Can cluster merger shocks reproduce the luminosity and shape distribution of radio relics?

Radio relics in galaxy clusters are believed to trace merger shock fronts. If cosmological structure formation determines the luminosity, size and shape distributions of radio relics, then merger shocks need to be lighted up in a homogeneous way. We investigate if a mock relic sample, obtained from zoomed galaxy cluster simulations, is able to match the properties of relics measured in the NRAO VLA Sky Survey (NVSS). We compile a list of all radio relics known to date and homogeneously measure their parameters in all NVSS images and apply the same procedure to relics in our simulations. Number counts in the mock relic sample increase more steeply towards lower relic flux densities, suggesting an incompleteness of NVSS in this regime. Overall, we find that NVSS and mock samples show similar properties. However, large simulated relics tend to be somewhat smaller and closer to the cluster centre than observed ones. Besides this, the mock sample reproduces very well-known correlations for radio relics, in particular those relating the radio luminosity with the largest linear size and the X-ray luminosity. We show that these correlations are largely governed by the sensitivity of the NVSS observations. Mock relics show a similar orientation with respect to the direction to the cluster centre as the NVSS sample. Moreover, we find that their maximum radio luminosity roughly correlates with cluster mass, although displaying a large scatter. The overall good agreement between NVSS and the mock sample suggests that properties of radio relics are indeed governed by merger shock fronts, emitting in a homogeneous fashion. Our study demonstrates that the combination of mock observations and data from upcoming radio surveys will allow us to shed light on both the origin of radio relics and the nature of the intracluster medium.Fil: Nuza, Sebastian Ernesto. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina. Universidad de Buenos Aires; ArgentinaFil: Gelszinnis, Jakob. Thüringer Landessternwarte; AlemaniaFil: Hoeft, Matthias. Thüringer Landessternwarte; AlemaniaFil: Yepes, Gustavo. Universidad Autónoma de Madrid; Españ

The Eleventh and Twelfth data releases of the Sloan Digital Sky Survey: Final data from SDSS-III

The third generation of the Sloan Digital Sky Survey (SDSS-III) tookdata from 2008 to 2014 using the original SDSS wide-field imager, theoriginal and an upgraded multi-object fiber-fed optical spectrograph, anew near-infrared high-resolution spectrograph, and a novel opticalinterferometer. All of the data from SDSS-III are now made public. Inparticular, this paper describes Data Release 11 (DR11) including alldata acquired through 2013 July, and Data Release 12 (DR12) adding dataacquired through 2014 July (including all data included in previous datareleases), marking the end of SDSS-III observing. Relative to ourprevious public release (DR10), DR12 adds one million new spectra ofgalaxies and quasars from the Baryon Oscillation Spectroscopic Survey(BOSS) over an additional 3000 deg2 of sky, more than triplesthe number of H-band spectra of stars as part of the Apache PointObservatory (APO) Galactic Evolution Experiment (APOGEE), and includesrepeated accurate radial velocity measurements of 5500 stars from theMulti-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS).The APOGEE outputs now include the measured abundances of 15 differentelements for each star. In total, SDSS-III added 5200 deg2 ofugriz imaging; 155,520 spectra of 138,099 stars as part of the SloanExploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey;2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and247,216 stars over 9376 deg2; 618,080 APOGEE spectra of156,593 stars; and 197,040 MARVELS spectra of 5513 stars. Since itsfirst light in 1998, SDSS has imaged over 1/3 of the Celestial sphere infive bands and obtained over five million astronomical spectra.Fil: Alam, Shadab. University of Carnegie Mellon; Estados UnidosFil: Albareti, Franco D.. Universidad Autónoma de Madrid; EspañaFil: Prieto, Carlos Allende. Universidad de La Laguna; EspañaFil: Anders, F.. Leibniz Institute For Astrophysics Potsdam; AlemaniaFil: Anderson, Scott F.. University of Utah; Estados UnidosFil: Anderton, Timothy. University of Utah; Estados UnidosFil: Andrews, Brett H.. Ohio State University; Estados Unidos. University of Pittsburgh; Estados UnidosFil: Armengaud, Eric. Service de Physique Des Particules; FranciaFil: Aubourg, Éric. Université Paris Diderot - Paris 7; FranciaFil: Bailey, Stephen. Lawrence Berkeley National Laboratory; Estados UnidosFil: Basu, Sarbani. University of Yale; Estados UnidosFil: Bautista, Julian E.. Université Paris Diderot - Paris 7; FranciaFil: Beaton, Rachael L.. University of Virginia; Estados UnidosFil: Beers, Timothy C.. University of Notre Dame; Estados UnidosFil: Bender, Chad F.. Pennsylvania State University; Estados UnidosFil: Berlind, Andreas A.. Vanderbilt University; Estados UnidosFil: Beutler, Florian. Lawrence Berkeley National Laboratory; Estados UnidosFil: Bhardwaj, Vaishali. Lawrence Berkeley National Laboratory; Estados UnidosFil: Bird, Jonathan C.. Vanderbilt University; Estados UnidosFil: Bizyaev, Dmitry. Apache Point Observatory; Estados UnidosFil: Blake, Cullen H.. University of Pennsylvania; Estados UnidosFil: Blanton, Michael R.. New York University; Estados UnidosFil: Blomqvist, Michael. University of California at Irvine; Estados UnidosFil: Bochanski, John J.. University of Washington; Estados UnidosFil: Bolton, Adam S.. University of Utah; Estados UnidosFil: Bovy, Jo. Institute For Advanced Studies; Estados UnidosFil: Shelden, Bradley, A.. Apache Point Observatory; Estados UnidosFil: Brandt, W. N.. Pennsylvania State University; Estados UnidosFil: Brauer, D. E.. Leibniz Institute For Astrophysics Potsdam; AlemaniaFil: Nuza, Sebastian Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina. Institut Max Planck Fuer Gesellschaft. Max Planck Institute For Extraterrestrial Physics; AlemaniaFil: Scoccola, Claudia Graciela. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentin

An HST/COS legacy survey of high-velocity ultraviolet absorption in the Milky Way's circumgalactic medium and the Local Group

Context. The Milky Way is surrounded by large amounts of diffuse gaseous matter that connects the stellar body of our Galaxy with its large-scale Local Group (LG) environment. Aims. To characterize the absorption properties of this circumgalactic medium (CGM) and its relation to the LG we present the so-far largest survey of metal absorption in Galactic high-velocity clouds (HVCs) using archival ultraviolet (UV) spectra of extragalactic background sources. The UV data are obtained with the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope (HST) and are supplemented by 21 cm radio observations of neutral hydrogen. Methods. Along 270 sightlines we measure metal absorption in the lines of Si ii, Si iii, Cii, and Civ and associated Hi 21 cm emission in HVCs in the velocity range jvLSRj = 100-500 km s-1. With this unprecedented large HVC sample we were able to improve the statistics on HVC covering fractions, ionization conditions, small-scale structure, CGM mass, and inflow rate. For the first time, we determine robustly the angular two point correlation function of the high-velocity absorbers, systematically analyze antipodal sightlines on the celestial sphere, and compare the HVC absorption characteristics with that of damped Lyman α absorbers (DLAs) and constrained cosmological simulations of the LG (CLUES project). Results. The overall sky-covering fraction of high-velocity absorption is 77 ± 6 percent for the most sensitive ion in our survey, Si iii, and for column densities log N(Si iii) ≥ 12.1. This value is ∼4-5 times higher than the covering fraction of 21 cm neutral hydrogen emission at log N(H i) ≥ 18.7 along the same lines of sight, demonstrating that the Milky Way's CGM is multi-phase and predominantly ionized. The measured equivalent-width ratios of Si ii, Si iii, Cii, and C iv are inhomogeneously distributed on large and small angular scales, suggesting a complex spatial distribution of multi-phase gas that surrounds the neutral 21 cm HVCs. We estimate that the total mass and accretion rate of the neutral and ionized CGM traced by HVCs is MHVC ≥ 3.0 × 109 M⊙ and dMHVC=dt ≥ 6.1 M⊙ yr-1, where the Magellanic Stream (MS) contributes with more than 90 percent to this mass/mass-flow. If seen from an external vantage point, the Milky Way disk plus CGM would appear as a DLA that would exhibit for most viewing angles an extraordinary large velocity spread of Δv ≈ 400-800 km s-1, a result of the complex kinematics of the Milky Way CGM that is dominated by the presence of the MS. We detect a velocity dipole of high-velocity absorption at low/high galactic latitudes that we associate with LG gas that streams to the LG barycenter. This scenario is supported by the gas kinematics predicted from the LG simulations. Conclusions. Our study confirms previous results, indicating that the Milky Way CGM contains sufficient gaseous material to feed the Milky Way disk over the next Gyr at a rate of a few solar masses per year, if the CGM gas can actually reach the MW disk. We demonstrate that the CGM is composed of discrete gaseous structures that exhibit a large-scale kinematics together with small-scale variations in physical conditions. The MS clearly dominates both the cross section and mass flow of high-velocity gas in the Milky Way's CGM. The possible presence of high-velocity LG gas underlines the important role of the local cosmological environment in the large-scale gas-circulation processes in and around the Milky Way.Fil: Richter, Philipp. Universitat Potsdam. Mathematisch Nautrwissenschaften Fakultat; AlemaniaFil: Nuza, Sebastian Ernesto. Leibniz Institut Fuer Astrophysik Potsdam; Alemania. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Fox, A. J.. Space Telescope Science Institute; Estados UnidosFil: Wakker, B. P.. University of Wisconsin; Estados UnidosFil: Lehner, N.. University of Notre Dame; Estados UnidosFil: Ben Bekhti, N.. Research Establishment For Applied Science (fgan)

Clustering properties of g-selected galaxies at z similar to 0.8

International audienceCurrent and future large redshift surveys, as the Sloan Digital Sky Survey IV extended Baryon Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) or the Dark Energy Spectroscopic Instrument (DESI), will use emission-line galaxies (ELGs) to probe cosmological models by mapping the large-scale structure of the Universe in the redshift range 0.6 \textless z \textless 1.7. With current data, we explore the halo-galaxy connection by measuring three clustering properties of g-selected ELGs as matter tracers in the redshift range 0.6 \textless z \textless 1: (i) the redshift-space two-point correlation function using spectroscopic redshifts from the BOSS ELG sample and VIPERS; (ii) the angular two-point correlation function on the footprint of the CFHT-LS; (iii) the galaxy-galaxy lensing signal around the ELGs using the CFHTLenS. We interpret these observations by mapping them on to the latest high-resolution MultiDark Planck N-body simulation, using a novel (Sub) Halo-Abundance Matching technique that accounts for the ELG incompleteness. ELGs at z similar to 0.8 live in haloes of (1 +/- 0.5) x 10(12) h(-1)M(circle dot) and 22.5 +/- 2.5 per cent of them are satellites belonging to a larger halo. The halo occupation distribution of ELGs indicates that we are sampling the galaxies in which stars form in the most efficient way, according to their stellar-to-halo mass ratio