The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform

S R S Varadhan - One of the best experts on this subject based on the ideXlab platform.

Stefano Borgani - One of the best experts on this subject based on the ideXlab platform.

  • Cosmology and fundamental physics with the Euclid satellite
    Living Reviews in Relativity, 2018
    Co-Authors: Luisa Amendola, Anastasios Avgoustidis, Tessa Baker, Camille Bonvin, Stephen Appleby, Alain Blanchard, Nicola Bartolo, Marco Baldi, David Bacon, Stefano Borgani
    Abstract:

    Euclid is a European Space Agency medium-class mission selected for launch in 2020 within the cosmic vision 2015–2025 program. The main goal of Euclid is to understand the origin of the accelerated expansion of the universe. Euclid will explore the expansion history of the universe and the evolution of cosmic structures by measuring shapes and red-shifts of galaxies as well as the distribution of clusters of galaxies over a large fraction of the sky. Although the main driver for Euclid is the nature of dark energy, Euclid science covers a vast range of topics, from cosmology to galaxy evolution to planetary research. In this review we focus on cosmology and fundamental physics, with a strong emphasis on science beyond the current standard models. We discuss five broad topics: dark energy and modified gravity, dark matter, initial conditions, basic assumptions and questions of methodology in the data analysis. This review has been planned and carried out within Euclid’s Theory Working Group and is meant to provide a guide to the scientific themes that will underlie the activity of the group during the preparation of the Euclid mission.

  • next generation cosmology constraints from the Euclid galaxy cluster survey
    Monthly Notices of the Royal Astronomical Society, 2016
    Co-Authors: Stefano Borgani, B Sartoris, A Biviano, C Fedeli, J Bartlett, M Costanzi, Carlo Giocoli, L Moscardini
    Abstract:

    We study the characteristics of the galaxy cluster samples expected from the European Space Agency's Euclid satellite and forecast constraints on parameters describing a variety of cosmological models. In this paper we use the same method of analysis already adopted in the Euclid Red Book, which is based on the Fisher matrix approach. Based on our analytical estimate of the cluster selection function in the photometric Euclid survey, we forecast the constraints on cosmological parameters corresponding to different extensions of the standard I \textgreater cold dark matter model. Using only Euclid clusters, we find that the amplitude of the matter power spectrum will be constrained to Delta sigma(8) = 0.0014 and the mass density parameter to Delta Omega(m) = 0.0011. The dynamical evolution of dark energy will be constrained to Delta w(0) = 0.03 and Delta w(a) = 0.2 with free curvature Omega(k), resulting in a (w(0), w(a)) figure of merit (FoM) of 291. In combination with Planck cosmic microwave background (CMB) constraints, the amplitude of primordial non-Gaussianity will be constrained to Delta f(NL) a parts per thousand integral 6.6 for the local shape scenario. The growth factor parameter gamma, which signals deviations from general relativity, will be constrained to Delta gamma = 0.02, and the neutrino density parameter to Delta Omega(nu) = 0.0013 (or Delta am(nu) = 0.01). Including the Planck CMB covariance matrix improves dark energy constraints to Delta w(0) = 0.02, Delta w(a) = 0.07, and a FoM = 802. Knowledge of the observable-cluster mass scaling relation is crucial to reach these accuracies. Imaging and spectroscopic capabilities of Euclid will enable internal mass calibration from weak lensing and the dynamics of cluster galaxies, supported by external cluster surveys.

L Bisigello - One of the best experts on this subject based on the ideXlab platform.

  • Euclid the selection of quiescent and star forming galaxies using observed colours
    Monthly Notices of the Royal Astronomical Society, 2020
    Co-Authors: L Bisigello, Ulrike Kuchner, Christopher J Conselice, S Andreon, M Bolzonella, B Garilli, A Humphrey, Claudia Maraston, M Moresco
    Abstract:

    The Euclid mission will observe well over a billion galaxies out to z ∼ 6 and beyond. This will offer an unrivalled opportunity to investigate several key questions for understanding galaxy formation and evolution. The first step for many of these studies will be the selection of a sample of quiescent and star-forming galaxies, as is often done in the literature by using well-known colour techniques such as the ‘UVJ’ diagram. However, given the limited number of filters available for the Euclid telescope, the recovery of such rest-frame colours will be challenging. We therefore investigate the use of observed Euclid colours, on their own and together with ground-based u-band observations, for selecting quiescent and star-forming galaxies. The most efficient colour combination, among the ones tested in this work, consists of the (u − VIS) and (VIS − J) colours. We find that this combination allows users to select a sample of quiescent galaxies complete to above ∼70 per cent and with less than 15 per cent contamination at redshifts in the range 0.75 65 per cent completeness level and contamination below 20 per cent at 1 < z < 2 for finding quiescent galaxies. In comparison, the sample of quiescent galaxies selected with the traditional UVJ technique is only ∼20 per cent complete at z < 3, when recovering the rest-frame colours using mock Euclid observations. This shows that our new methodology is the most suitable one when only Euclid bands, along with u-band imaging, are available.

  • Euclid the selection of quiescent and star forming galaxies using observed colours
    arXiv: Astrophysics of Galaxies, 2020
    Co-Authors: L Bisigello, Ulrike Kuchner, Christopher J Conselice, S Andreon, M Bolzonella, B Garilli, A Humphrey, Claudia Maraston, M Moresco
    Abstract:

    The Euclid mission will observe well over a billion galaxies out to $z\sim6$ and beyond. This will offer an unrivalled opportunity to investigate several key questions for understanding galaxy formation and evolution. The first step for many of these studies will be the selection of a sample of quiescent and star-forming galaxies, as is often done in the literature by using well known colour techniques such as the `UVJ' diagram. However, given the limited number of filters available for the Euclid telescope, the recovery of such rest-frame colours will be challenging. We therefore investigate the use of observed Euclid colours, on their own and together with ground-based u-band observations, for selecting quiescent and star-forming galaxies. The most efficient colour combination, among the ones tested in this work, consists of the (u-VIS) and (VIS-J) colours. We find that this combination allows users to select a sample of quiescent galaxies complete to above $\sim70\%$ and with less than 15$\%$ contamination at redshifts in the range $0.75 65\%$ completeness level and contamination below 20$\%$ at $1Euclid observations. This shows that our new methodology is the most suitable one when only Euclid bands, along with u-band imaging, are available.

B Sartoris - One of the best experts on this subject based on the ideXlab platform.

  • next generation cosmology constraints from the Euclid galaxy cluster survey
    Monthly Notices of the Royal Astronomical Society, 2016
    Co-Authors: Stefano Borgani, B Sartoris, A Biviano, C Fedeli, J Bartlett, M Costanzi, Carlo Giocoli, L Moscardini
    Abstract:

    We study the characteristics of the galaxy cluster samples expected from the European Space Agency's Euclid satellite and forecast constraints on parameters describing a variety of cosmological models. In this paper we use the same method of analysis already adopted in the Euclid Red Book, which is based on the Fisher matrix approach. Based on our analytical estimate of the cluster selection function in the photometric Euclid survey, we forecast the constraints on cosmological parameters corresponding to different extensions of the standard I \textgreater cold dark matter model. Using only Euclid clusters, we find that the amplitude of the matter power spectrum will be constrained to Delta sigma(8) = 0.0014 and the mass density parameter to Delta Omega(m) = 0.0011. The dynamical evolution of dark energy will be constrained to Delta w(0) = 0.03 and Delta w(a) = 0.2 with free curvature Omega(k), resulting in a (w(0), w(a)) figure of merit (FoM) of 291. In combination with Planck cosmic microwave background (CMB) constraints, the amplitude of primordial non-Gaussianity will be constrained to Delta f(NL) a parts per thousand integral 6.6 for the local shape scenario. The growth factor parameter gamma, which signals deviations from general relativity, will be constrained to Delta gamma = 0.02, and the neutrino density parameter to Delta Omega(nu) = 0.0013 (or Delta am(nu) = 0.01). Including the Planck CMB covariance matrix improves dark energy constraints to Delta w(0) = 0.02, Delta w(a) = 0.07, and a FoM = 802. Knowledge of the observable-cluster mass scaling relation is crucial to reach these accuracies. Imaging and spectroscopic capabilities of Euclid will enable internal mass calibration from weak lensing and the dynamics of cluster galaxies, supported by external cluster surveys.

M Moresco - One of the best experts on this subject based on the ideXlab platform.

  • Euclid the selection of quiescent and star forming galaxies using observed colours
    Monthly Notices of the Royal Astronomical Society, 2020
    Co-Authors: L Bisigello, Ulrike Kuchner, Christopher J Conselice, S Andreon, M Bolzonella, B Garilli, A Humphrey, Claudia Maraston, M Moresco
    Abstract:

    The Euclid mission will observe well over a billion galaxies out to z ∼ 6 and beyond. This will offer an unrivalled opportunity to investigate several key questions for understanding galaxy formation and evolution. The first step for many of these studies will be the selection of a sample of quiescent and star-forming galaxies, as is often done in the literature by using well-known colour techniques such as the ‘UVJ’ diagram. However, given the limited number of filters available for the Euclid telescope, the recovery of such rest-frame colours will be challenging. We therefore investigate the use of observed Euclid colours, on their own and together with ground-based u-band observations, for selecting quiescent and star-forming galaxies. The most efficient colour combination, among the ones tested in this work, consists of the (u − VIS) and (VIS − J) colours. We find that this combination allows users to select a sample of quiescent galaxies complete to above ∼70 per cent and with less than 15 per cent contamination at redshifts in the range 0.75 65 per cent completeness level and contamination below 20 per cent at 1 < z < 2 for finding quiescent galaxies. In comparison, the sample of quiescent galaxies selected with the traditional UVJ technique is only ∼20 per cent complete at z < 3, when recovering the rest-frame colours using mock Euclid observations. This shows that our new methodology is the most suitable one when only Euclid bands, along with u-band imaging, are available.

  • Euclid the selection of quiescent and star forming galaxies using observed colours
    arXiv: Astrophysics of Galaxies, 2020
    Co-Authors: L Bisigello, Ulrike Kuchner, Christopher J Conselice, S Andreon, M Bolzonella, B Garilli, A Humphrey, Claudia Maraston, M Moresco
    Abstract:

    The Euclid mission will observe well over a billion galaxies out to $z\sim6$ and beyond. This will offer an unrivalled opportunity to investigate several key questions for understanding galaxy formation and evolution. The first step for many of these studies will be the selection of a sample of quiescent and star-forming galaxies, as is often done in the literature by using well known colour techniques such as the `UVJ' diagram. However, given the limited number of filters available for the Euclid telescope, the recovery of such rest-frame colours will be challenging. We therefore investigate the use of observed Euclid colours, on their own and together with ground-based u-band observations, for selecting quiescent and star-forming galaxies. The most efficient colour combination, among the ones tested in this work, consists of the (u-VIS) and (VIS-J) colours. We find that this combination allows users to select a sample of quiescent galaxies complete to above $\sim70\%$ and with less than 15$\%$ contamination at redshifts in the range $0.75 65\%$ completeness level and contamination below 20$\%$ at $1Euclid observations. This shows that our new methodology is the most suitable one when only Euclid bands, along with u-band imaging, are available.