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G Zamorani - One of the best experts on this subject based on the ideXlab platform.
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the progeny of a cosmic titan a massive multi component proto supercluster in formation at z 2 45 in vuds
Astronomy and Astrophysics, 2018Co-Authors: O Cucciati, Le O Fevre, G Zamorani, B C Lemaux, L A M Tasca, N P Hathi, S Bardelli, P Cassata, B Garilli, Le V BrunAbstract:We unveil the complex shape of a proto-supercluster at z ∼ 2.45 in the Cosmos field exploiting the synergy of both spectroscopic and photometric redshifts. Thanks to the spectroscopic redshifts of the VIMOS Ultra-Deep Survey (VUDS), complemented by the zCosmos-Deep spectroscopic sample and high-quality photometric redshifts, we compute the three-dimensional (3D) overdensity field in a volume of ∼100 × 100 × 250 comoving Mpc3 in the central region of the Cosmos field, centred at z ∼ 2.45 along the line of sight. The method relies on a two-dimensional (2D) Voronoi tessellation in overlapping redshift slices that is converted into a 3D density field, where the galaxy distribution in each slice is constructed using a statistical treatment of both spectroscopic and photometric redshifts. In this volume, we identify a proto-supercluster, dubbed “Hyperion” for its immense size and mass, which extends over a volume of ∼60 × 60 × 150 comoving Mpc3 and has an estimated total mass of ∼4.8 × 1015 M⊙. This immensely complex structure contains at least seven density peaks within 2.4 ≲ z ≲ 2.5 connected by filaments that exceed the average density of the volume. We estimate the total mass of the individual peaks, Mtot, based on their inferred average matter density, and find a range of masses from ∼0.1 × 1014 M⊙ to ∼2.7 × 1014 M⊙. By using spectroscopic members of each peak, we obtain the velocity dispersion of the galaxies in the peaks, and then their virial mass Mvir (under the strong assumption that they are virialised). The agreement between Mvir and Mtot is surprisingly good, at less than 1−2σ, considering that (almost all) the peaks are probably not yet virialised. According to the spherical collapse model, these peaks have already started or are about to start collapsing, and they are all predicted to be virialised by redshift z ∼ 0.8−1.6. We finally perform a careful comparison with the literature, given that smaller components of this proto-supercluster had previously been identified using either heterogeneous galaxy samples (Lyα emitters, sub-mm starbursting galaxies, CO emitting galaxies) or 3D Lyα forest tomography on a smaller area. With VUDS, we obtain, for the first time across the central ∼1 deg2 of the Cosmos field, a panoramic view of this large structure, that encompasses, connects, and considerably expands in a homogeneous way on all previous detections of the various sub-components. The characteristics of this exceptional proto-supercluster, its redshift, its richness over a large volume, the clear detection of its sub-components, together with the extensive multi-wavelength imaging and spectroscopy granted by the Cosmos field, provide us the unique possibility to study a rich supercluster in formation.Key words: galaxies: clusters: general / galaxies: high-redshift / cosmology: observations / large-scale structure of Universe⋆ Based on data obtained with the European Southern Observatory Very Large Telescope, Paranal, Chile, under Large Program 185.A-0791.
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The progeny of a Cosmic Titan: a massive multi-component proto-supercluster in formation at $z=2.45$ in VUDS
Astron.Astrophys., 2018Co-Authors: O Cucciati, G Zamorani, B C Lemaux, L A M Tasca, N P Hathi, S Bardelli, P Cassata, O. Le Fèvre, K.g. Lee, B GarilliAbstract:We unveil the complex shape of a proto-supercluster at z ∼ 2.45 in the Cosmos field exploiting the synergy of both spectroscopic and photometric redshifts. Thanks to the spectroscopic redshifts of the VIMOS Ultra-Deep Survey (VUDS), complemented by the zCosmos-Deep spectroscopic sample and high-quality photometric redshifts, we compute the three-dimensional (3D) overdensity field in a volume of ∼100 × 100 × 250 comoving Mpc3 in the central region of the Cosmos field, centred at z ∼ 2.45 along the line of sight. The method relies on a two-dimensional (2D) Voronoi tessellation in overlapping redshift slices that is converted into a 3D density field, where the galaxy distribution in each slice is constructed using a statistical treatment of both spectroscopic and photometric redshifts. In this volume, we identify a proto-supercluster, dubbed “Hyperion” for its immense size and mass, which extends over a volume of ∼60 × 60 × 150 comoving Mpc3 and has an estimated total mass of ∼4.8 × 1015 M⊙. This immensely complex structure contains at least seven density peaks within 2.4 ≲ z ≲ 2.5 connected by filaments that exceed the average density of the volume. We estimate the total mass of the individual peaks, Mtot, based on their inferred average matter density, and find a range of masses from ∼0.1 × 1014 M⊙ to ∼2.7 × 1014 M⊙. By using spectroscopic members of each peak, we obtain the velocity dispersion of the galaxies in the peaks, and then their virial mass Mvir (under the strong assumption that they are virialised). The agreement between Mvir and Mtot is surprisingly good, at less than 1−2σ, considering that (almost all) the peaks are probably not yet virialised. According to the spherical collapse model, these peaks have already started or are about to start collapsing, and they are all predicted to be virialised by redshift z ∼ 0.8−1.6. We finally perform a careful comparison with the literature, given that smaller components of this proto-supercluster had previously been identified using either heterogeneous galaxy samples (Lyα emitters, sub-mm starbursting galaxies, CO emitting galaxies) or 3D Lyα forest tomography on a smaller area. With VUDS, we obtain, for the first time across the central ∼1 deg2 of the Cosmos field, a panoramic view of this large structure, that encompasses, connects, and considerably expands in a homogeneous way on all previous detections of the various sub-components. The characteristics of this exceptional proto-supercluster, its redshift, its richness over a large volume, the clear detection of its sub-components, together with the extensive multi-wavelength imaging and spectroscopy granted by the Cosmos field, provide us the unique possibility to study a rich supercluster in formation.Key words: galaxies: clusters: general / galaxies: high-redshift / cosmology: observations / large-scale structure of Universe⋆ Based on data obtained with the European Southern Observatory Very Large Telescope, Paranal, Chile, under Large Program 185.A-0791.
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sub millimetre interferometric imaging of a sample of Cosmos aztec submillimetre galaxies iii environments
Astronomy and Astrophysics, 2017Co-Authors: Vernesa Smolcic, G Zamorani, Oskari Miettinen, Neven Tomicic, A Finoguenov, B C Lemaux, M Aravena, P Capak, Yk Chiang, F CivanoAbstract:We investigate the environment of 23 submillimetre galaxies (SMGs) drawn from a signal-to-noise (S/N)-limited sample of SMGs originally discovered in the James Clerk Maxwell Telescope (JCMT)/AzTEC 1.1 mm continuum survey of a Cosmic Evolution Survey (Cosmos) subfield and then followed up with the Submillimetre Array and Plateau de Bure Interferometer at 890 μm and 1.3 mm, respectively. These SMGs already have well-defined multiwavelength counterparts and redshifts. We also analyse the environments of four Cosmos SMGs spectroscopically confirmed to lie at redshifts z_(spec) > 4.5, and one at z_(spec) = 2.49 resulting in a total SMG sample size of 28. We search for overdensities using the Cosmos photometric redshifts based on over 30 UV-NIR photometric measurements including the new UltraVISTA data release 2 and Spitzer/SPLASH data, and reaching an accuracy of σ_(Δz/ (1 + z)) = 0.0067 (0.0155) at z 3.5). To identify overdensities we apply the Voronoi tessellation analysis, and estimate the redshift-space overdensity estimator δ_g as a function of distance from the SMG and/or overdensity centre. We test and validate our approach via simulations, X-ray detected groups or clusters, and spectroscopic verifications using VUDS and zCosmos catalogues which show that even with photometric redshifts in the Cosmos field we can efficiently retrieve overdensities out to z ≈ 5. Our results yield that 11 out of 23 (48%) JCMT/AzTEC 1.1 mm SMGs occupy overdense environments. Considering the entire JCMT/AzTEC 1.1 mm S/N ≥ 4 sample and taking the expected fraction of spurious detections into account, this means that 35–61% of the SMGs in the S/N-limited sample occupy overdense environments. We perform an X-ray stacking analysis in the 0.5–2 keV band using a 32″ aperture and our SMG positions, and find statistically significant detections. For our z 2 subsample yields an average flux of (1.3 ± 0.5) × 10^(-16) erg s^(-1) cm^(-2) and a corresponding total massof M_(200) = 2 × 10^(13)M⊙. Our results suggest a higher occurrence of SMGs occupying overdense environments at z ≥ 3 than at z < 3. This may be understood if highly star-forming galaxies can only be formed in the highest peaks of the density field tracing the most massive dark matter haloes at early cosmic epochs, while at later times cosmic structure may have matured sufficiently that more modest overdensities correspond to sufficiently massive haloes to form SMGs.
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(Sub)millimetre interferometric imaging of a sample of Cosmos/AzTEC submillimetre galaxies III. Environments
Astron.Astrophys., 2017Co-Authors: V. Smolčić, G Zamorani, Oskari Miettinen, A Finoguenov, B C Lemaux, M Aravena, P Capak, Yk Chiang, N. Tomičić, F CivanoAbstract:We investigate the environment of 23 submillimetre galaxies (SMGs) drawn from a signal-to-noise (S/N)-limited sample of SMGs originally discovered in the James Clerk Maxwell Telescope (JCMT)/AzTEC 1.1 mm continuum survey of a Cosmic Evolution Survey (Cosmos) subfield and then followed up with the Submillimetre Array and Plateau de Bure Interferometer at 890 mum and 1.3 mm, respectively. These SMGs already have well-defined multiwavelength counterparts and redshifts. We also analyse the environments of four Cosmos SMGs spectroscopically confirmed to lie at redshifts z_spec > 4.5, and one at z_spec = 2.49 resulting in a total SMG sample size of 28. We search for overdensities using the Cosmos photometric redshifts based on over 30 UV-NIR photometric measurements including the new UltraVISTA data release 2 and Spitzer/SPLASH data, and reaching an accuracy of sigma_Deltaz/ (1 + z) = 0.0067 (0.0155) at z 3.5). To identify overdensities we apply the Voronoi tessellation analysis, and estimate the redshift-space overdensity estimator delta_g as a function of distance from the SMG and/or overdensity centre. We test and validate our approach via simulations, X-ray detected groups or clusters, and spectroscopic verifications using VUDS and zCosmos catalogues which show that even with photometric redshifts in the Cosmos field we can efficiently retrieve overdensities out to z sim 5. Our results yield that 11 out of 23 (48%) JCMT/AzTEC 1.1 mm SMGs occupy overdense environments. Considering the entire JCMT/AzTEC 1.1 mm S/N >= 4 sample and taking the expected fraction of spurious detections into account, this means that 35-61% of the SMGs in the S/N-limited sample occupy overdense environments. We perform an X-ray stacking analysis in the 0.5-2 keV band using a 32″ aperture and our SMG positions, and find statistically significant detections. For our z subsample we find an average flux of (4.0 +- 0.8) x 10^-16 erg s^-1 cm^-2 and a corresponding total mass of M_200 = 2.8 x 10^13M_⊙. The z > 2 subsample yields an average flux of (1.3 +- 0.5) x 10^-16 erg s^-1 cm^-2 and a corresponding total massof M_200 = 2 x 10^13M_⊙. Our results suggest a higher occurrence of SMGs occupying overdense environments at z >= 3 than at z . This may be understood if highly star-forming galaxies can only be formed in the highest peaks of the density field tracing the most massive dark matter haloes at early cosmic epochs, while at later times cosmic structure may have matured sufficiently that more modest overdensities correspond to sufficiently massive haloes to form SMGs.
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sub millimetre interferometric imaging of a sample of Cosmos aztec submillimetre galaxies iii environments
arXiv: Astrophysics of Galaxies, 2016Co-Authors: Vernesa Smolcic, G Zamorani, Oskari Miettinen, Neven Tomicic, A Finoguenov, B C Lemaux, M Aravena, P Capak, Yk Chiang, F CivanoAbstract:We study the environment of 23 submillimetre galaxies (SMGs) drawn from the JCMT/AzTEC 1.1mm S/N-limited sample in the Cosmos field, as well as 4 Cosmos SMGs at z_spec>4.5, and 1 at z_spec=2.49, yielding a sample of 28 SMGs. We search for overdensities using the Cosmos photometric redshifts based on over 30 UV-NIR photometric bands, reaching an accuracy of sigma(Delta z/(1+z))=0.0067 (0.0155) at z 3.5). To identify overdensities we apply the Voronoi tessellation analysis, and estimate the overdensity estimator delta_g as a function of distance from the SMG and/or overdensity center. We test and validate our approach via simulations, X-ray detected groups, and spectroscopic verifications using VUDS and zCosmos catalogues showing that even with photometric redshifts in Cosmos we can efficiently retrieve overdensities out to z~5. Our results yield that 11/23 (48%) JCMT/AzTEC 1.1mm SMGs occupy overdense environments. Considering the entire JCMT/AzTEC 1.1mm S/N>4 sample, and accounting for the expected fraction of spurious detections, yields that 35-61% of the SMGs in the S/N-limited sample occupy overdense environments. We perform an X-ray stacking analysis in the 0.5-2keV band using a 32" aperture and our SMG positions, and find statistically significant detections. For our z 2] subsample we find an average flux of (4.0+/-0.8)x10^{-16} [(1.3+/-0.5)x10^{-16}] erg/s/cm^2 and a corresponding total mass of M_200 = 2.8x10^{13} [2x10^{13}] MSol. Our results suggest a higher occurrence of SMGs occupying overdense environments at z>3, than at z<3. This may be understood if highly star forming galaxies can only be formed in the highest peaks of the density field tracing the most massive dark matter haloes at early cosmic epochs, while at later times cosmic structure may have matured sufficiently that more modest overdensities correspond to sufficiently massive haloes to form SMGs.
A Iovino - One of the best experts on this subject based on the ideXlab platform.
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A GROUP-GALAXY CROSS-CORRELATION FUNCTION ANALYSIS IN zCosmos
The Astrophysical Journal, 2012Co-Authors: A Iovino, P. Kampczyk, K. Kovac, F. Lamareille, J-f Le Borgne, V. Le Brun, C. Maier, M. Mignoli, R. Pelló, Y. PengAbstract:We present a group-galaxy cross-correlation analysis using a group catalog produced from the 16,500 spectra from the optical zCosmos galaxy survey. Our aim is to perform a consistency test in the redshift range 0.2 \textless= z \textless= 0.8 between the clustering strength of the groups and mass estimates that are based on the richness of the groups. We measure the linear bias of the groups by means of a group-galaxy cross-correlation analysis and convert it into mass using the bias-mass relation for a given cosmology, checking the systematic errors using realistic group and galaxy mock catalogs. The measured bias for the zCosmos groups increases with group richness as expected by the theory of cosmic structure formation and yields masses that are reasonably consistent with the masses estimated from the richness directly, considering the scatter that is obtained from the 24 mock catalogs. Some exceptions are the richest groups at high redshift (estimated to be more massive than 10(13.5) M-circle dot), for which the measured bias is significantly larger than for any of the 24 mock catalogs (corresponding to a 3 sigma effect), which is attributed to the extremely large structure that is present in the Cosmos field at z similar to 0.7. Our results are in general agreement with previous studies that reported unusually strong clustering in the Cosmos field.
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zCosmos a large vlt vimos redshift survey covering 0 z 3 in the Cosmos field
Astrophysical Journal Supplement Series, 2007Co-Authors: S J Lilly, Le O Fevre, A Renzini, G Zamorani, M Scodeggio, T Contini, C M Carollo, G Hasinger, J P Kneib, A IovinoAbstract:zCosmos is a large-redshift survey that is being undertaken in the Cosmos field using 600 hr of observation with the VIMOS spectrograph on the 8 m VLT. The survey is designed to characterize the environments of Cosmos galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCosmos survey consists of two parts: (1) zCosmosbright, a magnitude-limited I-band I_(AB) < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg^2 Cosmos ACS field, for which the survey parameters at z ~ 0.7 are designed to be directly comparable to those of the 2dFGRS at z ~ 0.1; and (2) zCosmos-deep, a survey of approximately 10,000 galaxies selected through color-selection criteria to have 1.4 < z < 3.0, within the central 1 deg^2. This paper describes the survey design and the construction of the target catalogs and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCosmos-bright targets and 977 zCosmos-deep targets have been obtained. These are briefly analyzed to demonstrate the characteristics that may be expected from zCosmos, and particularly zCosmos-bright, when it is finally completed between 2008 and 2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. These techniques bring the overall success rate in the zCosmos-bright so far to almost 90% and to above 97% in the 0.5 < z < 0.8 redshift range. Our zCosmos-deep spectra demonstrate the power of our selection techniques to isolate high-redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines.
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zCosmos a large vlt vimos redshift survey covering 0 z 3 in the Cosmos field
arXiv: Astrophysics, 2006Co-Authors: S J Lilly, Le O Fevre, A Renzini, G Zamorani, M Scodeggio, T Contini, C M Carollo, G Hasinger, J P Kneib, A IovinoAbstract:zCosmos is a large redshift survey that is being undertaken in the Cosmos field using 600 hours of observation with the VIMOS spectrograph on the 8-m VLT. The survey is designed to characterise the environments of Cosmos galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCosmos survey consists of two parts: (a) zCosmos-bright, a magnitude-limited I-band IAB < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg2 Cosmos ACS field and designed to mimic the parameters of the 2dfGRS; and (b) zCosmos-deep, a survey of approximately 10,000 galaxies selected through colour-selection criteria to have 1.4 < z < 3.0, within the central 1 deg2. This paper describes the survey design and the construction of the target catalogues, and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCosmos-bright targets and of 977 zCosmos-deep targets have been obtained. These are briefly analysed to demonstrate the characteristics that may be expected from zCosmos, and particularly zCosmos-bright, when it is finally completed between 2008-2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. Our zCosmos-deep spectra demonstrate the effectiveness of our selection techniques to isolate high redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines.
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zCosmos: A Large VLT/VIMOS redshift survey covering 0 < z < 3 in the Cosmos field
2006Co-Authors: S J Lilly, A Renzini, G Zamorani, M Scodeggio, T Contini, C M Carollo, G Hasinger, J P Kneib, O. Le Fevre, A IovinoAbstract:zCosmos is a large redshift survey that is being undertaken in the Cosmos field using 600 hours of observation with the VIMOS spectrograph on the 8-m VLT. The survey is designed to characterise the environments of Cosmos galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCosmos survey consists of two parts: (a) zCosmos-bright, a magnitude-limited I-band IAB < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg2 Cosmos ACS field and designed to mimic the parameters of the 2dfGRS; and (b) zCosmos-deep, a survey of approximately 10,000 galaxies selected through colour-selection criteria to have 1.4 < z < 3.0, within the central 1 deg2. This paper describes the survey design and the construction of the target catalogues, and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCosmos-bright targets and of 977 zCosmos-deep targets have been obtained. These are briefly analysed to demonstrate the characteristics that may be expected from zCosmos, and particularly zCosmos-bright, when it is finally completed between 2008-2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. Our zCosmos-deep spectra demonstrate the effectiveness of our selection techniques to isolate high redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines.
J P Kneib - One of the best experts on this subject based on the ideXlab platform.
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zCosmos a large vlt vimos redshift survey covering 0 z 3 in the Cosmos field
Astrophysical Journal Supplement Series, 2007Co-Authors: S J Lilly, Le O Fevre, A Renzini, G Zamorani, M Scodeggio, T Contini, C M Carollo, G Hasinger, J P Kneib, A IovinoAbstract:zCosmos is a large-redshift survey that is being undertaken in the Cosmos field using 600 hr of observation with the VIMOS spectrograph on the 8 m VLT. The survey is designed to characterize the environments of Cosmos galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCosmos survey consists of two parts: (1) zCosmosbright, a magnitude-limited I-band I_(AB) < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg^2 Cosmos ACS field, for which the survey parameters at z ~ 0.7 are designed to be directly comparable to those of the 2dFGRS at z ~ 0.1; and (2) zCosmos-deep, a survey of approximately 10,000 galaxies selected through color-selection criteria to have 1.4 < z < 3.0, within the central 1 deg^2. This paper describes the survey design and the construction of the target catalogs and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCosmos-bright targets and 977 zCosmos-deep targets have been obtained. These are briefly analyzed to demonstrate the characteristics that may be expected from zCosmos, and particularly zCosmos-bright, when it is finally completed between 2008 and 2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. These techniques bring the overall success rate in the zCosmos-bright so far to almost 90% and to above 97% in the 0.5 < z < 0.8 redshift range. Our zCosmos-deep spectra demonstrate the power of our selection techniques to isolate high-redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines.
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weak gravitational lensing with Cosmos galaxy selection and shape measurements
Astrophysical Journal Supplement Series, 2007Co-Authors: Alexie Leauthaud, J P Kneib, P Capak, Richard Massey, Jason Rhodes, David E Johnston, Catherine Heymans, Richard S Ellis, A. M. KoekemoerAbstract:With a primary goal of conducting precision weak-lensing measurements from space, the Cosmos survey has imaged the largest contiguous area observed by Hubble Space Telescope to date, using the Advanced Camera for Surveys (ACS). This is the first paper in a series in which we describe our strategy for addressing the various technical challenges in the production of weak-lensing measurements from Cosmos data. We first construct a source catalog from 575 ACS/WFC tiles (1.64 deg2) subsampled at a pixel scale of 0.03''. Defects and diffraction spikes are carefully removed, leaving a total of 1.2 × 106 objects to a limiting magnitude of F814W = 26.5. This catalog is made publicly available. Multiwavelength follow-up observations of the Cosmos field provide photometric redshifts for 73% of the source galaxies in the lensing catalog. We analyze and discuss the Cosmos redshift distribution and show broad agreement with other surveys to z ~ 1. Our next step is to measure the shapes of galaxies and correct them for the distortion induced by the time-varying ACS point-spread function and for charge transfer efficiency (CTE) effects. Simulated images are used to derive the shear susceptibility factors that are necessary in transforming shape measurements into unbiased shear estimators. For every galaxy we derive a shape measurement error and utilize this quantity to extract the intrinsic shape noise of the galaxy sample. Interestingly, our results indicate that intrinsic shape noise varies little with size, magnitude, or redshift. Representing a number density of 66 galaxies per arcmin2, the final Cosmos weak-lensing catalog contains 3.9 × 105 galaxies with accurate shape measurements. The properties of the Cosmos weak-lensing catalog described throughout this paper will provide key input numbers for the preparation and design of next-generation wide field space missions.
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zCosmos a large vlt vimos redshift survey covering 0 z 3 in the Cosmos field
arXiv: Astrophysics, 2006Co-Authors: S J Lilly, Le O Fevre, A Renzini, G Zamorani, M Scodeggio, T Contini, C M Carollo, G Hasinger, J P Kneib, A IovinoAbstract:zCosmos is a large redshift survey that is being undertaken in the Cosmos field using 600 hours of observation with the VIMOS spectrograph on the 8-m VLT. The survey is designed to characterise the environments of Cosmos galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCosmos survey consists of two parts: (a) zCosmos-bright, a magnitude-limited I-band IAB < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg2 Cosmos ACS field and designed to mimic the parameters of the 2dfGRS; and (b) zCosmos-deep, a survey of approximately 10,000 galaxies selected through colour-selection criteria to have 1.4 < z < 3.0, within the central 1 deg2. This paper describes the survey design and the construction of the target catalogues, and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCosmos-bright targets and of 977 zCosmos-deep targets have been obtained. These are briefly analysed to demonstrate the characteristics that may be expected from zCosmos, and particularly zCosmos-bright, when it is finally completed between 2008-2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. Our zCosmos-deep spectra demonstrate the effectiveness of our selection techniques to isolate high redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines.
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zCosmos: A Large VLT/VIMOS redshift survey covering 0 < z < 3 in the Cosmos field
2006Co-Authors: S J Lilly, A Renzini, G Zamorani, M Scodeggio, T Contini, C M Carollo, G Hasinger, J P Kneib, O. Le Fevre, A IovinoAbstract:zCosmos is a large redshift survey that is being undertaken in the Cosmos field using 600 hours of observation with the VIMOS spectrograph on the 8-m VLT. The survey is designed to characterise the environments of Cosmos galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCosmos survey consists of two parts: (a) zCosmos-bright, a magnitude-limited I-band IAB < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg2 Cosmos ACS field and designed to mimic the parameters of the 2dfGRS; and (b) zCosmos-deep, a survey of approximately 10,000 galaxies selected through colour-selection criteria to have 1.4 < z < 3.0, within the central 1 deg2. This paper describes the survey design and the construction of the target catalogues, and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCosmos-bright targets and of 977 zCosmos-deep targets have been obtained. These are briefly analysed to demonstrate the characteristics that may be expected from zCosmos, and particularly zCosmos-bright, when it is finally completed between 2008-2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. Our zCosmos-deep spectra demonstrate the effectiveness of our selection techniques to isolate high redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines.
G Hasinger - One of the best experts on this subject based on the ideXlab platform.
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The Cosmos2015 catalog: exploring the 1 < z < 6 universe with half a million galaxies
Astrophysical Journal Supplement, 2016Co-Authors: C. Laigle, G Hasinger, P Capak, H. J. Mccracken, O. Ilbert, B. C. Hsieh, I. Davidzon, J. D. Silverman, C. Pichon, J. CouponAbstract:We present the Cosmos2015(24) catalog, which contains precise photometric redshifts and stellar masses for more than half a million objects over the 2deg(2) Cosmos field. Including new YJHK(s) images from the UltraVISTA-DR2 survey, Y-band images from Subaru/Hyper-Suprime-Cam, and infrared data from the Spitzer Large Area Survey with the Hyper-Suprime-Cam Spitzer legacy program, this near-infrared-selected catalog is highly optimized for the study of galaxy evolution and environments in the early universe. To maximize catalog completeness for bluer objects and at higher redshifts, objects have been detected on a chi(2) sum of the YJHK(s) and z(++) images. The catalog contains similar to 6 x 10(5) objects in the 1.5 deg(2) UltraVISTA-DR2 region and similar to 1.5 x 10(5) objects are detected in the “ultra-deep stripes” (0.62 deg(2)) at K-s \textless= 24.7 (3 sigma, 3 `', AB magnitude). Through a comparison with the zCosmos-bright spectroscopic redshifts, we measure a photometric redshift precision of sigma(Delta z(1) (+ zs)) = 0.007 and a catastrophic failure fraction of eta = 0.5%. At 3 \textless z \textless 6, using the unique database of spectroscopic redshifts in Cosmos, we find sigma(Delta z(1) (+ zs)) = 0.021 and eta = 13.2%. The deepest regions reach a 90% completeness limit of 10(10)M(circle dot) to z = 4. Detailed comparisons of the color distributions, number counts, and clustering show excellent agreement with the literature in the same mass ranges. Cosmos2015 represents a unique, publicly available, valuable resource with which to investigate the evolution of galaxies within their environment back to the earliest stages of the history of the universe. The Cosmos2015 catalog is distributed via anonymous ftp and through the usual astronomical archive systems (CDS, ESO Phase 3, IRSA).
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zCosmos a large vlt vimos redshift survey covering 0 z 3 in the Cosmos field
Astrophysical Journal Supplement Series, 2007Co-Authors: S J Lilly, Le O Fevre, A Renzini, G Zamorani, M Scodeggio, T Contini, C M Carollo, G Hasinger, J P Kneib, A IovinoAbstract:zCosmos is a large-redshift survey that is being undertaken in the Cosmos field using 600 hr of observation with the VIMOS spectrograph on the 8 m VLT. The survey is designed to characterize the environments of Cosmos galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCosmos survey consists of two parts: (1) zCosmosbright, a magnitude-limited I-band I_(AB) < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg^2 Cosmos ACS field, for which the survey parameters at z ~ 0.7 are designed to be directly comparable to those of the 2dFGRS at z ~ 0.1; and (2) zCosmos-deep, a survey of approximately 10,000 galaxies selected through color-selection criteria to have 1.4 < z < 3.0, within the central 1 deg^2. This paper describes the survey design and the construction of the target catalogs and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCosmos-bright targets and 977 zCosmos-deep targets have been obtained. These are briefly analyzed to demonstrate the characteristics that may be expected from zCosmos, and particularly zCosmos-bright, when it is finally completed between 2008 and 2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. These techniques bring the overall success rate in the zCosmos-bright so far to almost 90% and to above 97% in the 0.5 < z < 0.8 redshift range. Our zCosmos-deep spectra demonstrate the power of our selection techniques to isolate high-redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines.
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zCosmos a large vlt vimos redshift survey covering 0 z 3 in the Cosmos field
arXiv: Astrophysics, 2006Co-Authors: S J Lilly, Le O Fevre, A Renzini, G Zamorani, M Scodeggio, T Contini, C M Carollo, G Hasinger, J P Kneib, A IovinoAbstract:zCosmos is a large redshift survey that is being undertaken in the Cosmos field using 600 hours of observation with the VIMOS spectrograph on the 8-m VLT. The survey is designed to characterise the environments of Cosmos galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCosmos survey consists of two parts: (a) zCosmos-bright, a magnitude-limited I-band IAB < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg2 Cosmos ACS field and designed to mimic the parameters of the 2dfGRS; and (b) zCosmos-deep, a survey of approximately 10,000 galaxies selected through colour-selection criteria to have 1.4 < z < 3.0, within the central 1 deg2. This paper describes the survey design and the construction of the target catalogues, and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCosmos-bright targets and of 977 zCosmos-deep targets have been obtained. These are briefly analysed to demonstrate the characteristics that may be expected from zCosmos, and particularly zCosmos-bright, when it is finally completed between 2008-2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. Our zCosmos-deep spectra demonstrate the effectiveness of our selection techniques to isolate high redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines.
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zCosmos: A Large VLT/VIMOS redshift survey covering 0 < z < 3 in the Cosmos field
2006Co-Authors: S J Lilly, A Renzini, G Zamorani, M Scodeggio, T Contini, C M Carollo, G Hasinger, J P Kneib, O. Le Fevre, A IovinoAbstract:zCosmos is a large redshift survey that is being undertaken in the Cosmos field using 600 hours of observation with the VIMOS spectrograph on the 8-m VLT. The survey is designed to characterise the environments of Cosmos galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCosmos survey consists of two parts: (a) zCosmos-bright, a magnitude-limited I-band IAB < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg2 Cosmos ACS field and designed to mimic the parameters of the 2dfGRS; and (b) zCosmos-deep, a survey of approximately 10,000 galaxies selected through colour-selection criteria to have 1.4 < z < 3.0, within the central 1 deg2. This paper describes the survey design and the construction of the target catalogues, and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCosmos-bright targets and of 977 zCosmos-deep targets have been obtained. These are briefly analysed to demonstrate the characteristics that may be expected from zCosmos, and particularly zCosmos-bright, when it is finally completed between 2008-2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. Our zCosmos-deep spectra demonstrate the effectiveness of our selection techniques to isolate high redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines.
S J Lilly - One of the best experts on this subject based on the ideXlab platform.
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The zCosmos redshift survey: the three-dimensional classification cube and bimodality in galaxy physical properties
Astronomy and Astrophysics - A&A, 2009Co-Authors: M. Mignoli, S J Lilly, G Zamorani, M Scodeggio, C M Carollo, Alessandro Cimatti, C. Halliday, L. Pozzetti, D. Vergani, T ContiniAbstract:Aims. We investigate the relationships between three main optical galaxy observables (spectral properties, colors, and morphology), exploiting the data set provided by the Cosmos/zCosmos survey. The purpose of this paper is to define a simple galaxy classification cube, with a carefully selected sample of ≈1000 galaxies. Methods: Using medium resolution spectra of the first 1k zCosmos-bright sample, optical photometry from the Subaru/Cosmos observations, and morphological measurements derived from ACS imaging, we analyze the properties of the galaxy population out to z ~ 1. Applying three straightforward classification schemes (spectral, photometric, and morphological), we identify two main galaxy types, which appear to be linked to the bimodality of galaxy population. The three parametric classifications constitute the axes of a “classification cube”. Results: A very good agreement exists between the classification from spectral data (quiescent/star-forming galaxies) and the one based on colors (red/blue galaxies). The third parameter (morphology) is not as well correlated with the first two; in fact, a good correlation between the spectral classification and the classification based on morphological analysis (early-/late-type galaxies) is achieved only after partially complementing the morphological classification with additional color information. Finally, analyzing the 3D-distribution of all galaxies in the sample, we find that about 85% of the galaxies show a fully concordant classification, being either quiescent, red, bulge-dominated galaxies (~20%) or star-forming, blue, disk-dominated galaxies (~65%). These results imply that the galaxy bimodality is a consistent behavior both in morphology, color, and dominant stellar population, at least out to z ~ 1. Based on observations undertaken at the European Southern Observatory (ESO) Very Large Telescope (VLT) under Large Program 175.A-0839. Also based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, operated by AURA Inc., under NASA contract NAS 5-26555, with the Subaru Telescope, operated by the National Astronomical Observatory of Japan, with the telescopes of the National Optical Astronomy Observatory, operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation, and with the Canada-France-Hawaii Telescope, operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France, and the University of Hawaii.
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zCosmos a large vlt vimos redshift survey covering 0 z 3 in the Cosmos field
Astrophysical Journal Supplement Series, 2007Co-Authors: S J Lilly, Le O Fevre, A Renzini, G Zamorani, M Scodeggio, T Contini, C M Carollo, G Hasinger, J P Kneib, A IovinoAbstract:zCosmos is a large-redshift survey that is being undertaken in the Cosmos field using 600 hr of observation with the VIMOS spectrograph on the 8 m VLT. The survey is designed to characterize the environments of Cosmos galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCosmos survey consists of two parts: (1) zCosmosbright, a magnitude-limited I-band I_(AB) < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg^2 Cosmos ACS field, for which the survey parameters at z ~ 0.7 are designed to be directly comparable to those of the 2dFGRS at z ~ 0.1; and (2) zCosmos-deep, a survey of approximately 10,000 galaxies selected through color-selection criteria to have 1.4 < z < 3.0, within the central 1 deg^2. This paper describes the survey design and the construction of the target catalogs and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCosmos-bright targets and 977 zCosmos-deep targets have been obtained. These are briefly analyzed to demonstrate the characteristics that may be expected from zCosmos, and particularly zCosmos-bright, when it is finally completed between 2008 and 2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. These techniques bring the overall success rate in the zCosmos-bright so far to almost 90% and to above 97% in the 0.5 < z < 0.8 redshift range. Our zCosmos-deep spectra demonstrate the power of our selection techniques to isolate high-redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines.
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zCosmos a large vlt vimos redshift survey covering 0 z 3 in the Cosmos field
arXiv: Astrophysics, 2006Co-Authors: S J Lilly, Le O Fevre, A Renzini, G Zamorani, M Scodeggio, T Contini, C M Carollo, G Hasinger, J P Kneib, A IovinoAbstract:zCosmos is a large redshift survey that is being undertaken in the Cosmos field using 600 hours of observation with the VIMOS spectrograph on the 8-m VLT. The survey is designed to characterise the environments of Cosmos galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCosmos survey consists of two parts: (a) zCosmos-bright, a magnitude-limited I-band IAB < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg2 Cosmos ACS field and designed to mimic the parameters of the 2dfGRS; and (b) zCosmos-deep, a survey of approximately 10,000 galaxies selected through colour-selection criteria to have 1.4 < z < 3.0, within the central 1 deg2. This paper describes the survey design and the construction of the target catalogues, and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCosmos-bright targets and of 977 zCosmos-deep targets have been obtained. These are briefly analysed to demonstrate the characteristics that may be expected from zCosmos, and particularly zCosmos-bright, when it is finally completed between 2008-2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. Our zCosmos-deep spectra demonstrate the effectiveness of our selection techniques to isolate high redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines.
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zCosmos: A Large VLT/VIMOS redshift survey covering 0 < z < 3 in the Cosmos field
2006Co-Authors: S J Lilly, A Renzini, G Zamorani, M Scodeggio, T Contini, C M Carollo, G Hasinger, J P Kneib, O. Le Fevre, A IovinoAbstract:zCosmos is a large redshift survey that is being undertaken in the Cosmos field using 600 hours of observation with the VIMOS spectrograph on the 8-m VLT. The survey is designed to characterise the environments of Cosmos galaxies from the 100 kpc scales of galaxy groups up to the 100 Mpc scale of the cosmic web and to produce diagnostic information on galaxies and active galactic nuclei. The zCosmos survey consists of two parts: (a) zCosmos-bright, a magnitude-limited I-band IAB < 22.5 sample of about 20,000 galaxies with 0.1 < z < 1.2 covering the whole 1.7 deg2 Cosmos ACS field and designed to mimic the parameters of the 2dfGRS; and (b) zCosmos-deep, a survey of approximately 10,000 galaxies selected through colour-selection criteria to have 1.4 < z < 3.0, within the central 1 deg2. This paper describes the survey design and the construction of the target catalogues, and briefly outlines the observational program and the data pipeline. In the first observing season, spectra of 1303 zCosmos-bright targets and of 977 zCosmos-deep targets have been obtained. These are briefly analysed to demonstrate the characteristics that may be expected from zCosmos, and particularly zCosmos-bright, when it is finally completed between 2008-2009. The power of combining spectroscopic and photometric redshifts is demonstrated, especially in correctly identifying the emission line in single-line spectra and in determining which of the less reliable spectroscopic redshifts are correct and which are incorrect. Our zCosmos-deep spectra demonstrate the effectiveness of our selection techniques to isolate high redshift galaxies at 1.4 < z < 3.0 and of VIMOS to measure their redshifts using ultraviolet absorption lines.
