Idit Zehavi
A5052786955- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Cosmology and Gravitation Theories
- Remote Sensing in Agriculture
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Scientific Research and Discoveries
- Astronomical Observations and Instrumentation
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Plant Water Relations and Carbon Dynamics
- Geophysics and Gravity Measurements
- Gaussian Processes and Bayesian Inference
- Astrophysics and Star Formation Studies
- Advanced Vision and Imaging
- Dark Matter and Cosmic Phenomena
- Climate variability and models
- Impact of Light on Environment and Health
- Data Visualization and Analytics
- Black Holes and Theoretical Physics
- Pulsars and Gravitational Waves Research
- Computational Physics and Python Applications
- Particle Accelerators and Free-Electron Lasers
- Adaptive optics and wavefront sensing
- Satellite Image Processing and Photogrammetry
Case Western Reserve University
2014-2023
University of Pennsylvania
2021
Institut d'Astrophysique de Paris
2018-2019
Université Paris Sciences et Lettres
2018-2019
Université Paris Cité
2018-2019
Centre National de la Recherche Scientifique
2018-2019
Sorbonne Université
2018-2019
Durham University
2015-2016
Fermi National Accelerator Laboratory
1998-2006
University of Arizona
2004-2006
We measure cosmological parameters using the three-dimensional power spectrum $P(k)$ from over 200 000 galaxies in Sloan Digital Sky Survey (SDSS) combination with Wilkinson Microwave Anisotropy Probe (WMAP) and other data. Our results are consistent a ``vanilla'' flat adiabatic cold dark matter model constant without tilt ${(n}_{s}=1),$ running tilt, tensor modes, or massive neutrinos. Adding SDSS information more than halves WMAP-only error bars on some parameters, tightening...
We present the large-scale correlation function measured from a spectroscopic sample of 46,748 luminous red galaxies Sloan Digital Sky Survey. The survey region covers 0.72 h-3 Gpc3 over 3816 deg2 and 0.16 < z 0.47, making it best yet for study structure. find well-detected peak in at 100 h-1 Mpc separation that is an excellent match to predicted shape location imprint recombination-epoch acoustic oscillations on low-redshift clustering matter. This detection demonstrates linear growth...
We present cosmological results from the final galaxy clustering data set of Baryon Oscillation Spectroscopic Survey, part Sloan Digital Sky Survey III. Our combined sample comprises 1.2 million massive galaxies over an effective area 9329 deg^2 and volume 18.7 Gpc^3, divided into three partially overlapping redshift slices centred at redshifts 0.38, 0.51, 0.61. measure angular diameter distance DM Hubble parameter H baryon acoustic oscillation (BAO) method after applying reconstruction to...
We present a one per cent measurement of the cosmic distance scale from detections baryon acoustic oscillations (BAO) in clustering galaxies Baryon Oscillation Spectroscopic Survey, which is part Sloan Digital Sky Survey III. Our results come Data Release 11 (DR11) sample, containing nearly million and covering approximately 8500 square degrees redshift range 0.2 < |$z$| 0.7. also compare these with those publicly released DR9 DR10 samples. Assuming concordance Λ cold dark matter (ΛCDM)...
We describe the algorithm that selects main sample of galaxies for spectroscopy in Sloan Digital Sky Survey from photometric data obtained by imaging survey. Galaxy properties are measured using Petrosian magnitude system, which measures flux apertures determined shape surface brightness profile. The metric aperture used is essentially independent cosmological dimming, foreground extinction, sky brightness, and galaxy central brightness. consists with r-band r < 17.77 half-light 24.5...
The spectroscopic Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) galaxy sample represents the final set of galaxies observed using original SDSS target selection criteria. We analyse clustering within this sample, including both luminous red and main samples, also include 2-degree Field Galaxy Redshift data. In total, comprises 893 319 over 9100 deg2. Baryon acoustic oscillations (BAO) are in power spectra measured for different slices redshift; allows us to constrain distance–redshift...
We measure the large-scale real-space power spectrum P(k) using a sample of 205,443 galaxies from Sloan Digital Sky Survey, covering 2417 square degrees with mean redshift z~0.1. employ matrix-based method pseudo-Karhunen-Loeve eigenmodes, producing uncorrelated minimum-variance measurements in 22 k-bands both clustering and its anisotropy due to redshift-space distortions, narrow well-behaved window functions range 0.02 h/Mpc < k 0.3h/Mpc. pay particular attention modeling, quantifying...
We measure the large-scale real-space power spectrum $P(k)$ using luminous red galaxies (LRGs) in Sloan Digital Sky Survey (SDSS) and use this measurement to sharpen constraints on cosmological parameters from Wilkinson Microwave Anisotropy Probe (WMAP). employ a matrix-based estimation method Pseudo-Karhunen-Lo\`eve eigenmodes, producing uncorrelated minimum-variance measurements 20 $k$-bands of both clustering its anisotropy due redshift-space distortions, with narrow well-behaved window...
Here we present the New York University Value-Added Galaxy Catalog (NYU-VAGC), a catalog of local galaxies (mostly below redshift about 0.3) based on set publicly-released surveys (including 2dFGRS, 2MASS, PSCz, FIRST, and RC3) matched to Sloan Digital Sky Survey (SDSS) Data Release 2. Excluding areas masked by bright stars, photometric sample covers 3514 square degrees spectroscopic 2627 (with 85% completeness). Earlier, proprietary versions this have formed basis many SDSS investigations...
We present measurements of galaxy clustering from the Baryon Oscillation Spectroscopic Survey (BOSS), which is part Sloan Digital Sky III (SDSS-III). These use Data Release 9 (DR9) CMASS sample, contains 264 283 massive galaxies covering 3275 square degrees with an effective redshift z = 0.57 and range 0.43 < 0.7. Assuming a concordance ΛCDM cosmological model, this sample covers volume 2.2 Gpc3, represents largest Universe ever surveyed at density, . measure angle-averaged correlation...
We study the luminosity and color dependence of galaxy two-point correlation function in Sloan Digital Sky Survey, starting from a sample ~200,000 galaxies over 2500 deg2. concentrate our analysis on volume-limited subsamples specified ranges, for which we measure projected wp(rp), is directly related to real-space ξ(r). The amplitude wp(rp) rises continuously with Mr ≈ -17.5 -22.5, most rapid increase occurring above characteristic L* (Mr -20.5). Over scales 0.1 h-1 Mpc < rp 10 Mpc,...
We measure the luminosity and color dependence of galaxy clustering in largest-ever redshift survey, main sample Sloan Digital Sky Survey Seventh Data Release. focus on projected correlation function wp(rp) volume-limited samples, extracted from parent ∼700,000 galaxies over 8000 deg2, extending up to 0.25. interpret our measurements using halo occupation distribution (HOD) modeling assuming a ΛCDM cosmology (inflationary cold dark matter with cosmological constant). The amplitude grows...
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 present the first measurements of clustering in Sloan Digital Sky Survey (SDSS) galaxy redshift survey. Our sample consists 29,300 galaxies with redshifts 5,700 km/s < cz 39,000 km/s, distributed several long but narrow (2.5-5 degree) segments, covering 690 square degrees. For full, flux-limited sample, redshift-space correlation length is approximately 8 Mpc/h. The two-dimensional function ξ(r_p,π) shows clear signatures both small-scale, ``fingers-of-God'' distortion caused by...
The Sloan Digital Sky Survey (SDSS) will observe around 10^6 spectra from targets distributed over an area of about 10,000 square degrees, using a multi-object fiber spectrograph which can simultaneously 640 objects in circular field-of-view (referred to as ``tile'') 1.49 degrees radius. No two fibers be placed closer than 55'' during the same observation; multiple this distance are said ``collide.'' We present here method allocating desired given set tile centers includes effects collisions...
We present the power spectrum of reconstructed halo density field derived from a sample luminous red galaxies (LRGs) Sloan Digital Sky Survey (SDSS) Seventh Data Release (DR7). The has direct connection to underlying dark matter for k≤ 0.2 h Mpc−1, well into quasi-linear regime. This enables us use factor ∼8 more modes in cosmological analysis than an with kmax= 0.1 as was adopted SDSS team DR4 LRG sample. observed 0.02 < k Mpc−1 is fitted by our model: χ2= 39.6 40 degrees freedom...
We analyze the anisotropic clustering of massive galaxies from Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic (BOSS) Data Release 9 (DR9) sample, which consists 264,283 in redshift range 0.43 < z 0.7 spanning 3,275 square degrees. Both peculiar velocities and errors assumed redshift-distance relation ("Alcock-Paczynski effect") generate correlations between amplitude orientation with respect to line-of-sight. Together sharp baryon acoustic oscillation (BAO) standard ruler, our...
We model the luminosity-dependent projected two-point correlation function of DEEP2 (z ~ 1) and SDSS 0) galaxies within HOD framework. At both epochs, there is a tight between central galaxy luminosity halo mass, with slope scatter decreasing for larger masses, fraction satellite decreases at higher luminosity. find little evolution in relation mass scales host halos above same threshold. Combining these results theoretical predictions typical growth halos, we establish an evolutionary...
We examine the dependence of mass-to-light (M/L) ratio large-scale structure on cosmological parameters, in models that are constrained to match observations projected galaxy correlation function w(rp). For a sequence with fixed P(k) shape and increasing normalization \sig8, we find parameters halo occupation distribution (HOD) reproduce SDSS measurements w(rp) as luminosity. Using these HOD calculate mean M/L ratios mass populate halos N-body simulations compute larger scale environments,...
We use the observed anisotropic clustering of galaxies in Baryon Oscillation Spectroscopic Survey Data Release 11 CMASS sample to measure linear growth rate structure, Hubble expansion and comoving distance scale. Our covers 8498 deg2 encloses an effective volume 6 Gpc3 at redshift |$\bar{z} = 0.57$|. find fσ8 0.441 ± 0.044, H 93.1 3.0 km s−1 Mpc−1 DA 1380 23 Mpc when fitting simultaneously. When we fix background one predicted by spatially flat Λ cold dark matter (ΛCDM) model agreement...
We analyse the density field of galaxies observed by Sloan Digital Sky Survey (SDSS)-III Baryon Oscillation Spectroscopic (BOSS) included in SDSS Data Release Nine (DR9). DR9 includes spectroscopic redshifts for over 400 000 spread a footprint 3275 deg2. identify, characterize and mitigate impact sources systematic uncertainty on large-scale clustering measurements, both angular moments redshift-space correlation function, ξℓ(s), spherically averaged power spectrum, P(k), order to ensure...
We identify galaxy groups and clusters in volume-limited samples of the SDSS redshift survey, using a redshift-space friends-of-friends algorithm. optimize linking lengths to recover systems that occupy same dark matter halos, set mock catalogs created by populating halos N-body simulations with galaxies. Extensive tests these show no combination perpendicular line-of-sight is able yield simultaneously true halo multiplicity function, projected size distribution, velocity dispersion. adopt...