origin of the emission. We studied the distribution of stars and galaxies in the cluster area using Palomar Survey data to check whether these distributions are affected by local dust. We found that a foreground obscuring cloud, overlapping accidentally the distant cluster ZW5897, may be responsible for some part of the detected FIR emission.

  2. Comparison of the VIMOS-VLT Deep Survey with the Munich semi-analytical model. I. Magnitude counts, redshift distribution, colour bimodality, and galaxy clustering

    NASA Astrophysics Data System (ADS)

    de la Torre, S.; Meneux, B.; De Lucia, G.; Blaizot, J.; Le Fèvre, O.; Garilli, B.; Cucciati, O.; Mellier, Y.; Pollo, A.; Abbas, U.; Bottini, D.; Le Brun, V.; Maccagni, D.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnouts, S.; Bardelli, S.; Bolzonella, M.; Cappi, A.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Franzetti, P.; Gavignaud, I.; Guzzo, L.; Ilbert, O.; Iovino, A.; McCracken, H. J.; Marinoni, C.; Mazure, A.; Merighi, R.; Paltani, S.; Pelló, R.; Pozzetti, L.; Vergani, D.; Zamorani, G.; Zucca, E.

    2011-01-01

    Aims: This paper presents a detailed comparison between high-redshift observations from the VIMOS-VLT Deep Survey (VVDS) and predictions from the Munich semi-analytical model of galaxy formation. In particular, we focus this analysis on the magnitude, redshift, and colour distributions of galaxies, as well as their clustering properties. Methods: We constructed 100 quasi-independent mock catalogues, using the output of the semi-analytical model presented in De Lucia & Blaizot (2007, MNRAS, 375, 2). We then applied the same observational selection function of the VVDS-Deep survey, so as to carry out a fair comparison between models and observations. Results: We find that the semi-analytical model reproduces well the magnitude counts in the optical bands. It tends, however, to overpredict the abundance of faint red galaxies, in particular in the i' and z' bands. Model galaxies exhibit a colour bimodality that is only in qualitative agreement with the data. In particular, we find that the model tends to overpredict the number of red galaxies at low redshift and of blue galaxies at all redshifts probed by VVDS-Deep observations, although a large fraction of the bluest observed galaxies is absent from the model. In addition, the model overpredicts by about 14 per cent the number of galaxies observed at 0.2 < z < 1 with IAB < 24. When comparing the galaxy clustering properties, we find that model galaxies are more strongly clustered than observed ones at all redshift from z = 0.2 to z = 2, with the difference being less significant above z ≃ 1. When splitting the samples into red and blue galaxies, we find that the observed clustering of blue galaxies is well reproduced by the model, while red model galaxies are much more clustered than observed ones, being principally responsible for the strong global clustering found in the model. Conclusions: Our results show that the discrepancies between Munich semi-analytical model predictions and VVDS-Deep observations

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

    SciTech Connect

    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. M.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; Desai, S.; Dietrich, J. P.; Dobbs, M. A.; Foley, R. J.; Forman, W. R.; George, E. M.; Gladders, M. D.; Gonzalez, A. H.; Halverson, N. W.; Hennig, C.; Hoekstra, H.; Holder, G. P.; Holzapfel, W. L.; Hrubes, J. D.; Jones, C.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Liu, J.; Lueker, M.; Luong-Van, D.; Mantz, A.; Marrone, D. P.; McDonald, M.; McMahon, J. J.; Meyer, S. S.; Mocanu, L.; Mohr, J. J.; Murray, S. S.; Padin, S.; Pryke, C.; Reichardt, C. L.; Rest, A.; Ruel, J.; Ruhl, J. E.; Saliwanchik, B. R.; Saro, A.; Sayre, J. T.; Schaffer, K. K.; Schrabback, T.; Shirokoff, E.; Song, J.; Spieler, H. G.; Stanford, S. A.; Staniszewski, Z.; Stark, A. A.; Story, K. T.; Stubbs, C. W.; Vanderlinde, K.; Vieira, J. D.; Vikhlinin, A.; Williamson, R.; Zahn, O.; Zenteno, A.

    2015-01-29

    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 ξ = 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 ξ > 4.5 candidates and 387 (or 95%) of the ξ > 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 ~ 0.25 leading to a sample of massive clusters that extends to high redshift. The median mass of the sample is M (500c)(ρ(crit)) $\\sim 3.5\\times 10^{14}\\,M_\\odot \\,h_{70}^{-1}$, 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.

  4. Annealing a Follow-up Program: Improvement of the Dark Energy Figure of Merit for Optical Galaxy Cluster Surveys

    SciTech Connect

    Wu, Hao-Yi; Rozo, Eduardo; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC /CCAPP, Columbus /KICP, Chicago /KIPAC, Menlo Park /SLAC

    2010-06-02

    The precision of cosmological parameters derived from galaxy cluster surveys is limited by uncertainty in relating observable signals to cluster mass. We demonstrate that a small mass-calibration follow-up program can significantly reduce this uncertainty and improve parameter constraints, particularly when the follow-up targets are judiciously chosen. To this end, we apply a simulated annealing algorithm to maximize the dark energy information at fixed observational cost, and find that optimal follow-up strategies can reduce the observational cost required to achieve a specified precision by up to an order of magnitude. Considering clusters selected from optical imaging in the Dark Energy Survey, we find that approximately 200 low-redshift X-ray clusters or massive Sunyaev-Zel'dovich clusters can improve the dark energy figure of merit by 50%, provided that the follow-up mass measurements involve no systematic error. In practice, the actual improvement depends on (1) the uncertainty in the systematic error in follow-up mass measurements, which needs to be controlled at the 5% level to avoid severe degradation of the results; and (2) the scatter in the optical richness-mass distribution, which needs to be made as tight as possible to improve the efficacy of follow-up observations.

  5. Star formation and substructure in galaxy clusters

    SciTech Connect

    Cohen, Seth A.; Hickox, Ryan C.; Wegner, Gary A.; Einasto, Maret; Vennik, Jaan

    2014-03-10

    We investigate the relationship between star formation (SF) and substructure in a sample of 107 nearby galaxy clusters using data from the Sloan Digital Sky Survey. Several past studies of individual galaxy clusters have suggested that cluster mergers enhance cluster SF, while others find no such relationship. The SF fraction in multi-component clusters (0.228 ± 0.007) is higher than that in single-component clusters (0.175 ± 0.016) for galaxies with M{sub r}{sup 0.1}<−20.5. In both single- and multi-component clusters, the fraction of star-forming galaxies increases with clustercentric distance and decreases with local galaxy number density, and multi-component clusters show a higher SF fraction than single-component clusters at almost all clustercentric distances and local densities. Comparing the SF fraction in individual clusters to several statistical measures of substructure, we find weak, but in most cases significant at greater than 2σ, correlations between substructure and SF fraction. These results could indicate that cluster mergers may cause weak but significant SF enhancement in clusters, or unrelaxed clusters exhibit slightly stronger SF due to their less evolved states relative to relaxed clusters.

  6. Tracking star formation in dwarf cluster galaxies

    NASA Astrophysics Data System (ADS)

    Rude, Cody Millard

    The evolution of galaxies in dense environments can be affected by close encounters with neighboring galaxies and interactions with the intracluster medium (ICM). Dwarf galaxies may be especially susceptible to these effects due to their low mass. The goal of my dissertation research is to look for signs of star formation in cluster dwarf galaxies by measuring and comparing the r- and u-band luminosity functions of 15 low redshift Abell galaxy clusters using archival data from the Canada-France-Hawaii Telescope (CFHT). Luminosity functions, dwarf-to-giant ratios, and blue fractions are measured in four cluster-centric annuli from stacked cluster data. To account for differences in cluster optical richness, each cluster is scaled according to r200, where r200 is the radius of a sphere, centered on the cluster, whose average density is 200 times the critical density of the universe. The outer region of the cluster sample shows an increase in the faint-end slope of the u-band luminosity function relative to the r-band, indicating star formation in dwarf galaxies. The blue fraction for dwarf galaxies steadily rises with increasing cluster-centric radii. The change in the blue fraction of giant galaxies also increases, but at a lower rate. Additionally, the inner regions of clusters ranging from 0.185 < z < 0.7 from the "Cluster Lensing and Supernova survey with Hubble (CLASH)" are used to generate blue- and red-band luminosity functions, dwarf-to-giant ratios, and blue fractions. Comparisons of the inner region of the CLASH and CFHT clusters show an increase in the blue fraction of dwarf galaxies with redshift that is not present in giant galaxies.

  7. Comparing Dark Energy Survey and HST –CLASH observations of the galaxy cluster RXC J2248.7–4431: Implications for stellar mass versus dark matter

    DOE PAGES

    Palmese, A.; Lahav, O.; Banerji, M.; ...

    2016-08-20

    We derive the stellar mass fraction in the galaxy cluster RXC J2248.7–4431 observed with the Dark Energy Survey (DES) during the Science Verification period. We compare the stellar mass results from DES (five filters) with those from the Hubble Space Telescope Cluster Lensing And Supernova Survey (CLASH; 17 filters). When the cluster spectroscopic redshift is assumed, we show that stellar masses from DES can be estimated within 25 per cent of CLASH values. We compute the stellar mass contribution coming from red and blue galaxies, and study the relation between stellar mass and the underlying dark matter using weak lensingmore » studies with DES and CLASH. An analysis of the radial profiles of the DES total and stellar mass yields a stellar-to-total fraction of f* = (6.8 ± 1.7) × 10–3 within a radius of r200c ≃ 2 Mpc. Our analysis also includes a comparison of photometric redshifts and star/galaxy separation efficiency for both data sets. We conclude that space-based small field imaging can be used to calibrate the galaxy properties in DES for the much wider field of view. In conclusion, the technique developed to derive the stellar mass fraction in galaxy clusters can be applied to the ~100 000 clusters that will be observed within this survey and yield important information about galaxy evolution.« less

  8. Comparing Dark Energy Survey and HST-CLASH observations of the galaxy cluster RXC J2248.7-4431: implications for stellar mass versus dark matter

    NASA Astrophysics Data System (ADS)

    Palmese, A.; Lahav, O.; Banerji, M.; Gruen, D.; Jouvel, S.; Melchior, P.; Aleksić, J.; Annis, J.; Diehl, H. T.; Hartley, W. G.; Jeltema, T.; Romer, A. K.; Rozo, E.; Rykoff, E. S.; Seitz, S.; Suchyta, E.; Zhang, Y.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Dietrich, J. P.; Doel, P.; Estrada, J.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Li, T. S.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Miller, C. J.; Miquel, R.; Nord, B.; Ogando, R.; Plazas, A. A.; Roodman, A.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Tucker, D.; Vikram, V.

    2016-12-01

    We derive the stellar mass fraction in the galaxy cluster RXC J2248.7-4431 observed with the Dark Energy Survey (DES) during the Science Verification period. We compare the stellar mass results from DES (five filters) with those from the Hubble Space Telescope Cluster Lensing And Supernova Survey (CLASH; 17 filters). When the cluster spectroscopic redshift is assumed, we show that stellar masses from DES can be estimated within 25 per cent of CLASH values. We compute the stellar mass contribution coming from red and blue galaxies, and study the relation between stellar mass and the underlying dark matter using weak lensing studies with DES and CLASH. An analysis of the radial profiles of the DES total and stellar mass yields a stellar-to-total fraction of f⋆ = (6.8 ± 1.7) × 10-3 within a radius of r200c ≃ 2 Mpc. Our analysis also includes a comparison of photometric redshifts and star/galaxy separation efficiency for both data sets. We conclude that space-based small field imaging can be used to calibrate the galaxy properties in DES for the much wider field of view. The technique developed to derive the stellar mass fraction in galaxy clusters can be applied to the ˜100 000 clusters that will be observed within this survey and yield important information about galaxy evolution.

  9. Searching for Distant Galaxy Clusters: Utilizing the Virtual Observatory for Multiwavelength Images and Survey Cross-correlation

    NASA Astrophysics Data System (ADS)

    Van Duyne, J.; Lucas, R.; Tamura, T.; Rohde, D.

    2004-12-01

    Through the tools and technology made available via the Virtual Observatory, we have explored the multiwavelength properties, survey coverage, and environments of a sample of 71 steep (-1.0 < α < 0.5) spectrum radio sources taken from the Texas Interferometer Radio catalog (Douglas et al. 1996). Through the VLA proposal by Lucas & Chambers (1989), these radio sources were observed with the A-array configuration at 20 cm and 1485 MHz and with 1 full Schmidt SRC-J, high-latitude sky survey plate ( ˜ 6 sq deg) down to J ˜ 22 with the purpose of finding optical counterparts of mid-to-high z galaxy clusters. With the knowledge that this field had been imaged via the Sloan Digital Sky Survey (SDSS DR2, r=22.2), we submitted the coordinates of the Lucas & Chambers survey sources to the VO image access protocol (SIAP) to quickly and efficiently explore the SDSS ugriz 5-band color images of these sources, specifically looking for u-band drop-outs. Additionally, we used this same technique to explore the multiwavelength coverage of this field with all surveys registered with the VO (2MASS, ROSAT, VLA FIRST/NVSS, Chandra, XMM) via ˜ 1 arcminute snapshots. This revealed a multitude of interesting objects, such as double-lobed radio galaxies with bent jets, implying intercluster medium interactions, extremely faint optical sources with point source 2MASS/J-band detections, and the re-discovery of 3C 273. Finally, as a proof of concept, we utilized the VO tool Topcat to cross-correlate the radio and X-ray positions of known galaxy clusters via the RBSC-NVSS Sample (Bauer et al. 2000) and ROSAT Brightest Cluster Sample (Ebeling et al. 1998), resulting in 17 clusters matched at < 15 arcsec separation. These results demonstrate the simple, yet highly effective utility of the Virtual Observatory on a sample data set to reveal scientifically interesting objects on a short timescale. We would like to acknowledge the National Virtual Observatory Summer School for supplying the

  10. The very wide-field gzK galaxy survey - I. Details of the clustering properties of star-forming galaxies at z ˜ 2

    NASA Astrophysics Data System (ADS)

    Ishikawa, Shogo; Kashikawa, Nobunari; Toshikawa, Jun; Onoue, Masafusa

    2015-11-01

    We present the results of clustering analysis on z ˜ 2 star-forming galaxies. By combining our data with data from publicly available archives, we collect g-, zB/z- and K-band imaging data over 5.2 deg2, which represents the largest area BzK/gzK survey. We apply colour corrections to translate our filter set to those used in the original BzK selection for the gzK selection. Because of the wide survey area, we obtain a sample of 41 112 star-forming gzK galaxies at z ˜ 2 (sgzK galaxies) down to KAB < 23.0, and we determine high-quality two-point angular correlation functions (ACFs). Our ACFs show an apparent excess from power-law behaviour at small angular scale (θ ≲ 0.01°), which corresponds to the virial radius of a dark halo at z ˜ 2 with a mass of ˜1013 M⊙. We find that the correlation lengths are consistent with the previous estimates over the whole magnitude range; however, our results are evaluated with a smaller margin of error than that in previous studies. The large amount of data enables us to determine ACFs differentially depending on the luminosity of the subset of the data. The mean halo mass of faint sgzK galaxies (22.0 < K ≤ 23.0) was found to be < M_h > = (1.32^{+0.09}_{-0.12}) × 10^{12} h^{-1} M⊙, whereas bright sgzK galaxies (18.0 ≤ K ≤ 21.0) were found to reside in dark haloes with a mass of < M_h > = (3.26^{+1.23}_{-1.02}) × 10^{13} h^{-1} M⊙.

  11. Galaxy and mass assembly (GAMA): projected galaxy clustering

    NASA Astrophysics Data System (ADS)

    Farrow, D. J.; Cole, Shaun; Norberg, Peder; Metcalfe, N.; Baldry, I.; Bland-Hawthorn, Joss; Brown, Michael J. I.; Hopkins, A. M.; Lacey, Cedric G.; Liske, J.; Loveday, Jon; Palamara, David P.; Robotham, A. S. G.; Sridhar, Srivatsan

    2015-12-01

    We measure the projected two-point correlation function of galaxies in the 180 deg2 equatorial regions of the GAMA II survey, for four different redshift slices between z = 0.0 and 0.5. To do this, we further develop the Cole method of producing suitable random catalogues for the calculation of correlation functions. We find that more r-band luminous, more massive and redder galaxies are more clustered. We also find that red galaxies have stronger clustering on scales less than ˜3 h-1 Mpc. We compare to two different versions of the GALFORM galaxy formation model, Lacey et al. (in preparation) and Gonzalez-Perez et al., and find that the models reproduce the trend of stronger clustering for more massive galaxies. However, the models underpredict the clustering of blue galaxies, can incorrectly predict the correlation function on small scales and underpredict the clustering in our sample of galaxies with {˜ } 3 Lr^*. We suggest possible avenues to explore to improve these clustering predictions. The measurements presented in this paper can be used to test other galaxy formation models, and we make the measurements available online to facilitate this.

  12. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Single-probe measurements from DR12 galaxy clustering – towards an accurate model

    SciTech Connect

    Chia -Hsun Chuang; Pellejero-Ibanez, Marco; Rodriguez-Torres, Sergio; Ross, Ashley J.; Zhao, Gong Bo; Wang, Yuting; Antonio J. Cuesta; Rubino-Martin, J. A.; Prada, Francisco; Alam, Shadab; Beutler, Florian; Eisenstein, Daniel J.; Gil-Martin, Hector; Grieb, Jan Kiklas; Ho, Shirley; Kitaura, Francisco -Shu; Percival, Will J.; Rossi, Graziano; Salazar-Albornoz, Salvador; Samushia, Lado; Sanchez, Ariel G.; Satpathy, Siddharth; Slosar, Anze; Tinker, Jeremy L.; Tojeiro, Rita; Vargas-Magana, Mariana; Vazquez, Jose A.; Brownstein, Joel R.; Nichol, Robert C.; Olmstead, Matthew D.

    2016-08-08

    We analyze the broad-range shape of the monopole and quadrupole correlation functions of the BOSS Data Release 12 (DR12) CMASS and LOWZ galaxy sample to obtain constraints on the Hubble expansion rate H(z), the angular-diameter distance DA(z), the normalised growth rate f(z)σ8(z), and the physical matter density Ωmh2. In addition, we adopt wide and flat priors on all model parameters in order to ensure the results are those of a `single-probe' galaxy clustering analysis. We also marginalize over three nuisance terms that account for potential observational systematics affecting the measured monopole. However, such Monte Carlo Markov Chain analysis is computationally expensive for advanced theoretical models, thus we develop a new methodology to speed up our analysis.

  13. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Single-probe measurements from DR12 galaxy clustering – towards an accurate model

    DOE PAGES

    Chia -Hsun Chuang; Pellejero-Ibanez, Marco; Rodriguez-Torres, Sergio; ...

    2016-08-08

    We analyze the broad-range shape of the monopole and quadrupole correlation functions of the BOSS Data Release 12 (DR12) CMASS and LOWZ galaxy sample to obtain constraints on the Hubble expansion rate H(z), the angular-diameter distance DA(z), the normalised growth rate f(z)σ8(z), and the physical matter density Ωmh2. In addition, we adopt wide and flat priors on all model parameters in order to ensure the results are those of a `single-probe' galaxy clustering analysis. We also marginalize over three nuisance terms that account for potential observational systematics affecting the measured monopole. However, such Monte Carlo Markov Chain analysis is computationallymore » expensive for advanced theoretical models, thus we develop a new methodology to speed up our analysis.« less

  14. Cosmology with the largest galaxy cluster surveys: going beyond Fisher matrix forecasts

    SciTech Connect

    Khedekar, Satej; Majumdar, Subhabrata E-mail: subha@tifr.res.in

    2013-02-01

    We make the first detailed MCMC likelihood study of cosmological constraints that are expected from some of the largest, ongoing and proposed, cluster surveys in different wave-bands and compare the estimates to the prevalent Fisher matrix forecasts. Mock catalogs of cluster counts expected from the surveys — eROSITA, WFXT, RCS2, DES and Planck, along with a mock dataset of follow-up mass calibrations are analyzed for this purpose. A fair agreement between MCMC and Fisher results is found only in the case of minimal models. However, for many cases, the marginalized constraints obtained from Fisher and MCMC methods can differ by factors of 30-100%. The discrepancy can be alarmingly large for a time dependent dark energy equation of state, w(a); the Fisher methods are seen to under-estimate the constraints by as much as a factor of 4-5. Typically, Fisher estimates become more and more inappropriate as we move away from ΛCDM, to a constant-w dark energy to varying-w dark energy cosmologies. Fisher analysis, also, predicts incorrect parameter degeneracies. There are noticeable offsets in the likelihood contours obtained from Fisher methods that is caused due to an asymmetry in the posterior likelihood distribution as seen through a MCMC analysis. From the point of mass-calibration uncertainties, a high value of unknown scatter about the mean mass-observable relation, and its redshift dependence, is seen to have large degeneracies with the cosmological parameters σ{sub 8} and w(a) and can degrade the cosmological constraints considerably. We find that the addition of mass-calibrated cluster datasets can improve dark energy and σ{sub 8} constraints by factors of 2-3 from what can be obtained from CMB+SNe+BAO only . Finally, we show that a joint analysis of datasets of two (or more) different cluster surveys would significantly tighten cosmological constraints from using clusters only. Since, details of future cluster surveys are still being planned, we emphasize

  15. Cluster Mass Calibration at High Redshift: HST Weak Lensing Analysis of 13 Distant Galaxy Clusters from the South Pole Telescope Sunyaev-Zel'dovich Survey

    SciTech Connect

    Schrabback, T.; et al.

    2016-11-11

    We present an HST/ACS weak gravitational lensing analysis of 13 massive high-redshift (z_median=0.88) galaxy clusters discovered in the South Pole Telescope (SPT) Sunyaev-Zel'dovich Survey. This study is part of a larger campaign that aims to robustly calibrate mass-observable scaling relations over a wide range in redshift to enable improved cosmological constraints from the SPT cluster sample. We introduce new strategies to ensure that systematics in the lensing analysis do not degrade constraints on cluster scaling relations significantly. First, we efficiently remove cluster members from the source sample by selecting very blue galaxies in V-I colour. Our estimate of the source redshift distribution is based on CANDELS data, where we carefully mimic the source selection criteria of the cluster fields. We apply a statistical correction for systematic photometric redshift errors as derived from Hubble Ultra Deep Field data and verified through spatial cross-correlations. We account for the impact of lensing magnification on the source redshift distribution, finding that this is particularly relevant for shallower surveys. Finally, we account for biases in the mass modelling caused by miscentring and uncertainties in the mass-concentration relation using simulations. In combination with temperature estimates from Chandra we constrain the normalisation of the mass-temperature scaling relation ln(E(z) M_500c/10^14 M_sun)=A+1.5 ln(kT/7.2keV) to A=1.81^{+0.24}_{-0.14}(stat.) +/- 0.09(sys.), consistent with self-similar redshift evolution when compared to lower redshift samples. Additionally, the lensing data constrain the average concentration of the clusters to c_200c=5.6^{+3.7}_{-1.8}.

  16. Galaxy clusters in the cosmic web

    NASA Astrophysics Data System (ADS)

    Acebrón, A.; Durret, F.; Martinet, N.; Adami, C.; Guennou, L.

    2014-12-01

    Simulations of large scale structure formation in the universe predict that matter is essentially distributed along filaments at the intersection of which lie galaxy clusters. We have analysed 9 clusters in the redshift range 0.4survey, which combines deep large field multi-band imaging and spectroscopic data, in order to detect filaments and/or structures around these clusters. Based on colour-magnitude diagrams, we have selected the galaxies likely to be in the cluster redshift range and studied their spatial distribution. We detect a number of structures and filaments around several clusters, proving that colour-magnitude diagrams are a reliable method to detect filaments around galaxy clusters. Since this method excludes blue (spiral) galaxies at the cluster redshift, we also apply the LePhare software to compute photometric redshifts from BVRIZ images to select galaxy cluster members and study their spatial distribution. We then find that, if only galaxies classified as early-type by LePhare are considered, we obtain the same distribution than with a red sequence selection, while taking into account late-type galaxies just pollutes the background level and deteriorates our detections. The photometric redshift based method therefore does not provide any additional information.

  17. X-RAY EMISSION FROM TWO INFRARED-SELECTED GALAXY CLUSTERS AT z > 1.4 IN THE IRAC SHALLOW CLUSTER SURVEY

    SciTech Connect

    Brodwin, M.; Vikhlinin, A.; Ashby, M. L. N.; Forman, W. R.; Jones, C.; Snyder, G.; Stern, D.; Eisenhardt, P. R.; Moustakas, L. A.; Stanford, S. A.; Zeimann, G.; Gonzalez, A. H.; Gettings, D.; Mancone, C.; Bautz, M.; Miller, E. D.; Dey, A.; Jannuzi, B. T.; Hickox, R. C.; Ruel, J.

    2011-05-01

    We report the X-ray detection of two z > 1.4 infrared-selected galaxy clusters from the IRAC Shallow Cluster Survey (ISCS). We present new data from the Hubble Space Telescope and the W. M. Keck Observatory that spectroscopically confirm cluster ISCS J1432.4+3250 at z = 1.49, the most distant of 18 confirmed z > 1 clusters in the ISCS to date. We also present new spectroscopy for ISCS J1438.1+3414, previously reported at z = 1.41, and measure its dynamical mass. Clusters ISCS J1432.4+3250 and ISCS J1438.1+3414 are detected in 36 ks and 143 ks Chandra exposures at significances of 5.2{sigma} and 9.7{sigma}, from which we measure total masses of log (M{sub 200,L{sub X}}/M{sub sun}) = 14.4 {+-} 0.2 and 14.35 {sup +0.14}{sub -0.11}, respectively. The consistency of the X-ray and dynamical properties of these high-redshift clusters further demonstrates that the ISCS is robustly detecting massive clusters to at least z = 1.5.

  18. The Next Generation Virgo Cluster Survey XVI: The Angular Momentum of Dwarf Early-type Galaxies from Globular Cluster Satellites

    NASA Astrophysics Data System (ADS)

    Toloba, Elisa; Li, Biao; Guhathakurta, Puragra; Peng, Eric W.; Ferrarese, Laura; Côté, Patrick; Emsellem, Eric; Gwyn, Stephen; Zhang, Hongxin; Boselli, Alessandro; Cuillandre, Jean-Charles; Jordan, Andres; Liu, Chengze

    2016-05-01

    We analyze the kinematics of six Virgo cluster dwarf early-type galaxies (dEs) from their globular cluster (GC) systems. We present new Keck/DEIMOS spectroscopy for three of them and re-analyze the data found in the literature for the remaining three. We use two independent methods to estimate the rotation amplitude (V rot) and velocity dispersion (σ GC) of the GC systems and evaluate their statistical significance by simulating non-rotating GC systems with the same number of GC satellites and velocity uncertainties. Our measured kinematics agree with the published values for the three galaxies from the literature and, in all cases, some rotation is measured. However, our simulations show that the null hypothesis of being non-rotating GC systems cannot be ruled out. In the case of VCC 1861, the measured V rot and the simulations indicate that it is not rotating. In the case of VCC 1528, the null hypothesis can be marginally ruled out, and thus it might be rotating although further confirmation is needed. In our analysis, we find that, in general, the measured V rot tends to be overestimated and the measured σ GC tends to be underestimated by amounts that depend on the intrinsic V rot/σ GC, the number of observed GCs (N GC), and the velocity uncertainties. The bias is negligible when N GC ≳ 20. In those cases where a large N GC is not available, it is imperative to obtain data with small velocity uncertainties. For instance, errors of ≤2 km s-1 lead to V rot < 10 km s-1 for a system that is intrinsically not rotating.

  19. The Clustering of Galaxies in the Completed SDSS-III Baryon Oscillation Spectroscopic Survey: Cosmic Flows and Cosmic Web from Luminous Red Galaxies

    NASA Astrophysics Data System (ADS)

    Ata, Metin; Kitaura, Francisco-Shu; Chuang, Chia-Hsun; Rodríguez-Torres, Sergio; Angulo, Raul E.; Ferraro, Simone; Gil-Marín, Hector; McDonald, Patrick; Monteagudo, Carlos Hernández; Müller, Volker; Yepes, Gustavo; Autefage, Mathieu; Baumgarten, Falk; Beutler, Florian; Brownstein, Joel R.; Burden, Angela; Eisenstein, Daniel J.; Guo, Hong; Ho, Shirley; McBride, Cameron; Neyrinck, Mark; Olmstead, Matthew D.; Padmanabhan, Nikhil; Percival, Will J.; Prada, Francisco; Rossi, Graziano; Sánchez, Ariel G.; Schlegel, David; Schneider, Donald P.; Seo, Hee-Jong; Streblyanska, Alina; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana

    2017-01-01

    We present a Bayesian phase-space reconstruction of the cosmic large-scale matter density and velocity fields from the SDSS-III Baryon Oscillations Spectroscopic Survey Data Release 12 (BOSS DR12) CMASS galaxy clustering catalogue. We rely on a given ΛCDM cosmology, a mesh resolution in the range of 6-10 h-1 Mpc, and a lognormal-Poisson model with a redshift dependent nonlinear bias. The bias parameters are derived from the data and a general renormalised perturbation theory approach. We use combined Gibbs and Hamiltonian sampling, implemented in the ARGO code, to iteratively reconstruct the dark matter density field and the coherent peculiar velocities of individual galaxies, correcting hereby for coherent redshift space distortions (RSD). Our tests relying on accurate N-body based mock galaxy catalogues, show unbiased real space power spectra of the nonlinear density field up to k ˜ 0.2 h Mpc-1, and vanishing quadrupoles down to r ˜ 20 h-1 Mpc. We also demonstrate that the nonlinear cosmic web can be obtained from the tidal field tensor based on the Gaussian component of the reconstructed density field. We find that the reconstructed velocities have a statistical correlation coefficient compared to the true velocities of each individual lightcone mock galaxy of r ˜ 0.68 including about 10% of satellite galaxies with virial motions (about r = 0.75 without satellites). The power spectra of the velocity divergence agree well with theoretical predictions up to k ˜ 0.2 h Mpc-1. This work will be especially useful to improve, e.g. BAO reconstructions, kinematic Sunyaev-Zeldovich (kSZ), integrated Sachs-Wolfe (ISW) measurements, or environmental studies.

  20. The Burrell Schmidt Deep Virgo Survey: Tidal Debris, Galaxy Halos, and Diffuse Intracluster Light in the Virgo Cluster

    NASA Astrophysics Data System (ADS)

    Mihos, J. Christopher; Harding, Paul; Feldmeier, John J.; Rudick, Craig; Janowiecki, Steven; Morrison, Heather; Slater, Colin; Watkins, Aaron

    2017-01-01

    We present the results of a deep imaging survey of the Virgo cluster of galaxies, concentrated around the cores of Virgo subclusters A and B. The goal of this survey was to detect and study very low surface brightness features present in Virgo, including discrete tidal features, the faint halos of luminous galaxies, and the diffuse intracluster light (ICL). Our observations span roughly 16 degrees2 in two filters, reaching a 3σ limiting depth of {μ }B = 29.5 and {μ }V = 28.5 mag arcsec‑2. At these depths, our limiting systematic uncertainties are astrophysical: variations in faint background sources as well as scattered light from galactic dust. We show that this dust-scattered light is well traced by deep far-infrared imaging, making it possible to separate it from true diffuse light in Virgo. We use our imaging to trace and measure the color of the diffuse tidal streams and ICL in the Virgo core near M87, in fields adjacent to the core including the M86/M84 region, and to the south of the core around M49 and subcluster B, along with the more distant W{}\\prime cloud around NGC 4365. Overall, the bulk of the projected ICL is found in the Virgo core and within the W{}\\prime cloud; we find little evidence for an extensive ICL component in the field around M49. The bulk of the ICL we detect is fairly red in color (B ‑ V = 0.7–0.9), indicative of old, evolved stellar populations. Based on the luminosity of the observed ICL features in the cluster, we estimate a total Virgo ICL fraction of 7%–15%. This value is somewhat smaller than that expected for massive, evolved clusters, suggesting that Virgo is still in the process of growing its extended ICL component. We also trace the shape of M87's extremely boxy outer halo out to ∼150 kpc, and show that the current tidal stripping rate from low luminosity galaxies is insufficient to have built M87's outer halo over a Hubble time. We identify a number of previously unknown low surface brightness structures

  1. Comparison of galaxy clusters selected by weak-lensing, optical spectroscopy, and X-rays in the deep lens survey F2 field

    SciTech Connect

    Starikova, Svetlana; Jones, Christine; Forman, William R.; Vikhlinin, Alexey; Kurtz, Michael J.; Fabricant, Daniel G.; Murray, Stephen S.; Geller, Margaret J.; Dell'Antonio, Ian P.

    2014-05-10

    We compare galaxy clusters selected in Chandra and XMM-Newton X-ray observations of the 4 deg{sup 2} Deep Lens Survey (DLS) F2 field to the cluster samples previously selected in the same field from a sensitive weak-lensing shear map derived from the DLS and from a detailed galaxy redshift survey—the Smithsonian Hectospec Lensing Survey (SHELS). Our Chandra and XMM-Newton observations cover 1.6 deg{sup 2} of the DLS F2 field, including all 12 weak-lensing peaks above a signal-to-noise ratio of 3.5, along with 16 of the 20 SHELS clusters with published velocity dispersions >500 km s{sup –1}. We detect 26 extended X-ray sources in this area and confirm 23 of them as galaxy clusters using the optical imaging. Approximately 75% of clusters detected in either X-ray or spectroscopic surveys are found in both; these follow the previously established scaling relations between velocity dispersion, L {sub X}, and T {sub X}. A lower percentage, 60%, of clusters are in common between X-ray and DLS samples. With the exception of a high false-positive rate in the DLS weak-lensing search (5 out of 12 DLS candidates appear to be false), differences between the three cluster detection methods can be attributed primarily to observational uncertainties and intrinsic scatter between different observables and cluster mass.

  2. Record-breaking ancient galaxy clusters

    NASA Astrophysics Data System (ADS)

    2003-12-01

    A tale of two record-breaking clusters hi-res Size hi-res: 768 kb Credits: for RDCS1252: NASA, ESA, J.Blakeslee (Johns Hopkins Univ.), M.Postman (Space Telescope Science Inst.) and P.Rosati, Chris Lidman & Ricardo Demarco (European Southern Observ.) for TNJ1338: NASA, ESA, G.Miley (Leiden Observ.) and R.Overzier (Leiden Obs) A tale of two record-breaking clusters Looking back in time to when the universe was in its formative youth, the Advanced Camera for Surveys (ACS) aboard the NASA/ESA Hubble Space Telescope captured these revealing images of two galaxy clusters. The image at left, which is made with an additional infrared exposure taken with the European Southern Observatory’s Very Large Telescope, shows mature galaxies in a massive cluster that existed when the cosmos was 5000 million years old. The cluster, called RDCS1252.9-2927, is as massive as ‘300 trillion’ suns and is the most massive known cluster for its epoch. The image reveals the core of the cluster and is part of a much larger mosaic of the entire cluster. Dominating the core are a pair of large, reddish elliptical galaxies [near centre of image]. Their red colour indicates an older population of stars. Most of the stars are at least 1000 million years old. The two galaxies appear to be interacting and may eventually merge to form a larger galaxy that is comparable to the brightest galaxies seen in present-day clusters. The red galaxies surrounding the central pair are also cluster members. The cluster probably contains many thousands of galaxies, but only about 50 can be seen in this image. The full mosaic (heic0313d) reveals several hundred cluster members. Many of the other galaxies in the image, including several of the blue galaxies, are foreground or background galaxies. The colour-composite image was assembled from two observations (through i and z filters) taken between May and June 2002 by the ACS Wide Field Camera, and one image with the ISAAC instrument on the VLT taken in 2002

  3. The Rotation of Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Tovmassian, H. M.

    2015-09-01

    The method for detection of the galaxy cluster rotation based on the study of distribution of member galaxies with velocities lower and higher than the cluster mean velocity over the cluster image is proposed. The search for rotation is made for flat clusters with a/b > 1.8 and BMI type clusters which are expected to be rotating. For comparison there were studied also round clusters and clusters of NBMI type, the second by brightness galaxy, which does not differ significantly from the cluster cD galaxy. Seventeen out of studied 65 clusters are found to be rotating. It was found that the detection rate is sufficiently high for flat clusters, over 60%, and clusters of BMI type with dominant cD galaxy, ≈ 35% . The obtained results show that clusters were formed from the huge primordial gas clouds and preserved the rotation of the primordial clouds, unless they did not experience mergings with other clusters and groups of galaxies, as a result of which the rotation was prevented.

  4. A NEW REDUCTION OF THE BLANCO COSMOLOGY SURVEY: AN OPTICALLY SELECTED GALAXY CLUSTER CATALOG AND A PUBLIC RELEASE OF OPTICAL DATA PRODUCTS

    SciTech Connect

    Bleem, L. E.; Stalder, B.; Brodwin, M.; Busha, M. T.; Wechsler, R. H.; Gladders, M. D.; High, F. W.; Rest, A.

    2015-01-01

    The Blanco Cosmology Survey is a four-band (griz) optical-imaging survey of ∼80 deg{sup 2} of the southern sky. The survey consists of two fields centered approximately at (R.A., decl.) = (23{sup h}, –55°) and (5{sup h}30{sup m}, –53°) with imaging sufficient for the detection of L {sub *} galaxies at redshift z ≤ 1. In this paper, we present our reduction of the survey data and describe a new technique for the separation of stars and galaxies. We search the calibrated source catalogs for galaxy clusters at z ≤ 0.75 by identifying spatial over-densities of red-sequence galaxies and report the coordinates, redshifts, and optical richnesses, λ, for 764 galaxy clusters at z ≤ 0.75. This sample, >85% of which are new discoveries, has a median redshift of z = 0.52 and median richness λ(0.4 L {sub *}) = 16.4. Accompanying this paper we also release full survey data products including reduced images and calibrated source catalogs. These products are available at http://data.rcc.uchicago.edu/dataset/blanco-cosmology-survey.

  5. Galaxies in X-Ray Selected Clusters and Groups in Dark Energy Survey Data. I. Stellar Mass Growth of Bright Central Galaxies since z~1.2

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Miller, C.; McKay, T.; Rooney, P.; Evrard, A. E.; Romer, A. K.; Perfecto, R.; Song, J.; Desai, S.; Mohr, J.; Wilcox, H.; Bermeo-Hernandez, A.; Jeltema, T.; Hollowood, D.; Bacon, D.; Capozzi, D.; Collins, C.; Das, R.; Gerdes, D.; Hennig, C.; Hilton, M.; Hoyle, B.; Kay, S.; Liddle, A.; Mann, R. G.; Mehrtens, N.; Nichol, R. C.; Papovich, C.; Sahlén, M.; Soares-Santos, M.; Stott, J.; Viana, P. T.; Abbott, T.; Abdalla, F. B.; Banerji, M.; Bauer, A. H.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Castander, F. J.; Diehl, H. T.; Doel, P.; Cunha, C. E.; Eifler, T. F.; Fausti Neto, A.; Fernandez, E.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gaztanaga, E.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marshall, J. L.; Martini, Paul; Miquel, R.; Ogando, R.; Plazas, A. A.; Roodman, A.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla, I.; Smith, R. C.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Tucker, D.; Vikram, V.; da Costa, L. N.

    2016-01-01

    Using the science verification data of the Dark Energy Survey for a new sample of 106 X-ray selected clusters and groups, we study the stellar mass growth of bright central galaxies (BCGs) since redshift z ~ 1.2. Compared with the expectation in a semi-analytical model applied to the Millennium Simulation, the observed BCGs become under-massive/under-luminous with decreasing redshift. We incorporate the uncertainties associated with cluster mass, redshift, and BCG stellar mass measurements into an analysis of a redshift-dependent BCG-cluster mass relation, m*∝ (M200/{1.5×10}14M⊙})0.24+/-0.08 (1+z)-0.19+/- 0.34, and compare the observed relation to the model prediction. We estimate the average growth rate since z = 1.0 for BCGs hosted by clusters of M200,z = 1013.8 M⊙ at z = 1.0: m*,BCG appears to have grown by 0.13 ± 0.11 dex, in tension at the ˜2.5σ significance level with the 0.40 dex growth rate expected from the semi-analytic model. We show that the build-up of extended intracluster light after z = 1.0 may alleviate this tension in BCG growth rates.

  6. Radio luminosity function of brightest cluster galaxies

    NASA Astrophysics Data System (ADS)

    Yuan, Z. S.; Han, J. L.; Wen, Z. L.

    2016-08-01

    By cross-matching the currently largest optical catalogue of galaxy clusters and the NVSS radio survey data base, we obtain a large complete sample of brightest cluster galaxies (BCGs) in the redshift range of 0.05 < z ≤ 0.45, which have radio emission and redshift information. We confirm that more powerful radio BCGs tend to be these optically very bright galaxies located in more relaxed clusters. We derived the radio luminosity functions of the largest sample of radio BCGs, and find that the functions depend on the optical luminosity of BCGs and the dynamic state of galaxy clusters. However, the radio luminosity function does not show significant evolution with redshift.

  7. Massive star clusters in galaxies.

    PubMed

    Harris, William E

    2010-02-28

    The ensemble of all star clusters in a galaxy constitutes its star cluster system. In this review, the focus of the discussion is on the ability of star clusters, particularly the systems of old massive globular clusters (GCs), to mark the early evolutionary history of galaxies. I review current themes and key findings in GC research, and highlight some of the outstanding questions that are emerging from recent work.

  8. On the clustering of faint red galaxies

    NASA Astrophysics Data System (ADS)

    Xu, Haojie; Zheng, Zheng; Guo, Hong; Zhu, Ju; Zehavi, Idit

    2016-08-01

    Faint red galaxies in the Sloan Digital Sky Survey show a puzzling clustering pattern in previous measurements. In the two-point correlation function (2PCF), they appear to be strongly clustered on small scales, indicating a tendency to reside in massive haloes as satellite galaxies. However, their weak clustering on large scales suggests that they are more likely to be found in low-mass haloes. The interpretation of the clustering pattern suffers from the large sample variance in the 2PCF measurements, given the small volume of the volume-limited sample of such faint galaxies. We present improved clustering measurements of faint galaxies by making a full use of a flux-limited sample to obtain volume-limited measurements with an increased effective volume. In the improved 2PCF measurements, the fractional uncertainties on large scales drop by more than 40 per cent, and the strong contrast between small-scale and large-scale clustering amplitudes seen in previous work is no longer prominent. From halo occupation distribution modelling of the measurements, we find that a considerable fraction of faint red galaxies to be satellites in massive haloes, a scenario supported by the strong covariance of small-scale 2PCF measurements and the relative spatial distribution of faint red galaxies and luminous galaxies. However, the satellite fraction is found to be degenerate with the slope of the distribution profile of satellites in inner haloes. We compare the modelling results with semi-analytic model predictions and discuss the implications.

  9. A serach for 'failed clusters' of galaxies

    NASA Technical Reports Server (NTRS)

    Tucker, W. H.; Tananbaum, H.; Remillard, R. A.

    1995-01-01

    We describe a search for a new type of object - large clouds of hot gas with no visible galaxies - which we call failed clusters of galaxies. We calculate the expected X-ray luminosity, temperature, and angular diameter of such objects as a function of total cloud mass and convert the results to expected X-ray fluxes from failed clusters at different redshifts. Using the Einstein Imaging Proportional Counter (IPC) database, we establish a strategy to search for candidate failed clusters. From this initial screening of 1435 IPC fields, 17 candidates are selected for more detailed analysis, which indicates that 10 of these are very probably extended X-ray sources. Optical follow-up on the 10 prime candidates finds eight clusters of galaxies (including six reproted for the first time in this paper), one stellar identification, and one without an obvious optical counterpart (the candidate with the weakest evidence for X-ray extent). Investigation of several candidates with less evidence for X-ray extent yields two additional new clusters of galaxies. A conservative comparison of our results with the Einstein Extended Medium Sensitivity Survey demonstrates that failed clusters are a relatively unimportant contributor to the mass density of the universe. Our inability to find failed clusters is consistent with the hierarchical clustering scenario for the formation of galaxies and clusters.

  10. The VIMOS-VLT Deep Survey (VVDS). The dependence of clustering on galaxy stellar mass at z ~ 1

    NASA Astrophysics Data System (ADS)

    Meneux, B.; Guzzo, L.; Garilli, B.; Le Fèvre, O.; Pollo, A.; Blaizot, J.; De Lucia, G.; Bolzonella, M.; Lamareille, F.; Pozzetti, L.; Cappi, A.; Iovino, A.; Marinoni, C.; McCracken, H. J.; de la Torre, S.; Bottini, D.; Le Brun, V.; Maccagni, D.; Picat, J. P.; Scaramella, R.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Abbas, U.; Adami, C.; Arnouts, S.; Bardelli, S.; Bongiorno, A.; Charlot, S.; Ciliegi, P.; Contini, T.; Cucciati, O.; Foucaud, S.; Franzetti, P.; Gavignaud, I.; Ilbert, O.; Marano, B.; Mazure, A.; Merighi, R.; Paltani, S.; Pellò, R.; Radovich, M.; Vergani, D.; Zamorani, G.; Zucca, E.

    2008-02-01

    We present a measurement of the dependence of galaxy clustering on galaxy stellar mass at redshift z˜0.9, based on the first-epoch data from the VVDS-Deep survey. Concentrating on the redshift interval 0.5survey, both from the data themselves and with a suite of realistic mock samples constructed by coupling the Millennium Simulation to semi-analytic models. We identify the range of masses within which our main conclusions are robust against these effects. Serious incompleteness in mass is present below log (M/M_⊙)=9.5, with about two thirds of the galaxies in the range 9clustering on the galaxy stellar mass at a redshift as high as z˜0.85. We quantify this by fitting the projected function w_p(r_p) with a power-law model. The clustering length increases from r_0=2.76-0.15+0.17~h-1 Mpc for galaxies with mass M>109~M_⊙ to r_0=4.28-0.45+0.43~h-1 Mpc when only the most massive (M>1010.5~M_⊙) are considered. At the same time, we observe a significant increase in the slope, which over the same range of masses, changes from γ=1.67-0.07+0.08 to γ=2.28-0.27+0.28. Comparison to the SDSS measurements at z˜0.15 shows that the evolution of w_p(r_p) is significant for samples of galaxies with M<1010.5~M_⊙, while it is negligible for more massive objects. Considering the growth of structure, this implies that the linear bias bL of the most massive galaxies evolves more rapidly between these two cosmic epochs. We quantify this effect by computing the value of bL from the SDSS and VVDS clustering

  11. THE IMACS CLUSTER BUILDING SURVEY. IV. THE LOG-NORMAL STAR FORMATION HISTORY OF GALAXIES

    SciTech Connect

    Gladders, Michael D.; Abramson, Louis; Oemler, Augustus; Dressler, Alan; Poggianti, Bianca; Vulcani, Benedetta

    2013-06-10

    We present here a simple model for the star formation history (SFH) of galaxies that is successful in describing both the star formation rate density (SFRD) over cosmic time, as well as the distribution of specific star formation rates (sSFRs) of galaxies at the current epoch, and the evolution of this quantity in galaxy populations to a redshift of z = 1. We show first that the cosmic SFRD is remarkably well described by a simple log-normal in time. We next postulate that this functional form for the ensemble is also a reasonable description for the SFHs of individual galaxies. Using the measured sSFRs for galaxies at z {approx} 0 from Paper III in this series, we then construct a realization of a universe populated by such galaxies in which the parameters of the log-normal SFH of each galaxy are adjusted to match the sSFRs at z {approx} 0 as well as fitting, in ensemble, the cosmic SFRD from z = 0 to z = 8. This model predicts, with striking fidelity, the distribution of sSFRs in mass-limited galaxy samples to z = 1; this match is not achieved by other models with a different functional form for the SFHs of individual galaxies, but with the same number of degrees of freedom, suggesting that the log-normal form is well matched to the likely actual histories of individual galaxies. We also impose the sSFR versus mass distributions at higher redshifts from Paper III as constraints on the model, and show that, as previously suggested, some galaxies in the field, particularly low mass galaxies, are quite young at intermediate redshifts. As emphasized in Paper III, starbursts are insufficient to explain the enhanced sSFRs in intermediate redshift galaxies; we show here that a model using only smoothly varying log-normal SFHs for galaxies, which allows for some fraction of the population to have peak star formation at late times, does however fully explain the observations. Finally, we show that this model, constrained in detail only at redshifts z < 1, also produces

  12. Astrophysics of galaxy clusters

    NASA Astrophysics Data System (ADS)

    Ettori, Stefano

    2016-07-01

    As the nodes of the cosmic web, clusters of galaxies trace the large-scale distribution of matter in the Universe. They are thus privileged sites in which to investigate the complex physics of structure formation. However, the complete story of how these structures grow, and how they dissipate the gravitational and non-thermal components of their energy budget over cosmic time, is still beyond our grasp. Most of the baryons gravitationally bound to the cluster's halo is in the form of a diffuse, hot, metal-enriched plasma that radiates primarily in the X-ray band. X-ray observations of the evolving cluster population provide a unique opportunity to address such fundamental open questions as: How do hot diffuse baryons accrete and dynamically evolve in dark matter potentials? How and when was the energy that we observe in the ICM generated and distributed? Where and when are heavy elements produced and how are they circulated? We will present the ongoing activities to define the strategy on how an X-ray observatory with large collecting area and an unprecedented combination of high spectral and angular resolution, such as Athena, can address these questions.

  13. Measuring the Scatter of the Mass-Richness Relation in Galaxy Clusters in Photometric Imaging Surveys by Means of Their Correlation Function

    SciTech Connect

    Campa, Julia; Flaugher, Brenna; Estrada, Juan

    2015-12-04

    The knowledge of the scatter in the mass-observable relation is a key ingredient for a cosmological analysis based on galaxy clusters in a photometric survey. We demonstrate here how the linear bias measured in the correlation function for clusters can be used to determine the value of the scatter. The new method is tested in simulations of a 5.000 square degrees optical survey up to z~1, similar to the ongoing Dark Energy Survey. The results indicate that the scatter can be measured with a precision of 5% using this technique.

  14. The Herschel Virgo Cluster Survey. IX. Dust-to-gas mass ratio and metallicity gradients in four Virgo spiral galaxies

    NASA Astrophysics Data System (ADS)

    Magrini, L.; Bianchi, S.; Corbelli, E.; Cortese, L.; Hunt, L.; Smith, M.; Vlahakis, C.; Davies, J.; Bendo, G. J.; Baes, M.; Boselli, A.; Clemens, M.; Casasola, V.; De Looze, I.; Fritz, J.; Giovanardi, C.; Grossi, M.; Hughes, T.; Madden, S.; Pappalardo, C.; Pohlen, M.; di Serego Alighieri, S.; Verstappen, J.

    2011-11-01

    Context. Using Herschel data from the open time key project the Herschel Virgo Cluster Survey (HeViCS), we investigated the relationship between the metallicity gradients expressed by metal abundances in the gas phase as traced by the chemical composition of HII regions, and in the solid phase, as traced by the dust-to-gas mass ratio. Aims: We derived the radial gradient of the dust-to-gas mass ratio for all galaxies observed by HeViCS whose metallicity gradients are available in the literature. They are all late type Sbc galaxies, namely NGC 4254, NGC 4303, NGC 4321, and NGC 4501. Methods: We fitted PACS and SPIRE observations with a single-temperature modified blackbody, inferred the dust mass, and calculated two dimensional maps of the dust-to-gas mass ratio, with the total mass of gas from available HI and CO maps. HI moment-1 maps were used to derive the geometric parameters of the galaxies and extract the radial profiles. We examined different dependencies on metallicity of the CO-to-H2 conversion factor (XCO), used to transform the 12CO observations into the amount of molecular hydrogen. Results: We found that in these galaxies the dust-to-gas mass ratio radial profile is extremely sensitive to choice of the XCO value, since the molecular gas is the dominant component in the inner parts. We found that for three galaxies of our sample, namely NGC 4254, NGC 4321, and NGC 4501, the slopes of the oxygen and of the dust-to-gas radial gradients agree up to ~0.6-0.7 R25 using XCO values in the range 1/3-1/2 Galactic XCO. For NGC 4303 a lower value of XCO ~ 0.1 × 1020 is necessary. Conclusions: We suggest that such low XCO values might be due to a metallicity dependence of XCO (from close to linear for NGC 4254, NGC 4321, and NGC 4501 to superlinear for NGC 4303), especially in the radial regions RG < 0.6-0.7 R25 where the molecular gas dominates. On the other hand, the outer regions, where the atomic gas component is dominant, are less affected by the choice of

  15. The structure of early-type galaxies from the ACS Virgo and Fornax cluster surveys: cores, nuclei and supermassive black holes

    NASA Astrophysics Data System (ADS)

    Ferrarese, Laura; Côté, Patrick

    2008-07-01

    The core structure of early-type galaxies is revisited in light of recent results from the ACS Virgo and Fornax Cluster Surveys. These surveys are comprised of HST/ACS g, z band images for a representative sample of 143 early-type galaxies, spanning a factor 720 in B-band luminosity. The data indicates a clear transition in the core structure going from the brightest to the faintest galaxies. In contrast to previous claims, however, this transition is found to be a continuous function of galaxy magnitude. We characterize the core structure in terms of deviations of the observed surface brightness profile measured within ~ 2% of the galaxy effective radius relative to the inner extrapolation of the Sérsic law that best fits the profiles on larger scales. Virtually all galaxies fainter than MB ~ -20 mag contain distinct stellar nuclei, and are described by surface brightness profiles that lie above the Sérsic extrapolation, while the reverse is true for brighter galaxies. The latter are also known to host supermassive black holes. A relation between SBHs and stellar nuclei is suggested by the fact that both types of “central massive objects” contain the same fraction, 0.2% of the total mass of the host galaxy.

  16. K2: A New Method for the Detection of Galaxy Clusters Based on Canada-France-Hawaii Telescope Legacy Survey Multicolor Images

    NASA Astrophysics Data System (ADS)

    Thanjavur, Karun; Willis, Jon; Crampton, David

    2009-11-01

    We have developed a new method, K2, optimized for the detection of galaxy clusters in multicolor images. Based on the Red Sequence approach, K2 detects clusters using simultaneous enhancements in both colors and position. The detection significance is robustly determined through extensive Monte Carlo simulations and through comparison with available cluster catalogs based on two different optical methods, and also on X-ray data. K2 also provides quantitative estimates of the candidate clusters' richness and photometric redshifts. Initially, K2 was applied to the two color (gri) 161 deg2 images of the Canada-France-Hawaii Telescope Legacy Survey Wide (CFHTLS-W) data. Our simulations show that the false detection rate for these data, at our selected threshold, is only ~1%, and that the cluster catalogs are ~80% complete up to a redshift of z = 0.6 for Fornax-like and richer clusters and to z ~ 0.3 for poorer clusters. Based on the g-, r-, and i-band photometric catalogs of the Terapix T05 release, 35 clusters/deg2 are detected, with 1-2 Fornax-like or richer clusters every 2 deg2. Catalogs containing data for 6144 galaxy clusters have been prepared, of which 239 are rich clusters. These clusters, especially the latter, are being searched for gravitational lenses—one of our chief motivations for cluster detection in CFHTLS. The K2 method can be easily extended to use additional color information and thus improve overall cluster detection to higher redshifts. The complete set of K2 cluster catalogs, along with the supplementary catalogs for the member galaxies, are available on request from the authors.

  17. K2: A NEW METHOD FOR THE DETECTION OF GALAXY CLUSTERS BASED ON CANADA-FRANCE-HAWAII TELESCOPE LEGACY SURVEY MULTICOLOR IMAGES

    SciTech Connect

    Thanjavur, Karun; Willis, Jon; Crampton, David

    2009-11-20

    We have developed a new method, K2, optimized for the detection of galaxy clusters in multicolor images. Based on the Red Sequence approach, K2 detects clusters using simultaneous enhancements in both colors and position. The detection significance is robustly determined through extensive Monte Carlo simulations and through comparison with available cluster catalogs based on two different optical methods, and also on X-ray data. K2 also provides quantitative estimates of the candidate clusters' richness and photometric redshifts. Initially, K2 was applied to the two color (gri) 161 deg{sup 2} images of the Canada-France-Hawaii Telescope Legacy Survey Wide (CFHTLS-W) data. Our simulations show that the false detection rate for these data, at our selected threshold, is only approx1%, and that the cluster catalogs are approx80% complete up to a redshift of z = 0.6 for Fornax-like and richer clusters and to z approx 0.3 for poorer clusters. Based on the g-, r-, and i-band photometric catalogs of the Terapix T05 release, 35 clusters/deg{sup 2} are detected, with 1-2 Fornax-like or richer clusters every 2 deg{sup 2}. Catalogs containing data for 6144 galaxy clusters have been prepared, of which 239 are rich clusters. These clusters, especially the latter, are being searched for gravitational lenses-one of our chief motivations for cluster detection in CFHTLS. The K2 method can be easily extended to use additional color information and thus improve overall cluster detection to higher redshifts. The complete set of K2 cluster catalogs, along with the supplementary catalogs for the member galaxies, are available on request from the authors.

  18. SUPERDENSE MASSIVE GALAXIES IN WINGS LOCAL CLUSTERS

    SciTech Connect

    Valentinuzzi, T.; D'Onofrio, M.; Fritz, J.; Poggianti, B. M.; Bettoni, D.; Fasano, G.; Moretti, A.; Omizzolo, A.; Varela, J.; Cava, A.; Couch, W. J.; Dressler, A.; Moles, M.; Kjaergaard, P.; Vanzella, E.

    2010-03-20

    Massive quiescent galaxies at z > 1 have been found to have small physical sizes, and hence to be superdense. Several mechanisms, including minor mergers, have been proposed for increasing galaxy sizes from high- to low-z. We search for superdense massive galaxies in the WIde-field Nearby Galaxy-cluster Survey (WINGS) of X-ray selected galaxy clusters at 0.04 < z < 0.07. We discover a significant population of superdense massive galaxies with masses and sizes comparable to those observed at high redshift. They approximately represent 22% of all cluster galaxies more massive than 3 x 10{sup 10} M{sub sun}, are mostly S0 galaxies, have a median effective radius (R{sub e} ) = 1.61 +- 0.29 kpc, a median Sersic index (n) = 3.0 +- 0.6, and very old stellar populations with a median mass-weighted age of 12.1 +- 1.3 Gyr. We calculate a number density of 2.9 x 10{sup -2} Mpc{sup -3} for superdense galaxies in local clusters, and a hard lower limit of 1.3 x 10{sup -5} Mpc{sup -3} in the whole comoving volume between z = 0.04 and z = 0.07. We find a relation between mass, effective radius, and luminosity-weighted age in our cluster galaxies, which can mimic the claimed evolution of the radius with redshift, if not properly taken into account. We compare our data with spectroscopic high-z surveys and find that-when stellar masses are considered-there is consistency with the local WINGS galaxy sizes out to z {approx} 2, while a discrepancy of a factor of 3 exists with the only spectroscopic z > 2 study. In contrast, there is strong evidence for a large evolution in radius for the most massive galaxies with M{sub *} > 4 x 10{sup 11} M{sub sun} compared to similarly massive galaxies in WINGS, i.e., the brightest cluster galaxies.

  19. SACS: Spitzer Archival Cluster Survey

    NASA Astrophysics Data System (ADS)

    Stern, Daniel

    Emerging from the cosmic web, galaxy clusters are the most massive gravitationally bound structures in the universe. Thought to have begun their assembly at z > 2, clusters provide insights into the growth of large-scale structure as well as the physics that drives galaxy evolution. Understanding how and when the most massive galaxies assemble their stellar mass, stop forming stars, and acquire their observed morphologies in these environments remain outstanding questions. The redshift range 1.3 < z < 2 is a key epoch in this respect: elliptical galaxies start to become the dominant population in cluster cores, and star formation in spiral galaxies is being quenched. Until recently, however, this redshift range was essentially unreachable with available instrumentation, with clusters at these redshifts exceedingly challenging to identify from either ground-based optical/nearinfrared imaging or from X-ray surveys. Mid-infrared (MIR) imaging with the IRAC camera on board of the Spitzer Space Telescope has changed the landscape. High-redshift clusters are easily identified in the MIR due to a combination of the unique colors of distant galaxies and a negative k-correction in the 3-5 μm range which makes such galaxies bright. Even 90-sec observations with Spitzer/IRAC, a depth which essentially all extragalactic observations in the archive achieve, is sufficient to robustly detect overdensities of L* galaxies out to z~2. Here we request funding to embark on a ambitious scientific program, the “SACS: Spitzer Archival Cluster Survey”, a comprehensive search for the most distant galaxy clusters in all Spitzer/IRAC extragalactic pointings available in the archive. With the SACS we aim to discover ~2000 of 1.3 < z < 2.5 clusters, thus provide the ultimate catalog for high-redshift MIR selected clusters: a lasting legacy for Spitzer. The study we propose will increase by more than a factor of 10 the number of high-redshift clusters discovered by all previous surveys

  20. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies

    NASA Astrophysics Data System (ADS)

    Gil-Marín, Héctor; Percival, Will J.; Brownstein, Joel R.; Chuang, Chia-Hsun; Grieb, Jan Niklas; Ho, Shirley; Kitaura, Francisco-Shu; Maraston, Claudia; Prada, Francisco; Rodríguez-Torres, Sergio; Ross, Ashley J.; Samushia, Lado; Schlegel, David J.; Thomas, Daniel; Tinker, Jeremy L.; Zhao, Gong-Bo

    2016-08-01

    We measure and analyse the clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) relative to the line of sight (LOS), for LOWZ and CMASS galaxy samples drawn from the final Data Release 12. The LOWZ sample contains 361 762 galaxies with an effective redshift of zlowz = 0.32, and the CMASS sample 777 202 galaxies with an effective redshift of zcmass = 0.57. From the power spectrum monopole and quadrupole moments around the LOS, we measure the growth of structure parameter f times the amplitude of dark matter density fluctuations σ8 by modelling the redshift-space distortion signal. When the geometrical Alcock-Paczynski effect is also constrained from the same data, we find joint constraints on fσ8, the product of the Hubble constant and the comoving sound horizon at the baryon-drag epoch H(z)rs(zd), and the angular distance parameter divided by the sound horizon DA(z)/rs(zd). We find f(zlowz)σ8(zlowz) = 0.394 ± 0.062, DA(zlowz)/rs(zd) = 6.35 ± 0.19, H(zlowz)rs(zd) = (11.41 ± 0.56) 103 km s- 1 for the LOWZ sample, and f(zcmass)σ8(zcmass) = 0.444 ± 0.038, DA(zcmass)/rs(zd) = 9.42 ± 0.15, H(zcmass)rs(zd) = (13.92 ± 0.44) 103 km s- 1 for the CMASS sample. We find general agreement with previous BOSS DR11 measurements. Assuming the Hubble parameter and angular distance parameter are fixed at fiducial Λcold dark matter values, we find f(zlowz)σ8(zlowz) = 0.485 ± 0.044 and f(zcmass)σ8(zcmass) = 0.436 ± 0.022 for the LOWZ and CMASS samples, respectively.

  1. Faint Submillimeter Galaxies Behind Lensing Clusters

    NASA Astrophysics Data System (ADS)

    Hsu, Li-Yen; Lauchlan Cowie, Lennox; Barger, Amy J.; Desai, Vandana; Murphy, Eric J.

    2017-01-01

    Faint submillimeter galaxies are the major contributors to the submillimeter extragalactic background light and hence the dominant star-forming population in the dusty universe. Determining how much these galaxies overlap the optically selected samples is critical to fully account for the cosmic star formation history. Observations of massive cluster fields are the best way to explore this faint submillimeter population, thanks to gravitational lensing effects. We have been undertaking a lensing cluster survey with the SCUBA-2 camera on the James Clerk Maxwell Telescope to map nine galaxy clusters, including the northern five clusters in the HST Frontier Fields program. We have also been using the Submillimeter Array and the Very Large Array to determine the accurate positions of our detected sources. Our observations have discovered high-redshift dusty galaxies with far-infrared luminosities similar to that of the Milky Way or luminous infrared galaxies. Some of these galaxies are still undetected in deep optical and near-infrared images. These results suggest that a substantial amount of star formation in even the faint submillimeter population may be hidden from rest-frame optical surveys.

  2. Brighter galaxy bias: underestimating the velocity dispersions of galaxy clusters

    NASA Astrophysics Data System (ADS)

    Old, L.; Gray, M. E.; Pearce, F. R.

    2013-09-01

    We study the systematic bias introduced when selecting the spectroscopic redshifts of brighter cluster galaxies to estimate the velocity dispersion of galaxy clusters from both simulated and observational galaxy catalogues. We select clusters with Ngal ≥ 50 at five low-redshift snapshots from the publicly available De Lucia & Blaziot semi-analytic model galaxy catalogue. Clusters are also selected from the Tempel Sloan Digital Sky Survey Data Release 8 groups and clusters catalogue across the redshift range 0.021 ≤ z ≤ 0.098. We employ various selection techniques to explore whether the velocity dispersion bias is simply due to a lack of dynamical information or is the result of an underlying physical process occurring in the cluster, for example, dynamical friction experienced by the brighter cluster members. The velocity dispersions of the parent dark matter (DM) haloes are compared to the galaxy cluster dispersions and the stacked distribution of DM particle velocities is examined alongside the corresponding galaxy velocity distribution. We find a clear bias between the halo and the semi-analytic galaxy cluster velocity dispersion on the order of σgal/σDM ˜ 0.87-0.95 and a distinct difference in the stacked galaxy and DM particle velocities distribution. We identify a systematic underestimation of the velocity dispersions when imposing increasing absolute I-band magnitude limits. This underestimation is enhanced when using only the brighter cluster members for dynamical analysis on the order of 5-35 per cent, indicating that dynamical friction is a serious source of bias when using galaxy velocities as tracers of the underlying gravitational potential. In contrast to the literature we find that the resulting bias is not only halo mass dependent but also that the nature of the dependence changes according to the galaxy selection strategy. We make a recommendation that, in the realistic case of limited availability of spectral observations, a strictly

  3. Weak-lensing Mass Calibration of RedMaPPer Galaxy Clusters in Dark Energy Survey Science Verification Data

    SciTech Connect

    Melchior, P.; et al.

    2016-10-21

    We use weak-lensing shear measurements to determine the mean mass of optically selected galaxy clusters in Dark Energy Survey Science Verification data. In a blinded analysis, we split the sample of more than 8,000 redMaPPer clusters into 15 subsets, spanning ranges in the richness parameter $5 \\leq \\lambda \\leq 180$ and redshift $0.2 \\leq z \\leq 0.8$, and fit the averaged mass density contrast profiles with a model that accounts for seven distinct sources of systematic uncertainty: shear measurement and photometric redshift errors; cluster-member contamination; miscentering; deviations from the NFW halo profile; halo triaxiality; and line-of-sight projections. We combine the inferred cluster masses to estimate the joint scaling relation between mass, richness and redshift, $\\mathcal{M}(\\lambda,z) \\varpropto M_0 \\lambda^{F} (1+z)^{G}$. We find $M_0 \\equiv \\langle M_{200\\mathrm{m}}\\,|\\,\\lambda=30,z=0.5\\rangle=\\left[ 2.35 \\pm 0.22\\ \\rm{(stat)} \\pm 0.12\\ \\rm{(sys)} \\right] \\cdot 10^{14}\\ M_\\odot$, with $F = 1.12\\,\\pm\\,0.20\\ \\rm{(stat)}\\, \\pm\\, 0.06\\ \\rm{(sys)}$ and $G = 0.18\\,\\pm\\, 0.75\\ \\rm{(stat)}\\, \\pm\\, 0.24\\ \\rm{(sys)}$. The amplitude of the mass-richness relation is in excellent agreement with the weak-lensing calibration of redMaPPer clusters in SDSS by Simet et al. (2016) and with the Saro et al. (2015) calibration based on abundance matching of SPT-detected clusters. Our results extend the redshift range over which the mass-richness relation of redMaPPer clusters has been calibrated with weak lensing from $z\\leq 0.3$ to $z\\leq0.8$. Calibration uncertainties of shear measurements and photometric redshift estimates dominate our systematic error budget and require substantial improvements for forthcoming studies.

  4. H I detection survey of a complete magnitude-limited sample of dwarf irregular galaxies in the Virgo Cluster area

    NASA Technical Reports Server (NTRS)

    Hoffman, G. Lyle; Glosson, John; Helou, George; Salpeter, E. E.; Sandage, A.

    1987-01-01

    New single-beam Arecibo H I observations of 298 late-type galaxies in the Virgo Cluster drawn mostly from the new catalog of Binggeli, Sandage, and Tammann (1985) are presented. Two hundred seventeen of these constitute a magnitude-limited 'complete sample' of such galaxies, types Sdm through Im and BCD. Sixty-one percent of this 'complete sample' was detected, greatly enhancing the store of redshifts and H I masses for such galaxies in the Virgo Cluster. For detected galaxies, heliocentric velocities, 50 percent profile widths, and single-beam fluxes are presented. For those that escaped detection, upper limits are computed to the flux appropriate to the redshift range (-600 to +3000 km/s).

  5. GALAXY CLUSTERS AT HIGH REDSHIFT AND EVOLUTION OF BRIGHTEST CLUSTER GALAXIES

    SciTech Connect

    Wen, Z. L.; Han, J. L.

    2011-06-10

    Identification of high-redshift clusters is important for studies of cosmology and cluster evolution. Using photometric redshifts of galaxies, we identify 631 clusters from the Canada-France-Hawaii Telescope (CFHT) wide field, 202 clusters from the CFHT deep field, 187 clusters from the Cosmic Evolution Survey (COSMOS) field, and 737 clusters from the Spitzer Wide-area InfraRed Extragalactic Survey (SWIRE) field. The redshifts of these clusters are in the range 0.1 {approx}< z {approx}< 1.6. Merging these cluster samples gives 1644 clusters in the four survey fields, of which 1088 are newly identified and more than half are from the large SWIRE field. Among 228 clusters of z {>=} 1, 191 clusters are newly identified, and most of them from the SWIRE field. With this large sample of high-redshift clusters, we study the color evolution of the brightest cluster galaxies (BCGs). The r' - z' and r{sup +} - m{sub 3.6{mu}m} colors of the BCGs are consistent with a stellar population synthesis model in which the BCGs are formed at redshift z{sub f} {>=} 2 and evolved passively. The g' - z' and B - m{sub 3.6{mu}m} colors of the BCGs at redshifts z > 0.8 are systematically bluer than the passive evolution model for galaxies formed at z{sub f} {approx} 2, indicating star formation in high-redshift BCGs.

  6. REDSHIFTS, SAMPLE PURITY, AND BCG POSITIONS FOR THE GALAXY CLUSTER CATALOG FROM THE FIRST 720 SQUARE DEGREES OF THE SOUTH POLE TELESCOPE SURVEY

    SciTech Connect

    Song, J.; Zenteno, A.; Desai, S.; Bazin, G.; Stalder, B.; Ashby, M. L. N.; Bayliss, M.; Bleem, L. E.; Benson, B. A.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T.; Aird, K. A.; Armstrong, R.; Bertin, E.; Brodwin, M.; Cho, H. M.; Clocchiatti, A.; De Haan, T.; and others

    2012-12-10

    We present the results of the ground- and space-based optical and near-infrared (NIR) follow-up of 224 galaxy cluster candidates detected with the Sunyaev-Zel'dovich (SZ) effect in the 720 deg{sup 2} of the South Pole Telescope (SPT) survey completed in the 2008 and 2009 observing seasons. We use the optical/NIR data to establish whether each candidate is associated with an overdensity of galaxies and to estimate the cluster redshift. Most photometric redshifts are derived through a combination of three different cluster redshift estimators using red-sequence galaxies, resulting in an accuracy of {Delta}z/(1 + z) = 0.017, determined through comparison with a subsample of 57 clusters for which we have spectroscopic redshifts. We successfully measure redshifts for 158 systems and present redshift lower limits for the remaining candidates. The redshift distribution of the confirmed clusters extends to z = 1.35 with a median of z{sub med} = 0.57. Approximately 18% of the sample with measured redshifts lies at z > 0.8. We estimate a lower limit to the purity of this SPT SZ-selected sample by assuming that all unconfirmed clusters are noise fluctuations in the SPT data. We show that the cumulative purity at detection significance {xi} > 5({xi} > 4.5) is {>=}95% ({>=}70%). We present the red brightest cluster galaxy (rBCG) positions for the sample and examine the offsets between the SPT candidate position and the rBCG. The radial distribution of offsets is similar to that seen in X-ray-selected cluster samples, providing no evidence that SZ-selected cluster samples include a different fraction of recent mergers from X-ray-selected cluster samples.

  7. Galaxy clustering and galaxy-galaxy lensing: a promising union to constrain cosmological parameters

    NASA Astrophysics Data System (ADS)

    Cacciato, Marcello; van den Bosch, Frank C.; More, Surhud; Li, Ran; Mo, H. J.; Yang, Xiaohu

    2009-04-01

    Galaxy clustering and galaxy-galaxy lensing probe the connection between galaxies and their dark matter haloes in complementary ways. Since the clustering of dark matter haloes depends on cosmology, the halo occupation statistics inferred from the observed clustering properties of galaxies are degenerate with the adopted cosmology. Consequently, different cosmologies imply different mass-to-light ratios for dark matter haloes. Galaxy-galaxy lensing, which yields direct constraints on the actual mass-to-light ratios, can therefore be used to break this degeneracy, and thus to constrain cosmological parameters. In this paper, we establish the link between galaxy luminosity and dark matter halo mass using the conditional luminosity function (CLF), Φ(L|M)dL, which gives the number of galaxies with luminosities in the range L +/- dL/2 that reside in a halo of mass M. We constrain the CLF parameters using the galaxy luminosity function and the luminosity dependence of the correlation lengths of galaxies. The resulting CLF models are used to predict the galaxy-galaxy lensing signal. For a cosmology that agrees with constraints from the cosmic microwave background, i.e. (Ωm,σ8) = (0.238,0.734), the model accurately fits the galaxy-galaxy lensing data obtained from the Sloan Digital Sky Survey. For a comparison cosmology with (Ωm,σ8) = (0.3,0.9), however, we can accurately fit the luminosity function and clustering properties of the galaxy population, but the model predicts mass-to-light ratios that are too high, resulting in a strong overprediction of the galaxy-galaxy lensing signal. We conclude that the combination of galaxy clustering and galaxy-galaxy lensing is a powerful probe of the galaxy-dark matter connection, with the potential to yield tight constraints on cosmological parameters. Since this method mainly probes the mass distribution on relatively small (non-linear) scales, it is complementary to constraints obtained from the galaxy power spectrum, which

  8. How robust are predictions of galaxy clustering?

    NASA Astrophysics Data System (ADS)

    Contreras, S.; Baugh, C. M.; Norberg, P.; Padilla, N.

    2013-07-01

    We use the Millennium Simulation data base to compare how different versions of the Durham and Munich semi-analytical galaxy formation models populate dark matter haloes with galaxies. The models follow the same physical processes but differ in how these are implemented. All of the models we consider use the Millennium N-body Simulation; however, the Durham and Munich groups use independent algorithms to construct halo merger histories from the simulation output. We compare the predicted halo occupation distributions (HODs) and correlation functions for galaxy samples defined by stellar mass, cold gas mass and star formation rate. The model predictions for the HOD are remarkably similar for samples ranked by stellar mass. The predicted bias averaged over pair separations in the range 5-25 h-1 Mpc is consistent between models to within 10 per cent. At small pair separations there is a clear difference in the predicted clustering. This arises because the Durham models allow some satellite galaxies to merge with the central galaxy in a halo when they are still associated with resolved dark matter subhaloes. The agreement between the models is less good for samples defined by cold gas mass or star formation rate, with the spread in predicted galaxy bias reaching 20 per cent and the small-scale clustering differing by an order of magnitude, reflecting the uncertainty in the modelling of star formation. The model predictions in these cases are nevertheless qualitatively similar, with a markedly shallower slope for the correlation function than is found for stellar mass selected samples and with the HOD displaying an asymmetric peak for central galaxies. We provide illustrative parametric fits to the HODs predicted by the models. Our results reveal the current limitations on how well we can predict galaxy bias in a fixed cosmology, which has implications for the interpretation of constraints on the physics of galaxy formation from galaxy clustering measurements and the

  9. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Cosmological implications of the configuration-space clustering wedges

    NASA Astrophysics Data System (ADS)

    Sánchez, Ariel G.; Scoccimarro, Román; Crocce, Martín; Grieb, Jan Niklas; Salazar-Albornoz, Salvador; Dalla Vecchia, Claudio; Lippich, Martha; Beutler, Florian; Brownstein, Joel R.; Chuang, Chia-Hsun; Eisenstein, Daniel J.; Kitaura, Francisco-Shu; Olmstead, Matthew D.; Percival, Will J.; Prada, Francisco; Rodríguez-Torres, Sergio; Ross, Ashley J.; Samushia, Lado; Seo, Hee-Jong; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magaña, Mariana; Wang, Yuting; Zhao, Gong-Bo

    2017-01-01

    We explore the cosmological implications of anisotropic clustering measurements in configuration space of the final galaxy samples from Data Release 12 of the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey. We implement a new detailed modelling of the effects of non-linearities, bias and redshift-space distortions that can be used to extract unbiased cosmological information from our measurements for scales s ≳ 20 h-1 Mpc. We combined the information from Baryon Oscillation Spectroscopic Survey (BOSS) with the latest cosmic microwave background (CMB) observations and Type Ia supernovae samples and found no significant evidence for a deviation from the Λ cold dark matter (ΛCDM) cosmological model. In particular, these data sets can constrain the dark energy equation-of-state parameter to wDE = -0.996 ± 0.042 when to be assumed time independent, the curvature of the Universe to Ωk = -0.0007 ± 0.0030 and the sum of the neutrino masses to ∑mν < 0.25 eV at 95 per cent confidence levels. We explore the constraints on the growth rate of cosmic structures assuming f(z) = Ωm(z)γ and obtain γ = 0.609 ± 0.079, in good agreement with the predictions of general relativity of γ = 0.55. We compress the information of our clustering measurements into constraints on the parameter combinations DV(z)/rd, FAP(z) and fσ8(z) at zeff = 0.38, 0.51 and 0.61 with their respective covariance matrices and find good agreement with the predictions for these parameters obtained from the best-fitting ΛCDM model to the CMB data from the Planck satellite. This paper is part of a set that analyses the final galaxy clustering data set from BOSS. The measurements and likelihoods presented here are combined with others by Alam et al. to produce the final cosmological constraints from BOSS.

  10. The VIMOS Public Extragalactic Redshift Survey (VIPERS). Ωm0 from the galaxy clustering ratio measured at z ~ 1

    NASA Astrophysics Data System (ADS)

    Bel, J.; Marinoni, C.; Granett, B. R.; Guzzo, L.; Peacock, J. A.; Branchini, E.; Cucciati, O.; de la Torre, S.; Iovino, A.; Percival, W. J.; Steigerwald, H.; Abbas, U.; Adami, C.; Arnouts, S.; Bolzonella, M.; Bottini, D.; Cappi, A.; Coupon, J.; Davidzon, I.; De Lucia, G.; Fritz, A.; Franzetti, P.; Fumana, M.; Garilli, B.; Ilbert, O.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; McCracken, H. J.; Paioro, L.; Polletta, M.; Pollo, A.; Schlagenhaufer, H.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Di Porto, C.; Marchetti, A.; Mellier, Y.; Moscardini, L.; Nichol, R. C.; Phleps, S.; Wolk, M.; Zamorani, G.

    2014-03-01

    We use a sample of about 22 000 galaxies at 0.65 < z < 1.2 from the VIMOS Public Extragalactic Redshift Survey (VIPERS) Public Data Release 1 (PDR-1) catalogue, to constrain the cosmological model through a measurement of the galaxy clustering ratio ηg,R. This statistic has favourable properties, which is defined as the ratio of two quantities characterizing the smoothed density field in spheres of a given radius R: the value of its correlation function on a multiple of this scale, ξ(nR), and its variance σ2(R). For sufficiently large values of R, this is a universal number, which captures 2-point clustering information independently of the linear bias and linear redshift-space distortions of the specific galaxy tracers. In this paper, we discuss how to extend the application of ηg,R to quasi-linear scales and how to control and remove observational selection effects, which are typical of redshift surveys as VIPERS, in detail. We verify the accuracy and efficiency of these procedures using mock catalogues that match the survey selection process. These results show the robustness of ηg,R to non-linearities and observational effects, which is related to its very definition as a ratio of quantities that are similarly affected. At an effective redshift z = 0.93, we measured the value ηg,R(15) = 0.141 ± 0.013 at R = 5h-1 Mpc. Within a flat ΛCDM cosmology and by including the best available priors on H0, ns and baryon density, we obtain a matter density parameter at the current epoch Ωm,0 = 0.270-0.025+0.029. In addition to the great precision achieved on our estimation of Ωm using VIPERS PDR-1, this result is remarkable because it appears to be in good agreement with a recent estimate at z ≃ 0.3, which was obtained by applying the same technique to the SDSS-LRG catalogue. It, therefore, supports the robustness of the present analysis. Moreover, the combination of these two measurements at z ~ 0.3 and z ~ 0.9 provides us with a very precise estimate of Ωm,0

  11. STUDYING INTERCLUSTER GALAXY FILAMENTS THROUGH STACKING gmBCG GALAXY CLUSTER PAIRS

    SciTech Connect

    Zhang Yuanyuan; Dietrich, Joerg P.; McKay, Timothy A.; Nguyen, Alex T. Q.; Sheldon, Erin S.

    2013-08-20

    We present a method to study the photometric properties of galaxies in filaments by stacking the galaxy populations between pairs of galaxy clusters. Using Sloan Digital Sky Survey data, this method can detect the intercluster filament galaxy overdensity with a significance of {approx}5{sigma} out to z = 0.40. Using this approach, we study the g - r color and luminosity distribution of filament galaxies as a function of redshift. Consistent with expectation, filament galaxies are bimodal in their color distribution and contain a larger blue galaxy population than clusters. Filament galaxies are also generally fainter than cluster galaxies. More interestingly, the observed filament population seems to show redshift evolution at 0.12 < z < 0.40: the blue galaxy fraction has a trend to increase at higher redshift; such evolution is parallel to the ''Butcher-Oemler effect'' of galaxy clusters. We test the dependence of the observed filament density on the richness of the cluster pair: richer clusters are connected by higher density filaments. We also test the spatial dependence of filament galaxy overdensity: this quantity decreases when moving away from the intercluster axis between a cluster pair. This method provides an economical way to probe the photometric properties of filament galaxies and should prove useful for upcoming projects like the Dark Energy Survey.

  12. Measuring the Scatter of the Mass–Richness Relation in Galaxy Clusters in Photometric Imaging Surveys by Means of Their Correlation Function

    NASA Astrophysics Data System (ADS)

    Campa, Julia; Estrada, Juan; Flaugher, Brenna

    2017-02-01

    Knowledge of the scatter in the mass-observable relation is a key ingredient for a cosmological analysis based on galaxy clusters in a photometric survey. In this paper we aim to quantify the capability of the correlation function of galaxy clusters to constrain the intrinsic scatter {σ }{lnM}. We demonstrate how the linear bias measured in the correlation function of clusters can be used to determine the value of this parameter. The new method is tested in simulations of a 5000 {\\deg }2 optical survey up to z∼ 1, similar to the ongoing Dark Energy Survey (DES). Our results show that our method works better at lower scatter values. We can measure the intrinsic scatter {σ }{lnM}=0.1 with a standard deviation of σ ({σ }{lnM})∼ 0.03 using this technique. However, the expected intrinsic scatter of the DES RedMaPPer cluster catalog {σ }{lnM}∼ 0.2 cannot be recovered with this method at suitable accuracy and precision because the area coverage is insufficient. For future photometric surveys with a larger area such as LSST and Euclid, the statistical errors will be reduced. Therefore, we forecast higher precision to measure the intrinsic scatter including the value mentioned before. We conclude that this method can be used as an internal consistency check method on their simplifying assumptions and complementary to cross-calibration techniques in multiwavelength cluster observations.

  13. The extended ROSAT-ESO Flux-Limited X-ray Galaxy Cluster Survey (REFLEX II) - III. Construction of the first flux-limited supercluster sample

    NASA Astrophysics Data System (ADS)

    Chon, Gayoung; Böhringer, Hans; Nowak, Nina

    2013-03-01

    We present the first supercluster catalogue constructed with the extended ROSAT-ESO Flux-Limited X-ray (REFLEX II) Galaxy Cluster survey data, which comprises 919 X-ray selected galaxy clusters with a flux limit of 1.8 × 10-12 erg s-1 cm-2. Based on this cluster catalogue we construct a supercluster catalogue using a friends-of-friends algorithm with a linking length depending on the (local) cluster density, which thus varies with redshift. The resulting catalogue comprises 164 superclusters at redshift z ≤ 0.4. The choice of the linking length in the friends-of-friends method modifies the properties of the superclusters. We study the properties of different catalogues such as the distributions of the redshift, extent and multiplicity by varying the choice of parameters. In addition to the supercluster catalogue for the entire REFLEX II sample, we compile a large volume-limited cluster sample from REFLEX II with the redshift and luminosity constraints of z ≤ 0.1 and LX ≥ 5 × 1043 erg s-1. With this catalogue we construct a volume-limited sample of superclusters. This sample is built with a homogeneous linking length, and hence selects effectively the same type of superclusters. By increasing the luminosity cut we can build a hierarchical tree structure of the volume-limited samples, where systems at the top of the tree are only formed via the most luminous clusters. This allows us to test if the same superclusters are found when only the most luminous clusters are visible, comparable to the situation at higher redshift in the REFLEX II sample. We find that the selection of superclusters is very robust, independent of the luminosity cut, and the contamination of spurious superclusters among cluster pairs is expected to be small. Numerical simulations and observations of the substructure of clusters suggest that regions of high cluster number density provide an astrophysically different environment for galaxy clusters, where the mass function and X

  14. Dust in Cluster Dwarf Elliptical Galaxies

    NASA Astrophysics Data System (ADS)

    De Looze, I.; Baes, M.; Fritz, J.; Verstappen, J.; Bendo, G. J.; Bianchi, S.; Bomans, D. J.; Boselli, A.; Clemens, M.; Corbelli, E.; Cortese, L.; Dariush, A.; Davies, J. I.; di Serego Alighieri, S.; Fadda, D.; Garcia-Appadoo, D. A.; Gavazzi, G.; Giovanardi, C.; Grossi, M.; Hughes, T. M.; Hunt, L. K.; Jones, A. P.; Madden, S.; Magrini, L.; Pierini, D.; Pohlen, M.; Sabatini, S.; Smith, M. W. L.; Vlahakis, C.; Xilouris, E. M.; Zibetti, S.

    Based on single cross-scan data of the Herschel Virgo Cluster Survey, we report the first detections of dust in cluster early-type dwarf galaxies: VCC 209, VCC 781 and VCC 951. All three galaxies have dust masses M d ≈ 105 - 106 M⊙ and average dust temperatures ≈ 16-20 K. Since these three early-type dwarfs reside in densely crowded regions close to the center of the Virgo cluster, and several H I-detected dwarfs in the outskirts of Virgo were not detected by Herschel(implying a dust content < 104 M⊙), this might imply that dust in dwarfs is more closely related to the molecular gas, which is more centrally peaked in a galaxy's potential well and therefore, not easily removed by any stripping mechanism. We conclude that the removal of interstellar dust from these early-type dwarfs appears to be less efficient than the removal of the H I gas.

  15. The KMOS Galaxy Clusters Project

    NASA Astrophysics Data System (ADS)

    Davies, Roger L.; Beifiori, A.; Bender, R.; Cappellari, M.; Chan, J.; Houghton, R.; Mendel, T.; Saglia, R.; Sharples, R.; Stott, J.; Smith, R.; Wilman, D.

    2015-04-01

    KMOS is a cryogenic infrared spectrograph fed by twentyfour deployable integral field units that patrol a 7.2 arcminute diameter field of view at the Nasmyth focus of the ESO VLT. It is well suited to the study of galaxy clusters at 1 < z < 2 where the well understood features in the restframe V-band are shifted into the KMOS spectral bands. Coupled with HST imagining, KMOS offers a window on the critical epoch for galaxy evolution, 7-10 Gyrs ago, when the key properties of cluster galaxies were established. We aim to investigate the size, mass, morphology and star formation history of galaxies in the clusters. Here we describe the instrument, discuss the status of the observations and report some preliminary results.

  16. AN OPTICAL CATALOG OF GALAXY CLUSTERS OBTAINED FROM AN ADAPTIVE MATCHED FILTER FINDER APPLIED TO SLOAN DIGITAL SKY SURVEY DATA RELEASE 6

    SciTech Connect

    Szabo, T.; Pierpaoli, E.; Pipino, A.; Dong, F.; Gunn, J. E-mail: pierpaol@usc.edu

    2011-07-20

    We present a new cluster catalog extracted from the Sloan Digital Sky Survey Data Release 6 (SDSS DR6) using an adaptive matched filter (AMF) cluster finder. We identify 69,173 galaxy clusters in the redshift range 0.045 {<=} z < 0.78 in 8420 deg{sup 2} of the sky. We provide angular position, redshift, richness, core, and virial radii estimates for these clusters, as well as an error analysis for each of these quantities. We also provide a catalog of more than 205,000 galaxies representing the three brightest galaxies in the r band which are possible brightest cluster galaxy (BCG) candidates. We show basic properties of the BCG candidates and study how their luminosity scales in redshift and cluster richness. We compare our catalog with the maxBCG and GMBCG catalogs, as well as with that of Wen et al. We match between 30% and 50% of clusters between catalogs over all overlapping redshift ranges. We find that the percentage of matches increases with the richness for all catalogs. We cross match the AMF catalog with available X-ray data in the same area of the sky and find 539 matches, 119 of which with temperature measurements. We present scaling relations between optical and X-ray properties and cluster center comparison. We find that both {Lambda}{sub 200} and R{sub 200} correlate well with both L{sub X} and T{sub X} , with no significant difference in trend if we restrict the matches to flux-limited X-ray samples.

  17. The SAMI Galaxy Survey: Early Data Release

    NASA Astrophysics Data System (ADS)

    Allen, J. T.; Croom, S. M.; Konstantopoulos, I. S.; Bryant, J. J.; Sharp, R.; Cecil, G. N.; Fogarty, L. M. R.; Foster, C.; Green, A. W.; Ho, I.-T.; Owers, M. S.; Schaefer, A. L.; Scott, N.; Bauer, A. E.; Baldry, I.; Barnes, L. A.; Bland-Hawthorn, J.; Bloom, J. V.; Brough, S.; Colless, M.; Cortese, L.; Couch, W. J.; Drinkwater, M. J.; Driver, S. P.; Goodwin, M.; Gunawardhana, M. L. P.; Hampton, E. J.; Hopkins, A. M.; Kewley, L. J.; Lawrence, J. S.; Leon-Saval, S. G.; Liske, J.; López-Sánchez, Á. R.; Lorente, N. P. F.; McElroy, R.; Medling, A. M.; Mould, J.; Norberg, P.; Parker, Q. A.; Power, C.; Pracy, M. B.; Richards, S. N.; Robotham, A. S. G.; Sweet, S. M.; Taylor, E. N.; Thomas, A. D.; Tonini, C.; Walcher, C. J.

    2015-01-01

    We present the Early Data Release of the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey. The SAMI Galaxy Survey is an ongoing integral field spectroscopic survey of ˜3400 low-redshift (z < 0.12) galaxies, covering galaxies in the field and in groups within the Galaxy And Mass Assembly (GAMA) survey regions, and a sample of galaxies in clusters. In the Early Data Release, we publicly release the fully calibrated data cubes for a representative selection of 107 galaxies drawn from the GAMA regions, along with information about these galaxies from the GAMA catalogues. All data cubes for the Early Data Release galaxies can be downloaded individually or as a set from the SAMI Galaxy Survey website. In this paper we also assess the quality of the pipeline used to reduce the SAMI data, giving metrics that quantify its performance at all stages in processing the raw data into calibrated data cubes. The pipeline gives excellent results throughout, with typical sky subtraction residuals in the continuum of 0.9-1.2 per cent, a relative flux calibration uncertainty of 4.1 per cent (systematic) plus 4.3 per cent (statistical), and atmospheric dispersion removed with an accuracy of 0.09 arcsec, less than a fifth of a spaxel.

  18. HUBBLE SPACE TELESCOPE Survey of Clusters in Nearby Galaxies. I. Detection and Photometry

    NASA Astrophysics Data System (ADS)

    Dolphin, Andrew E.; Kennicutt, Robert C., Jr.

    2002-01-01

    We have developed photometric techniques that can be applied to images with highly variable backgrounds, as well as to slightly extended objects (object size comparable to or smaller than point-spread function [PSF] size). We have shown that ordinary stellar PSF-fitting photometry can be applied to slightly extended objects provided that one applies a systematic correction to the photometry that is a function primarily of the observed sharpness. Applying these techniques to the Cepheid target NGC 3627, we find that we are successfully able to photometer the stars and clusters, as well as discriminate the cluster population with a negligible number of false detections.

  19. GALAXY CLUSTERING AND PROJECTED DENSITY PROFILES AS TRACED BY SATELLITES IN PHOTOMETRIC SURVEYS: METHODOLOGY AND LUMINOSITY DEPENDENCE

    SciTech Connect

    Wang Wenting; Jing, Y. P.; Li Cheng; Okumura, Teppei; Han Jiaxin

    2011-06-20

    We develop a new method which measures the projected density distribution w{sub p} (r{sub p} )n of photometric galaxies surrounding a set of spectroscopically identified galaxies and simultaneously the projected cross-correlation function w{sub p} (r{sub p} ) between the two populations. In this method, we are able to divide the photometric galaxies into subsamples in luminosity intervals even when redshift information is unavailable, enabling us to measure w{sub p} (r{sub p} )n and w{sub p} (r{sub p} ) as a function of not only the luminosity of the spectroscopic galaxy, but also that of the photometric galaxy. Extensive tests show that our method can measure w{sub p} (r{sub p} ) in a statistically unbiased way. The accuracy of the measurement depends on the validity of the assumption inherent to the method that the foreground/background galaxies are randomly distributed and are thus uncorrelated with those galaxies of interest. Therefore, our method can be applied to the cases where foreground/background galaxies are distributed in large volumes, which is usually valid in real observations. We have applied our method to data from the Sloan Digital Sky Survey (SDSS) including a sample of 10{sup 5} luminous red galaxies at z {approx} 0.4 and a sample of about half a million galaxies at z {approx} 0.1, both of which are cross-correlated with a deep photometric sample drawn from the SDSS. On large scales, the relative bias factor of galaxies measured from w{sub p} (r{sub p} ) at z {approx} 0.4 depends on luminosity in a manner similar to what is found for those at z {approx} 0.1, which are usually probed by autocorrelations of spectroscopic samples in previous studies. On scales smaller than a few Mpc and at both z {approx} 0.4 and z {approx} 0.1, the photometric galaxies of different luminosities exhibit similar density profiles around spectroscopic galaxies at fixed luminosity and redshift. This provides clear observational support for the assumption commonly

  20. Galaxy Clustering and Projected Density Profiles as Traced by Satellites in Photometric Surveys: Methodology and Luminosity Dependence

    NASA Astrophysics Data System (ADS)

    Wang, Wenting; Jing, Y. P.; Li, Cheng; Okumura, Teppei; Han, Jiaxin

    2011-06-01

    We develop a new method which measures the projected density distribution wp (rp )n of photometric galaxies surrounding a set of spectroscopically identified galaxies and simultaneously the projected cross-correlation function wp (rp ) between the two populations. In this method, we are able to divide the photometric galaxies into subsamples in luminosity intervals even when redshift information is unavailable, enabling us to measure wp (rp )n and wp (rp ) as a function of not only the luminosity of the spectroscopic galaxy, but also that of the photometric galaxy. Extensive tests show that our method can measure wp (rp ) in a statistically unbiased way. The accuracy of the measurement depends on the validity of the assumption inherent to the method that the foreground/background galaxies are randomly distributed and are thus uncorrelated with those galaxies of interest. Therefore, our method can be applied to the cases where foreground/background galaxies are distributed in large volumes, which is usually valid in real observations. We have applied our method to data from the Sloan Digital Sky Survey (SDSS) including a sample of 105 luminous red galaxies at z ~ 0.4 and a sample of about half a million galaxies at z ~ 0.1, both of which are cross-correlated with a deep photometric sample drawn from the SDSS. On large scales, the relative bias factor of galaxies measured from wp (rp ) at z ~ 0.4 depends on luminosity in a manner similar to what is found for those at z ~ 0.1, which are usually probed by autocorrelations of spectroscopic samples in previous studies. On scales smaller than a few Mpc and at both z ~ 0.4 and z ~ 0.1, the photometric galaxies of different luminosities exhibit similar density profiles around spectroscopic galaxies at fixed luminosity and redshift. This provides clear observational support for the assumption commonly adopted in halo occupation distribution models that satellite galaxies of different luminosities are distributed in a similar

  1. Spitzer UltRa Faint SUrvey Program (SURFS UP). II. IRAC-detected Lyman-Break Galaxies at 6 ≲ z ≲ 10 behind Strong-lensing Clusters

    NASA Astrophysics Data System (ADS)

    Huang, Kuang-Han; Bradač, Maruša; Lemaux, Brian C.; Ryan, R. E., Jr.; Hoag, Austin; Castellano, Marco; Amorín, Ricardo; Fontana, Adriano; Brammer, Gabriel B.; Cain, Benjamin; Lubin, L. M.; Merlin, Emiliano; Schmidt, Kasper B.; Schrabback, Tim; Treu, Tommaso; Gonzalez, Anthony H.; von der Linden, Anja; Knight, Robert I.

    2016-01-01

    We study the stellar population properties of the IRAC-detected 6 ≲ z ≲ 10 galaxy candidates from the Spitzer UltRa Faint SUrvey Program. Using the Lyman Break selection technique, we find a total of 17 galaxy candidates at 6 ≲ z ≲ 10 from Hubble Space Telescope images (including the full-depth images from the Hubble Frontier Fields program for MACS 1149 and MACS 0717) that have detections at signal-to-noise ratios ≥ 3 in at least one of the IRAC 3.6 and 4.5 μm channels. According to the best mass models available for the surveyed galaxy clusters, these IRAC-detected galaxy candidates are magnified by factors of ˜1.2-5.5. Due to the magnification of the foreground galaxy clusters, the rest-frame UV absolute magnitudes M1600 are between -21.2 and -18.9 mag, while their intrinsic stellar masses are between 2 × 108M⊙ and 2.9 × 109M⊙. We identify two Lyα emitters in our sample from the Keck DEIMOS spectra, one at zLyα = 6.76 (in RXJ 1347) and one at zLyα = 6.32 (in MACS 0454). We find that 4 out of 17 z ≳ 6 galaxy candidates are favored by z ≲ 1 solutions when IRAC fluxes are included in photometric redshift fitting. We also show that IRAC [3.6]-[4.5] color, when combined with photometric redshift, can be used to identify galaxies which likely have strong nebular emission lines or obscured active galactic nucleus contributions within certain redshift windows.

  2. SPITZER ULTRA FAINT SURVEY PROGRAM (SURFS UP). II. IRAC-DETECTED LYMAN-BREAK GALAXIES AT 6 ≲ z ≲ 10 BEHIND STRONG-LENSING CLUSTERS

    SciTech Connect

    Huang, Kuang-Han; Bradač, Maruša; Hoag, Austin; Cain, Benjamin; Lubin, L. M.; Knight, Robert I.; Lemaux, Brian C.; Ryan, R. E. Jr.; Brammer, Gabriel B.; Castellano, Marco; Amorin, Ricardo; Fontana, Adriano; Merlin, Emiliano; Schmidt, Kasper B.; Schrabback, Tim; Treu, Tommaso; Gonzalez, Anthony H.; Linden, Anja von der E-mail: astrokuang@gmail.com

    2016-01-20

    We study the stellar population properties of the IRAC-detected 6 ≲ z ≲ 10 galaxy candidates from the Spitzer UltRa Faint SUrvey Program. Using the Lyman Break selection technique, we find a total of 17 galaxy candidates at 6 ≲ z ≲ 10 from Hubble Space Telescope images (including the full-depth images from the Hubble Frontier Fields program for MACS 1149 and MACS 0717) that have detections at signal-to-noise ratios  ≥ 3 in at least one of the IRAC 3.6 and 4.5 μm channels. According to the best mass models available for the surveyed galaxy clusters, these IRAC-detected galaxy candidates are magnified by factors of ∼1.2–5.5. Due to the magnification of the foreground galaxy clusters, the rest-frame UV absolute magnitudes M{sub 1600} are between −21.2 and −18.9 mag, while their intrinsic stellar masses are between 2 × 10{sup 8}M{sub ⊙} and 2.9 × 10{sup 9}M{sub ⊙}. We identify two Lyα emitters in our sample from the Keck DEIMOS spectra, one at z{sub Lyα} = 6.76 (in RXJ 1347) and one at z{sub Lyα} = 6.32 (in MACS 0454). We find that 4 out of 17 z ≳ 6 galaxy candidates are favored by z ≲ 1 solutions when IRAC fluxes are included in photometric redshift fitting. We also show that IRAC [3.6]–[4.5] color, when combined with photometric redshift, can be used to identify galaxies which likely have strong nebular emission lines or obscured active galactic nucleus contributions within certain redshift windows.

  3. The Next Generation Virgo Cluster Survey (NGVS). XXIV. The Red Sequence to ~106 L ⊙ and Comparisons with Galaxy Formation Models

    NASA Astrophysics Data System (ADS)

    Roediger, Joel C.; Ferrarese, Laura; Côté, Patrick; MacArthur, Lauren A.; Sánchez-Janssen, Rúben; Blakeslee, John P.; Peng, Eric W.; Liu, Chengze; Munoz, Roberto; Cuillandre, Jean-Charles; Gwyn, Stephen; Mei, Simona; Boissier, Samuel; Boselli, Alessandro; Cantiello, Michele; Courteau, Stéphane; Duc, Pierre-Alain; Lançon, Ariane; Mihos, J. Christopher; Puzia, Thomas H.; Taylor, James E.; Durrell, Patrick R.; Toloba, Elisa; Guhathakurta, Puragra; Zhang, Hongxin

    2017-02-01

    We use deep optical photometry from the Next Generation Virgo Cluster Survey (NGVS) to investigate the color–magnitude diagram for the galaxies inhabiting the core of this cluster. The sensitivity of the NGVS imaging allows us to continuously probe galaxy colors over a factor of ∼2 × 105 in luminosity, from brightest cluster galaxies to scales overlapping classical satellites of the Milky Way ({M}g\\prime ∼ ‑9 M * ∼ 106 M ⊙), within a single environment. Remarkably, we find the first evidence that the red sequence (RS) flattens in all colors at the faint-magnitude end (starting between ‑14 ≤ {M}g\\prime ≤ ‑13, around M * ∼ 4 × 107 M ⊙), with the slope decreasing to ∼60% or less of its value at brighter magnitudes. This could indicate that the stellar populations of faint dwarfs in Virgo’s core share similar characteristics (e.g., constant mean age) over ∼3 mag in luminosity, suggesting that these galaxies were quenched coevally, likely via pre-processing in smaller hosts. We also compare our results to galaxy formation models, finding that the RS in model clusters have slopes at intermediate magnitudes that are too shallow, and in the case of semianalytic models, do not reproduce the flattening seen at both extremes (bright/faint) of the Virgo RS. Deficiencies in the chemical evolution of model galaxies likely contribute to the model-data discrepancies at all masses, while overly efficient quenching may also be a factor at dwarf scales. Deep UV and near-IR photometry are required to unambiguously diagnose the cause of the faint-end flattening.

  4. Mass calibration of galaxy clusters at redshift 0.1-1.0 using weak lensing in the Sloan Digital Sky Survey Stripe 82 co-add

    NASA Astrophysics Data System (ADS)

    Wiesner, Matthew P.; Lin, Huan; Soares-Santos, Marcelle

    2015-09-01

    We present galaxy cluster mass-richness relations found in the Sloan Digital Sky Survey Stripe 82 co-add using clusters found using a Voronoi tessellation cluster finder. These relations were found using stacked weak lensing shear observed in a large sample of galaxy clusters. These mass-richness relations are presented for four redshift bins, 0.1 < z ≤ 0.4, 0.4 < z ≤ 0.7, 0.7 < z ≤ 1.0 and 0.1 < z ≤ 1.0. We describe the sample of galaxy clusters and explain how these clusters were found using a Voronoi tessellation cluster finder. We fit a Navarro-Frenk-White profile to the stacked weak lensing shear signal in redshift and richness bins in order to measure virial mass (M200). We describe several effects that can bias weak lensing measurements, including photometric redshift bias, the effect of the central BCG, halo miscentering, photometric redshift uncertainty and foreground galaxy contamination. We present mass-richness relations using richness measure NVT with each of these effects considered separately as well as considered altogether. We also examine redshift evolution of the mass-richness relation. As a result, we present measurements of the mass coefficient (M200|20) and the power-law slope (α) for power-law fits to the mass and richness values in each of the redshift bins. We find values of the mass coefficient of 8.49 ± 0.526, 14.1 ± 1.78, 30.2 ± 8.74 and 9.23 ± 0.525 × 1013 h-1 M⊙ for each of the four redshift bins, respectively. We find values of the power-law slope of 0.905 ± 0.0585, 0.948 ± 0.100, 1.33 ± 0.260 and 0.883 ± 0.0500, respectively.

  5. The Grism Lens-amplified Survey from Space (Glass). IX. The Dual Origin of Low-mass Cluster Galaxies as Revealed by New Structural Analyses

    NASA Astrophysics Data System (ADS)

    Morishita, Takahiro; Abramson, Louis E.; Treu, Tommaso; Vulcani, Benedetta; Schmidt, Kasper B.; Dressler, Alan; Poggianti, Bianca M.; Malkan, Matthew A.; Wang, Xin; Huang, Kuang-Han; Trenti, Michele; Bradač, Maruša; Hoag, Austin

    2017-02-01

    Using deep Hubble Frontier Fields imaging and slitless spectroscopy from the Grism Survey from Space, we study 2200 cluster and 1748 field galaxies at 0.2≤slant z≤slant 0.7 to determine the impact of environment on galaxy size and structure at stellar masses {log}{M}* /{M}ȯ > 7.8, an unprecedented limit at these redshifts. Based on simple assumptions—{r}e=f({M}* )—we find no significant differences in half-light radii (re) between equal-mass cluster or field systems. More complex analyses—{r}e=f({M}* ,U-V,n,z,{{Σ }})—reveal local density (Σ) to induce only a 7% ± 3% (95% confidence) reduction in re beyond what can be accounted for by U ‑ V color, Sérsic index (n), and redshift (z) effects. Almost any size difference between galaxies in high- and low-density regions is thus attributable to their different distributions in properties other than environment. Indeed, we find a clear color–re correlation in low-mass passive cluster galaxies ({log}{M}* /{M}ȯ < 9.8) such that bluer systems have larger radii, with the bluest having sizes consistent with equal-mass star-forming galaxies. We take this as evidence that large-re low-mass passive cluster galaxies are recently acquired systems that have been environmentally quenched without significant structural transformation (e.g., by ram pressure stripping or starvation). Conversely, ∼20% of small-re low-mass passive cluster galaxies appear to have been in place since z≳ 3. Given the consistency of the small-re galaxies’ stellar surface densities (and even colors) with those of systems more than ten times as massive, our findings suggest that clusters mark places where galaxy evolution is accelerated for an ancient base population spanning most masses, with late-time additions quenched by environment-specific mechanisms mainly restricted to the lowest masses.

  6. A partial list of southern clusters of galaxies

    NASA Technical Reports Server (NTRS)

    Quintana, H.; White, R. A.

    1990-01-01

    An inspection of 34 SRC/ESO J southern sky fields is the basis of the present list of clusters of galaxies and their approximate classifications in terms of cluster concentration, defined independently of richness and shape-symmetry. Where possible, an estimate of the cluster morphological population is provided. The Bautz-Morgan classification was applied using a strict comparison with clusters on the Palomar Sky Survey. Magnitudes were estimated on the basis of galaxies with photoelectric or photographic magnitudes.

  7. Stormy weather in galaxy clusters

    PubMed

    Burns

    1998-04-17

    Recent x-ray, optical, and radio observations coupled with particle and gas dynamics numerical simulations reveal an unexpectedly complex environment within clusters of galaxies, driven by ongoing accretion of matter from large-scale supercluster filaments. Mergers between clusters and continuous infall of dark matter and baryons from the cluster periphery produce long-lived "stormy weather" within the gaseous cluster atmosphere-shocks, turbulence, and winds of more than 1000 kilometers per second. This weather may be responsible for shaping a rich variety of extended radio sources, which in turn act as "barometers" and "anemometers" of cluster weather.

  8. The Luminosity Functions of Low Redshift Field and Cluster Galaxies

    NASA Astrophysics Data System (ADS)

    Jorgensen, I.; Hill, G. J.; Bergmann, M. P.; Elston, R.; Vanden Berk, D.; Jurcevic, J. S.

    1999-12-01

    We present a comparison of the luminosity functions for low redshift field and cluster galaxies. The luminosity functions are established for field galaxies in UBVRI, and for galaxies in the Coma cluster in UBRI. The field galaxy sample is drawn from The Texas Deep Sky Survey (TDSS) of a 2.1 by 2.1 sq. deg. area around the North Galactic Pole. More than 40000 objects have been detected in our survey of this area. We have obtained spectra of approximately 700 galaxies, making the redshift information complete to a total R magnitude of 18.5 mag. We have surveyed the central square degree of the Coma cluster in UBRI. Approximately 16000 objects have been detected in our survey. We have obtained spectra for 220 galaxies in the area with no previous measurements. Together with published data these observations make the redshift information complete for galaxies brighter than a total R magnitude of 17.5. A total of 480 members of the cluster have measured redshifts, while 180 background and foreground galaxies in the field have measured redshifts. The accurate determination of the luminosity functions for low redshift galaxies is important for the interpretation of luminosity functions established for higher redshift galaxies, both in clusters and in the field. This research was supported in part by NASA through grant number HF-01073.01.94A to IJ from the Space Telescope Science Institute.

  9. Looking Wider and Further: The Evolution of Galaxies Inside Galaxy Clusters

    SciTech Connect

    Zhang, Yuanyuan

    2016-01-01

    Galaxy clusters are rare objects in the universe, but on-going wide field optical surveys are identifying many thousands of them to redshift 1.0 and beyond. Using early data from the Dark Energy Survey (DES) and publicly released data from the Sloan Digital Sky Survey (SDSS), this dissertation explores the evolution of cluster galaxies in the redshift range from 0 to 1.0. As it is common for deep wide field sky surveys like DES to struggle with galaxy detection efficiency at cluster core, the first component of this dissertation describes an efficient package that helps resolving the issue. The second part focuses on the formation of cluster galaxies. The study quantifies the growth of cluster bright central galaxies (BCGs), and argues for the importance of merging and intra-cluster light production during BCG evolution. An analysis of cluster red sequence galaxy luminosity function is also performed, demonstrating that the abundance of these galaxies is mildly dependent on cluster mass and redshift. The last component of the dissertation characterizes the properties of galaxy filaments to help understanding cluster environments

  10. A gravitationally-boosted MUSE survey for emission-line galaxies at z ≳ 5 behind the massive cluster RCS 0224

    NASA Astrophysics Data System (ADS)

    Smit, Renske; Swinbank, A. M.; Massey, Richard; Richard, Johan; Smail, Ian; Kneib, J.-P.

    2017-01-01

    We present a VLT/MUSE survey of lensed high-redshift galaxies behind the z = 0.77 cluster RCS 0224-0002. We study the detailed internal properties of a highly magnified (μ ˜ 29) z = 4.88 galaxy seen through the cluster. We detect wide-spread nebular C IVλλ1548,1551 Å emission from this galaxy as well as a bright Lyα halo with a spatially-uniform wind and absorption profile across 12 kpc in the image plane. Blueshifted high- and low-ionisation interstellar absorption indicate the presence of a high-velocity outflow (Δ v˜ 300 km s^{-1}) from the galaxy. Unlike similar observations of galaxies at z ˜ 2 - 3, the Lyα emission from the halo emerges close to the systemic velocity - an order of magnitude lower in velocity offset than predicted in "shell"-like outflow models. To explain these observations we favour a model of an outflow with a strong velocity gradient, which changes the effective column density seen by the Lyα photons. We also search for high-redshift Lyα emitters and identify 14 candidates between z = 4.8 - 6.6, including an over-density at z = 4.88, of which only one has a detected counterpart in HST/ACS+WFC3 imaging.

  11. A class of compact dwarf galaxies from disruptive processes in galaxy clusters.

    PubMed

    Drinkwater, M J; Gregg, M D; Hilker, M; Bekki, K; Couch, W J; Ferguson, H C; Jones, J B; Phillipps, S

    2003-05-29

    Dwarf galaxies have attracted increased attention in recent years, because of their susceptibility to galaxy transformation processes within rich galaxy clusters. Direct evidence for these processes, however, has been difficult to obtain, with a small number of diffuse light trails and intra-cluster stars being the only signs of galaxy disruption. Furthermore, our current knowledge of dwarf galaxy populations may be very incomplete, because traditional galaxy surveys are insensitive to extremely diffuse or compact galaxies. Aware of these concerns, we recently undertook an all-object survey of the Fornax galaxy cluster. This revealed a new population of compact members, overlooked in previous conventional surveys. Here we demonstrate that these 'ultra-compact' dwarf galaxies are structurally and dynamically distinct from both globular star clusters and known types of dwarf galaxy, and thus represent a new class of dwarf galaxy. Our data are consistent with the interpretation that these are the remnant nuclei of disrupted dwarf galaxies, making them an easily observed tracer of galaxy disruption.

  12. QUASAR-GALAXY CLUSTERING THROUGH PROJECTED GALAXY COUNTS AT z = 0.6-1.2

    SciTech Connect

    Zhang Shaohua; Zhou Hongyan; Wang Tinggui; Wang Huiyuan E-mail: twang@ustc.edu.cn

    2013-08-20

    We investigate the spatial clustering of galaxies around quasars at z = 0.6-1.2 using photometric data from Sloan Digital Sky Survey Stripe 82. The quasar and galaxy cross-correlation functions are measured through the projected galaxy number density n(r{sub p} ) on scales of 0.05 < r{sub p} < 20 h {sup -1} Mpc around quasars for a sample of 2300 quasars from Schneider et al. We detect strong clustering signals at all redshifts and find that the clustering amplitude increases significantly with redshift. We examine the dependence of quasar-galaxy clustering on quasar and galaxy properties and find that the clustering amplitude is significantly larger for quasars with more massive black holes or with bluer colors, while there is no dependence on quasar luminosity. We also show that quasars have a stronger correlation amplitude with blue galaxies than with red galaxies. We finally discuss the implications of our findings.

  13. Galaxy Evolution in Rich Clusters

    NASA Astrophysics Data System (ADS)

    Schwarzkopf, U.; Hill, J. M.

    2000-12-01

    We present the first results of a study of the morphological and spectral evolution of galaxies within the dense cores of distant clusters at redshifts between z=0.4 and 1. The morphology, colors, concentration index, and asymmetry parameters of these cluster members are compared by using a combination of deep HST NICMOS and WFPC2 imaging, covering the rest-frame U and J bands. We also discuss the influence of dust obscuration on the derived measurements. Of particular interest is the morphology of galaxies at near-infrared wavelengths in rich clusters which show an excess of blue galaxies (Butcher-Oelmer effect), namely Abell 851 (z=0.4) and CL 1603+43 (z=0.92). We focus our study on optical/near-infrared measurements of galaxy asymmetry and central concentration, derived from a large number (>400) of objects detected within the core of Abell 851. The sensitivity and reliability of these parameters for galaxy classification and physical diagnostic purposes are tested. In conjunction with the use of recent source extraction software we are able to establish a fast, robust, and highly automated procedure of mapping the structural parameters of large galaxy samples. This work is supported by NASA, under contract NAS5-26555.

  14. Galaxy clusters: Radio relics from fossil electrons

    NASA Astrophysics Data System (ADS)

    Johnston-Hollitt, Melanie

    2017-01-01

    The detection of a tailed radio galaxy in a galaxy cluster conjoined to a region of diffuse radio emission confirms that radio galaxies provide the energetic electrons needed to explain the origin of this enigmatic emission.

  15. THE GEMINI CLUSTER ASTROPHYSICS SPECTROSCOPIC SURVEY (GCLASS): THE ROLE OF ENVIRONMENT AND SELF-REGULATION IN GALAXY EVOLUTION AT z {approx} 1

    SciTech Connect

    Muzzin, Adam; Van Dokkum, Pieter; Wilson, Gillian; Rettura, Alessandro; Yee, H. K. C.; Gilbank, David; Hoekstra, Henk; Franx, Marijn; Demarco, Ricardo; Nantais, Julie; Balogh, Michael; Ellingson, Erica; Hicks, Amalia; Noble, Allison; Webb, Tracy; Lacy, Mark; Lidman, Chris; Surace, Jason

    2012-02-20

    We evaluate the effects of environment and stellar mass on galaxy properties at 0.85 cluster and field galaxies drawn from the Gemini Cluster Astrophysics Spectroscopic Survey. We confirm that for galaxies with log M{sub *}/M{sub Sun} > 9.3 the well-known correlations between environment and properties such as star-forming fraction (f{sub SF}), star formation rate (SFR), specific SFR (SSFR), D{sub n}(4000), and color are already in place at z {approx} 1. We separate the effects of environment and stellar mass on galaxies by comparing the properties of star-forming and quiescent galaxies at fixed environment and fixed stellar mass. The SSFR of star-forming galaxies at fixed environment is correlated with stellar mass; however, at fixed stellar mass it is independent of environment. The same trend exists for the D{sub n}(4000) measures of both the star-forming and quiescent galaxies and shows that their properties are determined primarily by their stellar mass, not by their environment. Instead, it appears that environment's primary role is to control the fraction of star-forming galaxies. Using the spectra we identify candidate poststarburst galaxies and find that those with 9.3 < log M{sub *}/M{sub Sun} < 10.7 are 3.1 {+-} 1.1 times more common in high-density regions compared to low-density regions. The clear association of poststarbursts with high-density regions as well as the lack of a correlation between the SSFRs and D{sub n}(4000)s of star-forming galaxies with their environment strongly suggests that at z {approx} 1 the environmental-quenching timescale must be rapid. Lastly, we construct a simple quenching model which demonstrates that the lack of a correlation between the D{sub n}(4000) of quiescent galaxies and their environment results naturally if self quenching dominates over environmental quenching at z > 1, or if the evolution of the self-quenching rate mirrors the evolution of the

  16. The Gemini Cluster Astrophysics Spectroscopic Survey (GCLASS): The Role of Environment and Self-regulation in Galaxy Evolution at z ~ 1

    NASA Astrophysics Data System (ADS)

    Muzzin, Adam; Wilson, Gillian; Yee, H. K. C.; Gilbank, David; Hoekstra, Henk; Demarco, Ricardo; Balogh, Michael; van Dokkum, Pieter; Franx, Marijn; Ellingson, Erica; Hicks, Amalia; Nantais, Julie; Noble, Allison; Lacy, Mark; Lidman, Chris; Rettura, Alessandro; Surace, Jason; Webb, Tracy

    2012-02-01

    We evaluate the effects of environment and stellar mass on galaxy properties at 0.85 cluster and field galaxies drawn from the Gemini Cluster Astrophysics Spectroscopic Survey. We confirm that for galaxies with log M */M ⊙ > 9.3 the well-known correlations between environment and properties such as star-forming fraction (f SF), star formation rate (SFR), specific SFR (SSFR), D n (4000), and color are already in place at z ~ 1. We separate the effects of environment and stellar mass on galaxies by comparing the properties of star-forming and quiescent galaxies at fixed environment and fixed stellar mass. The SSFR of star-forming galaxies at fixed environment is correlated with stellar mass; however, at fixed stellar mass it is independent of environment. The same trend exists for the D n (4000) measures of both the star-forming and quiescent galaxies and shows that their properties are determined primarily by their stellar mass, not by their environment. Instead, it appears that environment's primary role is to control the fraction of star-forming galaxies. Using the spectra we identify candidate poststarburst galaxies and find that those with 9.3 < log M */M ⊙ < 10.7 are 3.1 ± 1.1 times more common in high-density regions compared to low-density regions. The clear association of poststarbursts with high-density regions as well as the lack of a correlation between the SSFRs and D n (4000)s of star-forming galaxies with their environment strongly suggests that at z ~ 1 the environmental-quenching timescale must be rapid. Lastly, we construct a simple quenching model which demonstrates that the lack of a correlation between the D n (4000) of quiescent galaxies and their environment results naturally if self quenching dominates over environmental quenching at z > 1, or if the evolution of the self-quenching rate mirrors the evolution of the environmental-quenching rate at z > 1, regardless of which

  17. K-band Properties of Galaxy Clusters and Groups: Brightest Cluster Galaxies and Intracluster Light

    NASA Astrophysics Data System (ADS)

    Lin, Yen-Ting; Mohr, Joseph J.

    2004-12-01

    We investigate the near-infrared K-band properties of the brightest cluster galaxies (BCGs) in a sample of 93 X-ray galaxy clusters and groups, using data from the Two Micron All Sky Survey. Our cluster sample spans a factor of 70 in mass, making it sensitive to any cluster mass-related trends. We derive the cumulative radial distribution for the BCGs in the ensemble and find that 70% of the BCGs are centered in the cluster to within 5% of the virial radius r200; this quantifies earlier findings that BCG position coincides with the cluster center as defined by the X-ray emission peak. We study the correlations between the luminosity of the BCGs (Lb) and the mass and the luminosity of the host clusters, finding that BCGs in more massive clusters are more luminous than their counterparts in less massive systems and that the BCGs become less important in the overall cluster light (L200) as cluster mass increases. By examining a large sample of optically selected groups, we find that these correlations hold for galactic systems less massive than our clusters (<3×1013 Msolar). From the differences between luminosity functions in high- and low-mass clusters, we argue that BCGs grow in luminosity mainly by merging with other luminous galaxies as the host clusters grow hierarchically; the decreasing BCG luminosity fraction (Lb/L200) with cluster mass indicates that the rate of luminosity growth in BCGs is slow compared to the rate at which clusters acquire galaxy light from the field or other merging clusters. Utilizing the observed correlation between the cluster luminosity and mass and a merger tree model for cluster formation, we estimate that the amount of intracluster light (ICL) increases with cluster mass; our calculations suggest that in 1015 Msolar clusters more than 50% of total stellar mass is in ICL, making the role of ICL very important in the evolution and thermodynamic history of clusters. The cluster baryon fraction accounting for the ICL is in good

  18. Cosmology with Clusters of Galaxies

    NASA Astrophysics Data System (ADS)

    Borgani, Stefano

    I reviewed in my talk recent results on the cosmological constraints that can be obtained by following the evolution of the population of galaxy clusters. Using extended samples of X-ray selected clusters, I have shown how they can be used to trace this evolution out to redshift z ~ 1. This evolution can be compared to model predictions and, therefore, to constrain cosmological parameters, such as the density parameter Omega_m and the shape and amplitude of the power spectrum of density perturbations. I have emphasized that the robustness of such constraints is quite sensitive to the relation between cluster collapsed mass and X-ray luminosity and temperature. This demonstrates that our ability to place significant constraints on cosmology using clusters of galaxies relies on our capability to understand the physical processes, which determine the properties of the intra-cluster medium (ICM). In this context, I have discussed how numerical simulations of cluster formation in cosmological context can play an important role in uderstanding the ICM physics. I have presented results from a very large cosmological simulation, which also includes the hydrodynamical description of the cosmic baryons, the processes of star formation and feedback from the stellar populations. The results from this simulation represent a unique baseline to describe the processes of formation and evolution of clusters of galaxies.

  19. A Cluster and a Sea of Galaxies

    NASA Astrophysics Data System (ADS)

    2010-05-01

    accounting for another ten percent [2]. The remaining 80 percent is made of an invisible and unknown ingredient called dark matter that lies in between the galaxies. The presence of dark matter is revealed through its gravitational effect: the enormous mass of a galaxy cluster acts on the light from galaxies behind the cluster like a cosmic magnifying glass, bending the trajectory of the light and thus making the galaxies appear slightly distorted [3]. By observing and analysing the twisted shapes of these background galaxies, astronomers can infer the total mass of the cluster responsible for the distortion, even when this mass is mostly invisible. However, this effect is usually tiny, and it is necessary to measure it over a huge number of galaxies to obtain significant results: in the case of Abell 315, the shapes of almost 10 000 faint galaxies in this image were studied in order to estimate the total mass of the cluster, which amounts to over a hundred thousand billion times the mass of our Sun [4]. To complement the enormous range of cosmic distances and sizes surveyed by this image, a handful of objects much smaller than galaxies and galaxy clusters and much closer to Earth are scattered throughout the field: besides several stars belonging to our galaxy, many asteroids are also visible as blue, green or red trails [5]. These objects belong to the main asteroid belt, located between the orbits of Mars and Jupiter, and their dimensions vary from some tens of kilometres, for the brightest ones, to just a few kilometres in the case of the faintest ones. This image has been taken with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at ESO's La Silla Observatory in Chile. It is a composite of several exposures acquired using three different broadband filters, for a total of almost one hour in the B filter and about one and a half hours in the V and R filters. The field of view is 34 x 33 arcminutes. Notes [1] The Abell catalogue from 1958 comprised 2712 clusters

  20. VizieR Online Data Catalog: Hα survey of nearby clusters of galaxies (Sakai+, 2012)

    NASA Astrophysics Data System (ADS)

    Sakai, S.; Kennicutt, R. C. Jr; Moss, C.

    2012-06-01

    Our survey required a CCD imager with a wide field of view (~1°) and equipped with narrowband filters covering the wavelength range corresponding to Hα redshifted by 3000-9000km/s. This requirement was met by the MOSAIC-1 Imager on the Kitt Peak National Observatory (KPNO) 0.9m telescope. Observations were made over three observing runs in 1999-2001. The instrument was equipped with a standard set of Kron-Cousins UBVRI broadband filters along with a set of five narrowband filters (~80Å FWHM) with central wavelengths of 6569, 6609, 6650, 6689, and 6730Å (or the wavelength of rest Hα redshifted by roughly 0, 40, 80, 120, and 160Å). These are referred to in the instrument documentation as Ha, Ha4, Ha8, Ha12, and Ha16. (4 data files).

  1. THE GRISM LENS-AMPLIFIED SURVEY FROM SPACE (GLASS). V. EXTENT AND SPATIAL DISTRIBUTION OF STAR FORMATION IN z ∼ 0.5 CLUSTER GALAXIES

    SciTech Connect

    Vulcani, Benedetta; Treu, Tommaso; Malkan, Matthew; Abramson, Louis; Schmidt, Kasper B.; Poggianti, Bianca M.; Dressler, Alan; Fontana, Adriano; Pentericci, Laura; Bradac, Marusa; Hoag, Austin; Huang, Kuan-Han; He, Julie; Brammer, Gabriel B.; Trenti, Michele; Linden, Anja von der; Morris, Glenn

    2015-12-01

    We present the first study of the spatial distribution of star formation in z ∼ 0.5 cluster galaxies. The analysis is based on data taken with the Wide Field Camera 3 as part of the Grism Lens-Amplified Survey from Space (GLASS). We illustrate the methodology by focusing on two clusters (MACS 0717.5+3745 and MACS 1423.8+2404) with different morphologies (one relaxed and one merging) and use foreground and background galaxies as a field control sample. The cluster+field sample consists of 42 galaxies with stellar masses in the range 10{sup 8}–10{sup 11} M{sub ⊙} and star formation rates in the range 1–20 M{sub ⊙} yr{sup −1}. Both in clusters and in the field, Hα is more extended than the rest-frame UV continuum in 60% of the cases, consistent with diffuse star formation and inside-out growth. In ∼20% of the cases, the Hα emission appears more extended in cluster galaxies than in the field, pointing perhaps to ionized gas being stripped and/or star formation being enhanced at large radii. The peak of the Hα emission and that of the continuum are offset by less than 1 kpc. We investigate trends with the hot gas density as traced by the X-ray emission, and with the surface mass density as inferred from gravitational lens models, and find no conclusive results. The diversity of morphologies and sizes observed in Hα illustrates the complexity of the environmental processes that regulate star formation. Upcoming analysis of the full GLASS data set will increase our sample size by almost an order of magnitude, verifying and strengthening the inference from this initial data set.

  2. Cosmology and astrophysics with galaxy clusters

    SciTech Connect

    Nagai, Daisuke

    2014-11-20

    Galaxy clusters are the largest gravitationally bound objects in the universe, whose formation is driven by dark energy and dark matter. The majority of the baryonic mass in clusters resides in the hot X-ray emitting plasma, which also leaves imprints in the cosmic microwave background radiation. Recent X-ray and microwave observations have revealed detailed thermodynamic structure of the hot X-ray emitting plasma from their cores to the virial radii, making comparisons of baryonic component in simulations to observations a strong cosmological probe. However, the statistical power of these future surveys can only be exploited for cosmology if and only if we are able to measure the cluster mass with a very high precision. I will discuss recent progress and future challenges for the use of galaxy clusters as precise cosmological probes, with highlights on (1) the importance of understanding thermodynamics and plasma physics in the outskirts of galaxy clusters and (2) prospects for improving the power of cluster-based cosmological measurements using numerical simulations and multi-wavelength observations.

  3. Detection of CO emission in Hydra 1 cluster galaxies

    NASA Technical Reports Server (NTRS)

    Huchtmeier, W. K.

    1990-01-01

    A survey of bright Hydra cluster spiral galaxies for the CO(1-0) transition at 115 GHz was performed with the 15m Swedish-ESO submillimeter telescope (SEST). Five out of 15 galaxies observed have been detected in the CO(1-0) line. The largest spiral galaxy in the cluster, NGC 3312, got more CO than any spiral of the Virgo cluster. This Sa-type galaxy is optically largely distorted and disrupted on one side. It is a good candidate for ram pressure stripping while passing through the cluster's central region. A comparison with global CO properties of Virgo cluster spirals shows a relatively good agreement with the detected Hydra cluster galaxies.

  4. Nonthermal Emission from Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Storm, Emma

    Galaxy clusters are the most massive gravitationally-bound objects in the universe. The bulk of the mass in a cluster is dark matter, while the dominant baryonic component is a thermal, X-ray emitting plasma. Radio observations of diffuse synchrotron emission indicate that galaxy clusters host a population of cosmic rays; however, the nature of this nonthermal component is not well-understood. In this dissertation, I investigate three sources of nonthermal emission in galaxy clusters. The first is star formation in galaxies, which is correlated to gamma-ray emission. I derive lower limits on the gamma-ray emission for nearby clusters by considering the emission from star formation in cluster galaxies. These lower limits sit about an order of magnitude below current upper limits on gamma rays in clusters and will be an important contributor to gamma-ray emission as upper limits improve over time. Dark matter annihilation, which produces relativistic particles that can result in a broad spectrum of emission in cluster environments, is another source of nonthermal emission. I use nondetections and marginal detections of diffuse radio emission in clusters to constrain dark matter annihilation. I derive limits on the annihilation cross section that are competitive with limits from the nondetection of gamma rays in clusters and show that the best objects for study in the radio are different than those in gamma rays, indicating that dark matter searches in the radio can be complementary to searches in other energy bands. I also investigate the cosmic ray population in the merging cluster A2319, which hosts a previously detected radio halo. I present new observations which reveal a two-component radio halo: a 2 Mpc region that extends far past the observable X-ray emission, and an 800 kpc "core" that is bounded by the X-ray cold front. I speculate on the origins of this structure, and show that a hadronic origin for this radio halo is disfavored. Finally, I discuss current

  5. RELICS: Reionization Lensing Cluster Survey

    NASA Astrophysics Data System (ADS)

    Coe, Dan A.; RELICS Team

    2017-01-01

    Hubble and Spitzer imaging programs observing galaxy cluster lenses have delivered some of the highest redshift galaxy candidates to date (z ~ 9 - 11, or 540 - 410 Myr after the Big Bang). These magnified galaxies are intrinsically faint, and thus more representative of the sources believed to be primarily responsible for reionization. Magnified galaxies are also observed brightly enough to be prime targets for detailed follow-up study with current and future observatories, including JWST. Building on the successes of CLASH and the Frontier Fields, we have begun RELICS, the Reionization Lensing Cluster Survey. By observing 41 massive clusters for the first time at infrared wavelengths, RELICS will deliver more of the best and brightest high-redshift candidates to the community in time for the November 2017 JWST GO Cycle 1 call for proposals. I will present our early results. I will also discuss prospects for JWST to follow-up known candidates and discover new galaxies at even higher redshifts (z > 11). The discovery efficiency gains from lensing will be even more pronounced at z > 11 if luminosity function faint end slopes are steeper than alpha ~ -2, as suggested by current models and observational extrapolations.

  6. Detecting galaxy clusters in the DLS and CARS: a Bayesian cluster finder

    NASA Astrophysics Data System (ADS)

    Ascaso, B.; Wittman, D.; Benítez, N.

    2011-11-01

    The detection of galaxy clusters in present and future surveys enables measuring mass-to-light ratios, clustering properties or galaxy cluster abundances and therefore, constraining cosmological parameters. We present a new technique for detecting galaxy clusters, which is based on the Matched Filter Algorithm from a Bayesian point of view. The method is able to determine the position, redshift and richness of the cluster through the maximization of a filter depending on galaxy luminosity, density and photometric redshift combined with a galaxy cluster prior. We tested the algorithm through realistic mock galaxy catalogs, revealing that the detections are 100% complete and 80% pure for clusters up to z < 1.2 and richer than λ ≥ 25 (Abell richness ≥ 0). We applied the algorithm to the CFHTLS Archive Research Survey (CARS) data, recovering similar detections as previously published using the same data plus additional clusters that are very probably real. We also applied this algorithm to the Deep Lens Survey (DLS), obtaining the first sample of optical-selected galaxy in this survey. The sample is complete up to redshift 0.7 and we detect more than 780 cluster candidates up to redshift 1.2. We conclude by discussing the differences between previous weak lensing detections in this survey and optical detections in both samples.

  7. The XXL Survey. VIII. MUSE characterisation of intracluster light in a z ~ 0.53 cluster of galaxies

    NASA Astrophysics Data System (ADS)

    Adami, C.; Pompei, E.; Sadibekova, T.; Clerc, N.; Iovino, A.; McGee, S. L.; Guennou, L.; Birkinshaw, M.; Horellou, C.; Maurogordato, S.; Pacaud, F.; Pierre, M.; Poggianti, B.; Willis, J.

    2016-06-01

    Aims: Within a cluster, gravitational effects can lead to the removal of stars from their parent galaxies and their subsequent dispersal into the intracluster medium. Gas hydrodynamical effects can additionally strip gas and dust from galaxies; both gas and stars contribute to intracluster light (ICL). The properties of the ICL can therefore help constrain the physical processes at work in clusters by serving as a fossil record of the interaction history. Methods: The present study is designed to characterise this ICL for the first time in a ~1014 M⊙ and z ~ 0.53 cluster of galaxies from imaging and spectroscopic points of view. By applying a wavelet-based method to CFHT Megacam and WIRCAM images, we detect significant quantities of diffuse light and are able to constrain their spectral energy distributions. These sources were then spectroscopically characterised with ESO Multi Unit Spectroscopic Explorer (MUSE) spectroscopic data. MUSE data were also used to compute redshifts of 24 cluster galaxies and search for cluster substructures. Results: An atypically large amount of ICL, equivalent in i' to the emission from two brightest cluster galaxies, has been detected in this cluster. Part of the detected diffuse light has a very weak optical stellar component and apparently consists mainly of gas emission, while other diffuse light sources are clearly dominated by old stars. Furthermore, emission lines were detected in several places of diffuse light. Our spectral analysis shows that this emission likely originates from low-excitation parameter gas. Globally, the stellar contribution to the ICL is about 2.3 × 109 yr old even though the ICL is not currently forming a large number of stars. On the other hand, the contribution of the gas emission to the ICL in the optical is much greater than the stellar contribution in some regions, but the gas density is likely too low to form stars. These observations favour ram pressure stripping, turbulent viscous stripping, or

  8. The VIMOS Public Extragalactic Redshift Survey (VIPERS) . Galaxy clustering and redshift-space distortions at z ≃ 0.8 in the first data release

    NASA Astrophysics Data System (ADS)

    de la Torre, S.; Guzzo, L.; Peacock, J. A.; Branchini, E.; Iovino, A.; Granett, B. R.; Abbas, U.; Adami, C.; Arnouts, S.; Bel, J.; Bolzonella, M.; Bottini, D.; Cappi, A.; Coupon, J.; Cucciati, O.; Davidzon, I.; De Lucia, G.; Fritz, A.; Franzetti, P.; Fumana, M.; Garilli, B.; Ilbert, O.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; McCracken, H. J.; Moscardini, L.; Paioro, L.; Percival, W. J.; Polletta, M.; Pollo, A.; Schlagenhaufer, H.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Di Porto, C.; Marchetti, A.; Marinoni, C.; Mellier, Y.; Monaco, P.; Nichol, R. C.; Phleps, S.; Wolk, M.; Zamorani, G.

    2013-09-01

    We present the general real- and redshift-space clustering properties of galaxies as measured in the first data release of the VIPERS survey. VIPERS is a large redshift survey designed to probe in detail the distant Universe and its large-scale structure at 0.5 < z < 1.2. We describe in this analysis the global properties of the sample and discuss the survey completeness and associated corrections. This sample allows us to measure the galaxy clustering with an unprecedented accuracy at these redshifts. From the redshift-space distortions observed in the galaxy clustering pattern we provide a first measurement of the growth rate of structure at z = 0.8: fσ8 = 0.47 ± 0.08. This is completely consistent with the predictions of standard cosmological models based on Einstein gravity, although this measurement alone does not discriminate between different gravity models. Based on observations collected at the European Southern Observatory, Cerro Paranal, Chile, using the Very Large Telescope under programmes 182.A-0886 and partly 070.A-9007. Also based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii. This work is based in part on data products produced at TERAPIX and the Canadian Astronomy Data Centre as part of the Canada-France-Hawaii Telescope Legacy Survey, a collaborative project of NRC and CNRS. The VIPERS web site is http://www.vipers.inaf.it/

  9. Decaying neutrinos in galaxy clusters

    NASA Technical Reports Server (NTRS)

    Melott, Adrian L.; Splinter, Randall J.; Persic, Massimo; Salucci, Paolo

    1994-01-01

    Davidsen et al. (1991) have argued that the failure to detect UV photons from the dark matter (DM) in cluster A665 excludes the decaying neutrino hypothesis. Sciama et al. (1993) argued that because of high central concentration the DM in that cluster must be baryonic. We study the DM profile in clusters of galaxies simulated using the Harrison-Zel'dovich spectrum of density fluctuations, and an amplitude previously derived from numerical simulations (Melott 1984b; Anninos et al. 1991) and in agreement with microwave background fluctuations (Smoot et al. 1992). We find that with this amplitude normalization cluster neutrino DM densities are comparable to observed cluster DM values. We conclude that given this normalization, the cluster DM should be at least largely composed of neutrinos. The constraint of Davidsen et al. can be somewhat weakened by the presence of baryonic DM; but it cannot be eliminated given our assumptions.

  10. The XMM-BCS galaxy cluster survey: I. The X-ray selected cluster catalog from the initial 6 deg$^2$

    SciTech Connect

    Suhada, R.; Song, J.; Bohringer, H.; Mohr, J.J.; Chon, G.; Finoguenov, A.; Fassbender, R.; Desai, S.; Armstrong, R.; Zenteno, A.; Barkhouse, W.A.; /North Dakota U. /Paris, Inst. Astrophys.

    2011-11-01

    The XMM-Newton - Blanco Cosmology Survey project (XMM-BCS) is a coordinated X-ray, optical and mid-infrared cluster survey in a field also covered by Sunyaev-Zel dovich effect (SZE) surveys by the South Pole Telescope and the Atacama Cosmology Telescope. The aim of the project is to study the cluster population in a 14 deg{sup 2} field (center: {alpha} {approx} 23:29:18.4, {delta} {approx} -54:40:33.6). The uniform multi-wavelength coverage will also allow us for the first time to comprehensively compare the selection function of the different cluster detection approaches in a single test field and perform a cross-calibration of cluster scaling relations. In this work, we present a catalog of 46 X-ray selected clusters from the initial 6 deg{sup 2} survey core.We describe the XMM-BCS source detection pipeline and derive physical properties of the clusters. We provide photometric redshift estimates derived from the BCS imaging data and spectroscopic redshift measurements for a low redshift subset of the clusters. The photometric redshift estimates are found to be unbiased and in good agreement with the spectroscopic values. Our multi-wavelength approach gives us a comprehensive look at the cluster and group population up to redshifts z {approx} 1. The median redshift of the sample is 0.47 and the median mass M{sub 500} {approx} 1 x 10{sup 14} M{sub {circle_dot}} ({approx} 2 keV). From the sample, we derive the cluster log N - log S using an approximation to the survey selection function and find it in good agreement with previous studies. We compare optical mass estimates from the Southern Cosmology Survey available for part of our cluster sample with our estimates derived from the X-ray luminosity. Weak lensing masses available for a subset of the cluster sample are in agreement with our estimates. Optical masses based on cluster richness and total optical luminosity are found to be significantly higher than the X-ray values. The present results illustrate the

  11. Cluster Physics with Merging Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Molnar, Sandor

    Collisions between galaxy clusters provide a unique opportunity to study matter in a parameter space which cannot be explored in our laboratories on Earth. In the standard ΛCDM model, where the total density is dominated by the cosmological constant (Λ) and the matter density by cold dark matter (CDM), structure formation is hierarchical, and clusters grow mostly by merging. Mergers of two massive clusters are the most energetic events in the universe after the Big Bang, hence they provide a unique laboratory to study cluster physics. The two main mass components in clusters behave differently during collisions: the dark matter is nearly collisionless, responding only to gravity, while the gas is subject to pressure forces and dissipation, and shocks and turbulence are developed during collisions. In the present contribution we review the different methods used to derive the physical properties of merging clusters. Different physical processes leave their signatures on different wavelengths, thus our review is based on a multifrequency analysis. In principle, the best way to analyze multifrequency observations of merging clusters is to model them using N-body/HYDRO numerical simulations. We discuss the results of such detailed analyses. New high spatial and spectral resolution ground and space based telescopes will come online in the near future. Motivated by these new opportunities, we briefly discuss methods which will be feasible in the near future in studying merging clusters.

  12. Intermediate Redshift Galaxy Clusters from DPOSS

    NASA Astrophysics Data System (ADS)

    Lopes, P. A. A.

    2003-06-01

    In this thesis we discuss the selection of intermediate redshift galaxy cluster candidates based on the Digitized Second Palomar Observatory Sky Survey (DPOSS). Clusters are detected using the best DPOSS plates based on seeing and limiting magnitude. The search is further restricted to high galactic latitudes (|b| > 50 °), where stellar contamination is mild and nearly uniform. The input galaxy catalogs used for this search are limited to r = 21.1. The cluster selection is based on two techniques, the adaptive kernel and the voronoi tesselation methods. The final combined catalog contains ~ 10,000 candidates over ~ 2,700 square degrees, with ~ 0.30 and ~ 40 (Ngals is a richness estimate we provide). Rich clusters are detected down to z ~ 0.5. This cluster catalog is a supplement to the previous DPOSS catalogs, being the largest resource of rich clusters in this redshift range to date. In order to optimize the detection algorithms and estimate the contamination and completeness rates, we perform a large number of simulations for both catalogs. Redshift and richness estimates are also provided for all candidates in the two catalogs. As a by-product we present a comparison between the DPOSS and SDSS surveys. This comparison is used to estimate the DPOSS detection limits. Some of the projects to be developed in the future are also discussed.

  13. Size Bias in Galaxy Surveys

    NASA Astrophysics Data System (ADS)

    Schmidt, Fabian; Rozo, Eduardo; Dodelson, Scott; Hui, Lam; Sheldon, Erin

    2009-07-01

    Only certain galaxies are included in surveys: those bright and large enough to be detectable as extended sources. Because gravitational lensing can make galaxies appear both brighter and larger, the presence of foreground inhomogeneities can scatter galaxies across not only magnitude cuts but also size cuts, changing the statistical properties of the resulting catalog. Here we explore this size bias and how it combines with magnification bias to affect galaxy statistics. We demonstrate that photometric galaxy samples from current and upcoming surveys can be even more affected by size bias than by magnification bias.

  14. Decaying neutrinos in galaxy clusters

    NASA Technical Reports Server (NTRS)

    Melott, Adrian L.; Splinter, Randall J.; Persic, Massimo; Salucci, Paolo

    1993-01-01

    The DM profile in clusters of galaxies was studied and simulated using the Harrison-Zel'dovich spectrum of density fluctuations, and an amplitude previously derived from numerical simulations and in agreement with microwave background fluctuations. Neutrino DM densities, with this amplitude normalization cluster, are comparable to observed cluster DM values. It was concluded that given this normalization, the cluster DM should be al least largely composed of neutrinos. The constraint of Davidson et al., who argued that the failure to detect uv photons from the dark matter (DM) in cluster A665 excludes the decaying neutrino hypothesis, could be somewhat weakened by the presence of baryonic DM; but it cannot be eliminated given our assumptions.

  15. 3D galaxy clustering with future wide-field surveys: Advantages of a spherical Fourier-Bessel analysis

    NASA Astrophysics Data System (ADS)

    Lanusse, F.; Rassat, A.; Starck, J.-L.

    2015-06-01

    Context. Upcoming spectroscopic galaxy surveys are extremely promising to help in addressing the major challenges of cosmology, in particular in understanding the nature of the dark universe. The strength of these surveys, naturally described in spherical geometry, comes from their unprecedented depth and width, but an optimal extraction of their three-dimensional information is of utmost importance to best constrain the properties of the dark universe. Aims: Although there is theoretical motivation and novel tools to explore these surveys using the 3D spherical Fourier-Bessel (SFB) power spectrum of galaxy number counts Cℓ(k,k'), most survey optimisations and forecasts are based on the tomographic spherical harmonics power spectrum C(ij)_ℓ. The goal of this paper is to perform a new investigation of the information that can be extracted from these two analyses in the context of planned stage IV wide-field galaxy surveys. Methods: We compared tomographic and 3D SFB techniques by comparing the forecast cosmological parameter constraints obtained from a Fisher analysis. The comparison was made possible by careful and coherent treatment of non-linear scales in the two analyses, which makes this study the first to compare 3D SFB and tomographic constraints on an equal footing. Nuisance parameters related to a scale- and redshift-dependent galaxy bias were also included in the computation of the 3D SFB and tomographic power spectra for the first time. Results: Tomographic and 3D SFB methods can recover similar constraints in the absence of systematics. This requires choosing an optimal number of redshift bins for the tomographic analysis, which we computed to be N = 26 for zmed ≃ 0.4, N = 30 for zmed ≃ 1.0, and N = 42 for zmed ≃ 1.7. When marginalising over nuisance parameters related to the galaxy bias, the forecast 3D SFB constraints are less affected by this source of systematics than the tomographic constraints. In addition, the rate of increase of the

  16. Dynamic evolution of nearby galaxy clusters

    NASA Astrophysics Data System (ADS)

    Biernacka, M.; Flin, P.

    2011-06-01

    A study of the evolution of 377 rich ACO clusters with redshift z<0.2 is presented. The data concerning galaxies in the investigated clusters were obtained using FOCAS packages applied to Digital Sky Survey I. The 377 galaxy clusters constitute a statistically uniform sample to which visual galaxy/star reclassifications were applied. Cluster shape within 2.0 h-1 Mpc from the adopted cluster centre (the mean and the median of all galaxy coordinates, the position of the brightest and of the third brightest galaxy in the cluster) was determined through its ellipticity calculated using two methods: the covariance ellipse method (hereafter CEM) and the method based on Minkowski functionals (hereafter MFM). We investigated ellipticity dependence on the radius of circular annuli, in which ellipticity was calculated. This was realized by varying the radius from 0.5 to 2 Mpc in steps of 0.25 Mpc. By performing Monte Carlo simulations, we generated clusters to which the two ellipticity methods were applied. We found that the covariance ellipse method works better than the method based on Minkowski functionals. We also found that ellipticity distributions are different for different methods used. Using the ellipticity-redshift relation, we investigated the possibility of cluster evolution in the low-redshift Universe. The correlation of cluster ellipticities with redshifts is undoubtly an indicator of structural evolution. Using the t-Student statistics, we found a statistically significant correlation between ellipticity and redshift at the significance level of α = 0.95. In one of the two shape determination methods we found that ellipticity grew with redshift, while the other method gave opposite results. Monte Carlo simulations showed that only ellipticities calculated at the distance of 1.5 Mpc from cluster centre in the Minkowski functional method are robust enough to be taken into account, but for that radius we did not find any relation between e and z. Since CEM

  17. The Herschel Virgo Cluster Survey. III. A constraint on dust grain lifetime in early-type galaxies

    NASA Astrophysics Data System (ADS)

    Clemens, M. S.; Jones, A. P.; Bressan, A.; Baes, M.; Bendo, G. J.; Bianchi, S.; Bomans, D. J.; Boselli, A.; Corbelli, E.; Cortese, L.; Dariush, A.; Davies, J. I.; De Looze, I.; di Serego Alighieri, S.; Fadda, D.; Fritz, J.; Garcia-Appadoo, D. A.; Gavazzi, G.; Giovanardi, C.; Grossi, M.; Hughes, T. M.; Hunt, L. K.; Madden, S.; Pierini, D.; Pohlen, M.; Sabatini, S.; Smith, M. W. L.; Verstappen, J.; Vlahakis, C.; Xilouris, E. M.; Zibetti, S.

    2010-07-01

    Passive early-type galaxies (ETGs) provide an ideal laboratory for studying the interplay between dust formation around evolved stars and its subsequent destruction in a hot gas. Using Spitzer-IRS and Herschel data we compare the dust production rate in the envelopes of evolved AGB stars with a constraint on the total dust mass. Early-type galaxies which appear to be truly passively evolving are not detected by Herschel. We thus derive a distance independent upper limit to the dust grain survival time in the hostile environment of ETGs of <46±25 Myr for amorphous silicate grains. This implies that ETGs which are detected at far-infrared wavelengths have acquired a cool dusty medium via interaction. Given likely time-scales for ram-pressure stripping, this also implies that only galaxies with dust in a cool (atomic) medium can release dust into the intra-cluster medium. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  18. Understanding Galaxy Cluster MKW10

    NASA Astrophysics Data System (ADS)

    Sanders, Tim; Henry, Swain; Coble, Kimberly A.; Rosenberg, Jessica L.; Koopmann, Rebecca A.

    2015-01-01

    As part of the Undergraduate ALFALFA Team (UAT), we are studying the galaxy cluster MKW 10 (RA = 175.454, Dec = 10.306, z ~ 0.02), a poor cluster with a compact core in which tidal interactions have occurred. This cluster has been observed in HI and Hα. We used SDSS and NED to search for optical counterparts. By comparing data at multiple wavelengths, we hope to understand the structure, environment, and star formation history of this cluster. Following the techniques of others involved in the groups project and using the program TOPCAT to manipulate the data, we explored both the spatial and velocity distributions to determine cluster membership. We have determined that this cluster consists of 11 galaxies, mostly spiral in shape. Chicago State University is new the UAT and we began our work after taking part in the winter workshop at Arecibo.This work was supported by: Undergraduate ALFALFA Team NSF Grant AST-1211005 and the Illinois Space Grant Consortium.

  19. Joint Analysis of Galaxy-Galaxy Lensing and Galaxy Clustering: Methodology and Forecasts for DES

    SciTech Connect

    Park, Y.

    2015-07-19

    The joint analysis of galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth function of large scale structure. Our analysis will be carried out on data from the Dark Energy Survey (DES), with its measurements of both the distribution of galaxies and the tangential shears of background galaxies induced by these foreground lenses. We develop a practical approach to modeling the assumptions and systematic effects affecting small scale lensing, which provides halo masses, and large scale galaxy clustering. Introducing parameters that characterize the halo occupation distribution (HOD), photometric redshift uncertainties, and shear measurement errors, we study how external priors on different subsets of these parameters affect our growth constraints. Degeneracies within the HOD model, as well as between the HOD and the growth function, are identified as the dominant source of complication, with other systematic effects sub-dominant. The impact of HOD parameters and their degeneracies necessitate the detailed joint modeling of the galaxy sample that we employ. Finally, we conclude that DES data will provide powerful constraints on the evolution of structure growth in the universe, conservatively/optimistically constraining the growth function to 7.9%/4.8% with its first-year data that covered over 1000 square degrees, and to 3.9%/2.3% with its full five-year data that will survey 5000 square degrees, including both statistical and systematic uncertainties.

  20. Cluster Position Angle Alignments in the CLASH Survey

    NASA Astrophysics Data System (ADS)

    McIntosh, Melissa; de Propris, Roberto; West, Michael

    2016-01-01

    There exists strong evidence for nearby brightest cluster galaxies (BCGs) to exhibit preferential orientation with respect to their surroundings. Primarily, we see these bright member galaxies aligning themselves with the cluster's principal axis. We have examined the orientations of the 25 CLASH Survey galaxy clusters to see whether this tendency for BCGs to share the same major axis orientation as their host cluster extends to galaxy clusters at redshifts up to 0.9. We find evidence of preferential orientations existing in clusters at these redshifts. The significance of this finding for theories of the formation of clusters are discussed. Supported by NSF Grant #1358980 and the MA Space Grant Consortium.

  1. The Next Generation Virgo Cluster Survey. XII. Stellar Populations and Kinematics of Compact, Low-mass Early-type Galaxies from Gemini GMOS-IFU Spectroscopy

    NASA Astrophysics Data System (ADS)

    Guérou, Adrien; Emsellem, Eric; McDermid, Richard M.; Côté, Patrick; Ferrarese, Laura; Blakeslee, John P.; Durrell, Patrick R.; MacArthur, Lauren A.; Peng, Eric W.; Cuillandre, Jean-Charles; Gwyn, Stephen

    2015-05-01

    We present Gemini Multi Object Spectrograph integral-field unit (GMOS-IFU) data of eight compact, low-mass early-type galaxies (ETGs) in the Virgo cluster. We analyze their stellar kinematics and stellar population and present two-dimensional maps of these properties covering the central 5″ × 7″ region. We find a large variety of kinematics, from nonrotating to highly rotating objects, often associated with underlying disky isophotes revealed by deep images from the Next Generation Virgo Cluster Survey. In half of our objects, we find a centrally concentrated younger and more metal-rich stellar population. We analyze the specific stellar angular momentum through the λR parameter and find six fast rotators and two slow rotators, one having a thin counterrotating disk. We compare the local galaxy density and stellar populations of our objects with those of 39 more extended low-mass Virgo ETGs from the SMAKCED survey and 260 massive (M > 1010 {{M}⊙ }) ETGs from the ATLAS3D sample. The compact low-mass ETGs in our sample are located in high-density regions, often close to a massive galaxy, and have, on average, older and more metal-rich stellar populations than less compact low-mass galaxies. We find that the stellar population parameters follow lines of constant velocity dispersion in the mass-size plane, smoothly extending the comparable trends found for massive ETGs. Our study supports a scenario where low-mass compact ETGs have experienced long-lived interactions with their environment, including ram-pressure stripping and gravitational tidal forces, that may be responsible for their compact nature.

  2. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: observational systematics and baryon acoustic oscillations in the correlation function

    NASA Astrophysics Data System (ADS)

    Ross, Ashley J.; Beutler, Florian; Chuang, Chia-Hsun; Pellejero-Ibanez, Marcos; Seo, Hee-Jong; Vargas-Magaña, Mariana; Cuesta, Antonio J.; Percival, Will J.; Burden, Angela; Sánchez, Ariel G.; Grieb, Jan Niklas; Reid, Beth; Brownstein, Joel R.; Dawson, Kyle S.; Eisenstein, Daniel J.; Ho, Shirley; Kitaura, Francisco-Shu; Nichol, Robert C.; Olmstead, Matthew D.; Prada, Francisco; Rodríguez-Torres, Sergio A.; Saito, Shun; Salazar-Albornoz, Salvador; Schneider, Donald P.; Thomas, Daniel; Tinker, Jeremy; Tojeiro, Rita; Wang, Yuting; White, Martin; Zhao, Gong-bo

    2017-01-01

    We present baryon acoustic oscillation (BAO) scale measurements determined from the clustering of 1.2 million massive galaxies with redshifts 0.2 < z < 0.75 distributed over 9300 deg2, as quantified by their redshift-space correlation function. In order to facilitate these measurements, we define, describe, and motivate the selection function for galaxies in the final data release (DR12) of the SDSS III Baryon Oscillation Spectroscopic Survey (BOSS). This includes the observational footprint, masks for image quality and Galactic extinction, and weights to account for density relationships intrinsic to the imaging and spectroscopic portions of the survey. We simulate the observed systematic trends in mock galaxy samples and demonstrate that they impart no bias on BAO scale measurements and have a minor impact on the recovered statistical uncertainty. We measure transverse and radial BAO distance measurements in 0.2 < z < 0.5, 0.5 < z < 0.75, and (overlapping) 0.4 < z < 0.6 redshift bins. In each redshift bin, we obtain a precision that is 2.7 per cent or better on the radial distance and 1.6 per cent or better on the transverse distance. The combination of the redshift bins represents 1.8 per cent precision on the radial distance and 1.1 per cent precision on the transverse distance. This paper is part of a set that analyses the final galaxy clustering data set from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. to produce the final cosmological constraints from BOSS.

  3. Mass calibration of galaxy clusters at redshift 0.1–1.0 using weak lensing in the Sloan Digital Sky Survey Stripe 82 co-add

    SciTech Connect

    Wiesner, Matthew P.; Lin, Huan; Soares-Santos, Marcelle

    2015-07-08

    We present galaxy cluster mass–richness relations found in the Sloan Digital Sky Survey Stripe 82 co-add using clusters found using a Voronoi tessellation cluster finder. These relations were found using stacked weak lensing shear observed in a large sample of galaxy clusters. These mass–richness relations are presented for four redshift bins, 0.1 < z ≤ 0.4, 0.4 < z ≤ 0.7, 0.7 < z ≤ 1.0 and 0.1 < z ≤ 1.0. We describe the sample of galaxy clusters and explain how these clusters were found using a Voronoi tessellation cluster finder. We fit a Navarro-Frenk-White profile to the stacked weak lensing shear signal in redshift and richness bins in order to measure virial mass (M200). We describe several effects that can bias weak lensing measurements, including photometric redshift bias, the effect of the central BCG, halo miscentering, photometric redshift uncertainty and foreground galaxy contamination. We present mass–richness relations using richness measure NVT with each of these effects considered separately as well as considered altogether. We also examine redshift evolution of the mass–richness relation. As a result, we present measurements of the mass coefficient (M200|20) and the power-law slope (α) for power-law fits to the mass and richness values in each of the redshift bins. We find values of the mass coefficient of 8.49 ± 0.526, 14.1 ± 1.78, 30.2 ± 8.74 and 9.23 ± 0.525 × 1013 h–1 M for each of the four redshift bins, respectively. As a result, we find values of the power-law slope of 0.905 ± 0.0585, 0.948 ± 0.100, 1.33 ± 0.260 and 0.883 ± 0.0500, respectively.

  4. Mass calibration of galaxy clusters at redshift 0.1–1.0 using weak lensing in the Sloan Digital Sky Survey Stripe 82 co-add

    DOE PAGES

    Wiesner, Matthew P.; Lin, Huan; Soares-Santos, Marcelle

    2015-07-08

    We present galaxy cluster mass–richness relations found in the Sloan Digital Sky Survey Stripe 82 co-add using clusters found using a Voronoi tessellation cluster finder. These relations were found using stacked weak lensing shear observed in a large sample of galaxy clusters. These mass–richness relations are presented for four redshift bins, 0.1 < z ≤ 0.4, 0.4 < z ≤ 0.7, 0.7 < z ≤ 1.0 and 0.1 < z ≤ 1.0. We describe the sample of galaxy clusters and explain how these clusters were found using a Voronoi tessellation cluster finder. We fit a Navarro-Frenk-White profile to the stackedmore » weak lensing shear signal in redshift and richness bins in order to measure virial mass (M200). We describe several effects that can bias weak lensing measurements, including photometric redshift bias, the effect of the central BCG, halo miscentering, photometric redshift uncertainty and foreground galaxy contamination. We present mass–richness relations using richness measure NVT with each of these effects considered separately as well as considered altogether. We also examine redshift evolution of the mass–richness relation. As a result, we present measurements of the mass coefficient (M200|20) and the power-law slope (α) for power-law fits to the mass and richness values in each of the redshift bins. We find values of the mass coefficient of 8.49 ± 0.526, 14.1 ± 1.78, 30.2 ± 8.74 and 9.23 ± 0.525 × 1013 h–1 M⊙ for each of the four redshift bins, respectively. As a result, we find values of the power-law slope of 0.905 ± 0.0585, 0.948 ± 0.100, 1.33 ± 0.260 and 0.883 ± 0.0500, respectively.« less

  5. Galaxy formation through hierarchical clustering

    NASA Technical Reports Server (NTRS)

    White, Simon D. M.; Frenk, Carlos S.

    1991-01-01

    Analytic methods for studying the formation of galaxies by gas condensation within massive dark halos are presented. The present scheme applies to cosmogonies where structure grows through hierarchical clustering of a mixture of gas and dissipationless dark matter. The simplest models consistent with the current understanding of N-body work on dissipationless clustering, and that of numerical and analytic work on gas evolution and cooling are adopted. Standard models for the evolution of the stellar population are also employed, and new models for the way star formation heats and enriches the surrounding gas are constructed. Detailed results are presented for a cold dark matter universe with Omega = 1 and H(0) = 50 km/s/Mpc, but the present methods are applicable to other models. The present luminosity functions contain significantly more faint galaxies than are observed.

  6. The Grism Lens-Amplified Survey from Space (GLASS). VIII. The Influence of the Cluster Properties on Hα Emitter Galaxies at 0.3 < z < 0.7

    NASA Astrophysics Data System (ADS)

    Vulcani, Benedetta; Treu, Tommaso; Nipoti, Carlo; Schmidt, Kasper B.; Dressler, Alan; Morshita, Takahiro; Poggianti, Bianca M.; Malkan, Matthew; Hoag, Austin; Bradač, Marusa; Abramson, Louis; Trenti, Michele; Pentericci, Laura; von der Linden, Anja; Morris, Glenn; Wang, Xin

    2017-03-01

    Exploiting the data of the Grism Lens-Amplified Survey from Space (GLASS), we characterize the spatial distribution of star formation in 76 highly active star-forming galaxies in 10 clusters at 0.3< z< 0.7. All of these galaxies are likely restricted to first infall. In a companion paper, we contrast the properties of field and cluster galaxies, whereas here we correlate the properties of Hα emitters to a number of tracers of the cluster environment to investigate its role in driving galaxy transformations. Hα emitters are found in the clusters out to 0.5 virial radii, the maximum radius covered by GLASS. The peak of the Hα emission is offset with respect to the peak of the UV continuum. We decompose these offsets into a radial and a tangential component. The radial component points away from the cluster center in 60% of the cases, with 95% confidence. The decompositions agree with cosmological simulations; that is, the Hα emission offset correlates with galaxy velocity and ram-pressure stripping signatures. Trends between Hα emitter properties and surface mass density distributions and X-ray emissions emerge only for unrelaxed clusters. The lack of strong correlations with the global environment does not allow us to identify a unique environmental effect originating from the cluster center. In contrast, correlations between Hα morphology and local number density emerge. We conclude that local effects, uncorrelated to the cluster-centric radius, play a more important role in shaping galaxy properties.

  7. Comparing Dark Energy Survey and HST –CLASH observations of the galaxy cluster RXC J2248.7–4431: Implications for stellar mass versus dark matter

    SciTech Connect

    Palmese, A.; Lahav, O.; Banerji, M.; Gruen, D.; Jouvel, S.; Melchior, P.; Aleksić, J.; Annis, J.; Diehl, H. T.; Hartley, W. G.; Jeltema, T.; Romer, A. K.; Rozo, E.; Rykoff, E. S.; Seitz, S.; Suchyta, E.; Zhang, Y.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Dietrich, J. P.; Doel, P.; Estrada, J.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Li, T. S.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Miller, C. J.; Miquel, R.; Nord, B.; Ogando, R.; Plazas, A. A.; Roodman, A.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Tucker, D.; Vikram, V.

    2016-08-20

    We derive the stellar mass fraction in the galaxy cluster RXC J2248.7–4431 observed with the Dark Energy Survey (DES) during the Science Verification period. We compare the stellar mass results from DES (five filters) with those from the Hubble Space Telescope Cluster Lensing And Supernova Survey (CLASH; 17 filters). When the cluster spectroscopic redshift is assumed, we show that stellar masses from DES can be estimated within 25 per cent of CLASH values. We compute the stellar mass contribution coming from red and blue galaxies, and study the relation between stellar mass and the underlying dark matter using weak lensing studies with DES and CLASH. An analysis of the radial profiles of the DES total and stellar mass yields a stellar-to-total fraction of f* = (6.8 ± 1.7) × 10–3 within a radius of r200c ≃ 2 Mpc. Our analysis also includes a comparison of photometric redshifts and star/galaxy separation efficiency for both data sets. We conclude that space-based small field imaging can be used to calibrate the galaxy properties in DES for the much wider field of view. In conclusion, the technique developed to derive the stellar mass fraction in galaxy clusters can be applied to the ~100 000 clusters that will be observed within this survey and yield important information about galaxy evolution.

  8. The Nature of LSB galaxies revealed by their Globular Clusters

    NASA Astrophysics Data System (ADS)

    Kissler-Patig, Markus

    2005-07-01

    Low Surface Brightness {LSB} galaxies encompass many of the extremes in galaxy properties. Their understanding is essential to complete our picture of galaxy formation and evolution. Due to their historical under-representation on galaxy surveys, their importance to many areas of astronomy has only recently began to be realized. Globular clusters are superb tracers of the formation histories of galaxies and have been extensively used as such in high surface brightness galaxies. We propose to investigate the nature of massive LSB galaxies by studying their globular cluster systems. No globular cluster study has been reported for LSB galaxies to date. Yet, both the presence or absence of globular clusters set very strong constraints on the conditions prevailing during LSB galaxy formation and evolution. Both in dwarf and giant high surface brightness {HSB} galaxies, globular clusters are known to form as a constant fraction of baryonic mass. Their presence/absence immediately indicates similarities or discrepancies in the formation and evolution conditions of LSB and HSB galaxies. In particular, the presence/absence of metal-poor halo globular clusters infers similarities/differences in the halo formation and assembly processes of LSB vs. HSB galaxies, while the presence/absence of metal-rich globular clusters can be used to derive the occurrence and frequency of violent events {such as mergers} in the LSB galaxy assembly history. Two band imaging with ACS will allow us to identify the globular clusters {just resolved at the selected distance} and to determine their metallicity {potentially their rough age}. The composition of the systems will be compared to the extensive census built up on HSB galaxies. Our representative sample of six LSB galaxies {cz < 2700 km/s} are selected such, that a large system of globular clusters is expected. Globular clusters will constrain phases of LSB galaxy formation and evolution that can currently not be probed by other means. HST

  9. The HST/ACS Coma Cluster Survey - III. Structural parameters of galaxies using single Sérsic fits

    NASA Astrophysics Data System (ADS)

    Hoyos, Carlos; den Brok, Mark; Verdoes Kleijn, Gijs; Carter, David; Balcells, Marc; Guzmán, Rafael; Peletier, Reynier; Ferguson, Henry C.; Goudfrooij, Paul; Graham, Alister W.; Hammer, Derek; Karick, Arna M.; Lucey, John R.; Matković, Ana; Merritt, David; Mouhcine, Mustapha; Valentijn, Edwin

    2011-03-01

    We present a catalogue of structural parameters for 8814 galaxies in the 25 fields of the Hubble Space Telescope/ACS Coma Treasury Survey. Parameters from Sérsic fits to the two-dimensional surface brightness distributions are given for all galaxies from our published Coma photometric catalogue with mean effective surface brightness brighter than 26.0 mag arcsec-2 and brighter than 24.5 mag (equivalent to absolute magnitude -10.5), as given by the fits, all in F814W(AB). The sample comprises a mixture of Coma members and background objects; 424 galaxies have redshifts and of these 163 are confirmed members. The fits were carried out using both the GIM2D and GALFIT codes. We provide the following parameters: galaxy ID, RA, Dec., the total corrected automatic magnitude from the photometric catalogue, the total magnitude of the model (F814WAB), the geometric mean effective radius Re, the mean surface brightness within the effective radius <μ>e, the Sérsic index n, the ellipticity and the source position angle. The selection limits of the catalogue and the errors listed for the Sérsic parameters come from extensive simulations of the fitting process using synthetic galaxy models. The agreement between GIM2D and GALFIT parameters is sensitive to details of the fitting procedure; for the settings employed here the agreement is excellent over the range of parameters covered in the catalogue. We define and present two goodness-of-fit indices which quantify the degree to which the image can be approximated by a Sérsic model with concentric, coaxial elliptical isophotes; such indices may be used to objectively select galaxies with more complex structures such as bulge-disc, bars or nuclear components. We make the catalogue available in electronic format at ASTRO-WISE and MAST. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in

  10. High Frequency Cluster Radio Galaxies: Luminosity Functions and Implications for SZE Selected Cluster Samples

    NASA Astrophysics Data System (ADS)

    Gupta, N.; Saro, A.; Mohr, J. J.; Benson, B. A.; Bocquet, S.; Capasso, R.; Carlstrom, J. E.; Chiu, I.; Crawford, T. M.; de Haan, T.; Dietrich, J. P.; Gangkofner, C.; Holzapfel, W. L.; McDonald, M.; Rapetti, D.; Reichardt, C. L.

    2017-01-01

    We study the overdensity of point sources in the direction of X-ray-selected galaxy clusters from the Meta-Catalog of X-ray detected Clusters of galaxies (MCXC; = 0.14) at South Pole Telescope (SPT) and Sydney University Molonglo Sky Survey (SUMSS) frequencies. Flux densities at 95, 150 and 220 GHz are extracted from the 2500 deg2 SPT-SZ survey maps at the locations of SUMSS sources, producing a multi-frequency catalog of radio galaxies. In the direction of massive galaxy clusters, the radio galaxy flux densities at 95 and 150 GHz are biased low by the cluster Sunyaev-Zel'dovich Effect (SZE) signal, which is negative at these frequencies. We employ a cluster SZE model to remove the expected flux bias and then study these corrected source catalogs. We find that the high frequency radio galaxies are centrally concentrated within the clusters and that their luminosity functions (LFs) exhibit amplitudes that are characteristically an order of magnitude lower than the cluster LF at 843 MHz. We use the 150 GHz LF to estimate the impact of cluster radio galaxies on an SPT-SZ like survey. The radio galaxy flux typically produces a small bias on the SZE signal and has negligible impact on the observed scatter in the SZE mass-observable relation. If we assume there is no redshift evolution in the radio galaxy LF then 1.8 ± 0.7 percent of the clusters with detection significance ξ ≥ 4.5 would be lost from the sample. Allowing for redshift evolution of the form (1 + z)2.5 increases the incompleteness to 5.6 ± 1.0 percent. Improved constraints on the evolution of the cluster radio galaxy LF require a larger cluster sample extending to higher redshift.

  11. The Next Generation Virgo Cluster Survey. VII. The Intrinsic Shapes of Low-luminosity Galaxies in the Core of the Virgo Cluster, and a Comparison with the Local Group

    NASA Astrophysics Data System (ADS)

    Sánchez-Janssen, Rubén; Ferrarese, Laura; MacArthur, Lauren A.; Côté, Patrick; Blakeslee, John P.; Cuillandre, Jean-Charles; Duc, Pierre-Alain; Durrell, Patrick; Gwyn, Stephen; McConnacchie, Alan W.; Boselli, Alessandro; Courteau, Stéphane; Emsellem, Eric; Mei, Simona; Peng, Eric; Puzia, Thomas H.; Roediger, Joel; Simard, Luc; Boyer, Fred; Santos, Matthew

    2016-03-01

    We investigate the intrinsic shapes of low-luminosity galaxies in the central 300 kpc of the Virgo Cluster using deep imaging obtained as part of the Next Generation Virgo Cluster Survey (NGVS). We build a sample of nearly 300 red-sequence cluster members in the yet-unexplored -14 < Mg < -8 mag range, and we measure their apparent axis ratios, q, through Sérsic fits to their two-dimensional light distribution, which is well described by a constant ellipticity parameter. The resulting distribution of apparent axis ratios is then fit by families of triaxial models with normally distributed intrinsic ellipticities, E = 1 - C/A, and triaxialities, T = (A2 - B2)/(A2 - C2). We develop a Bayesian framework to explore the posterior distribution of the model parameters, which allows us to work directly on discrete data, and to account for individual, surface-brightness-dependent axis ratio uncertainties. For this population we infer a mean intrinsic ellipticity \\bar{E} = {0.43}-0.02+0.02 and a mean triaxiality \\bar{T} = {0.16}-0.06+0.07. This implies that faint Virgo galaxies are best described as a family of thick, nearly oblate spheroids with mean intrinsic axis ratios 1:0.94:0.57. The core of Virgo lacks highly elongated low-luminosity galaxies, with 95% of the population having q > 0.45. We additionally attempt a study of the intrinsic shapes of Local Group (LG) satellites of similar luminosities. For the LG population we infer a slightly larger mean intrinsic ellipticity \\bar{E} = {0.51}-0.06+0.07, and the paucity of objects with round apparent shapes translates into more triaxial mean shapes, 1:0.76:0.49. Numerical studies that follow the tidal evolution of satellites within LG-sized halos are in good agreement with the inferred shape distributions, but the mismatch for faint galaxies in Virgo highlights the need for more adequate simulations of this population in the cluster environment. We finally compare the intrinsic shapes of NGVS low-mass galaxies with

  12. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: tomographic BAO analysis of DR12 combined sample in Fourier space

    NASA Astrophysics Data System (ADS)

    Zhao, Gong-Bo; Wang, Yuting; Saito, Shun; Wang, Dandan; Ross, Ashley J.; Beutler, Florian; Grieb, Jan Niklas; Chuang, Chia-Hsun; Kitaura, Francisco-Shu; Rodriguez-Torres, Sergio; Percival, Will J.; Brownstein, Joel R.; Cuesta, Antonio J.; Eisenstein, Daniel J.; Gil-Marín, Héctor; Kneib, Jean-Paul; Nichol, Robert C.; Olmstead, Matthew D.; Prada, Francisco; Rossi, Graziano; Salazar-Albornoz, Salvador; Samushia, Lado; Sánchez, Ariel G.; Thomas, Daniel; Tinker, Jeremy L.; Tojeiro, Rita; Weinberg, David H.; Zhu, Fangzhou

    2017-04-01

    We perform a tomographic baryon acoustic oscillations (BAO) analysis using the monopole, quadrupole and hexadecapole of the redshift-space galaxy power spectrum measured from the pre-reconstructed combined galaxy sample of the completed Sloan Digital Sky Survey Baryon Oscillation Spectroscopic Survey (BOSS) Data Release12 covering the redshift range of 0.20 < z < 0.75. By allowing for overlap between neighbouring redshift slices, we successfully obtained the isotropic and anisotropic BAO distance measurements within nine redshift slices to a precision of 1.5-3.4 per cent for DV/rd, 1.8-4.2 per cent for DA/rd and 3.7-7.5 per cent for H rd, depending on effective redshifts. We provide our BAO measurement of DA/rd and H rd with the full covariance matrix, which can be used for cosmological implications. Our measurements are consistent with those presented in Alam et al., in which the BAO distances are measured at three effective redshifts. We constrain dark energy parameters using our measurements and find an improvement of the Figure-of-Merit of dark energy in general due to the temporal BAO information resolved. This paper is a part of a set that analyses the final galaxy clustering data set from BOSS.

  13. ON THE CLUSTERING OF SUBMILLIMETER GALAXIES

    SciTech Connect

    Williams, Christina C.; Giavalisco, Mauro; Yun, Min S.; Pope, Alexandra; Wilson, Grant W.; Cybulski, Ryan; Schloerb, F. Peter; Porciani, Cristiano; Scott, Kimberly S.; Austermann, Jason E.; Aretxaga, Itziar; Hughes, David H.; Hatsukade, Bunyo; Kawabe, Ryo; Lee, Kyoung-Soo; Kohno, Kotaro; Perera, Thushara

    2011-06-01

    We measure the angular two-point correlation function of submillimeter galaxies (SMGs) from 1.1 mm imaging of the COSMOS field with the AzTEC camera and ASTE 10 m telescope. These data yield one of the largest contiguous samples of SMGs to date, covering an area of 0.72 deg{sup 2} down to a 1.26 mJy beam{sup -1} (1{sigma}) limit, including 189 (328) sources with S/N {>=}3.5 (3). We can only set upper limits to the correlation length r{sub 0}, modeling the correlation function as a power law with pre-assigned slope. Assuming existing redshift distributions, we derive 68.3% confidence level upper limits of r{sub 0} {approx}< 6-8h{sup -1} Mpc at 3.7 mJy and r{sub 0} {approx}< 11-12 h{sup -1} Mpc at 4.2 mJy. Although consistent with most previous estimates, these upper limits imply that the real r{sub 0} is likely smaller. This casts doubts on the robustness of claims that SMGs are characterized by significantly stronger spatial clustering (and thus larger mass) than differently selected galaxies at high redshift. Using Monte Carlo simulations we show that even strongly clustered distributions of galaxies can appear unclustered when sampled with limited sensitivity and coarse angular resolution common to current submillimeter surveys. The simulations, however, also show that unclustered distributions can appear strongly clustered under these circumstances. From the simulations, we predict that at our survey depth, a mapped area of 2 deg{sup 2} is needed to reconstruct the correlation function, assuming smaller beam sizes of future surveys (e.g., the Large Millimeter Telescope's 6'' beam size). At present, robust measures of the clustering strength of bright SMGs appear to be below the reach of most observations.

  14. Spectroscopic Confirmation of Two Massive Red-sequence-selected Galaxy Clusters at Z Approximately Equal to 1.2 in the Sparcs-North Cluster Survey

    NASA Technical Reports Server (NTRS)

    Muzzin, Adam; Wilson, Gillian; Yee, H.K.C.; Hoekstra, Henk; Gilbank, David; Surace, Jason; Lacy, Mark; Blindert, Kris; Majumdar, Subhabrata; Demarco, Ricardo; Gardner, Jonathan P.; Gladders, Mike; Lonsdale, Carol

    2008-01-01

    The Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) is a deep z -band imaging survey covering the Spitzer SWIRE Legacy fields designed to create the first large homogeneously-selected sample of massive clusters at z > 1 using an infrared adaptation of the cluster red-sequence method. We present an overview of the northern component of the survey which has been observed with CFHT/MegaCam and covers 28.3 deg(sup 2). The southern component of the survey was observed with CTIO/MOSAICII, covers 13.6 deg(sup 2), and is summarized in a companion paper by Wilson et al. (2008). We also present spectroscopic confirmation of two rich cluster candidates at z approx. 1.2. Based on Nod-and- Shuffle spectroscopy from GMOS-N on Gemini there are 17 and 28 confirmed cluster members in SpARCS J163435+402151 and SpARCS J163852+403843 which have spectroscopic redshifts of 1.1798 and 1.1963, respectively. The clusters have velocity dispersions of 490 +/- 140 km/s and 650 +/- 160 km/s, respectively which imply masses (M(sub 200)) of (1.0 +/- 0.9) x 10(exp 14) Stellar Mass and (2.4 +/- 1.8) x 10(exp 14) Stellar Mass. Confirmation of these candidates as bonafide massive clusters demonstrates that two-filter imaging is an effective, yet observationally efficient, method for selecting clusters at z > 1.

  15. The SLUGGS survey: multipopulation dynamical modelling of the elliptical galaxy NGC 1407 from stars and globular clusters

    NASA Astrophysics Data System (ADS)

    Pota, Vincenzo; Romanowsky, Aaron J.; Brodie, Jean P.; Peñarrubia, Jorge; Forbes, Duncan A.; Napolitano, Nicola R.; Foster, Caroline; Walker, Matthew G.; Strader, Jay; Roediger, Joel C.

    2015-07-01

    We perform in-depth dynamical modelling of the luminous and dark matter (DM) content of the elliptical galaxy NGC 1407. Our strategy consists of solving the spherical Jeans equations for three independent dynamical tracers: stars, blue globular clusters (GCs) and red GCs in a self-consistent manner. We adopt a maximum-likelihood Markov Chain Monte Carlo fitting technique in the attempt to constrain the inner slope of the DM density profile (the cusp/core problem), and the stellar initial mass function (IMF) of the galaxy. We find the inner logarithmic slope of the DM density profiles to be γ = 0.6 ± 0.4, which is consistent with either a DM cusp (γ = 1) or with a DM core (γ = 0). Our findings are consistent with a Salpeter IMF, and marginally consistent with a Kroupa IMF. We infer tangential orbits for the blue GCs, and radial anisotropy for red GCs and stars. The modelling results are consistent with the virial mass-concentration relation predicted by Λ cold dark matter (CDM) simulations. The virial mass of NGC 1407 is log Mvir = 13.3 ± 0.2M⊙, whereas the stellar mass is log M* = 11.8 ± 0.1 M⊙. The overall uncertainties on the mass of NGC 1407 are only 5 per cent at the projected stellar effective radius. We attribute the disagreement between our results and previous X-ray results to the gas not being in hydrostatic equilibrium in the central regions of the galaxy. The halo of NGC 1407 is found be DM-dominated, with a dynamical mass-to-light ratio of M/L=260_{-100} ^{+174} M_{⊙}/L_{⊙, B}. However, this value can be larger up to a factor of 3 depending on the assumed prior on the DM scale radius.

  16. The Hierarchical Distribution of Young Stellar Clusters in Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    Grasha, Kathryn; Calzetti, Daniela

    2017-01-01

    We investigate the spatial distributions of young stellar clusters in six nearby galaxies to trace the large scale hierarchical star-forming structures. The six galaxies are drawn from the Legacy ExtraGalactic UV Survey (LEGUS). We quantify the strength of the clustering among stellar clusters as a function of spatial scale and age to establish the survival timescale of the substructures. We separate the clusters into different classes, compact (bound) clusters and associations (unbound), and compare the clustering among them. We find that younger star clusters are more strongly clustered over small spatial scales and that the clustering disappears rapidly for ages as young as a few tens of Myr, consistent with clusters slowly losing the fractal dimension inherited at birth from their natal molecular clouds.

  17. Construction of luminosity function for galaxy clusters

    NASA Astrophysics Data System (ADS)

    Godłowski, Włodzimierz; Popiela, Joanna; Bajan, Katarzyna; Biernacka, Monika; Flin, Piotr; Panko, Elena

    2015-02-01

    The luminosity function is an important quantity for analysis of large scale structure statistics, interpretation of galaxy counts (Lin & Kirshner 1996). We investigate the luminosity function of galaxy clusters. This is performed by counting the brightness of galaxies belonging to clusters in PF Catalogue. The obtained luminosity function is significantly different than that obtained both for optical and radiogalaxies (Machalski & Godowski 2000). The implications of this result for theories of galaxy formation are discussed as well.

  18. Joint signal extraction from galaxy clusters in X-ray and SZ surveys: A matched-filter approach

    NASA Astrophysics Data System (ADS)

    Tarrío, P.; Melin, J.-B.; Arnaud, M.; Pratt, G. W.

    2016-06-01

    The hot ionized gas of the intra-cluster medium emits thermal radiation in the X-ray band and also distorts the cosmic microwave radiation through the Sunyaev-Zel'dovich (SZ) effect. Combining these two complementary sources of information through innovative techniques can therefore potentially improve the cluster detection rate when compared to using only one of the probes. Our aim is to build such a joint X-ray-SZ analysis tool, which will allow us to detect fainter or more distant clusters while maintaining high catalogue purity. We present a method based on matched multifrequency filters (MMF) for extracting cluster catalogues from SZ and X-ray surveys. We first designed an X-ray matched-filter method, analogous to the classical MMF developed for SZ observations. Then, we built our joint X-ray-SZ algorithm by combining our X-ray matched filter with the classical SZ-MMF, for which we used the physical relation between SZ and X-ray observations. We show that the proposed X-ray matched filter provides correct photometry results, and that the joint matched filter also provides correct photometry when the FX/Y500 relation of the clusters is known. Moreover, the proposed joint algorithm provides a better signal-to-noise ratio than single-map extractions, which improves the detection rate even if we do not exactly know the FX/Y500 relation. The proposed methods were tested using data from the ROSAT all-sky survey and from the Planck survey.

  19. Cosmological Constraints from Galaxy Clustering and the Mass-to-number Ratio of Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Tinker, Jeremy L.; Sheldon, Erin S.; Wechsler, Risa H.; Becker, Matthew R.; Rozo, Eduardo; Zu, Ying; Weinberg, David H.; Zehavi, Idit; Blanton, Michael R.; Busha, Michael T.; Koester, Benjamin P.

    2012-01-01

    We place constraints on the average density (Ω m ) and clustering amplitude (σ8) of matter using a combination of two measurements from the Sloan Digital Sky Survey: the galaxy two-point correlation function, wp (rp ), and the mass-to-galaxy-number ratio within galaxy clusters, M/N, analogous to cluster M/L ratios. Our wp (rp ) measurements are obtained from DR7 while the sample of clusters is the maxBCG sample, with cluster masses derived from weak gravitational lensing. We construct nonlinear galaxy bias models using the Halo Occupation Distribution (HOD) to fit both wp (rp ) and M/N for different cosmological parameters. HOD models that match the same two-point clustering predict different numbers of galaxies in massive halos when Ω m or σ8 is varied, thereby breaking the degeneracy between cosmology and bias. We demonstrate that this technique yields constraints that are consistent and competitive with current results from cluster abundance studies, without the use of abundance information. Using wp (rp ) and M/N alone, we find Ω0.5 m σ8 = 0.465 ± 0.026, with individual constraints of Ω m = 0.29 ± 0.03 and σ8 = 0.85 ± 0.06. Combined with current cosmic microwave background data, these constraints are Ω m = 0.290 ± 0.016 and σ8 = 0.826 ± 0.020. All errors are 1σ. The systematic uncertainties that the M/N technique are most sensitive to are the amplitude of the bias function of dark matter halos and the possibility of redshift evolution between the SDSS Main sample and the maxBCG cluster sample. Our derived constraints are insensitive to the current level of uncertainties in the halo mass function and in the mass-richness relation of clusters and its scatter, making the M/N technique complementary to cluster abundances as a method for constraining cosmology with future galaxy surveys.

  20. Nature of multiple-nucleus cluster galaxies

    SciTech Connect

    Merritt, D.

    1984-05-01

    In models for the evolution of galaxy clusters which include dynamical friction with the dark binding matter, the distribution of galaxies becomes more concentrated to the cluster center with time. In a cluster like Coma, this evolution could increase by a factor of approximately 3 the probability of finding a galaxy very close to the cluster center, without decreasing the typical velocity of such a galaxy significantly below the cluster mean. Such an enhancement is roughly what is needed to explain the large number of first-ranked cluster galaxies which are observed to have extra ''nuclei''; it is also consistent with the high velocities typically measured for these ''nuclei.'' Unlike the cannibalism model, this model predicts that the majority of multiple-nucleus systems are transient phenomena, and not galaxies in the process of merging.

  1. GLACE survey: OSIRIS/GTC tuneable filter Hα imaging of the rich galaxy cluster ZwCl 0024.0+1652 at z = 0.395. I. Survey presentation, TF data reduction techniques, and catalogue

    NASA Astrophysics Data System (ADS)

    Sánchez-Portal, M.; Pintos-Castro, I.; Pérez-Martínez, R.; Cepa, , J.; Pérez García, A. M.; Domínguez-Sánchez, H.; Bongiovanni, A.; Serra, A. L.; Alfaro, E.; Altieri, B.; Aragón-Salamanca, A.; Balkowski, C.; Biviano, A.; Bremer, M.; Castander, F.; Castañeda, H.; Castro-Rodríguez, N.; Chies-Santos, A. L.; Coia, D.; Diaferio, A.; Duc, P. A.; Ederoclite, A.; Geach, J.; González-Serrano, I.; Haines, C. P.; McBreen, B.; Metcalfe, L.; Oteo, I.; Pérez-Fournón, I.; Poggianti, B.; Polednikova, J.; Ramón-Pérez, M.; Rodríguez-Espinosa, J. M.; Santos, J. S.; Smail, I.; Smith, G. P.; Temporin, S.; Valtchanov, I.

    2015-06-01

    The cores of clusters at 0 ≲ z ≲ 1 are dominated by quiescent early-type galaxies, whereas the field is dominated by star-forming late-type galaxies. Clusters grow through the accretion of galaxies and groups from the surrounding field, which implies that galaxy properties, notably the star formation ability, are altered as they fall into overdense regions. The critical issues for understanding this evolution are how the truncation of star formation is connected to the morphological transformation and what physical mechanism is responsible for these changes. The GaLAxy Cluster Evolution Survey (GLACE) is conducting a thorough study of the variations in galaxy properties (star formation, AGN activity, and morphology) as a function of environment in a representative and well-studied sample of clusters. To address these questions, the GLACE survey is making a deep panoramic survey of emission line galaxies (ELG), mapping a set of optical lines ([O ii], [O iii], Hβ andHα/[N ii] when possible) in several galaxy clusters at z ~ 0.40, 0.63, and 0.86. Using the tunable filters (TF) of the OSIRIS instrument at the 10.4 m GTC telescope, the GLACE survey applies the technique of TF tomography: for each line, a set of images are taken through the OSIRIS TF, each image tuned at a different wavelength (equally spaced), to cover a rest frame velocity range of several thousand km s-1 centred on the mean cluster redshift, and scanned for the full TF field of view of an 8 arcmin diameter. Here we present the first results of the GLACE project, targeting the Hα/[N ii] lines in the intermediate-redshift cluster ZwCl 0024.0+1652 at z = 0.395. Two pointings have been performed that cover ~2 × rvir. We discuss the specific techniques devised to process the TF tomography observations in order to generate the catalogue of cluster Hα emitters, which contains more than 200 sources down to a star formation rate (SFR) ≲1 M⊙/yr. An ancillary broadband catalogue is constructed

  2. Comparing Dark Energy Survey and HST –CLASH observations of the galaxy cluster RXC J2248.7-4431: implications for stellar mass versus dark matter

    SciTech Connect

    Palmese, A.; Lahav, O.; Banerji, M.; Gruen, D.; Jouvel, S.; Melchior, P.; Aleksić, J.; Annis, J.; Diehl, H. T.; Hartley, W. G.; Jeltema, T.; Romer, A. K.; Rozo, E.; Rykoff, E. S.; Seitz, S.; Suchyta, E.; Zhang, Y.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Dietrich, J. P.; Doel, P.; Estrada, J.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Goldstein, D. A.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Li, T. S.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Miller, C. J.; Miquel, R.; Nord, B.; Ogando, R.; Plazas, A. A.; Roodman, A.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Tucker, D.; Vikram, V.

    2016-08-20

    We derive the stellar mass fraction in the galaxy cluster RXC J2248.7-4431 observed with the Dark Energy Survey (DES) during the Science Verification period. We compare the stellar mass results from DES (5 filters) with those from the Hubble Space Telescope CLASH (17 filters). When the cluster spectroscopic redshift is assumed, we show that stellar masses from DES can be estimated within 25% of CLASH values. We compute the stellar mass contribution coming from red and blue galaxies, and study the relation between stellar mass and the underlying dark matter using weak lensing studies with DES and CLASH. An analysis of the radial profiles of the DES total and stellar mass yields a stellar-to-total fraction of f*=7.0+-2.2x10^-3 within a radius of r_200c~3 Mpc. Our analysis also includes a comparison of photometric redshifts and star/galaxy separation efficiency for both datasets. We conclude that space-based small field imaging can be used to calibrate the galaxy properties in DES for the much wider field of view. The technique developed to derive the stellar mass fraction in galaxy clusters can be applied to the ~100 000 clusters that will be observed within this survey. The stacking of all the DES clusters would reduce the errors on f* estimates and deduce important information about galaxy evolution.

  3. VLA Discovers Giant Rings Around Galaxy Cluster

    NASA Astrophysics Data System (ADS)

    2006-11-01

    Astronomers using the National Science Foundation's Very Large Array (VLA) radio telescope have discovered giant, ring-like structures around a cluster of galaxies. The discovery provides tantalizing new information about how such galaxy clusters are assembled, about magnetic fields in the vast spaces between galaxy clusters, and possibly about the origin of cosmic rays. Radio-Optical Image of Cluster Galaxy Cluster Abell 3376 (Radio/Optical) CREDIT: Joydeep Bagchi, IUCAA, NRAO/AUI/NSF Above, a combined radio/optical image shows the galaxy cluster Abell 3376 in visible light (blue) and radio (red) images. The giant radio arcs surrounding the cluster were discovered using the Very Large Array. The visible-light image is from the Digitized Sky survey. Below, an X-ray image of Abell 3376 made using the European Space Agency's XMM-Newton telescope shows a spectacular, bullet-shaped region of X-rays coming from gas heated to 60 million degrees Kelvin. The bullet shape results from the supersonic collision of a smaller smaller galaxy subcluster with the main body of the larger cluster. Click on images for larger version. X-Ray Image of Cluster Galaxy Cluster Abell 3376 (X-Ray) CREDIT: Joydeep Bagchi, IUCAA, ESA "These giant, radio-emitting rings probably are the result of shock waves caused by violent collisions of smaller groups of galaxies within the cluster," said Joydeep Bagchi, of the Inter-University Centre for Astronomy and Astrophysics in Pune, India, who led an international research team. The scientists reported their findings in the November 3 edition of the journal Science. The newly-discovered ring segments, some 6 million light-years across, surround a galaxy cluster called Abell 3376, more than 600 million light-years from Earth. They were revealed because fast-moving electrons emitted radio waves as they spiraled around magnetic field lines in intergalactic space. "Even from this large distance, the feeble radio waves were easily picked up by the VLA

  4. Statistical Issues in Galaxy Cluster Cosmology

    NASA Technical Reports Server (NTRS)

    Mantz, Adam

    2013-01-01

    The number and growth of massive galaxy clusters are sensitive probes of cosmological structure formation. Surveys at various wavelengths can detect clusters to high redshift, but the fact that cluster mass is not directly observable complicates matters, requiring us to simultaneously constrain scaling relations of observable signals with mass. The problem can be cast as one of regression, in which the data set is truncated, the (cosmology-dependent) underlying population must be modeled, and strong, complex correlations between measurements often exist. Simulations of cosmological structure formation provide a robust prediction for the number of clusters in the Universe as a function of mass and redshift (the mass function), but they cannot reliably predict the observables used to detect clusters in sky surveys (e.g. X-ray luminosity). Consequently, observers must constrain observable-mass scaling relations using additional data, and use the scaling relation model in conjunction with the mass function to predict the number of clusters as a function of redshift and luminosity.

  5. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the power spectrum and bispectrum of the DR12 BOSS galaxies

    NASA Astrophysics Data System (ADS)

    Gil-Marín, Héctor; Percival, Will J.; Verde, Licia; Brownstein, Joel R.; Chuang, Chia-Hsun; Kitaura, Francisco-Shu; Rodríguez-Torres, Sergio A.; Olmstead, Matthew D.

    2017-02-01

    We measure and analyse the bispectrum of the final data release 12 (DR12), galaxy sample provided by the Baryon Oscillation Spectroscopic Survey, splitting by selection algorithm into LOWZ and CMASS galaxies. The LOWZ sample contains 361 762 galaxies with an effective redshift of zLOWZ = 0.32, and the CMASS sample contains 777 202 galaxies with an effective redshift of zCMASS = 0.57. Combining the power spectrum, measured relative to the line of sight, with the spherically averaged bispectrum, we are able to constrain the product of the growth of structure parameter, f, and the amplitude of dark matter density fluctuations, σ8, along with the geometric Alcock-Paczynski parameters, the product of the Hubble constant and the comoving sound horizon at the baryon drag epoch, H(z)rs(zd), and the angular distance parameter divided by the sound horizon, DA(z)/rs(zd). After combining pre-reconstruction RSD analyses of the power spectrum monopole, quadrupole and bispectrum monopole with post-reconstruction analysis of the BAO power spectrum monopole and quadrupole, we find f(zLOWZ)σ8(zLOWZ) = 0.427 ± 0.056, DA(zLOWZ)/rs(zd) = 6.60 ± 0.13, H(zLOWZ)rs(zd) = (11.55 ± 0.38)103 km s-1 for the LOWZ sample, and f(zCMASS)σ8(zCMASS) = 0.426 ± 0.029, DA(zCMASS)/rs(zd) = 9.39 ± 0.10, H(zCMASS)rs(zd) = (14.02 ± 0.22)103 km s-1 for the CMASS sample. We find general agreement with previous Baryon Oscillation Spectroscopic Survey DR11 and DR12 measurements. Combining our data set with Planck15 we perform a null test of General Relativity through the γ-parametrization finding γ =0.733^{+0.068}_{-0.069}, which is ∼2.7σ away from the General Relativity predictions.

  6. The SAMI Galaxy Survey: instrument specification and target selection

    NASA Astrophysics Data System (ADS)

    Bryant, J. J.; Owers, M. S.; Robotham, A. S. G.; Croom, S. M.; Driver, S. P.; Drinkwater, M. J.; Lorente, N. P. F.; Cortese, L.; Scott, N.; Colless, M.; Schaefer, A.; Taylor, E. N.; Konstantopoulos, I. S.; Allen, J. T.; Baldry, I.; Barnes, L.; Bauer, A. E.; Bland-Hawthorn, J.; Bloom, J. V.; Brooks, A. M.; Brough, S.; Cecil, G.; Couch, W.; Croton, D.; Davies, R.; Ellis, S.; Fogarty, L. M. R.; Foster, C.; Glazebrook, K.; Goodwin, M.; Green, A.; Gunawardhana, M. L.; Hampton, E.; Ho, I.-T.; Hopkins, A. M.; Kewley, L.; Lawrence, J. S.; Leon-Saval, S. G.; Leslie, S.; McElroy, R.; Lewis, G.; Liske, J.; López-Sánchez, Á. R.; Mahajan, S.; Medling, A. M.; Metcalfe, N.; Meyer, M.; Mould, J.; Obreschkow, D.; O'Toole, S.; Pracy, M.; Richards, S. N.; Shanks, T.; Sharp, R.; Sweet, S. M.; Thomas, A. D.; Tonini, C.; Walcher, C. J.

    2015-03-01

    The SAMI Galaxy Survey will observe 3400 galaxies with the Sydney-AAO Multi-object Integral-field spectrograph (SAMI) on the Anglo-Australian Telescope in a 3-yr survey which began in 2013. We present the throughput of the SAMI system, the science basis and specifications for the target selection, the survey observation plan and the combined properties of the selected galaxies. The survey includes four volume-limited galaxy samples based on cuts in a proxy for stellar mass, along with low-stellar-mass dwarf galaxies all selected from the Galaxy And Mass Assembly (GAMA) survey. The GAMA regions were selected because of the vast array of ancillary data available, including ultraviolet through to radio bands. These fields are on the celestial equator at 9, 12 and 14.5 h, and cover a total of 144 deg2 (in GAMA-I). Higher density environments are also included with the addition of eight clusters. The clusters have spectroscopy from 2-degree Field Galaxy Redshift Survey (2dFGRS) and Sloan Digital Sky Survey (SDSS) and photometry in regions covered by the SDSS and/or VLT Survey Telescope/ATLAS. The aim is to cover a broad range in stellar mass and environment, and therefore the primary survey targets cover redshifts 0.004 < z < 0.095, magnitudes rpet < 19.4, stellar masses 107-1012 M⊙, and environments from isolated field galaxies through groups to clusters of ˜1015 M⊙.

  7. The Swift AGN and Cluster Survey

    NASA Astrophysics Data System (ADS)

    Danae Griffin, Rhiannon; Dai, Xinyu; Kochanek, Christopher S.; Bregman, Joel N.; Nugent, Jenna

    2016-01-01

    The Swift active galactic nucleus (AGN) and Cluster Survey (SACS) uses 125 deg^2 of Swift X-ray Telescope serendipitous fields with variable depths surrounding X-ray bursts to provide a medium depth (4 × 10^-15 erg cm^-2 s^-1) and area survey filling the gap between deep, narrow Chandra/XMM-Newton surveys and wide, shallow ROSAT surveys. Here, we present the first two papers in a series of publications for SACS. In the first paper, we introduce our method and catalog of 22,563 point sources and 442 extended sources. We examine the number counts of the AGN and galaxy cluster populations. SACS provides excellent constraints on the AGN number counts at the bright end with negligible uncertainties due to cosmic variance, and these constraints are consistent with previous measurements. The depth and areal coverage of SACS is well suited for galaxy cluster surveys outside the local universe, reaching z ˜ 1 for massive clusters. In the second paper, we use Sloan Digital Sky Survey (SDSS) DR8 data to study the 203 extended SACS sources that are located within the SDSS footprint. We search for galaxy over-densities in 3-D space using SDSS galaxies and their photometric redshifts near the Swift galaxy cluster candidates. We find 103 Swift clusters with a > 3σ over-density. The remaining targets are potentially located at higher redshifts and require deeper optical follow-up observations for confirmations as galaxy clusters. We present a series of cluster properties including the redshift, BCG magnitude, BCG-to-X-ray center offset, optical richness, X-ray luminosity and red sequences. We compare the observed redshift distribution of the sample with a theoretical model, and find that our sample is complete for z ≤ 0.3 and 80% complete for z ≤ 0.4, consistent with the survey depth of SDSS. We also match our SDSS confirmed Swift clusters to existing cluster catalogs, and find 42, 2 and 1 matches in optical, X-ray and SZ catalogs, respectively, so the majority of these

  8. Hot outflows in galaxy clusters

    NASA Astrophysics Data System (ADS)

    Kirkpatrick, C. C.; McNamara, B. R.

    2015-10-01

    The gas-phase metallicity distribution has been analysed for the hot atmospheres of 29 galaxy clusters using Chandra X-ray Observatory observations. All host brightest cluster galaxies (BCGs) with X-ray cavity systems produced by radio AGN. We find high elemental abundances projected preferentially along the cavities of 16 clusters. The metal-rich plasma was apparently lifted out of the BCGs with the rising X-ray cavities (bubbles) to altitudes between twenty and several hundred kiloparsecs. A relationship between the maximum projected altitude of the uplifted gas (the `iron radius') and jet power is found with the form R_Fe ∝ P_jet^{0.45}. The estimated outflow rates are typically tens of solar masses per year but exceed 100 M⊙ yr- 1 in the most powerful AGN. The outflow rates are 10-20 per cent of the cooling rates, and thus alone are unable to offset a cooling inflow. Nevertheless, hot outflows effectively redistribute the cooling gas and may play a significant role at regulating star formation and AGN activity in BCGs and presumably in giant elliptical galaxies. The metallicity distribution overall can be complex, perhaps due to metal-rich gas returning in circulation flows or being blown around in the hot atmospheres. Roughly 15 per cent of the work done by the cavities is expended lifting the metal-enriched gas, implying their nuclear black holes have increased in mass by at least ˜107-109 M⊙. Finally, we show that hot outflows can account for the broad, gas-phase metallicity distribution compared to the stellar light profiles of BCGs, and we consider a possible connection between hot outflows and cold molecular gas flows discovered in recent Atacama Large Millimeter Array observations.

  9. A redshift survey of IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Smith, Beverly J.; Kleinmann, S. G.; Huchra, J. P.; Low, F. J.

    1987-01-01

    Results are presented from a redshift survey of all 72 galaxies detected by IRAS in Band 3 at flux levels equal to or greater then 2 Jy. The luminosity function at the high luminosity end is proportional to L sup -2, however, a flattening was observed at the low luminosity end indicating that a single power law is not a good description of the entire luminosity function. Only three galaxies in the sample have emission line spectra indicative of AGN's, suggesting that, at least in nearby galaxies, unobscured nuclear activity is not a strong contributor to the far infrared flux. Comparisons between the selected IRAS galaxies and an optically complete sample taken from the CfA redshift survey show that they are more narrowly distributed than those optically selected, in the sence that the IRAS sample includes few galaxies of low absolute blue luminosity. It was also found that the space distributions of the two samples differ: the density enhancement or IRAS galaxies is only approx. 1/3 that of the optically selected galaxies in the core of the Coma cluster.

  10. BRIGHTEST CLUSTER GALAXIES AT THE PRESENT EPOCH

    SciTech Connect

    Lauer, Tod R.; Postman, Marc; Strauss, Michael A.; Graves, Genevieve J.; Chisari, Nora E.

    2014-12-20

    We have obtained photometry and spectroscopy of 433 z ≤ 0.08 brightest cluster galaxies (BCGs) in a full-sky survey of Abell clusters to construct a BCG sample suitable for probing deviations from the local Hubble flow. The BCG Hubble diagram over 0 < z < 0.08 is consistent to within 2% of the Hubble relation specified by a Ω {sub m} = 0.3, Λ = 0.7 cosmology. This sample allows us to explore the structural and photometric properties of BCGs at the present epoch, their location in their hosting galaxy clusters, and the effects of the cluster environment on their structure and evolution. We revisit the L{sub m} -α relation for BCGs, which uses α, the log-slope of the BCG photometric curve of growth, to predict the metric luminosity in an aperture with 14.3 kpc radius, L{sub m} , for use as a distance indicator. Residuals in the relation are 0.27 mag rms. We measure central stellar velocity dispersions, σ, of the BCGs, finding the Faber-Jackson relation to flatten as the metric aperture grows to include an increasing fraction of the total BCG luminosity. A three-parameter ''metric plane'' relation using α and σ together gives the best prediction of L{sub m} , with 0.21 mag residuals. The distribution of projected spatial offsets, r{sub x} of BCGs from the X-ray-defined cluster center is a steep γ = –2.33 power law over 1 < r{sub x} < 10{sup 3} kpc. The median offset is ∼10 kpc, but ∼15% of the BCGs have r{sub x} > 100 kpc. The absolute cluster-dispersion normalized BCG peculiar velocity |ΔV {sub 1}|/σ {sub c} follows an exponential distribution with scale length 0.39 ± 0.03. Both L{sub m} and α increase with σ {sub c}. The α parameter is further moderated by both the spatial and velocity offset from the cluster center, with larger α correlated with the proximity of the BCG to the cluster mean velocity or potential center. At the same time, position in the cluster has little effect on L{sub m} . Likewise, residuals from the metric plane

  11. The ACS Virgo Cluster Survey. I. Introduction to the Survey

    NASA Astrophysics Data System (ADS)

    Côté, Patrick; Blakeslee, John P.; Ferrarese, Laura; Jordán, Andrés; Mei, Simona; Merritt, David; Milosavljević, Miloš; Peng, Eric W.; Tonry, John L.; West, Michael J.

    2004-07-01

    The Virgo Cluster is the dominant mass concentration in the Local Supercluster and the largest collection of elliptical and lenticular galaxies in the nearby universe. In this paper, we present an introduction to the ACS Virgo Cluster Survey: a program to image, in the F475W and F850LP bandpasses (~Sloan g and z), 100 early-type galaxies in the Virgo Cluster using the Advanced Camera for Surveys on the Hubble Space Telescope. We describe the selection of the program galaxies and their ensemble properties, the choice of filters, the field placement and orientation, the limiting magnitudes of the survey, coordinated parallel observations of 100 ``intergalactic'' fields with WFPC2, and supporting ground-based spectroscopic observations of the program galaxies. In terms of depth, spatial resolution, sample size, and homogeneity, this represents the most comprehensive imaging survey to date of early-type galaxies in a cluster environment. We briefly describe the main scientific goals of the survey, which include the measurement of luminosities, metallicities, ages, and structural parameters for the many thousands of globular clusters associated with these galaxies, a high-resolution isophotal analysis of galaxies spanning a factor of ~450 in luminosity and sharing a common environment, the measurement of accurate distances for the full sample of galaxies using the method of surface brightness fluctuations, and a determination of the three-dimensional structure of Virgo itself. ID="FN1"> 1Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  12. Distributions of Gas and Galaxies from Galaxy Clusters to Larger Scales

    NASA Astrophysics Data System (ADS)

    Patej, Anna

    2017-01-01

    We address the distributions of gas and galaxies on three scales: the outskirts of galaxy clusters, the clustering of galaxies on large scales, and the extremes of the galaxy distribution. In the outskirts of galaxy clusters, long-standing analytical models of structure formation and recent simulations predict the existence of density jumps in the gas and dark matter profiles. We use these features to derive models for the gas density profile, obtaining a simple fiducial model that is in agreement with both observations of cluster interiors and simulations of the outskirts. We next consider the galaxy density profiles of clusters; under the assumption that the galaxies in cluster outskirts follow similar collisionless dynamics as the dark matter, their distribution should show a steep jump as well. We examine the profiles of a low-redshift sample of clusters and groups, finding evidence for the jump in some of these clusters. Moving to larger scales where massive galaxies of different types are expected to trace the same large-scale structure, we present a test of this prediction by measuring the clustering of red and blue galaxies at z 0.6, finding low stochasticity between the two populations. These results address a key source of systematic uncertainty - understanding how target populations of galaxies trace large-scale structure - in galaxy redshift surveys. Such surveys use baryon acoustic oscillations (BAO) as a cosmological probe, but are limited by the expense of obtaining sufficiently dense spectroscopy. With the intention of leveraging upcoming deep imaging data, we develop a new method of detecting the BAO in sparse spectroscopic samples via cross-correlation with a dense photometric catalog. This method will permit the extension of BAO measurements to higher redshifts than possible with the existing spectroscopy alone. Lastly, we connect galaxies near and far: the Local Group dwarfs and the high redshift galaxies observed by Hubble and Spitzer. We

  13. VizieR Online Data Catalog: Galaxy clusters discovered in the SPT-SZ survey (Bleem+, 2015)

    NASA Astrophysics Data System (ADS)

    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. M.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; Desai, S.; Dietrich, J. P.; Dobbs, M. A.; Foley, R. J.; Forman, W. R.; George, E. M.; Gladders, M. D.; Gonzalez, A. H.; Halverson, N. W.; Hennig, C.; Hoekstra, H.; Holder, G. P.; Holzapfel, W. L.; Hrubes, J. D.; Jones, C.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Liu, J.; Lueker, M.; Luong-van, D.; Mantz, A.; Marrone, D. P.; McDonald, M.; McMahon, J. J.; Meyer, S. S.; Mocanu, L.; Mohr, J. J.; Murray, S. S.; Padin, S.; Pryke, C.; Reichardt, C. L.; Rest, A.; Ruel, J.; Ruhl, J. E.; Saliwanchik, B. R.; Saro, A.; Sayre, J. T.; Schaffer, K. K.; Schrabback, T.; Shirokoff, E.; Song, J.; Spieler, H. G.; Stanford, S. A.; Staniszewski, Z.; Stark, A. A.; Story, K. T.; Stubbs, C. W.; Vanderlinde, K.; Vieira, J. D.; Vikhlinin, A.; Williamson, R.; Zahn, O.; Zenteno, A.

    2015-03-01

    The South Pole Telescope (SPT) is a 10m diameter telescope located at the National Science Foundation Amundsen-Scott South Pole station in Antarctica. From 2008 to 2011 the telescope was used to conduct the SPT-SZ survey, a survey of ~2500deg2 of the southern sky at 95, 150, and 220GHz. The survey covers a contiguous region from 20h to 7h in right ascension (R.A.) and -65 to -40° in declination (see, e.g., Figure 1 in Story et al. 2013ApJ...779...86S) and was mapped to depths of approximately 40, 18, and 70uK-arcmin at 95, 150, and 220GHz respectively. We use optical and in some cases NIR imaging (Blanco Telescope, Magellan/Baade, Magellan/Clay, Swope, MPG/ESO, New Technology Telescope, Spitzer, WISE) to confirm candidates as clusters and to obtain redshifts for confirmed systems (see section 4). We have also used a variety of facilities to obtain spectroscopic observations of SPT clusters (including VLT/FORS2 & Gemini/GMOS-S). (3 data files).

  14. ROSAT Discovers Unique, Distant Cluster of Galaxies

    NASA Astrophysics Data System (ADS)

    1995-06-01

    Brightest X-ray Cluster Acts as Strong Gravitational Lens Based on exciting new data obtained with the ROSAT X-ray satellite and a ground-based telescope at the ESO La Silla Observatory, a team of European astronomers [2] has just discovered a very distant cluster of galaxies with unique properties. It emits the strongest X-ray emission of any cluster ever observed by ROSAT and is accompanied by two extraordinarily luminous arcs that represent the gravitationally deflected images of even more distant objects. The combination of these unusual characteristics makes this cluster, now known as RXJ1347.5-1145, a most interesting object for further cosmological studies. DISCOVERY AND FOLLOW-UP OBSERVATIONS This strange cluster of galaxies was discovered during the All Sky Survey with the ROSAT X-ray satellite as a moderately intense X-ray source in the constellation of Virgo. It could not be identified with any already known object and additional ground-based observations were therefore soon after performed with the Max-Planck-Society/ESO 2.2-metre telescope at the La Silla observatory in Chile. These observations took place within a large--scale redshift survey of X-ray clusters of galaxies detected by the ROSAT All Sky Survey, a so-called ``ESO Key Programme'' led by astronomers from the Max-Planck-Institut fur Extraterrestrische Physik and the Osservatorio Astronomico di Brera. The main aim of this programme is to identify cluster X-ray sources, to determine the distance to the X-ray emitting clusters and to investigate their overall properties. These observations permitted to measure the redshift of the RXJ1347.5-1145 cluster as z = 0.45, i.e. it moves away from us with a velocity (about 106,000 km/sec) equal to about one-third of the velocity of light. This is an effect of the general expansion of the universe and it allows to determine the distance as about 5,000 million light-years (assuming a Hubble constant of 75 km/sec/Mpc). In other words, we see these

  15. Investigations of galaxy clusters using gravitational lensing

    NASA Astrophysics Data System (ADS)

    Wiesner, Matthew P.

    In this dissertation, we discuss the properties of galaxy clusters that have been determined using strong and weak gravitational lensing. A galaxy cluster is a collection of galaxies that are bound together by the force of gravity, while gravitational lensing is the bending of light by gravity. Strong lensing is the formation of arcs or rings of light surrounding clusters and weak lensing is a change in the apparent shapes of many galaxies. In this work we examine the properties of several samples of galaxy clusters using gravitational lensing. In Chapter 1 we introduce astrophysical theory of galaxy clusters and gravitational lensing. In Chapter 2 we examine evidence from our data that galaxy clusters are more concentrated than cosmology would predict. In Chapter 3 we investigate whether our assumptions about the number of galaxies in our clusters was valid by examining new data. In Chapter 4 we describe a determination of a relationship between mass and number of galaxies in a cluster at higher redshift than has been found before. In Chapter 5 we describe a model of the mass distribution in one of the ten lensing systems discovered by our group at Fermilab. Finally in Chapter 6 we summarize our conclusions.

  16. Investigations of Galaxy Clusters Using Gravitational Lensing

    SciTech Connect

    Wiesner, Matthew P.

    2014-08-01

    In this dissertation, we discuss the properties of galaxy clusters that have been determined using strong and weak gravitational lensing. A galaxy cluster is a collection of galaxies that are bound together by the force of gravity, while gravitational lensing is the bending of light by gravity. Strong lensing is the formation of arcs or rings of light surrounding clusters and weak lensing is a change in the apparent shapes of many galaxies. In this work we examine the properties of several samples of galaxy clusters using gravitational lensing. In Chapter 1 we introduce astrophysical theory of galaxy clusters and gravitational lensing. In Chapter 2 we examine evidence from our data that galaxy clusters are more concentrated than cosmology would predict. In Chapter 3 we investigate whether our assumptions about the number of galaxies in our clusters was valid by examining new data. In Chapter 4 we describe a determination of a relationship between mass and number of galaxies in a cluster at higher redshift than has been found before. In Chapter 5 we describe a model of the mass distribution in one of the ten lensing systems discovered by our group at Fermilab. Finally in Chapter 6 we summarize our conclusions.

  17. SAMI Galaxy Survey: Spectrally Dissecting 3400 Galaxies By the Dozen

    NASA Astrophysics Data System (ADS)

    Cecil, Gerald N.; Croom, S.; The SAMI Galaxy Survey Team

    2014-01-01

    More than 440 mapped, less than 3000 to go in the Sydney-AAO Multi-object IFU (SAMI) Galaxy Survey! SAMI uses novel, photonic fused-optical fiber “hexabundles” that were developed successfully at The University of Sydney and the Australian Astronomical Observatory AAO), with support from the Australian Research Council Centre of Excellence for All-Sky Astrophysics (CAASTRO). The SAMI Galaxy Survey, led by Assoc. Prof. Croom, is backed by an international team. This spectro-bolometric survey mitigates against “aperture effects” that may mislead when stacking single-fiber galaxy spectra. We seek to answer questions such as “what is the physical role of environment in galaxy evolution? How is stellar mass growth and angular momentum development related in galaxies? How does gas get into and out of galaxies, and how do such flows drive star formation?” SAMI maps stellar and gas properties with 13 integral-field units (IFU) plugged onto a dozen galaxies over the 1° field of the AAT prime-focus corrector. 78% of each bundle's area is filled by sixty-one 1.6-arcsec diameter fibers that are packed closely into concentric circles then their etched, thinned cladding is fused without deforming their cores. The fiber hexabundles route to the bench-mounted AAOmega double-beam spectrograph to cover simultaneously 373-570 nm at R=1730 and 620-735 nm at R=4500. Full spatial resolution of the observing site is recovered by dithered exposures totaling 3.5 hours per field. Target stellar masses generally exceed 108 M⊙, and span a range of environments: ˜650 are within clusters of virial mass 1014-15 M⊙ at 0.03 < z < 0.06, the rest are in the z < 0.1 field with extensive frequency data ancillary to the GAMA Survey. We display some key early results of major science themes being addressed by the SAMI survey team, from rotation curve dependence on group halo mass, through galaxy winds and AGN feedback mechanisms, to oxygen abundance gradients, kinematic decomposition

  18. VizieR Online Data Catalog: 3XMM/SDSS Stripe 82 Galaxy Cluster Survey. I. (Takey+, 2016)

    NASA Astrophysics Data System (ADS)

    Takey, A.; Durret, F.; Mahmoud, E.; Ali, G.

    2016-06-01

    The 3XMM/SDSS Stripe 82 cluster survey is mainly based on the XMM X-ray serendipitous source catalogue. The latest version of the catalogue, 3XMM-DR5, was released on 2015 April 28. The 3XMM-DR5 catalogue contains 565962 X-ray detections comprising 396910 X-ray sources, which were detected in 7781 EPIC (PN, MOS1, MOS2) observations made public on/or before 2013 December 31. These observations cover 877deg2 of the sky (Rosen et al. 2016A&A...590A...1R, Cat. IX/46). (4 data files).

  19. Galaxy Infall by Interacting with Its Environment: A Comprehensive Study of 340 Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Gu, Liyi; Wen, Zhonglue; Gandhi, Poshak; Inada, Naohisa; Kawaharada, Madoka; Kodama, Tadayuki; Konami, Saori; Nakazawa, Kazuhiro; Xu, Haiguang; Makishima, Kazuo

    2016-07-01

    To study systematically the evolution of the angular extents of the galaxy, intracluster medium (ICM), and dark matter components in galaxy clusters, we compiled the optical and X-ray properties of a sample of 340 clusters with redshifts <0.5, based on all the available data from the Sloan Digital Sky Survey and Chandra/XMM-Newton. For each cluster, the member galaxies were determined primarily with photometric redshift measurements. The radial ICM mass distribution, as well as the total gravitational mass distribution, was derived from a spatially resolved spectral analysis of the X-ray data. When normalizing the radial profile of galaxy number to that of the ICM mass, the relative curve was found to depend significantly on the cluster redshift; it drops more steeply toward the outside in lower-redshift subsamples. The same evolution is found in the galaxy-to-total mass profile, while the ICM-to-total mass profile varies in an opposite way. The behavior of the galaxy-to-ICM distribution does not depend on the cluster mass, suggesting that the detected redshift dependence is not due to mass-related effects, such as sample selection bias. Also, it cannot be ascribed to various redshift-dependent systematic errors. We interpret that the galaxies, the ICM, and the dark matter components had similar angular distributions when a cluster was formed, while the galaxies traveling in the interior of the cluster have continuously fallen toward the center relative to the other components, and the ICM has slightly expanded relative to the dark matter although it suffers strong radiative loss. This cosmological galaxy infall, accompanied by an ICM expansion, can be explained by considering that the galaxies interact strongly with the ICM while they are moving through it. The interaction is considered to create a large energy flow of 1044-45 erg s-1 per cluster from the member galaxies to their environment, which is expected to continue over cosmological timescales.

  20. THE DYNAMICAL STATE OF BRIGHTEST CLUSTER GALAXIES AND THE FORMATION OF CLUSTERS

    SciTech Connect

    Coziol, R.; Andernach, H.; Caretta, C. A.; Alamo-MartInez, K. A.; Tago, E. E-mail: heinz@astro.ugto.mx E-mail: k.alamo@astrosmo.unam.mx

    2009-06-15

    A large sample of Abell clusters of galaxies, selected for the likely presence of a dominant galaxy, is used to study the dynamical properties of the brightest cluster members (BCMs). From visual inspection of Digitized Sky Survey images combined with redshift information we identify 1426 candidate BCMs located in 1221 different redshift components associated with 1169 different Abell clusters. This is the largest sample published so far of such galaxies. From our own morphological classification we find that {approx}92% of the BCMs in our sample are early-type galaxies and 48% are of cD type. We confirm what was previously observed based on much smaller samples, namely, that a large fraction of BCMs have significant peculiar velocities. From a subsample of 452 clusters having at least 10 measured radial velocities, we estimate a median BCM peculiar velocity of 32% of their host clusters' radial velocity dispersion. This suggests that most BCMs are not at rest in the potential well of their clusters. This phenomenon is common to galaxy clusters in our sample, and not a special trait of clusters hosting cD galaxies. We show that the peculiar velocity of the BCM is independent of cluster richness and only slightly dependent on the Bautz-Morgan type. We also find a weak trend for the peculiar velocity to rise with the cluster velocity dispersion. The strongest dependence is with the morphological type of the BCM: cD galaxies tend to have lower relative peculiar velocities than elliptical galaxies. This result points to a connection between the formation of the BCMs and that of their clusters. Our data are qualitatively consistent with the merging-groups scenario, where BCMs in clusters formed first in smaller subsystems comparable to compact groups of galaxies. In this scenario, clusters would have formed recently from the mergers of many such groups and would still be in a dynamically unrelaxed state.

  1. The Shocked POststarburst Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Alatalo, Katherine A.; SPOGS Team

    2017-01-01

    Modern day galaxies are found to be in a bimodal distribution, both in terms of their morphologies, and in terms of their colors, and these properties are inter-related. In color space, there is a genuine dearth of intermediate colored galaxies, which has been taken to mean that the transition a galaxy undergoes to transform must be rapid. Given that this transformation is largely one-way (at z=0), identifying all initial conditions that catalyze it becomes essential. The Shocked POststarburst Galaxy Survey (http://www.spogs.org) is able to pinpoint transitioning galaxies at an earlier stage of transition than other traditional searches, possibly opening a new door to identifying new pathways over which galaxies transform from blue spirals to red ellipticals.

  2. Emission line galaxies and active galactic nuclei in WINGS clusters

    NASA Astrophysics Data System (ADS)

    Marziani, P.; D'Onofrio, M.; Bettoni, D.; Poggianti, B. M.; Moretti, A.; Fasano, G.; Fritz, J.; Cava, A.; Varela, J.; Omizzolo, A.

    2017-03-01

    We present the analysis of the emission line galaxies members of 46 low-redshift (0.04 < z < 0.07) clusters observed by WINGS (WIde-field Nearby Galaxy cluster Survey). Emission line galaxies were identified following criteria that are meant to minimize biases against non-star-forming galaxies and classified employing diagnostic diagrams. We examined the emission line properties and frequencies of star-forming galaxies, transition objects, and active galactic nuclei (AGNs: LINERs and Seyferts), unclassified galaxies with emission lines, and quiescent galaxies with no detectable line emission. A deficit of emission line galaxies in the cluster environment is indicated by both a lower frequency, and a systematically lower Balmer emission line equivalent width and luminosity with respect to control samples; this implies a lower amount of ionized gas per unit mass and a lower star formation rate if the source is classified as Hii region. A sizable population of transition objects and of low-luminosity LINERs (≈ 10-20% of all emission line galaxies) are detected among WINGS cluster galaxies. These sources are a factor of ≈1.5 more frequent, or at least as frequent, as in control samples with respect to Hii sources. Transition objects and LINERs in clusters are most affected in terms ofline equivalent width by the environment and appear predominantly consistent with so-called retired galaxies. Shock heating can be a possible gas excitation mechanism that is able to account for observed line ratios. Specific to the cluster environment, we suggest interaction between atomic and molecular gas and the intracluster medium as a possible physical cause of line-emitting shocks. The data whose description is provided in Table B.1, and emission line catalog of the WINGS database are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/599/A83

  3. STAR CLUSTERS IN PSEUDOBULGES OF SPIRAL GALAXIES

    SciTech Connect

    Di Nino, Daiana; Trenti, Michele; Stiavelli, Massimo; Carollo, C. Marcella; Scarlata, Claudia; Wyse, Rosemary F. G.

    2009-11-15

    We present a study of the properties of the star-cluster systems around pseudobulges of late-type spiral galaxies using a sample of 11 galaxies with distances from 17 Mpc to 37 Mpc. Star clusters are identified from multiband Hubble Space Telescope ACS and WFPC2 imaging data by combining detections in three bands (F435W and F814W with ACS and F606W with WFPC2). The photometric data are then compared to population synthesis models to infer the masses and ages of the star clusters. Photometric errors and completeness are estimated by means of artificial source Monte Carlo simulations. Dust extinction is estimated by considering F160W NICMOS observations of the central regions of the galaxies, augmenting our wavelength coverage. In all galaxies we identify star clusters with a wide range of ages, from young (age {approx}< 8 Myr) blue clusters, with typical mass of 10{sup 3} M {sub sun} to older (age >100-250 Myr), more massive, red clusters. Some of the latter might likely evolve into objects similar to the Milky Way's globular clusters. We compute the specific frequencies for the older clusters with respect to the galaxy and bulge luminosities. Specific frequencies relative to the galaxy light appear consistent with the globular cluster specific frequencies of early-type spirals. We compare the specific frequencies relative to the bulge light with the globular cluster specific frequencies of dwarf galaxies, which have a surface brightness profile that is similar to that of the pseudobulges in our sample. The specific frequencies we derive for our sample galaxies are higher than those of the dwarf galaxies, supporting an evolutionary scenario in which some of the dwarf galaxies might be the remnants of harassed late-type spiral galaxies that hosted a pseudobulge.

  4. The VIMOS Public Extragalactic Redshift Survey (VIPERS) . Luminosity and stellar mass dependence of galaxy clustering at 0.5 < z < 1.1

    NASA Astrophysics Data System (ADS)

    Marulli, F.; Bolzonella, M.; Branchini, E.; Davidzon, I.; de la Torre, S.; Granett, B. R.; Guzzo, L.; Iovino, A.; Moscardini, L.; Pollo, A.; Abbas, U.; Adami, C.; Arnouts, S.; Bel, J.; Bottini, D.; Cappi, A.; Coupon, J.; Cucciati, O.; De Lucia, G.; Fritz, A.; Franzetti, P.; Fumana, M.; Garilli, B.; Ilbert, O.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; McCracken, H. J.; Paioro, L.; Polletta, M.; Schlagenhaufer, H.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Di Porto, C.; Marchetti, A.; Marinoni, C.; Mellier, Y.; Nichol, R. C.; Peacock, J. A.; Percival, W. J.; Phleps, S.; Wolk, M.; Zamorani, G.

    2013-09-01

    Aims: We investigate the dependence of galaxy clustering on luminosity and stellar mass in the redshift range 0.5 < z < 1.1, using the first ~ 55 000 redshifts from the VIMOS Public Extragalactic Redshift Survey (VIPERS). Methods: We measured the redshift-space two-point correlation functions (2PCF), ξ(s) and ξ(rp,π) , and the projected correlation function, wp(rp), in samples covering different ranges of B-band absolute magnitudes and stellar masses. We considered both threshold and binned galaxy samples, with median B-band absolute magnitudes - 21.6 ≲ MB - 5log (h) ≲ - 19.5 and median stellar masses 9.8 ≲ log (M⋆ [h-2 M⊙]) ≲ 10.7. We assessed the real-space clustering in the data from the projected correlation function, which we model as a power law in the range 0.2 < rp [h-1 Mpc ] < 20. Finally, we estimated the galaxy bias as a function of luminosity, stellar mass, and redshift, assuming a flat Λ cold dark matter model to derive the dark matter 2PCF. Results: We provide the best-fit parameters of the power-law model assumed for the real-space 2PCF - the correlation length, r0, and the slope, γ - as well as the linear bias parameter, as a function of the B-band absolute magnitude, stellar mass, and redshift. We confirm and provide the tightest constraints on the dependence of clustering on luminosity at 0.5 < z < 1.1. We prove the complexity of comparing the clustering dependence on stellar mass from samples that are originally flux-limited and discuss the possible origin of the observed discrepancies. Overall, our measurements provide stronger constraints on galaxy formation models, which are now required to match, in addition to local observations, the clustering evolution measured by VIPERS galaxies between z = 0.5 and z = 1.1 for a broad range of luminosities and stellar masses. Based on observations collected at the European Southern Observatory, Paranal, Chile, under programmes 182.A-0886 (LP) at the Very Large Telescope, and also based on

  5. PHAT Stellar Cluster Survey. II. Andromeda Project Cluster Catalog

    NASA Astrophysics Data System (ADS)

    Johnson, L. Clifton; Seth, Anil C.; Dalcanton, Julianne J.; Wallace, Matthew L.; Simpson, Robert J.; Lintott, Chris J.; Kapadia, Amit; Skillman, Evan D.; Caldwell, Nelson; Fouesneau, Morgan; Weisz, Daniel R.; Williams, Benjamin F.; Beerman, Lori C.; Gouliermis, Dimitrios A.; Sarajedini, Ata

    2015-04-01

    We construct a stellar cluster catalog for the Panchromatic Hubble Andromeda Treasury (PHAT) survey using image classifications collected from the Andromeda Project citizen science website. We identify 2753 clusters and 2270 background galaxies within ˜0.5 deg2 of PHAT imaging searched, or ˜400 kpc2 in deprojected area at the distance of the Andromeda Galaxy (M31). These identifications result from 1.82 million classifications of ˜20,000 individual images (totaling ˜7 gigapixels) by tens of thousands of volunteers. We show that our crowd-sourced approach, which collects >80 classifications per image, provides a robust, repeatable method of cluster identification. The high spatial resolution Hubble Space Telescope images resolve individual stars in each cluster and are instrumental in the factor of ˜6 increase in the number of clusters known within the survey footprint. We measure integrated photometry in six filter passbands, ranging from the near-UV to the near-IR. PHAT clusters span a range of ˜8 magnitudes in F475W (g-band) luminosity, equivalent to ˜4 decades in cluster mass. We perform catalog completeness analysis using >3000 synthetic cluster simulations to determine robust detection limits and demonstrate that the catalog is 50% complete down to ˜500 {{M}⊙ } for ages <100 Myr. We include catalogs of clusters, background galaxies, remaining unselected candidates, and synthetic cluster simulations, making all information publicly available to the community. The catalog published here serves as the definitive base data product for PHAT cluster science, providing a census of star clusters in an {{L}\\star } spiral galaxy with unmatched sensitivity and quality.

  6. The Herschel Virgo Cluster Survey - XVI. A cluster inventory

    NASA Astrophysics Data System (ADS)

    Davies, J. I.; Bianchi, S.; Baes, M.; Bendo, G. J.; Clemens, M.; De Looze, I.; di Serego Alighieri, S.; Fritz, J.; Fuller, C.; Pappalardo, C.; Hughes, T. M.; Madden, S.; Smith, M. W. L.; Verstappen, J.; Vlahakis, C.

    2014-03-01

    Herschel far-infrared (FIR) observations are used to construct Virgo cluster galaxy luminosity functions and to show that the cluster lacks the very bright and the numerous faint sources detected in field galaxy surveys. The FIR spectral energy distributions are fitted to obtain dust masses and temperatures and the dust mass function. The cluster is overdense in dust by about a factor of 100 compared to the field. The same emissivity (β)-temperature relation applies for different galaxies as that found for different regions of M31. We use optical and H I data to show that Virgo is overdense in stars and atomic gas by about a factor of 100 and 20, respectively. Metallicity values are used to measure the mass of metals in the gas phase. The mean metallicity is ˜0.7 solar, and ˜50 per cent of the metals are in the dust. For the cluster as a whole, the mass density of stars in galaxies is eight times that of the gas and the gas mass density is 130 times that of the metals. We use our data to consider the chemical evolution of the individual galaxies, inferring that the measured variations in the effective yield are due to galaxies having different ages, being affected to varying degrees by gas loss. Four galaxy scaling relations are considered: mass-metallicity, mass-velocity, mass-star formation rate and mass-radius - we suggest that initial galaxy mass is the prime driver of a galaxy's ultimate destiny. Finally, we use X-ray observations and galaxy dynamics to assess the dark and baryonic matter content compared to the cosmological model.

  7. XMM-NEWTON/SLOAN DIGITAL SKY SURVEY: STAR FORMATION EFFICIENCY IN GALAXY CLUSTERS AND CONSTRAINTS ON THE MATTER-DENSITY PARAMETER

    SciTech Connect

    Lagana, Tatiana F.; Zhang Yuying; Reiprich, Thomas H.; Schneider, Peter

    2011-12-10

    It is believed that the global baryon content of clusters of galaxies is representative of the matter distribution of the universe, and can, therefore, be used to reliably determine the matter-density parameter {Omega}{sub m}. This assumption is challenged by the growing evidence from optical and X-ray observations that the total baryon mass fraction increases toward rich clusters. In this context, we investigate the dependence of stellar and total baryon mass fractions as a function of mass. To do so, we used a subsample of 19 clusters extracted from the X-ray flux-limited sample HIFLUGCS that have available Sloan Digital Sky Survey Data Release 7 data. From the optical analysis we derived the stellar masses. Using XMM-Newton we derived the gas masses. Then, adopting a scaling relation we estimate the total masses. Adding the gas and the stellar mass fractions we obtain the total baryonic content that we find to increase with cluster mass, reaching seven-year Wilkinson Microwave Anisotropy Probe (WMAP7) prediction for clusters with M{sub 500} = 1.6 Multiplication-Sign 10{sup 15} M{sub Sun }. We observe a decrease of the stellar mass fraction (from 4.5% to {approx}1.0%) with increasing total mass where our findings for the stellar mass fraction agree with previous studies. This result suggests a difference in the number of stars formed per unit of halo mass, though with a large scatter for low-mass systems. That is, the efficiency of star formation varies on a cluster scale that lower mass systems are likely to have higher star formation efficiencies. It follows immediately that the dependence of the stellar mass fraction on total mass results in an increase of the mass-to-light ratio from lower to higher mass systems. We also discuss the consequences of these results in the context of determining the cosmic matter-density parameter {Omega}{sub m}.

  8. X-ray morphological study of galaxy cluster catalogues

    NASA Astrophysics Data System (ADS)

    Democles, Jessica; Pierre, Marguerite; Arnaud, Monique

    2016-07-01

    Context : The intra-cluster medium distribution as probed by X-ray morphology based analysis gives good indication of the system dynamical state. In the race for the determination of precise scaling relations and understanding their scatter, the dynamical state offers valuable information. Method : We develop the analysis of the centroid-shift so that it can be applied to characterize galaxy cluster surveys such as the XXL survey or high redshift cluster samples. We use it together with the surface brightness concentration parameter and the offset between X-ray peak and brightest cluster galaxy in the context of the XXL bright cluster sample (Pacaud et al 2015) and a set of high redshift massive clusters detected by Planck and SPT and observed by both XMM-Newton and Chandra observatories. Results : Using the wide redshift coverage of the XXL sample, we see no trend between the dynamical state of the systems with the redshift.

  9. ORIENTATION OF BRIGHTER GALAXIES IN NEARBY GALAXY CLUSTERS

    SciTech Connect

    Panko, E.; Juszczyk, T.; Flin, P. E-mail: sfflin@cyf-kr.edu.pl

    2009-12-15

    A sample of 6188 nearby galaxy structures, complete to r{sub F} = 18fm3 and containing at least 10 members each, was the observational basis for an investigation of the alignment of bright galaxies with the major axes for the parent clusters. The distribution of position angles for galaxies within the clusters, specifically the brightest, the second brightest, the third, and the tenth brightest galaxies was tested for isotropy. Galaxy position angles appear to be distributed isotropically, as are the distributions of underlying cluster structure position angles. The characterization of galaxy structures according to richness class also appears to be isotropic. Characterization according to BM types, which are known for 1056 clusters, is more interesting. Only in the case of clusters of BM type I is there an alignment of the brightest cluster member with the major axis of the parent cluster. The effect is observed at the 2 significance level. In other investigated cases the distributions are isotropic. The results confirm the special role of cD galaxies in the origin/evolution of large-scale structures.

  10. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: BAO measurement from the LOS-dependent power spectrum of DR12 BOSS galaxies

    NASA Astrophysics Data System (ADS)

    Gil-Marín, Héctor; Percival, Will J.; Cuesta, Antonio J.; Brownstein, Joel R.; Chuang, Chia-Hsun; Ho, Shirley; Kitaura, Francisco-Shu; Maraston, Claudia; Prada, Francisco; Rodríguez-Torres, Sergio; Ross, Ashley J.; Schlegel, David J.; Schneider, Donald P.; Thomas, Daniel; Tinker, Jeremy L.; Tojeiro, Rita; Vargas Magaña, Mariana; Zhao, Gong-Bo

    2016-08-01

    We present an anisotropic analysis of the baryon acoustic oscillation (BAO) scale in the twelfth and final data release of the Baryon Oscillation Spectroscopic Survey (BOSS). We independently analyse the LOWZ and CMASS galaxy samples: the LOWZ sample contains 361 762 galaxies with an effective redshift of zLOWZ = 0.32; the CMASS sample consists of 777 202 galaxies with an effective redshift of zCMASS = 0.57. We extract the BAO peak position from the monopole power-spectrum moment, α0, and from the μ2 moment, α2, where μ is the cosine of the angle to the line of sight. The μ2-moment provides equivalent information to that available in the quadrupole but is simpler to analyse. After applying a reconstruction algorithm to reduce the BAO suppression by bulk motions, we measure the BAO peak position in the monopole and μ2-moment, which are related to radial and angular shifts in scale. We report H(zLOWZ)rs(zd) = (11.60 ± 0.60) × 103 km s-1 and DA(zLOWZ)/rs(zd) = 6.66 ± 0.16 with a cross-correlation coefficient of r_{HD_A}=0.41, for the LOWZ sample; and H(zCMASS)rs(zd) = (14.56 ± 0.37) × 103 km s-1 and DA(zCMASS)/rs(zd) = 9.42 ± 0.13 with a cross-correlation coefficient of r_{HD_A}=0.47, for the CMASS sample. We demonstrate that our results are not affected by the fiducial cosmology assumed for the analysis. We combine these results with the measurements of the BAO peak position in the monopole and quadrupole correlation function of the same data set (Cuesta et al. 2016, companion paper) and report the consensus values: H(zLOWZ)rs(zd) = (11.63 ± 0.69) × 103 km s-1 and DA(zLOWZ)/rs(zd) = 6.67 ± 0.15 with r_{HD_A}=0.35 for the LOWZ sample; H(zCMASS)rs(zd) = (14.67 ± 0.42) × 103 km s-1 and DA(zCMASS)/rs(zd) = 9.47 ± 0.12 with r_{HD_A}=0.52 for the CMASS sample.

  11. Estimating Cosmological Parameters and Cluster Masses through Escape Velocity Measurements in Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Gifford, Daniel William

    2016-08-01

    Galaxy clusters are large virialized structures that exist at the intersection of filaments of matter that make up the cosmic web. Due to their hierarchical growth history, they are excellent probes of the cosmology that governs our universe. Here, we aim to use clusters to better constrain cosmological parameters by systematically studying the uncertainties on galaxy cluster mass estimation for use in a halo mass function analysis. We find that the caustic technique is capable on average of recovering unbiased cluster masses to within 30% for well sampled systems. We also quantify potential statistical and systematic biases due to observational challenges. To address statistical biases in the caustic technique, we developed a new stacking algorithm to measure the average cluster mass for a single stack of projected cluster phase-spaces. By varying the number of galaxies and number of clusters we stack, we find that the single limited value is the total number of galaxies in the stack opening up the possibility for self-calibrated mass estimates of low mass or poorly sampled clusters in large surveys. We then utilize the SDSS-C4 catalog of galaxy clusters to place some of the tightest galaxy cluster based constraints on the matter density and power spectrum normalization for matter in our universe.

  12. The real-space clustering of luminous red galaxies around z < 0.6 quasars in the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Padmanabhan, Nikhil; White, Martin; Norberg, Peder; Porciani, Cristiano

    2009-08-01

    We measure the clustering of a sample of photometrically selected luminous red galaxies (LRGs) around a low-redshift (0.2 < z < 0.6) sample of quasars selected from the Sloan Digital Sky Survey Data Release 5. We make use of a new statistical estimator to obtain precise measurements of the LRG autocorrelations and constrain halo occupation distributions for them. These are used to generate mock catalogues which aid in interpreting our quasar-LRG cross-correlation measurements. The cross-correlation is well described by a power law with slope 1.8 +/- 0.1 and r0 = 6 +/- 0.5h-1Mpc, consistent with observed galaxy correlation functions. We find no evidence for `excess' clustering on 0.1Mpc scales and demonstrate that this is consistent with the results of Serber et al. and Strand, Brunner and Myers, when one accounts for several subtleties in the interpretation of their measurements. Combining the quasar-LRG cross-correlation with the LRG autocorrelations, we determine a large-scale quasar bias bQSO = 1.09 +/- 0.15 at a median redshift of 0.43, with no observed redshift or luminosity evolution. This corresponds to a mean halo mass ~ 1012h-1Msolar, Eddington ratios from 0.01 to 1 and lifetimes less than 107yr. Using simple models of halo occupation, these correspond to a number density of quasar hosts greater than 10-3 h3Mpc-3 and stellar masses less than 1011 h-1Msolar. The small-scale clustering signal can be interpreted with the aid of our mock LRG catalogues, and depends on the manner in which quasars inhabit haloes. We find that our small-scale measurements are inconsistent with quasar positions being randomly subsampled from halo centres above a mass threshold, requiring a satellite fraction >25 per cent.

  13. Constraints on the alignment of galaxies in galaxy clusters from ~14 000 spectroscopic members

    NASA Astrophysics Data System (ADS)

    Sifón, Cristóbal; Hoekstra, Henk; Cacciato, Marcello; Viola, Massimo; Köhlinger, Fabian; van der Burg, Remco F. J.; Sand, David J.; Graham, Melissa L.

    2015-03-01

    Torques acting on galaxies lead to physical alignments, but the resulting ellipticity correlations are difficult to predict. As they constitute a major contaminant for cosmic shear studies, it is important to constrain the intrinsic alignment signal observationally. We measured the alignments of satellite galaxies within 90 massive galaxy clusters in the redshift range 0.05 galaxies with spectroscopic redshifts with high-quality data from the Canada-France-Hawaii Telescope. We used phase-space information to select 14 576 cluster members, 14 250 of which have shape measurements and measured three different types of alignment: the radial alignment of satellite galaxies toward the brightest cluster galaxies (BCGs), the common orientations of satellite galaxies and BCGs, and the radial alignments of satellites with each other. Residual systematic effects are much smaller than the statistical uncertainties. We detect no galaxy alignment of any kind out to at least 3r200. The signal is consistent with zero for both blue and red galaxies, bright and faint ones, and also for subsamples of clusters based on redshift, dynamical mass, and dynamical state. These conclusions are unchanged if we expand the sample with bright cluster members from the red sequence. We augment our constraints with those from the literature to estimate the importance of the intrinsic alignments of satellites compared to those of central galaxies, for which the alignments are described by the linear alignment model. Comparison of the alignment signals to the expected uncertainties of current surveys such as the Kilo-Degree Survey suggests that the linear alignment model is an adequate treatment of intrinsic alignments, but it is not clear whether this will be the case for larger surveys. Table is available in electronic form at

  14. FAR-FLUNG GALAXY CLUSTERS MAY REVEAL FATE OF UNIVERSE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A selection of NASA Hubble Space Telescope snapshots of huge galaxy clusters that lie far away and far back in time. These are selected from a catalog of 92 new clusters uncovered during a six-year Hubble observing program known as the Medium Deep Survey. If the distances and masses of the clusters are confirmed by ground based telescopes, the survey may hold clues to how galaxies quickly formed into massive large-scale structures after the big bang, and what that may mean for the eventual fate of the expanding universe. The images are each a combination of two exposures in yellow and deep red taken with Hubble's Wide Field and Planetary Camera 2. Each cluster's distance is inferred from the reddening of the starlight, which is due to the expansion of space. Astronomers assume these clusters all formed early in the history of the universe. HST133617-00529 (left) This collection of spiral and elliptical galaxies lies an estimated 4 to 6 billion light-years away. It is in the constellation of Virgo not far from the 3rd magnitude star Zeta Virginis. The brighter galaxies in this cluster have red magnitudes between 20 and 22 near the limit of the Palomar Sky Survey. The bright blue galaxy (upper left) is probably a foreground galaxy, and not a cluster member. The larger of the galaxies in the cluster are probably about the size of our Milky Way Galaxy. The diagonal line at lower right is an artificial satellite trail. HST002013+28366 (upper right) This cluster of galaxies lies in the constellation of Andromeda a few degrees from the star Alpheratz in the northeast corner of the constellation Pegasus. It is at an estimated distance of 4 billion light-years, which means the light we are seeing from the cluster is as it appeared when the universe was roughly 2/3 of its present age. HST035528+09435 (lower right) At an estimated distance of about 7 to 10 billion light-years (z=1), this is one of the farthest clusters in the Hubble sample. The cluster lies in the

  15. Tracing galaxy evolution through resolved stellar populations and star clusters

    NASA Astrophysics Data System (ADS)

    Silva-Villa, E.

    2011-09-01

    Field stars and star clusters contain a big part of the galaxy’s history. To understand galaxy formation and evolution we need then to understand the parts of which galaxies are composed. It has commonly been assumed that most stars formed in clusters. However, the connection between these two systems is not clear, and the fraction of actual star formation happening in clusters is still uncertain. Through this thesis, we aim to use field stars and star clusters to attack different problems regarding galaxy formation and evolution, named: 1. the cluster formation efficiency and its (co-)relation with environment (i.e. the host galaxy), 2. the star formation rate in the arms and inter-arm regions of spiral galaxies, and 3. the indications of a possible interaction between two galaxies observed through their resolved stellar populations. We performed a systematic and homogeneous study over the galaxies NGC45, NGC1313, NGC4395, NGC5236 and NGC7793, where star clusters and field stars are analyze separately. For this aim, we used Hubble Space Telescope observations in the optical bands U, B, V and I, using the Advanced Camera for Surveys and the Wide Field Planetary Camera 2. Standard photometric procedures are use to study the properties of these two main parts of the galaxies. However, incompleteness constrains our results to ages younger than 100 Myr. Following the synthetic CMD method we recovered the star formation history for the last 100 Myr over the five galaxies. Comparing observed clusters properties with simple stellar population models, we estimate ages and masses of star clusters. We observe that the galaxies NGC5236 and NGC1313 show higher star and cluster formation rates, while NGC45, NGC4395 and NGC7793 show lower values. We found that the actual fraction of star formation happening in clusters presents low values (< 10%), contrary to common assumptions, however in agreement with studies in other galaxies. Observations of the surface star formation

  16. Galaxy and Mass Assembly (GAMA): Selection of the Most Massive Clusters

    NASA Astrophysics Data System (ADS)

    Ibarra-Medel, Héctor J.; Lara-López, Maritza; López-Cruz, Omar

    2016-10-01

    We have developed a galaxy cluster finding technique based on the Delaunay Tessellation Field Estimator (DTFE) combined with caustic analysis. Our method allows us to recover clusters of galaxies within the mass range of $1012$ to $1016\\ \\mathcal{M}\\odot$. We have found a total of 113 galaxy clusters in the Galaxy and Mass Assembly survey (GAMA). In the corresponding mass range, the density of clusters found in this work is comparable to the density traced by clusters selected by the thermal Sunyaev Zel'dovich Effect; however, we are able to cover a wider mass range. We present the analysis of the two-point correlation function for our cluster sample.

  17. THE GALAXY CONTENT OF SDSS CLUSTERS AND GROUPS

    SciTech Connect

    Hansen, Sarah M.; Wechsler, Risa H.; Koester, Benjamin P.

    2009-07-10

    Imaging data from the Sloan Digital Sky Survey are used to characterize the population of galaxies in groups and clusters detected with the MaxBCG algorithm. We investigate the dependence of brightest cluster galaxy (BCG) luminosity, and the distributions of satellite galaxy luminosity and satellite color, on cluster properties over the redshift range 0.1 {<=} z {<=} 0.3. The size of the data set allows us to make measurements in many bins of cluster richness, radius and redshift. We find that, within r {sub 200} of clusters with mass above 3 x 10{sup 13} h {sup -1} M {sub sun}, the luminosity function (LF) of both red and blue satellites is only weakly dependent on richness. We further find that the shape of the satellite LF does not depend on cluster-centric distance for magnitudes brighter than {sup 0.25} M{sub i} - 5log{sub 10} h =-19. However, the mix of faint red and blue galaxies changes dramatically. The satellite red fraction is dependent on cluster-centric distance, galaxy luminosity, and cluster mass, and also increases by {approx}5% between redshifts 0.28 and 0.2, independent of richness. We find that BCG luminosity is tightly correlated with cluster richness, scaling as L {sub BCG} {approx} M {sup 0.3} {sub 200}, and has a Gaussian distribution at fixed richness, with {sigma}{sub logL} {approx} 0.17 for massive clusters. The ratios of BCG luminosity to total cluster luminosity and characteristic satellite luminosity scale strongly with cluster richness: in richer systems, BCGs contribute a smaller fraction of the total light, but are brighter compared to typical satellites. This study demonstrates the power of cross-correlation techniques for measuring galaxy populations in purely photometric data.

  18. The Galaxy Content of SDSS Clusters And Groups

    SciTech Connect

    Hansen, Sarah M.; Sheldon, Erin S.; Wechsler, Risa H.; Koester, Benjamin P.; /Chicago U., Astron. Astrophys. Ctr.

    2007-11-09

    Imaging data from the Sloan Digital Sky Survey are used to characterize the population of galaxies in groups and clusters detected with the MaxBCG algorithm. We investigate the dependence of Brightest Cluster Galaxy (BCG) luminosity, and the distributions of satellite galaxy luminosity and satellite color, on cluster properties over the redshift range 0.1 {le} z {le} 0.3. The size of the dataset allows us to make measurements in many bins of cluster richness, radius and redshift. We find that, within r200 of clusters with mass above 3x10{sup 13}h{sup -1}M{sub {circle_dot}}, the luminosity function of both red and blue satellites is only weakly dependent on richness. We further find that the shape of the satellite luminosity function does not depend on cluster-centric distance for magnitudes brighter than {sup 0.25}M{sub i} - 5log{sub 10}h = -19. However, the mix of faint red and blue galaxies changes dramatically. The satellite red fraction is dependent on cluster-centric distance, galaxy luminosity and cluster mass, and also increases by {approx}5% between redshifts 0.28 and 0.2, independent of richness. We find that BCG luminosity is tightly correlated with cluster richness, scaling as L{sub BCG} {approx} M{sup 0.3}{sub 200}, and has a Gaussian distribution at fixed richness, with {sigma}{sub log}L {approx} 0.17 for massive clusters. The ratios of BCG luminosity to total cluster luminosity and characteristic satellite luminosity scale strongly with cluster richness: in richer systems, BCGs contribute a smaller fraction of the total light, but are brighter compared to typical satellites. This study demonstrates the power of cross-correlation techniques for measuring galaxy populations in purely photometric data.

  19. The Dependence of Cluster Galaxy Properties on the Central Entropy of their Host Cluster

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Woo; Ko, Jongwan; Hwang, Ho Seong; Edge, Alastair C.; Lee, Joon Hyeop; Lee, Jong Chul; Jeong, Hyunjin

    2017-02-01

    We present a study of the connection between brightest cluster galaxies (BCGs) and their host galaxy clusters. Using galaxy clusters at 0.1< z< 0.3 from the Hectospec Cluster Survey (HeCS) with X-ray information from the Archive of Chandra Cluster Entropy Profile Tables (ACCEPT), we confirm that BCGs in low central entropy clusters are well aligned with the X-ray center. Additionally, the magnitude difference between BCG and the second brightest galaxy also correlates with the central entropy of the intracluster medium. From the red-sequence (RS) galaxies, we cannot find significant dependence of RS color scatter and stellar population on the central entropy of the intracluster medium of their host cluster. However, BCGs in low-entropy clusters are systematically less massive than those in high-entropy clusters, although this is dependent on the method used to derive the stellar mass of BCGs. In contrast, the stellar velocity dispersion of BCGs shows no dependence on BCG activity and cluster central entropy. This implies that the potential of the BCG is established earlier and the activity leading to optical emission lines is dictated by the properties of the intracluster medium in the cluster core.

  20. Violent galaxy evolution in the Frontier Fields clusters

    NASA Astrophysics Data System (ADS)

    Ebeling, Harald; McPartland, Conor; Blumenthal, Kelly; Roediger, Elke

    2015-08-01

    In a recent study we used customized morphological selection criteria to identify potential ram-pressure stripping events in shallow HST images of MACS clusters at z=0.3-0.7 and found tantalising evidence of such violent evolution (a) being at least partly triggered by galaxy mergers and (b) causing extensive star formation and thus brightening of the affected galaxies. Due to the limited depth of the HST data used, our project focused (by design and necessity) on the brightest galaxies. We here present results of a similar survey for “jellyfish” galaxies conducted using the much deeper, multi-passband imaging data of the Frontier Fields clusters that allow us to probe much farther into the luminosity function of ram-pressure stripping in some of the most massive and most dynamically disturbed clusters known.

  1. Galaxy Clustering Around Nearby Luminous Quasars

    NASA Technical Reports Server (NTRS)

    Fisher, Karl B.; Bahcall, John N.; Kirhakos, Sofia; Schneider, Donald P.

    1996-01-01

    We examine the clustering of galaxies around a sample of 20 luminous low redshift (z approx. less than 0.30) quasars observed with the Wide Field Camera-2 on the Hubble Space Telescope (HST). The HST resolution makes possible galaxy identification brighter than V = 24.5 and as close as 1 min or 2 min to the quasar. We find a significant enhancement of galaxies within a projected separation of approx. less than 100 1/h kpc of the quasars. If we model the QSO/galaxy correlation function as a power law with a slope given by the galaxy/galaxy correlation function, we find that the ratio of the QSO/galaxy to galaxy/galaxy correlation functions is 3.8 +/- 0.8. The galaxy counts within r less than 15 1/h kpc of the quasars are too high for the density profile to have an appreciable core radius (approx. greater than 100 1/h kpc). Our results reinforce the idea that low redshift quasars are located preferentially in groups of 10-20 galaxies rather than in rich clusters. We see no significant difference in the clustering amplitudes derived from radio-loud and radio-quiet subsamples.

  2. Low mass galaxy clusters and galaxy morphology evolution

    NASA Astrophysics Data System (ADS)

    Nilo Castellón, J. L.; Órdenes, Y.; Ramos, F.; Alonso, M. V.; Cuevas, H.; García Lambas, D.; Ramírez, A.

    We present preliminary results about the galaxy morphology evolution in three low mass galaxy clusters: RX J0533.9-5809 ([VMF98]046, z 0.198), RX J1204.3-0350 ([VMF98]113, z 0.261) and RX J0533.8-5746 ([VMF98]045, z 0.295). Full photometric catalogues were created using SExtractor v2.8.0. Also, photometric redshifts (z phot ) were obtained for all the object classified as galaxies, using the ANNz code. Color-Magnitude Diagrams (CMD) were generated for those galaxies clas- sified as cluster members. Clear Red Cluster Sequences (RCS) with a me- dian slopes of -0.03 are observed for all the tree clusters. Based on the RCS best fit, a blue and a red population of galaxies were defined, observ- ing that the color distribution of the cluster [VMF98]045 is well fitted by a double Gaussian function (2 0.2), while the clusters [VMF98]046 and [VMF98]113 presents a third population between the blue and red peak dis- tributions. These preliminary results would show the existence of a possible transi- tion population between the blue and the red population in these low mass galaxy clusters at low redshifts.

  3. Small-scale Conformity of the Virgo Cluster Galaxies

    NASA Astrophysics Data System (ADS)

    Lee, Hye-Ran; Lee, Joon Hyeop; Jeong, Hyunjin; Park, Byeong-Gon

    2016-06-01

    We investigate the small-scale conformity in color between bright galaxies and their faint companions in the Virgo Cluster. Cluster member galaxies are spectroscopically determined using the Extended Virgo Cluster Catalog and the Sloan Digital Sky Survey Data Release 12. We find that the luminosity-weighted mean color of faint galaxies depends on the color of adjacent bright galaxy as well as on the cluster-scale environment (gravitational potential index). From this result for the entire area of the Virgo Cluster, it is not distinguishable whether the small-scale conformity is genuine or if it is artificially produced due to cluster-scale variation of galaxy color. To disentangle this degeneracy, we divide the Virgo Cluster area into three sub-areas so that the cluster-scale environmental dependence is minimized: A1 (central), A2 (intermediate), and A3 (outermost). We find conformity in color between bright galaxies and their faint companions (color-color slope significance S ˜ 2.73σ and correlation coefficient {cc}˜ 0.50) in A2, where the cluster-scale environmental dependence is almost negligible. On the other hand, the conformity is not significant or very marginal (S ˜ 1.75σ and {cc}˜ 0.27) in A1. The conformity is not significant either in A3 (S ˜ 1.59σ and {cc}˜ 0.44), but the sample size is too small in this area. These results are consistent with a scenario in which the small-scale conformity in a cluster is a vestige of infallen groups and these groups lose conformity as they come closer to the cluster center.

  4. Galaxies in x-ray selected clusters and groups in Dark Energy Survey Data I: Stellar mass growth of bright central galaxies since Z similar to 1.2

    SciTech Connect

    Zhang, Y.; Miller, C.; McKay, T.; Rooney, P.; Evrard, A. E.; Romer, A. K.; Perfecto, R.; Song, J; Desai, S.; Mohr, J. J.; Vikram, V.

    2016-01-10

    Using the science verification data of the Dark Energy Survey for a new sample of 106 X-ray selected clusters and groups, we study the stellar mass growth of bright central galaxies (BCGs) since redshift z similar to 1.2. Compared with the expectation in a semi-analytical model applied to the Millennium Simulation, the observed BCGs become under-massive/under-luminous with decreasing redshift. We incorporate the uncertainties associated with cluster mass, redshift, and BCG stellar mass measurements into an analysis of a redshift-dependent BCG-cluster mass relation, m(*) proportional to (M-200/1.5 x 10(14)M(circle dot))(0.24 +/- 0.08)(1+z)(-0.19 +/- 0.34), and compare the observed relation to the model prediction. We estimate the average growth rate since z = 1.0 for BCGs hosted by clusters of M-200,M-z = 10(13.8)M(circle dot); at z = 1.0: m(*, BCG) appears to have grown by 0.13 +/- 0.11 dex, in tension at the similar to 2.5 sigma significance level with the 0.40 dex growth rate expected from the semi-analytic model. We show that the build-up of extended intracluster light after z = 1.0 may alleviate this tension in BCG growth rates.

  5. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Cosmological implications of the Fourier space wedges of the final sample

    NASA Astrophysics Data System (ADS)

    Grieb, Jan Niklas; Sánchez, Ariel G.; Salazar-Albornoz, Salvador; Scoccimarro, Román; Crocce, Martín; Dalla Vecchia, Claudio; Montesano, Francesco; Gil-Marín, Héctor; Ross, Ashley J.; Beutler, Florian; Rodríguez-Torres, Sergio; Chuang, Chia-Hsun; Prada, Francisco; Kitaura, Francisco-Shu; Cuesta, Antonio J.; Eisenstein, Daniel J.; Percival, Will J.; Vargas-Magaña, Mariana; Tinker, Jeremy L.; Tojeiro, Rita; Brownstein, Joel R.; Maraston, Claudia; Nichol, Robert C.; Olmstead, Matthew D.; Samushia, Lado; Seo, Hee-Jong; Streblyanska, Alina; Zhao, Gong-bo

    2017-01-01

    We extract cosmological information from the anisotropic power spectrum measurements from the recently completed Baryon Oscillation Spectroscopic Survey (BOSS), extending the concept of clustering wedges to Fourier space. Making use of new FFT-based estimators, we measure the power spectrum clustering wedges of the BOSS sample by filtering out the information of Legendre multipoles ℓ > 4. Our modelling of these measurements is based on novel approaches to describe non-linear evolution, bias, and redshift-space distortions, which we test using synthetic catalogues based on large-volume N-body simulations. We are able to include smaller scales than in previous analyses, resulting in tighter cosmological constraints. Using three overlapping redshift bins, we measure the angular diameter distance, the Hubble parameter, and the cosmic growth rate, and explore the cosmological implications of our full shape clustering measurements in combination with CMB and SN Ia data. Assuming a ΛCDM cosmology, we constrain the matter density to Ω M= 0.311_{-0.010}^{+0.009} and the Hubble parameter to H_0 = 67.6_{-0.6}^{+0.7} km s^{-1} Mpc^{-1}, at a confidence level (CL) of 68 per cent. We also allow for non-standard dark energy models and modifications of the growth rate, finding good agreement with the ΛCDM paradigm. For example, we constrain the equation-of-state parameter to w = -1.019_{-0.039}^{+0.048}. This paper is part of a set that analyses the final galaxy clustering dataset from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. (2016) to produce the final cosmological constraints from BOSS.

  6. New Ultra-Compact Dwarf Galaxies in Clusters

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2017-02-01

    How do ultra-compact dwarf galaxies (UCDs) galaxies that are especially small and dense form and evolve? Scientists have recently examined distant galaxy clusters, searching for more UCDs to help us answer this question.Origins of DwarfsIn recent years we have discovered a growing sample of small, very dense galaxies. Galaxies that are tens to hundreds of light-years across, with masses between a million and a billion solar masses, fall into category of ultra-compact dwarfs (UCDs).An example of an unresolved compact object from the authors survey that is likely an ultra-compact dwarf galaxy. [Adapted from Zhang Bell 2017]How do these dense and compact galaxies form? Two possibilities are commonly suggested:An initially larger galaxy was tidally stripped during interactions with other galaxies in a cluster, leaving behind only its small, dense core as a UCD.UCDs formed as compact galaxies at very early cosmic times. The ones living in a massive dark matter halo may have been able to remain compact over time, evolving into the objectswe see today.To better understand which of these formation scenarios applies to which galaxies, we need a larger sample size! Our census of UCDs is fairly limited and because theyare small and dim, most of the ones weve discovered are in the nearby universe. To build a good sample, we need to find UCDs at higher redshifts as well.A New SampleIn a recent study, two scientists from University of Michigan have demonstrated how we might find more UCDs. Yuanyuan Zhang (also affiliated with Fermilab) and Eric Bell used the Cluster Lensing and Supernova Survey with Hubble (CLASH) to search 17 galaxy clusters at intermediate redshifts of 0.2 z 0.6, looking for unresolved objects that might be UCDs.The mass and size distributions of the UCD candidates reported in this study, in the context of previously known nuclear star clusters, globular clusters (GCs), UCDs, compact elliptical galaxies (cEs), and dwarf galaxies. [Zhang Bell 2017]Zhang and

  7. STAR FORMATION AND RELAXATION IN 379 NEARBY GALAXY CLUSTERS

    SciTech Connect

    Cohen, Seth A.; Hickox, Ryan C.; Wegner, Gary A.

    2015-06-10

    We investigate the relationship between star formation (SF) and level of relaxation in a sample of 379 galaxy clusters at z < 0.2. We use data from the Sloan Digital Sky Survey to measure cluster membership and level of relaxation, and to select star-forming galaxies based on mid-infrared emission detected with the Wide-Field Infrared Survey Explorer. For galaxies with absolute magnitudes M{sub r} < −19.5, we find an inverse correlation between SF fraction and cluster relaxation: as a cluster becomes less relaxed, its SF fraction increases. Furthermore, in general, the subtracted SF fraction in all unrelaxed clusters (0.117 ± 0.003) is higher than that in all relaxed clusters (0.097 ± 0.005). We verify the validity of our SF calculation methods and membership criteria through analysis of previous work. Our results agree with previous findings that a weak correlation exists between cluster SF and dynamical state, possibly because unrelaxed clusters are less evolved relative to relaxed clusters.

  8. Cosmology with EMSS Clusters of Galaxies

    NASA Technical Reports Server (NTRS)

    Donahue, Megan; Voit, G. Mark

    1999-01-01

    We use ASCA observations of the Extended Medium Sensitivity Survey sample of clusters of galaxies to construct the first z = 0.5 - 0.8 cluster temperature function. This distant cluster temperature function, when compared to local z approximately 0 and to a similar moderate redshift (z = 0.3 - 0.4) temperature function strongly constrains the matter density of the universe. Best fits to the distributions of temperatures and redshifts of these cluster samples results in Omega(sub M) = 0.45 +/- 0.1 if Lambda = 0 and Omega = 0.27 +/- 0.1 if Lambda + Omega(sub M) = 1. The uncertainties are 1sigma statistical. We examine the systematics of our approach and find that systematics, stemming mainly from model assumptions and not measurement errors, are about the same size as the statistical uncertainty +/- 0.1. In this poster proceedings, we clarify the issue of a8 as reported in our paper Donahue & Voit (1999), since this was a matter of discussion at the meeting.

  9. Brightest cluster galaxies in the extended GMRT radio halo cluster sample. Radio properties and cluster dynamics

    NASA Astrophysics Data System (ADS)

    Kale, R.; Venturi, T.; Cassano, R.; Giacintucci, S.; Bardelli, S.; Dallacasa, D.; Zucca, E.

    2015-09-01

    Aims: First-ranked galaxies in clusters, usually referred to as brightest cluster galaxies (BCGs), show exceptional properties over the whole electromagnetic spectrum. They are the most massive elliptical galaxies and show the highest probability to be radio loud. Moreover, their special location at the centres of galaxy clusters raises the question of the role of the environment in shaping their radio properties. In the attempt to separate the effect of the galaxy mass and of the environment on their statistical radio properties, we investigate the possible dependence of the occurrence of radio loudness and of the fractional radio luminosity function on the dynamical state of the hosting cluster. Methods: We studied the radio properties of the BCGs in the Extended GMRT Radio Halo Survey (EGRHS), which consists of 65 clusters in the redshift range 0.2-0.4, with X-ray luminosity LX ≥ 5 × 1044 erg s-1, and quantitative information on their dynamical state from high-quality Chandra imaging. We obtained a statistical sample of 59 BCGs, which we divided into two classes, depending on whether the dynamical state of the host cluster was merging (M) or relaxed (R). Results: Of the 59 BCGs, 28 are radio loud and 31 are radio quiet. The radio-loud sources are favourably located in relaxed clusters (71%), while the reverse is true for the radio-quiet BCGs, which are mostly located in merging systems (81%). The fractional radio luminosity function for the BCGs in merging and relaxed clusters is different, and it is considerably higher for BCGs in relaxed clusters, where the total fraction of radio loudness reaches almost 90%, to be compared to the ~30% in merging clusters. For relaxed clusters, we found a positive correlation between the radio power of the BCGs and the strength of the cool core, consistent with previous studies on local samples. Conclusions: Our study suggests that the radio loudness of the BCGs strongly depends on the cluster dynamics; their fraction is

  10. Globular Cluster Systems in Brightest Cluster Galaxies. II. NGC 6166

    NASA Astrophysics Data System (ADS)

    Harris, William E.; Blakeslee, John P.; Whitmore, Bradley C.; Gnedin, Oleg Y.; Geisler, Douglas; Rothberg, Barry

    2016-01-01

    We present new deep photometry of the globular cluster system (GCS) around NGC 6166, the central supergiant galaxy in Abell 2199. Hubble Space Telescope data from the Advanced Camera for Surveys and WFC3 cameras in F475W and F814W are used to determine the spatial distribution of the GCS, its metallicity distribution function (MDF), and the dependence of the MDF on galactocentric radius and on GC luminosity. The MDF is extremely broad, with the classic red and blue subpopulations heavily overlapped, but a double-Gaussian model can still formally match the MDF closely. The spatial distribution follows a Sérsic-like profile detectably to a projected radius of at least Rgc = 250 kpc. To that radius, the total number of clusters in the system is NGC = 39000 ± 2000, the global specific frequency is SN = 11.2 ± 0.6, and 57% of the total are blue, metal-poor clusters. The GCS may fade smoothly into the intracluster medium (ICM) of A2199; we see no clear transition from the core of the galaxy to the cD halo or the ICM. The radial distribution, projected ellipticity, and mean metallicity of the red (metal-richer) clusters match the halo light extremely well for {R}{gc}≳ 15 {{kpc}}, both of them varying as {σ }{MRGC}∼ {σ }{light}∼ {R}-1.8. By comparison, the blue (metal-poor) GC component has a much shallower falloff {σ }{MPGC}∼ {R}-1.0 and a more nearly spherical distribution. This strong difference in their density distributions produces a net metallicity gradient in the GCS as a whole that is primarily generated by the population gradient. With NGC 6166 we appear to be penetrating into a regime of high enough galaxy mass and rich enough environment that the bimodal two-phase description of GC formation is no longer as clear or effective as it has been in smaller galaxies.

  11. The Morphologies and Alignments of Gas, Mass, and the Central Galaxies of CLASH Clusters of Galaxies

    NASA Astrophysics Data System (ADS)

    Donahue, Megan; Ettori, Stefano; Rasia, Elena; Sayers, Jack; Zitrin, Adi; Meneghetti, Massimo; Voit, G. Mark; Golwala, Sunil; Czakon, Nicole; Yepes, Gustavo; Baldi, Alessandro; Koekemoer, Anton; Postman, Marc

    2016-03-01

    Morphology is often used to infer the state of relaxation of galaxy clusters. The regularity, symmetry, and degree to which a cluster is centrally concentrated inform quantitative measures of cluster morphology. The Cluster Lensing and Supernova survey with Hubble Space Telescope (CLASH) used weak and strong lensing to measure the distribution of matter within a sample of 25 clusters, 20 of which were deemed to be “relaxed” based on their X-ray morphology and alignment of the X-ray emission with the Brightest Cluster Galaxy. Toward a quantitative characterization of this important sample of clusters, we present uniformly estimated X-ray morphological statistics for all 25 CLASH clusters. We compare X-ray morphologies of CLASH clusters with those identically measured for a large sample of simulated clusters from the MUSIC-2 simulations, selected by mass. We confirm a threshold in X-ray surface brightness concentration of C ≳ 0.4 for cool-core clusters, where C is the ratio of X-ray emission inside 100 h70-1 kpc compared to inside 500 {h}70-1 kpc. We report and compare morphologies of these clusters inferred from Sunyaev-Zeldovich Effect (SZE) maps of the hot gas and in from projected mass maps based on strong and weak lensing. We find a strong agreement in alignments of the orientation of major axes for the lensing, X-ray, and SZE maps of nearly all of the CLASH clusters at radii of 500 kpc (approximately 1/2 R500 for these clusters). We also find a striking alignment of clusters shapes at the 500 kpc scale, as measured with X-ray, SZE, and lensing, with that of the near-infrared stellar light at 10 kpc scales for the 20 “relaxed” clusters. This strong alignment indicates a powerful coupling between the cluster- and galaxy-scale galaxy formation processes.

  12. Radio Selected Clusters of Galaxies at High Redshift

    NASA Astrophysics Data System (ADS)

    Wing, Joshua; Blanton, Elizabeth

    2010-08-01

    Previous studies have shown that three-component radio sources exhibiting some degree of bending between components are likely to be found in galaxy clusters. Often this radio emission is associated with a cD type galaxy at the center of a cluster. We have cross-correlated the Sloan Digital Sky Survey (SDSS) with samples selected from the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) catalog and measured the richness of the cluster environments surrounding three- component sources exhibiting both bent and straight lobes. This has lead to the discovery and classification of a large number of galaxy clusters out to a redshift of z ~ 0.5. For both bent- and straight- lobed sources without an optical counterpart it is likely that the radio emission is associated with a galaxy fainter than m_r=22 (the limiting magnitude of the SDSS) and at a redshift higher than z~0.8. We propose to observe a small sub-sample of these sources with the FLAMINGOS instrument on the Mayall 4-m telescope in an attempt to discover if these sources are located in high redshift (z≳0.8) galaxy clusters. In our visually-selected bent radio source sample, 78% of sources with counterparts in the SDSS are associated with clusters.

  13. Gaussian covariance matrices for anisotropic galaxy clustering measurements

    NASA Astrophysics Data System (ADS)

    Grieb, Jan Niklas; Sánchez, Ariel G.; Salazar-Albornoz, Salvador; Dalla Vecchia, Claudio

    2016-04-01

    Measurements of the redshift-space galaxy clustering have been a prolific source of cosmological information in recent years. Accurate covariance estimates are an essential step for the validation of galaxy clustering models of the redshift-space two-point statistics. Usually, only a limited set of accurate N-body simulations is available. Thus, assessing the data covariance is not possible or only leads to a noisy estimate. Further, relying on simulated realizations of the survey data means that tests of the cosmology dependence of the covariance are expensive. With these points in mind, this work presents a simple theoretical model for the linear covariance of anisotropic galaxy clustering observations with synthetic catalogues. Considering the Legendre moments (`multipoles') of the two-point statistics and projections into wide bins of the line-of-sight parameter (`clustering wedges'), we describe the modelling of the covariance for these anisotropic clustering measurements for galaxy samples with a trivial geometry in the case of a Gaussian approximation of the clustering likelihood. As main result of this paper, we give the explicit formulae for Fourier and configuration space covariance matrices. To validate our model, we create synthetic halo occupation distribution galaxy catalogues by populating the haloes of an ensemble of large-volume N-body simulations. Using linear and non-linear input power spectra, we find very good agreement between the model predictions and the measurements on the synthetic catalogues in the quasi-linear regime.

  14. The Formation of Galaxies and Clusters.

    ERIC Educational Resources Information Center

    Gregory, Stephen; Morrison, Nancy D.

    1985-01-01

    Summarizes recent research on the formation of galaxies and clusters, focusing on research examining how the materials in galaxies seen today separated from the universal expansion and collapsed into stable bodies. A list of six nontechnical books and articles for readers with less background is included. (JN)

  15. Arms pattern speed of galaxies in clusters

    NASA Astrophysics Data System (ADS)

    Rodrigues, I.; Dottori, H.; Reichert, D.

    We aim to study arm pattern speed and consequently pattern resonances in galaxies of clusters. If the perturbation of cluster galaxies is mainly produced by the interaction with the cluster ambient the pattern speed might well depend on the history of the galaxy orbit within the cluster. We are trying to determine if this constrain exist. We use published data cube of HII regions velocity fields (Asram et al. 1992, Garrido et al. 2004, 2005) and 2-mass images to apply the Tremaine-Weinberg (1984)method to determine pattern speed in barred galaxies. The use of a 2-mass image to obtain the galaxies brightness distribution is justified since it traces the distribution of disk stars and consequently the position of the original perturbation that influence the velocity field of all the matter, including that of the HII regions. First results for the Pegasus cluster indicates that NGC 7536 and NGC 7593 present pattern speeds Ω_p= 26±3 km/sec/kpc and 41±4km/sec/kpc with correlation coefficient of 0.97 and 0.99 respectively. A third galaxy, NGC 7643, presents a quite noisy vs , that does not allow to determine a reliable pattern speed, indicating probably that the perturbation is to weak in this galaxy as to be detected with T-W method.

  16. Galaxy Population in the Infall Regions of Intermediate Redshift Clusters

    NASA Astrophysics Data System (ADS)

    Verdugo, Miguel; Ziegler, Bodo L.

    2007-05-01

    We investigate 6 clusters of galaxies at intermediate redshift (0.18galaxies. Our Calar Alto MOSCA spectra cover large fields of view reaching out to 2-4 virial radii. This outer region is often called the infall region since here newly arriving galaxies from the surrounding field encounter the special environment of clusters for the first time. We selected 3 fields containing 2 clusters each from the X-ray Dark Cluster Survey (XDC, Gilbank et al. 2004 MNRAS, 348, 551G, G04). Each 40'x 40' field was observed with 7-8 slit-masks yielding 553 low-resolution galaxy spectra (R≈500). The results for the first field (R285) were already published by Gerken et al. (2004A&A, 421, 59G). We select [OII]λ3717 and Hα equivalent widths as indicators of star formation activity. In the analysis, we "averaged" 4 clusters: VMF73 (z=0.254) & VMF74 (z=0.18) in XDCS field R285 and VMF131 (z=0.295) & VMF132 (z=0.246) in field R265. We have found an increase of the star forming activity towards larger cluster-centric distances as well as towards shallower projected galaxy densities. Galaxies in the third field R220 exhibit a complex redshift structure which makes membership determination difficulty and were excluded of the overall analysis. However, we clearly identified the cluster VMF194 (z=0.211) and confirm another cluster at z=0.261 detected by G04. In addition, a group of galaxies with similar coordinates to VMF194 at z=0.243 is significant. We also detected a population of red star-forming galaxies, belonging to the red-sequence of the clusters and even redder. Those galaxies show a moderate star-forming activity and do not show any other spectral peculiarities. We do not detect any post-starburst galaxy nor AGN in our cluster sample.

  17. Galaxy Recycling in the Centaurus Cluster

    NASA Astrophysics Data System (ADS)

    Gregg, M. D.; West, M. J.

    2002-12-01

    The Centaurus cluster of galaxies contains a spectacular example of galaxy destruction and recycling, a giant plume of stellar debris over 100 kpc in length and ~ 15 kpc wide. We have obtained HST/WFPC2 V and I band images of a tiny portion of the Centaurus plume. A highly significant excess of objects is detected in the plume, compared to surrounding regions. The excess objects, assuming they are in Centaurus, range from -6 > MV> -12, providing evidence that globular clusters and dwarf galaxies can be born from tidal debris in rich galaxy clusters, just as is known to occur in field galaxy tidal interactions. Over time, the recycled debris from many such disruption events augments the intracluster population of stars, clusters, dwarf galaxies, and gas, and is a major driver of the global evolution of the cluster. We will also discuss our deep u'g'r'i'z' multicolor images of Centaurus, obtained with the CTIO 4m 8K Mosaic to investigate the entire plume and enabling a cluster-wide search for additional tidal debris to very faint levels. We acknowledge financial support from the National Science Foundation and the Space Telescope Science Institute. Part of this work was done at the Institute of Geophysics and Planetary Physics, under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

  18. Featured Image: A Galaxy Plunges Into a Cluster Core

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-10-01

    The galaxy that takes up most of the frame in this stunning image (click for the full view!) is NGC 1427A. This is a dwarf irregular galaxy (unlike the fortuitously-located background spiral galaxy in the lower right corner of the image), and its currently in the process of plunging into the center of the Fornax galaxy cluster. Marcelo Mora (Pontifical Catholic University of Chile) and collaborators have analyzed observations of this galaxy made by both the Very Large Telescope in Chile and the Hubble Advanced Camera for Surveys, which produced the image shown here as a color composite in three channels. The team worked to characterize the clusters of star formation within NGC 1427A identifiable in the image as bright knots within the galaxy and determine how the interactions of this galaxy with its cluster environment affect the star formation within it. For more information and the original image, see the paper below.Citation:Marcelo D. Mora et al 2015 AJ 150 93. doi:10.1088/0004-6256/150/3/93

  19. The Distances to Nearby Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Scodeggio, Marco

    1997-12-01

    The properties of the Fundamental Plane (FP) of E and S0 galaxies are analyzed using a sample of early-type galaxies in s nearby clusters of galaxies. I band CCD observations are presented for 631 galaxies in the A262, Cancer, A1367, Coma, Pegasus, and A2634 clusters, and in the NGC 383 and NGC 507 groups. Medium dispersion spectroscopic observations are presented for a sub-set composed of 212 galaxies. Combining this data-set with data taken from the literature, gives a FP sample of 294 galaxies. The clusters are chosen to span as large as possible a range of environmental conditions, from a rich, relaxed, X-ray luminous cluster like Coma, to rather poor groups of galaxies like the NGC 383 group. They are also chosen among the clusters that have the largest available samples of Tully-Fisher (TF) measurements, to allow an accurate comparison of the distance scales obtained using the FP and TF relations independently. Both selection criteria are aimed at quantifying the possible presence of environmental effects on the FP relation. The scatter observed around the FP template implies that the distance to a single galaxy can be obtained, using the FP, with a 22% uncertainty (a 0.48 mag uncertainty on the galaxy distance modulus). The peculiar velocity estimates for the 8 clusters in the sample are all small, consistent with the clusters being at rest in the Cosmic Microwave Background reference frame. Monte Carlo simulations are used to quantify the effects of sample selection and measurement uncertainties on the FP template, and correct the resulting biases. After these corrections are applied, it is found that the properties of the FP do not change significantly as a function of the cluster richness, or as a function of the galaxy position within the cluster. Moreover there is very good agreement between the distance measurements obtained using the FP relation, and those obtained using the TF relation. These results are used to derive an upper limit of 5% on

  20. QSO clustering - II. The correlation function of IRAS seyfert galaxies.

    NASA Astrophysics Data System (ADS)

    Georgantopoulos, I.; Shanks, T.

    1994-12-01

    We investigate the clustering properties of 192 Seyfert galaxies from the IRAS all-sky survey. Using the spatial correlation function, we detect evidence of Seyfert clustering at the 2σ confidence level at < 10 h^-1^ Mpc separations, and at the 3{SIGMA} level at < 20 h^-1^ Mpc separations. Comparison of the QSO correlation function amplitude at high redshifts, z = 1.4, with that of Seyferts below 10 h^-1^ comoving Mpc leads us to reject the stable model of AGN clustering evolution at the 4σ level, whereas a comoving model where QSOs randomly sample the galaxy distribution is more consistent. The main uncertainty here now lies in the statistical error on the amplitude of the clustering in the faint QSO surveys at z = 1.4. The Seyfert-QDOT cross-correlation function is measured to be approximately a factor of 2 higher than the QDOT galaxy autocorrelation function, suggesting an enhanced environment for Seyferts with respect to IRAS galaxies, but it is not clear whether this is also the case with respect to optical galaxies. We conclude that the comoving model is probably favoured overall, at least on the r < 10 h^-1^ Mpc scales investigated here, but it is not yet possible to rule out intermediate models: for example, an enhanced-environment, stable model with ξ(r)=(r/3)^-1.8^ at z = 1.4, which is statistically consistent with the faint QSO data.

  1. Comparing the clustering of galaxies and galaxy group by using the SDSS DR7

    NASA Astrophysics Data System (ADS)

    Wang, Yiran; Brunner, R. J.

    2014-01-01

    By using the angular two-point correlation function, we measure the clustering strength of a clean sample of galaxies (explored in Wang, Brunner, & Dolence 2013) for the Sloan Digital Sky Survey Data Release Seven. By using these same data, we first find isolated pairs, triplets, quads, and larger groups of galaxies, and subsequently measure the clustering of these subsamples. We find the clustering strength increases with groups size, which supports the halo model of galaxy clustering and demonstrates the efficacy of our isolated group catalog for general studies such as the galaxy merger rate. Finally, we explore the effects of galaxy spectral type and photometric redshift on the clustering behavior of these galaxy group samples. References: Blake, C., Collister, A., Lahav, O. 2008, MNRAS, 385, 1257 Hickson, P. 1982, ApJ, 255, 382 Ross, A. J., Brunner, R. J. 2009, MNRAS, 399, 878 Wang Y., Brunner R. J., Dolence J. C. 2013, MNRAS, 432, 1961 Zehavi, I., et al. 2004, ApJ, 608, 16

  2. THE ATACAMA COSMOLOGY TELESCOPE: SUNYAEV-ZEL'DOVICH-SELECTED GALAXY CLUSTERS AT 148 GHz IN THE 2008 SURVEY

    SciTech Connect

    Marriage, Tobias A.; Acquaviva, Viviana; Das, Sudeep; Dunkley, Joanna; Ade, Peter A. R.; Aguirre, Paula; Barrientos, L. Felipe; Duenner, Rolando; Amiri, Mandana; Battistelli, Elia S.; Burger, Bryce; Appel, John William; Essinger-Hileman, Thomas; Fisher, Ryan P.; Bond, J. Richard; Brown, Ben; Chervenak, Jay; Doriese, W. Bertrand

    2011-08-20

    We report on 23 clusters detected blindly as Sunyaev-ZEL'DOVICH (SZ) decrements in a 148 GHz, 455 deg{sup 2} map of the southern sky made with data from the Atacama Cosmology Telescope 2008 observing season. All SZ detections announced in this work have confirmed optical counterparts. Ten of the clusters are new discoveries. One newly discovered cluster, ACT-CL J0102-4915, with a redshift of 0.75 (photometric), has an SZ decrement comparable to the most massive systems at lower redshifts. Simulations of the cluster recovery method reproduce the sample purity measured by optical follow-up. In particular, for clusters detected with a signal-to-noise ratio greater than six, simulations are consistent with optical follow-up that demonstrated this subsample is 100% pure. The simulations further imply that the total sample is 80% complete for clusters with mass in excess of 6 x 10{sup 14} solar masses referenced to the cluster volume characterized by 500 times the critical density. The Compton y-X-ray luminosity mass comparison for the 11 best-detected clusters visually agrees with both self-similar and non-adiabatic, simulation-derived scaling laws.

  3. The Atacama Cosmology Telescope: Sunyaev-Zel'dovich-Selected Galaxy Clusters AT 148 GHz in the 2008 Survey

    NASA Technical Reports Server (NTRS)

    Marriage, Tobias A.; Acquaviva, Viviana; Ade, Peter A. R.; Aguirre, Paula; Amiri, Mandana; Appel, John William; Barrientos, L. Felipe; Battistelli, Elia S.; Bond, J. Richard; Brown, Ben; Burger, Bryce; Chervenak, Jay; Das, Sudeep; Devlin, Mark J.; Dicker, Simon R.; Doriese, W. Bertrand; Dunkley, Joanna; Dunner, Rolando; Essinger-Hileman, Thomas; Fisher, Ryan P.; Fowler, Joseph W.; Hajian, Amir; Halpern, Mark; Moseley, Harvey; Wollack, Ed

    2011-01-01

    We report on 23 clusters detected blindly as Sunyaev-Zel'dovich (SZ) decrements in a 148 GHz, 455 deg (exp 2) map of the southern sky made with data from the Atacama Cosmology Telescope 2008 observing season. All SZ detections announced in this work have confirmed optical counterparts. Ten of the clusters are new discoveries. One newly discovered cluster, ACT-CL 10102-4915, with a redshift of 0.75 (photometric), has an SZ decrement comparable to the most massive systems at lower redshifts. Simulations of the cluster recovery method reproduce the sample purity measured by optical follow-up. In particular, for clusters detected with a signal-to-noise ratio greater than six, simulations are consistent with optical follow-up that demonstrated this subsample is 100% pure, The simulations further imply that the total sample is 80% complete for clusters with mass in excess of 6 x 10(exp 14) solar masses referenced to the cluster volume characterized by 500 times the critical density. The Compton gamma-X-ray luminosity mass comparison for the 11 best-detected clusters visually agrees with both self-similar and non-adiabatic, simulation-derived scaling laws,

  4. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: baryon acoustic oscillations in the Fourier space

    NASA Astrophysics Data System (ADS)

    Beutler, Florian; Seo, Hee-Jong; Ross, Ashley J.; McDonald, Patrick; Saito, Shun; Bolton, Adam S.; Brownstein, Joel R.; Chuang, Chia-Hsun; Cuesta, Antonio J.; Eisenstein, Daniel J.; Font-Ribera, Andreu; Grieb, Jan Niklas; Hand, Nick; Kitaura, Francisco-Shu; Modi, Chirag; Nichol, Robert C.; Percival, Will J.; Prada, Francisco; Rodriguez-Torres, Sergio; Roe, Natalie A.; Ross, Nicholas P.; Salazar-Albornoz, Salvador; Sánchez, Ariel G.; Schneider, Donald P.; Slosar, Anže; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magaña, Mariana; Vazquez, Jose A.

    2017-01-01

    We analyse the baryon acoustic oscillation (BAO) signal of the final Baryon Oscillation Spectroscopic Survey (BOSS) data release (DR12). Our analysis is performed in the Fourier space, using the power spectrum monopole and quadrupole. The data set includes 1198 006 galaxies over the redshift range 0.2 < z < 0.75. We divide this data set into three (overlapping) redshift bins with the effective redshifts zeff = 0.38, 0.51 and 0.61. We demonstrate the reliability of our analysis pipeline using N-body simulations as well as ˜1000 MultiDark-Patchy mock catalogues that mimic the BOSS-DR12 target selection. We apply density field reconstruction to enhance the BAO signal-to-noise ratio. By including the power spectrum quadrupole we can separate the line of sight and angular modes, which allows us to constrain the angular diameter distance DA(z) and the Hubble parameter H(z) separately. We obtain two independent 1.6 and 1.5 per cent constraints on DA(z) and 2.9 and 2.3 per cent constraints on H(z) for the low (zeff = 0.38) and high (zeff = 0.61) redshift bin, respectively. We obtain two independent 1 and 0.9 per cent constraints on the angular averaged distance DV(z), when ignoring the Alcock-Paczynski effect. The detection significance of the BAO signal is of the order of 8σ (post-reconstruction) for each of the three redshift bins. Our results are in good agreement with the Planck prediction within Λ cold dark matter. This paper is part of a set that analyses the final galaxy clustering data set from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. to produce the final cosmological constraints from BOSS.

  5. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in Fourier-space

    SciTech Connect

    Beutler, Florian; Seo, Hee -Jong; Ross, Ashley J.; McDonald, Patrick; Saito, Shun; Bolton, Adam S.; Joel R. Brownstein; Chuang, Chia -Hsun; Cuesta, Antonio J.; Eisenstein, Daniel J.; Font-Ribera, Andreu; Grieb, Jan Niklas; Hand, Nick; Kitaura, Francisco -Shu; Modi, Chirag; Nichol, Robert C.; Percival, Will J.; Prada, Francisco; Rodriguez-Torres, Sergio; Roe, Natalie A.; Ross, Nicholas P.; Salazar-Albornoz, Salvador; Sanchez, Ariel G.; Schneider, Donald P.; Slosar, Anze; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana; Vazquez, Jose A.

    2016-07-13

    Here, we analyse the Baryon Acoustic Oscillation (BAO) signal of the final Baryon Oscillation Spectroscopic Survey (BOSS) data release (DR12). Our analysis is performed in Fourier-space, using the power spectrum monopole and quadrupole. The dataset includes 1 198 006 galaxies over the redshift range 0.2 < z < 0.75. We divide this dataset into three (overlapping) redshift bins with the effective redshifts zeff = 0.38, 0.51 and 0.61. We demonstrate the reliability of our analysis pipeline using N-body simulations as well as 1000 MultiDark-Patchy mock catalogues, which mimic the BOSS-DR12 target selection. We apply density eld reconstruction to enhance the BAO signal-to-noise ratio. By including the power spectrum quadrupole we can sep-arate the line-of-sight and angular modes, which allows us to constrain the angular diameter distance DA(z) and the Hubble parameter H ( z ) separately. We obtain two independent 1 : 6% and 1 : 5% constraints on DA(z) and 2.9% and 2.3% constraints on H(z) for the low (zeff = 0.38) and high (zeff = 0.61) redshift bin, respectively. We obtain two independent 1% and 0.9% constraints on the angular averaged distance DV(z), when ignoring the Alcock-Paczynski e ect. The detection significance of the BAO signal is of the order of 8σ (post-reconstruction) for each of the three redshift bins. Our results are in good agreement with the Planck prediction within CDM. This paper is part of a set that analyses the final galaxy clustering dataset from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. (2016) to produce the final cosmological constraints from BOSS.

  6. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in Fourier-space

    DOE PAGES

    Beutler, Florian; Seo, Hee -Jong; Ross, Ashley J.; ...

    2016-07-13

    Here, we analyse the Baryon Acoustic Oscillation (BAO) signal of the final Baryon Oscillation Spectroscopic Survey (BOSS) data release (DR12). Our analysis is performed in Fourier-space, using the power spectrum monopole and quadrupole. The dataset includes 1 198 006 galaxies over the redshift range 0.2 < z < 0.75. We divide this dataset into three (overlapping) redshift bins with the effective redshifts zeff = 0.38, 0.51 and 0.61. We demonstrate the reliability of our analysis pipeline using N-body simulations as well as 1000 MultiDark-Patchy mock catalogues, which mimic the BOSS-DR12 target selection. We apply density eld reconstruction to enhance themore » BAO signal-to-noise ratio. By including the power spectrum quadrupole we can sep-arate the line-of-sight and angular modes, which allows us to constrain the angular diameter distance DA(z) and the Hubble parameter H ( z ) separately. We obtain two independent 1 : 6% and 1 : 5% constraints on DA(z) and 2.9% and 2.3% constraints on H(z) for the low (zeff = 0.38) and high (zeff = 0.61) redshift bin, respectively. We obtain two independent 1% and 0.9% constraints on the angular averaged distance DV(z), when ignoring the Alcock-Paczynski e ect. The detection significance of the BAO signal is of the order of 8σ (post-reconstruction) for each of the three redshift bins. Our results are in good agreement with the Planck prediction within CDM. This paper is part of a set that analyses the final galaxy clustering dataset from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. (2016) to produce the final cosmological constraints from BOSS.« less

  7. Characterizing galaxy clusters with gravitational potential

    NASA Astrophysics Data System (ADS)

    Lau, Erwin Tin-Hay

    2010-11-01

    We propose a simple estimator for the gravitational potential of cluster-size halos using the temperature and density profiles of the intracluster gas based on the assumptions of hydro-static equilibrium and spherical symmetry. Using high resolution cosmological simulations of galaxy clusters, we show that the scaling relation between this estimator and the gravitational potential has a small intrinsic scatter of ˜ 10%, and it is insensitive to baryon physics outside the cluster core. The slope and the normalization of the scaling relation vary weakly with redshift, and they are relatively independent of the choice of radial range used and the dynamical states of the clusters. The results presented here provide a way for using the cluster potential function as an alternative to the cluster mass function in constraining cosmology using galaxy clusters.

  8. The Dynamical Equilibrium of Galaxy Clusters

    NASA Astrophysics Data System (ADS)

    Carlberg, R. G.; Yee, H. K. C.; Ellingson, E.; Morris, S. L.; Abraham, R.; Gravel, P.; Pritchet, C. J.; Smecker-Hane, T.; Hartwick, F. D. A.; Hesser, J. E.; Hutchings, J. B.; Oke, J. B.

    1997-02-01

    If a galaxy cluster is effectively in dynamical equilibrium, then all galaxy populations within the cluster must have distributions in velocity and position that individually reflect the same underlying mass distribution, although the derived virial masses can be quite different. Specifically, within the Canadian Network for Observational Cosmology cluster sample, the virial radius of the red galaxy population is, on the average, a factor of 2.05 +/- 0.34 smaller than that of the blue population. The red galaxies also have a smaller rms velocity dispersion, a factor of 1.31 +/- 0.13 within our sample. Consequently, the virial mass calculated from the blue galaxies is 3.5 +/- 1.3 times larger than from the red galaxies. However, applying the Jeans equation of stellar hydrodynamic equilibrium to the red and blue subsamples separately gives statistically identical cluster mass profiles. This is strong evidence that these clusters are effectively equilibrium systems and therefore demonstrates empirically that the masses in the virialized region are reliably estimated using dynamical techniques.

  9. DUST-OBSCURED STAR FORMATION IN INTERMEDIATE REDSHIFT GALAXY CLUSTERS

    SciTech Connect

    Finn, Rose A.; Desai, Vandana; Rudnick, Gregory; Poggianti, Bianca; Bell, Eric F.; Hinz, Joannah; Zaritsky, Dennis; Jablonka, Pascale; Milvang-Jensen, Bo; Moustakas, John; Rines, Kenneth E-mail: jmoustakas@ucsd.ed

    2010-09-01

    We present Spitzer MIPS 24 {mu}m observations of sixteen 0.4 < z < 0.8 galaxy clusters drawn from the ESO Distant Cluster Survey. This is the first large 24 {mu}m survey of clusters at intermediate redshift. The depth of our imaging corresponds to a total IR luminosity of 8 x 10{sup 10} L{sub sun}, just below the luminosity of luminous infrared galaxies (LIRGs), and 6{sup +1}{sub -1}% of M{sub V} < -19 cluster members show 24 {mu}m emission at or above this level. We compare with a large sample of coeval field galaxies and find that while the fraction of cluster LIRGs lies significantly below that of the field, the IR luminosities of the field and cluster galaxies are consistent. However, the stellar masses of the EDisCS LIRGs are systematically higher than those of the field LIRGs. A comparison with optical data reveals that {approx}80% of cluster LIRGs are blue and the remaining 20% lie on the red sequence. Of LIRGs with optical spectra, 88{sup +4} {sub -5}% show [O II] emission with EW([O II]) > 5 A, and {approx}75% exhibit optical signatures of dusty starbursts. On average, the fraction of cluster LIRGs increases with projected clustercentric radius but remains systematically lower than the field fraction over the area probed (<1.5x R {sub 200}). The amount of obscured star formation declines significantly over the 2.4 Gyr interval spanned by the EDisCS sample, and the rate of decline is the same for the cluster and field populations. Our results are consistent with an exponentially declining LIRG fraction, with the decline in the field delayed by {approx}1 Gyr relative to the clusters.

  10. Tidal Stripping of Globular Clusters in a Simulated Galaxy Cluster

    NASA Astrophysics Data System (ADS)

    Ramos, F.; Coenda, V.; Muriel, H.; Abadi, M.

    2015-06-01

    Using a cosmological N-body numerical simulation of the formation of a galaxy-cluster-sized halo, we analyze the temporal evolution of its globular cluster population. We follow the dynamical evolution of 38 galactic dark matter halos orbiting in a galaxy cluster that at redshift z = 0 has a virial mass of 1.71 × 1014 M⊙ h-1. In order to mimic both “blue” and “red” populations of globular clusters, for each galactic halo we select two different sets of particles at high redshift (z ≈ 1), constrained by the condition that, at redshift z = 0, their average radial density profiles are similar to the observed profiles. As expected, the general galaxy cluster tidal field removes a significant fraction of the globular cluster populations to feed the intracluster population. On average, halos lost approximately 16% and 29% of their initial red and blue globular cluster populations, respectively. Our results suggest that these fractions strongly depend on the orbital trajectory of the galactic halo, specifically on the number of orbits and on the minimum pericentric distance to the galaxy cluster center that the halo has had. At a given time, these fractions also depend on the current clustercentric distance, just as observations show that the specific frequency of globular clusters SN depends on their clustercentric distance.

  11. TIDAL STRIPPING OF GLOBULAR CLUSTERS IN A SIMULATED GALAXY CLUSTER

    SciTech Connect

    Ramos, F.; Coenda, V.; Muriel, H.; Abadi, M.

    2015-06-20

    Using a cosmological N-body numerical simulation of the formation of a galaxy-cluster-sized halo, we analyze the temporal evolution of its globular cluster population. We follow the dynamical evolution of 38 galactic dark matter halos orbiting in a galaxy cluster that at redshift z = 0 has a virial mass of 1.71 × 10{sup 14} M{sub ⊙} h{sup −1}. In order to mimic both “blue” and “red” populations of globular clusters, for each galactic halo we select two different sets of particles at high redshift (z ≈ 1), constrained by the condition that, at redshift z = 0, their average radial density profiles are similar to the observed profiles. As expected, the general galaxy cluster tidal field removes a significant fraction of the globular cluster populations to feed the intracluster population. On average, halos lost approximately 16% and 29% of their initial red and blue globular cluster populations, respectively. Our results suggest that these fractions strongly depend on the orbital trajectory of the galactic halo, specifically on the number of orbits and on the minimum pericentric distance to the galaxy cluster center that the halo has had. At a given time, these fractions also depend on the current clustercentric distance, just as observations show that the specific frequency of globular clusters S{sub N} depends on their clustercentric distance.

  12. HIGH-REDSHIFT COOL-CORE GALAXY CLUSTERS DETECTED VIA THE SUNYAEV-ZEL'DOVICH EFFECT IN THE SOUTH POLE TELESCOPE SURVEY

    SciTech Connect

    Semler, D. R.; Suhada, R.; Bazin, G.; Bocquet, S.; Desai, S.; Aird, K. A.; Ashby, M. L. N.; Bayliss, M.; Bautz, M.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T.; Brodwin, M.; Cho, H. M.; Clocchiatti, A.; De Haan, T.; Dobbs, M. A.; and others

    2012-12-20

    We report the first investigation of cool-core properties of galaxy clusters selected via their Sunyaev-Zel'dovich (SZ) effect. We use 13 galaxy clusters uniformly selected from 178 deg{sup 2} observed with the South Pole Telescope (SPT) and followed up by the Chandra X-ray Observatory. They form an approximately mass-limited sample (>3 Multiplication-Sign 10{sup 14} M{sub Sun} h {sup -1}{sub 70}) spanning redshifts 0.3 < z < 1.1. Using previously published X-ray-selected cluster samples, we compare two proxies of cool-core strength: surface brightness concentration (c{sub SB}) and cuspiness ({alpha}). We find that c{sub SB} is better constrained. We measure c{sub SB} for the SPT sample and find several new z > 0.5 cool-core clusters, including two strong cool cores. This rules out the hypothesis that there are no z > 0.5 clusters that qualify as strong cool cores at the 5.4{sigma} level. The fraction of strong cool-core clusters in the SPT sample in this redshift regime is between 7% and 56% (95% confidence). Although the SPT selection function is significantly different from the X-ray samples, the high-z c{sub SB} distribution for the SPT sample is statistically consistent with that of X-ray-selected samples at both low and high redshifts. The cool-core strength is inversely correlated with the offset between the brightest cluster galaxy and the X-ray centroid, providing evidence that the dynamical state affects the cool-core strength of the cluster. Larger SZ-selected samples will be crucial in understanding the evolution of cluster cool cores over cosmic time.

  13. INTRINSIC ALIGNMENT OF CLUSTER GALAXIES: THE REDSHIFT EVOLUTION

    SciTech Connect

    Hao Jiangang; Kubo, Jeffrey M.; Feldmann, Robert; Annis, James; Johnston, David E.; Lin Huan; McKay, Timothy A.

    2011-10-10

    We present measurements of two types of cluster galaxy alignments based on a volume limited and highly pure ({>=}90%) sample of clusters from the GMBCG catalog derived from Data Release 7 of the Sloan Digital Sky Survey (SDSS DR7). We detect a clear brightest cluster galaxy (BCG) alignment (the alignment of major axis of the BCG toward the distribution of cluster satellite galaxies). We find that the BCG alignment signal becomes stronger as the redshift and BCG absolute magnitude decrease and becomes weaker as BCG stellar mass decreases. No dependence of the BCG alignment on cluster richness is found. We can detect a statistically significant ({>=}3{sigma}) satellite alignment (the alignment of the major axes of the cluster satellite galaxies toward the BCG) only when we use the isophotal fit position angles (P.A.s), and the satellite alignment depends on the apparent magnitudes rather than the absolute magnitudes of the BCGs. This suggests that the detected satellite alignment based on isophotal P.A.s from the SDSS pipeline is possibly due to the contamination from the diffuse light of nearby BCGs. We caution that this should not be simply interpreted as non-existence of the satellite alignment, but rather that we cannot detect them with our current photometric SDSS data. We perform our measurements on both SDSS r-band and i-band data, but do not observe a passband dependence of the alignments.

  14. Super Star Clusters in the Antenna Galaxies

    NASA Video Gallery

    Zooming through the nighttime sky into the constellation Corvus the crow, deeper into the Hubble's Advanced Camera for Surveys image of the Antennae galaxies. The "stellar fireworks" contain brilli...

  15. The Alignment effect of brightest cluster galaxies in the SDSS

    SciTech Connect

    Kim, R. S. J.; Annis, J.; Strauss, M. A.; Lupton, R. H.; Bahcall, N. A.; Gunn, J. E.; Kepner, J. V.; Postman, M.

    2001-10-01

    One of the most vital observational clues for unraveling the origin of Brightest Cluster Galaxies (BCG) is the observed alignment of the BCGs with their host cluster and its surroundings. We have examined the BCG-cluster alignment effect, using clusters of galaxies detected from the Sloan Digital Sky Survey (SDSS). We find that the BCGs are preferentially aligned with the principal axis of their hosts, to a much higher redshift (z >~ 0.3) than probed by previous studies (z <~ 0.1). The alignment effect strongly depends on the magnitude difference of the BCG and the second and third brightest cluster members: we find a strong alignment effect for the dominant BCGs, while less dominant BCGs do not show any departure from random alignment with respect to the cluster. We therefore claim that the alignment process originates from the same process that makes the BCG grow dominant, be it direct mergers in the early stage of cluster formation, or a later process that resembles the galactic cannibalism scenario. We do not find strong evidence for (or against) redshift evolution between 0clusters). However, we have developed a framework by which we can examine many more clusters in an automated fashion for the upcoming SDSS cluster catalogs, which will provide us with better statistics for systematic investigations of the alignment with redshift, richness and morphology of both the cluster and the BCG.

  16. New Fast Lane towards Discoveries of Clusters of Galaxies Inaugurated

    NASA Astrophysics Data System (ADS)

    2003-07-01

    Space and Ground-Based Telescopes Cooperate to Gain Deep Cosmological Insights Summary Using the ESA XMM-Newton satellite, a team of European and Chilean astronomers [2] has obtained the world's deepest "wide-field" X-ray image of the cosmos to date. This penetrating view, when complemented with observations by some of the largest and most efficient ground-based optical telescopes, including the ESO Very Large Telescope (VLT), has resulted in the discovery of several large clusters of galaxies. These early results from an ambitious research programme are extremely promising and pave the way for a very comprehensive and thorough census of clusters of galaxies at various epochs. Relying on the foremost astronomical technology and with an unequalled observational efficiency, this project is set to provide new insights into the structure and evolution of the distant Universe. PR Photo 19a/03: First image from the XMM-LSS survey. PR Photo 19b/03: Zoom-in on PR Photo 19b/03. PR Photo 19c/03: XMM-Newton contour map of the probable extent of a cluster of galaxies, superimposed upon a CHFT I-band image. PR Photo 19d/03: Velocity distribution in the cluster field shown in PR Photo 19c/03. The universal web Unlike grains of sand on a beach, matter is not uniformly spread throughout the Universe. Instead, it is concentrated into galaxies which themselves congregate into clusters (and even clusters of clusters). These clusters are "strung" throughout the Universe in a web-like structure, cf. ESO PR 11/01. Our Galaxy, the Milky Way, for example, belongs to the so-called Local Group which also comprises "Messier 31", the Andromeda Galaxy. The Local Group contains about 30 galaxies and measures a few million light-years across. Other clusters are much larger. The Coma cluster contains thousands of galaxies and measures more than 20 million light-years. Another well known example is the Virgo cluster, covering no less than 10 degrees on the sky ! Clusters of galaxies are the most

  17. Galaxy cluster center detection methods with weak lensing

    NASA Astrophysics Data System (ADS)

    Simet, Melanie

    The precise location of galaxy cluster centers is a persistent problem in weak lensing mass estimates and in interpretations of clusters in a cosmological context. In this work, we test methods of centroid determination from weak lensing data and examine the effects of such self-calibration on the measured masses. Drawing on lensing data from the Sloan Digital Sky Survey Stripe 82, a 275 square degree region of coadded data in the Southern Galactic Cap, together with a catalog of MaxBCG clusters, we show that halo substructure as well as shape noise and stochasticity in galaxy positions limit the precision of such a self-calibration (in the context of Stripe 82, to ˜ 500 h-1 kpc or larger) and bias the mass estimates around these points to a level that is likely unacceptable for the purposes of making cosmological measurements. We also project the usefulness of this technique in future surveys.

  18. Unbiased methods for removing systematics from galaxy clustering measurements

    NASA Astrophysics Data System (ADS)

    Elsner, Franz; Leistedt, Boris; Peiris, Hiranya V.

    2016-02-01

    Measuring the angular clustering of galaxies as a function of redshift is a powerful method for extracting information from the three-dimensional galaxy distribution. The precision of such measurements will dramatically increase with ongoing and future wide-field galaxy surveys. However, these are also increasingly sensitive to observational and astrophysical contaminants. Here, we study the statistical properties of three methods proposed for controlling such systematics - template subtraction, basic mode projection, and extended mode projection - all of which make use of externally supplied template maps, designed to characterize and capture the spatial variations of potential systematic effects. Based on a detailed mathematical analysis, and in agreement with simulations, we find that the template subtraction method in its original formulation returns biased estimates of the galaxy angular clustering. We derive closed-form expressions that should be used to correct results for this shortcoming. Turning to the basic mode projection algorithm, we prove it to be free of any bias, whereas we conclude that results computed with extended mode projection are biased. Within a simplified setup, we derive analytical expressions for the bias and discuss the options for correcting it in more realistic configurations. Common to all three methods is an increased estimator variance induced by the cleaning process, albeit at different levels. These results enable unbiased high-precision clustering measurements in the presence of spatially varying systematics, an essential step towards realizing the full potential of current and planned galaxy surveys.

  19. WINGS Data Release: a database of galaxies in nearby clusters

    NASA Astrophysics Data System (ADS)

    Moretti, A.; Poggianti, B. M.; Fasano, G.; Bettoni, D.; D'Onofrio, M.; Fritz, J.; Cava, A.; Varela, J.; Vulcani, B.; Gullieuszik, M.; Couch, W. J.; Omizzolo, A.; Valentinuzzi, T.; Dressler, A.; Moles, M.; Kjærgaard, P.; Smareglia, R.; Molinaro, M.

    2014-04-01

    Context. To effectively investigate galaxy formation and evolution, it is of paramount importance to exploit homogeneous data for large samples of galaxies in different environments. Aims: The WIde-field Nearby Galaxy-cluster Survey (WINGS) project aim is to evaluate physical properties of galaxies in a complete sample of low redshift clusters to be used as reference sample for evolutionary studies. The WINGS survey is still ongoing and the original dataset will be enlarged with new observations. This paper presents the entire collection of WINGS measurements obtained so far. M