A5003259518- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Cosmology and Gravitation Theories
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Radio Astronomy Observations and Technology
- Dark Matter and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Scientific Research and Discoveries
- Adaptive optics and wavefront sensing
- Astronomical Observations and Instrumentation
- History and Developments in Astronomy
- Particle physics theoretical and experimental studies
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- Calibration and Measurement Techniques
- Geophysics and Gravity Measurements
- Black Holes and Theoretical Physics
- Space Science and Extraterrestrial Life
- Spacecraft Design and Technology
- Superconducting and THz Device Technology
Institució Catalana de Recerca i Estudis Avançats
2015-2024
Universitat de Barcelona
2015-2024
Institut d'Estudis Espacials de Catalunya
2003-2024
Institut Català de Ciències del Clima
2010-2023
Institute for Advanced Study
1995-2020
Institut de Ciències del Cosmos
2011-2014
Institute of Space Sciences
2006-2010
The Ohio State University
2000-2008
University of Pennsylvania
1996-2006
Alfred P. Sloan Foundation
1998-2002
The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in clustering matter over a larger volume than combined efforts all previous spectroscopic surveys large-scale structure. BOSS uses 1.5 million luminous galaxies as faint i = 19.9 10,000 deg2 BAO redshifts z < 0.7. Observations neutral hydrogen Lyα forest more 150,000 quasar spectra (g 22) will constrain redshift range 2.15 3.5. Early results from include first detection...
We derive constraints on cosmological parameters and tests of dark energy models from the combination baryon acoustic oscillation (BAO) measurements with cosmic microwave background (CMB) Type Ia supernova (SN) data. take advantage high-precision BAO galaxy clustering Ly-alpha forest (LyaF) in BOSS survey SDSS-III. data alone yield a high confidence detection energy, CMB angular scale they further imply nearly flat universe. Combining SN into an "inverse distance ladder" yields 1.7%...
We measure the large-scale cross-correlation of quasars with Lyman alpha forest absorption, using over 164,000 from Data Release 11 SDSS-III Baryon Oscillation Spectroscopic Survey. extend previous study roughly 60,000 9 to larger separations, allowing a measurement Baryonic Acoustic (BAO) scale along line sight $c/(H(z=2.36) ~ r_s) = 9.0 \pm 0.3$ and across $D_A(z=2.36) / r_s 10.8 0.4$, consistent CMB other BAO data. Using best fit value sound horizon Planck data ($r_s=147.49 Mpc$), we can...
We report a detection of the baryon acoustic oscillation (BAO) feature in flux-correlation function Ly{\alpha} forest high-redshift quasars with statistical significance five standard deviations. The study uses 137,562 redshift range $2.1\le z \le 3.5$ from Data Release 11 (DR11) Baryon Oscillation Spectroscopic Survey (BOSS) SDSS-III. This sample contains three times number used previous studies. measured position BAO peak determines angular distance, $D_A(z=2.34)$ and expansion rate,...
Cosmological simulations with gas provide a detailed description of the intergalactic medium, which makes possible predictions neutral hydrogen absorption in spectra background QSOs. We present results from high-resolution calculation an Ω = 1 cold dark matter model. Our simulation reproduces many observed properties Lyα forest surprisingly well.
We construct evolutionary models of the populations active galactic nuclei (AGNs) and supermassive black holes, in which hole mass function grows at rate implied by observed luminosity function, given assumptions about radiative efficiency Eddington units. draw on a variety recent X-ray optical measurements to estimate bolometric AGN compare background data independent Hopkins et al. assess remaining systematic uncertainties. The integrated emissivity closely tracks cosmic star-formation...
We present the first results from an ongoing survey for damped Lyman-α systems (DLAs) in spectra of z > 2 quasars observed course Baryon Oscillation Spectroscopic Survey (BOSS), which is part Sloan Digital Sky (SDSS) III. Our full (non-statistical) sample, based on Data Release 9, comprises 12 081 with log N(H i) ≥ 20, out 6839 have 20.3. This largest DLA sample ever compiled, superseding that SDSS-II by a factor seven.
We report a detection of the baryon acoustic oscillation (BAO) feature in three-dimensional correlation function transmitted flux fraction \Lya forest high-redshift quasars. The study uses 48,640 quasars redshift range $2.1\le z \le 3.5$ from Baryon Oscillation Spectroscopic Survey (BOSS) third generation Sloan Digital Sky (SDSS-III). At mean $z=2.3$, we measure monopole and quadrupole components for separations $20\hMpc<r<200\hMpc$. A peak is seen at separation equal to $(1.01\pm0.03)$...
We use the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 9 (DR9) to detect and measure position of Baryonic Acoustic (BAO) feature in three-dimensional correlation function Lyman-α flux fluctuations at a redshift zeff = 2.4. The is clearly detected significance between 3 5 sigma (depending on broadband model method error covariance matrix estimation) consistent with predictions standard ΛCDM model. assess biases our method, stability possible systematic effects. fit resulting...
We present the Data Release 9 Quasar (DR9Q) catalog from Baryon Oscillation Spectroscopic Survey (BOSS) of Sloan Digital Sky III. The includes all BOSS objects that were targeted as quasar candidates during survey, are spectrocopically confirmed quasars via visual inspection, have luminosities Mi[z=2]<-20.5 (in a $\Lambda$CDM cosmology with H0 = 70 km/s/Mpc, $\Omega_{\rm M}$ 0.3, and $\Omega_{\Lambda}$ 0.7) either display at least one emission line full width half maximum (FWHM) larger than...
We present a measurement of baryon acoustic oscillations (BAO) in the cross-correlation quasars with Ly$\alpha$-forest flux-transmission at mean redshift $z=2.40$. The uses complete SDSS-III data sample: 168,889 forests and 234,367 from SDSS Data Release DR12. In addition to statistical improvement on our previous study using DR11, we have implemented numerous improvements analysis level allowing more accurate this cross-correlation. also developed first simulations us test different aspects...
We present the Data Release 10 Quasar (DR10Q) catalog from Baryon Oscillation Spectroscopic Survey (BOSS) of Sloan Digital Sky III. The includes all BOSS objects that were targeted as quasar candidates during first 2.5 years survey and are confirmed quasars via visual inspection spectra. also known (mostly SDSS-I II) reobserved by BOSS. contains 166,583 (74,454 new discoveries since SDSS-DR9) detected over 6,373 deg$^{2}$ with robust identification redshift measured a combination principal...
The SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), a five-year spectroscopic survey of 10,000 deg^2, achieved first light in late 2009. One the key goals BOSS is to measure signature baryon acoustic oscillations distribution Ly-alpha absorption from spectra sample ~150,000 z>2.2 quasars. Along with measuring angular diameter distance at z\approx2.5, will provide direct measurement expansion rate Universe z > 2. biggest challenges achieving this goal an efficient target selection...
We have used flux-transmission correlations in Lyα forests to measure the imprint of baryon acoustic oscillations (BAO). The study uses spectra 157 783 quasars redshift range 2.1 ≤ z 3.5 from Sloan Digital Sky Survey (SDSS) data release 12 (DR12). Besides statistical improvements on our previous studies using SDSS DR9 and DR11, we implemented numerous analysis procedure, allowing us construct a physical model correlation function investigate potential systematic errors determination BAO peak...
A model of the density distribution in intergalactic medium (IGM), motivated by that found numerical simulations, is used to demonstrate effect a clumpy IGM and discrete sources on reionization universe. In an inhomogeneous universe occurs outside-in, starting voids gradually penetrating into overdense regions. Reionization should not be sudden but gradual, with continuous rise photon mean free path over fair fraction Hubble time as emissivity increases. We show hydrogen Gunn-Peterson trough...
We have measured the distribution function of flux decrement D = 1 - e-τ caused by Lyα forest absorption from intervening gas in lines sight to high-redshift QSOs a sample seven high-resolution QSO spectra obtained with Keck telescope. The observed (FDDF) is compared FDDF two simulations forest: ΛCDM model (with Ω 0.4, Λ 0.6), computed Eulerian code Cen & Ostriker, and standard cold dark matter (SCDM) 1), smoothed particle hydrodynamics Hernquist et al. Good agreement between shapes...
view Abstract Citations (499) References (33) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Gravitational Collapse of Small-Scale Structure as the Origin Lyman-Alpha Forest Cen, Renyue ; Miralda-Escudé, Jordi Ostriker, Jeremiah P. Rauch, Michael If gravitational clustering is a hierarchical process, present large-scale structure galaxy distribution implies that structures on smaller scales must have formed at high redshift. We simulate formation small-scale...
We use an Eulerian hydrodynamic cosmological simulation to model the Lyα forest in a spatially flat, COBE-normalized, cold dark matter with) Ω = 0.4. find that intergalactic, photoionized gas is predicted collapse into sheetlike and filamentary structures which give rise absorption lines having characteristics similar observed forest. A typical filament ~500 h–1 kpc long with thickness ~50 (in proper units), baryonic mass ~ 1010 h−1 M☉. In comparison our cell size (2.5, 9) two simulations we...
Observations of high-redshift quasars show that the intergalactic medium (IGM) must have been reionized at some redshift z > 5. If a source radiation could be observed rest-frame Lyα wavelength, sufficiently high where IGM in line sight was not yet reionized, Gunn-Peterson trough should present. Longward damping wing observed, caused by neutral whose absorption profile can predicted. Measuring shape this would provide irrefutable evidence observation before reionization and determination...
A sample of eight quasars observed at high resolution and signal-to-noise ratio is used to determine the transmitted flux probability distribution function (TFPDF), power spectrum correlation in Lyα forest, three redshift bins centered z = 2.41, 3.00, 3.89. All results are presented tabular form, with full error covariance matrices, allow for comparisons any numerical simulations other data sets. The observations compared a simulation forest ΛCDM model Ω 0.4, known agree large-scale...
The recent discovery of a planetary transit in the star HD 209458, and subsequent highly precise observation light curve with Hubble Space Telescope, is encouraging to search for any phenomena that might induce small changes curve. Here we consider effect quadrupole moment parent possible second planet perturbing orbit transiting planet. Both these cause precession orbital plane periastron planet, which result long-term variation duration period transits. For at 0.05 AU, either similar Sun...
view Abstract Citations (266) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Correlation Function of Galaxy Ellipticities Produced by Gravitational Lensing Miralda-Escude, Jordi gravitational potential mass fluctuations in the universe deflects light rays background sources, distorting their shapes. This distortion introduces a correlation ellipticities sources lying within given area sky. In this paper, we calculate produced lensing, as...
We investigate the interaction of Lyα photons produced by first stars in universe with intergalactic hydrogen prior to reionization. The background spectral profile is obtained solving a Fokker-Planck equation. present accurate values heating and scattering rates spin-kinetic temperature coupling coefficient. show that rate induced much lower than found previously basically negligible. dominant source most likely X-rays from ionizing sources, which are able penetrate into atomic medium....
Spergel & Steinhardt proposed the possibility that dark matter particles are self-interacting as a solution to two discrepancies between predictions of cold models and observations: First, observed distribution in some dwarf galaxies has large, constant-density cores, opposed predicted central cusps; second, small satellites normal much less abundant than predicted. The self-interaction would produce isothermal cores halos expel from dwarfs orbiting large halos. Another consequence model is...
We revisit the well known discrepancy between observed number of Milky Way (MW) dwarf satellite companions and predicted population cold dark matter (CDM) sub-halos, in light dozen new low luminosity satellites found SDSS imaging data our recent calibration detection efficiency, which implies a total far larger than these discoveries. combine dynamical model for CDM sub-halo with simple, physically motivated prescriptions assigning stellar content to each sub-halo, then apply observational...