The morphology of haloes inform about both cosmological and galaxy formation models. We use the M... more The morphology of haloes inform about both cosmological and galaxy formation models. We use the Minkowski Functionals (MFs) to characterize the actual morphology of haloes, only partially captured by smooth density profile, going beyond the spherical or ellipsoidal symmetry. We employ semi-analytical haloes with NFW and $\alpha\beta\gamma$-profile and spherical or ellipsoidal shape to obtain a clear interpretation of MFs as function of inner and outer slope, concentration and sphericity parameters. We use the same models to mimic the density profile of $N$-body haloes, showing that their MFs clearly differ as sensitive to internal substructures. This highlights the benefit of MFs at the halo scales as promising statistics to improve the spatial modeling of dark matter, crucial for future lensing, Sunyaev-Zel'dovich, and X-ray mass maps as well as dark matter detection based on high-accuracy data.
Journal of Cosmology and Astroparticle Physics, 2022
We extend the analysis of Pace et al. [1] by considering the virialization process in the extende... more We extend the analysis of Pace et al. [1] by considering the virialization process in the extended spherical collapse model for clustering dark-energy models, i.e., accounting for dark-energy fluctuations. Differently from the standard approach, here virialization is naturally achieved by properly modelling deviations from sphericity due to shear and rotation induced by tidal interactions. We investigate the time evolution of the virial overdensity Δvir in seven clustering dynamical dark energy models and compare the results to the ΛCDM model and to the corresponding smooth dark-energy models. Taking into account all the appropriate corrections, we deduce the abundance of convergence peaks for Rubin Observatory-LSST and Euclid-like weak-lensing surveys, of Sunyaev-Zel'dovich peaks for a Simon Observatory-like CMB survey, and of X-ray peaks for an eROSITA-like survey. Despite the tiny differences in Δvir between clustering and smooth dark-energy models, owing to the large volumes...
Monthly Notices of the Royal Astronomical Society, 2022
Galaxy clusters are biased tracers of the underlying matter density field. At very large radii be... more Galaxy clusters are biased tracers of the underlying matter density field. At very large radii beyond about 10 Mpc/h, the shear profile shows evidence of a second-halo term. This is related to the correlated matter distribution around galaxy clusters and proportional to the so-called halo bias. We present an observational analysis of the halo bias-mass relation based on the AMICO galaxy cluster catalog, comprising around 7000 candidates detected in the third release of the KiDS survey. We split the cluster sample into 14 redshift-richness bins and derive the halo bias and the virial mass in each bin by means of a stacked weak lensing analysis. The observed halo bias-mass relation and the theoretical predictions based on the ΛCDM standard cosmological model show an agreement within 2σ. The mean measurements of bias and mass over the full catalog give M200c = (4.9 ± 0.3) × 1013M⊙/h and $b_h \sigma _8^2 = 1.2 \pm 0.1$. With the additional prior of a bias-mass relation from numerical si...
Through a Lens Darkly According to recent measurements, 72% of the energy content in the universe... more Through a Lens Darkly According to recent measurements, 72% of the energy content in the universe is in the form of dark energy, a gravitationally repulsive constituent that is powering the accelerating expansion of the universe but whose nature is unknown. Now, Jullo et al. (p. 924 ) show how observations of systems of multiple images produced by the strong gravitational lensing effect of a single mass distribution can be used to constrain the properties of dark energy. Applied to the cluster Abel 1689—a galaxy cluster that is known for its lensing properties—and combined with the results of other techniques, this method brings down the overall error in the equation of state parameter of dark energy by 30%.
Weak lensing tomography is a powerful new tool for constraining cosmology in a way that is indepe... more Weak lensing tomography is a powerful new tool for constraining cosmology in a way that is independent of both the physics and systematics of other methods. By measuring the variation in the weak lensing shear as a function of background galaxy redshift, we make a purely geometric measurement of the expansion rate history. This has the ability to measure dark
Context. Dark energy can be investigated in two complementary ways, by considering either general... more Context. Dark energy can be investigated in two complementary ways, by considering either general parameterizations or physically well-defined models. This article follows the second route and explores the observational constraints on quintessence models where the acceleration of our universe is driven by a slow-rolling scalar field. The analysis focuses on cosmic shear, combined with type Ia supernovae data and cosmic microwave background observations. Aims. This article examines how weak lensing surveys can constrain dark energy, how they complement supernovae data to lift some degeneracies and addresses some issues regarding the limitations due to the lack of knowledge concerning the non-linear regime. Methods. Using a Boltzmann code that includes quintessence models and the computation of weak lensing observables, we determine the shear power spectrum and several two-point statistics. The non-linear regime is described by two different mappings. The likelihood analysis is based ...
arXiv: Instrumentation and Methods for Astrophysics, 2018
The "Square Kilometre Array" (SKA) is a large international radio telescope project cha... more The "Square Kilometre Array" (SKA) is a large international radio telescope project characterised, as suggested by its name, by a total collecting area of approximately one square kilometre, and consisting of several interferometric arrays to observe at metric and centimetric wavelengths. The deployment of the SKA will take place in two sites, in South Africa and Australia, and in two successive phases. From its Phase 1, the SKA will be one of the most formidable scientific machines ever deployed by mankind, and by far the most impressive in terms of data throughput and required computing power. With the participation of almost 200 authors from forty research institutes and six private companies, the publication of this French SKA white paper illustrates the strong involvement in the SKA project of the French astronomical community and of a rapidly growing number of major scientific and technological players in the fields of Big Data, high performance computing, energy pro...
arXiv: Instrumentation and Methods for Astrophysics, 2017
MSE is an 11.25m aperture observatory with a 1.5 square degree field of view that will be fully d... more MSE is an 11.25m aperture observatory with a 1.5 square degree field of view that will be fully dedicated to multi-object spectroscopy. More than 3200 fibres will feed spectrographs operating at low (R ~ 2000 - 3500) and moderate (R ~ 6000) spectral resolution, and approximately 1000 fibers will feed spectrographs operating at high (R ~ 40000) resolution. MSE is designed to enable transformational science in areas as diverse as tomographic mapping of the interstellar and intergalactic media; the in-situ chemical tagging of thick disk and halo stars; connecting galaxies to their large scale structure; measuring the mass functions of cold dark matter sub-halos in galaxy and cluster-scale hosts; reverberation mapping of supermassive black holes in quasars; next generation cosmological surveys using redshift space distortions and peculiar velocities. MSE is an essential follow-up facility to current and next generations of multi-wavelength imaging surveys, including LSST, Gaia, Euclid, ...
Galaxy clusters exhibit a rich morphology during the early and intermediate stages of mass assemb... more Galaxy clusters exhibit a rich morphology during the early and intermediate stages of mass assembly, especially beyond their boundary. A classification scheme based on shapefinders deduced from the Minkowski functionals is examined to fully account for the morphological diversity of galaxy clusters, including relaxed and merging clusters, clusters fed by filamentary structures, and cluster-pair bridges. These configurations are conveniently treated with idealised geometric models and analytical formulae, some of which are novel. Examples from CLASH and LC2 clusters and observed cluster-pair bridges are discussed.
The mean and the scatter of the H i content of a dark matter halo as a function of the halo mass ... more The mean and the scatter of the H i content of a dark matter halo as a function of the halo mass are useful statistics that can be used to test models of structure and galaxy formation. We investigate the possibility of constraining this H i–halo mass relation (HIHMR) from intensity maps of the redshifted 21-cm line. In particular, we use the geometry and topology of the brightness-temperature isocontours in a single frequency channel as quantified by the Minkowski functionals. First, we generate mock maps from a large N-body simulation considering the impact of thermal noise and foreground removal. We then use the Fisher information formalism to forecast constraints on a parametric model for the HIHMR. We consider a 20 000 deg2 survey (originally proposed for dark energy science) conducted with the Square Kilometre Array Phase 1 (SKA-1) MID observatory operating in single-dish mode. For a channel bandwidth of 2 MHz, we show that an integration time of a few$\, \times \, 10^4$ s pe...
ABSTRACT This review surveys the signatures of dark energy on large-scale structures (LSS) at low... more ABSTRACT This review surveys the signatures of dark energy on large-scale structures (LSS) at low redshift, focusing on observables relying on the evolution of matter perturbations, i.e. on the growth of structures. We discuss in particular galaxy clustering, weak-gravitational lensing by LSS, also called cosmic-shear, and Lyman-alpha forest, which respectively describe the 3D, 2D, and 1D power spectrum of matter density fluctuations. We illustrate some example of data analysis for each these observables.
The morphology of haloes inform about both cosmological and galaxy formation models. We use the M... more The morphology of haloes inform about both cosmological and galaxy formation models. We use the Minkowski Functionals (MFs) to characterize the actual morphology of haloes, only partially captured by smooth density profile, going beyond the spherical or ellipsoidal symmetry. We employ semi-analytical haloes with NFW and $\alpha\beta\gamma$-profile and spherical or ellipsoidal shape to obtain a clear interpretation of MFs as function of inner and outer slope, concentration and sphericity parameters. We use the same models to mimic the density profile of $N$-body haloes, showing that their MFs clearly differ as sensitive to internal substructures. This highlights the benefit of MFs at the halo scales as promising statistics to improve the spatial modeling of dark matter, crucial for future lensing, Sunyaev-Zel'dovich, and X-ray mass maps as well as dark matter detection based on high-accuracy data.
Journal of Cosmology and Astroparticle Physics, 2022
We extend the analysis of Pace et al. [1] by considering the virialization process in the extende... more We extend the analysis of Pace et al. [1] by considering the virialization process in the extended spherical collapse model for clustering dark-energy models, i.e., accounting for dark-energy fluctuations. Differently from the standard approach, here virialization is naturally achieved by properly modelling deviations from sphericity due to shear and rotation induced by tidal interactions. We investigate the time evolution of the virial overdensity Δvir in seven clustering dynamical dark energy models and compare the results to the ΛCDM model and to the corresponding smooth dark-energy models. Taking into account all the appropriate corrections, we deduce the abundance of convergence peaks for Rubin Observatory-LSST and Euclid-like weak-lensing surveys, of Sunyaev-Zel'dovich peaks for a Simon Observatory-like CMB survey, and of X-ray peaks for an eROSITA-like survey. Despite the tiny differences in Δvir between clustering and smooth dark-energy models, owing to the large volumes...
Monthly Notices of the Royal Astronomical Society, 2022
Galaxy clusters are biased tracers of the underlying matter density field. At very large radii be... more Galaxy clusters are biased tracers of the underlying matter density field. At very large radii beyond about 10 Mpc/h, the shear profile shows evidence of a second-halo term. This is related to the correlated matter distribution around galaxy clusters and proportional to the so-called halo bias. We present an observational analysis of the halo bias-mass relation based on the AMICO galaxy cluster catalog, comprising around 7000 candidates detected in the third release of the KiDS survey. We split the cluster sample into 14 redshift-richness bins and derive the halo bias and the virial mass in each bin by means of a stacked weak lensing analysis. The observed halo bias-mass relation and the theoretical predictions based on the ΛCDM standard cosmological model show an agreement within 2σ. The mean measurements of bias and mass over the full catalog give M200c = (4.9 ± 0.3) × 1013M⊙/h and $b_h \sigma _8^2 = 1.2 \pm 0.1$. With the additional prior of a bias-mass relation from numerical si...
Through a Lens Darkly According to recent measurements, 72% of the energy content in the universe... more Through a Lens Darkly According to recent measurements, 72% of the energy content in the universe is in the form of dark energy, a gravitationally repulsive constituent that is powering the accelerating expansion of the universe but whose nature is unknown. Now, Jullo et al. (p. 924 ) show how observations of systems of multiple images produced by the strong gravitational lensing effect of a single mass distribution can be used to constrain the properties of dark energy. Applied to the cluster Abel 1689—a galaxy cluster that is known for its lensing properties—and combined with the results of other techniques, this method brings down the overall error in the equation of state parameter of dark energy by 30%.
Weak lensing tomography is a powerful new tool for constraining cosmology in a way that is indepe... more Weak lensing tomography is a powerful new tool for constraining cosmology in a way that is independent of both the physics and systematics of other methods. By measuring the variation in the weak lensing shear as a function of background galaxy redshift, we make a purely geometric measurement of the expansion rate history. This has the ability to measure dark
Context. Dark energy can be investigated in two complementary ways, by considering either general... more Context. Dark energy can be investigated in two complementary ways, by considering either general parameterizations or physically well-defined models. This article follows the second route and explores the observational constraints on quintessence models where the acceleration of our universe is driven by a slow-rolling scalar field. The analysis focuses on cosmic shear, combined with type Ia supernovae data and cosmic microwave background observations. Aims. This article examines how weak lensing surveys can constrain dark energy, how they complement supernovae data to lift some degeneracies and addresses some issues regarding the limitations due to the lack of knowledge concerning the non-linear regime. Methods. Using a Boltzmann code that includes quintessence models and the computation of weak lensing observables, we determine the shear power spectrum and several two-point statistics. The non-linear regime is described by two different mappings. The likelihood analysis is based ...
arXiv: Instrumentation and Methods for Astrophysics, 2018
The "Square Kilometre Array" (SKA) is a large international radio telescope project cha... more The "Square Kilometre Array" (SKA) is a large international radio telescope project characterised, as suggested by its name, by a total collecting area of approximately one square kilometre, and consisting of several interferometric arrays to observe at metric and centimetric wavelengths. The deployment of the SKA will take place in two sites, in South Africa and Australia, and in two successive phases. From its Phase 1, the SKA will be one of the most formidable scientific machines ever deployed by mankind, and by far the most impressive in terms of data throughput and required computing power. With the participation of almost 200 authors from forty research institutes and six private companies, the publication of this French SKA white paper illustrates the strong involvement in the SKA project of the French astronomical community and of a rapidly growing number of major scientific and technological players in the fields of Big Data, high performance computing, energy pro...
arXiv: Instrumentation and Methods for Astrophysics, 2017
MSE is an 11.25m aperture observatory with a 1.5 square degree field of view that will be fully d... more MSE is an 11.25m aperture observatory with a 1.5 square degree field of view that will be fully dedicated to multi-object spectroscopy. More than 3200 fibres will feed spectrographs operating at low (R ~ 2000 - 3500) and moderate (R ~ 6000) spectral resolution, and approximately 1000 fibers will feed spectrographs operating at high (R ~ 40000) resolution. MSE is designed to enable transformational science in areas as diverse as tomographic mapping of the interstellar and intergalactic media; the in-situ chemical tagging of thick disk and halo stars; connecting galaxies to their large scale structure; measuring the mass functions of cold dark matter sub-halos in galaxy and cluster-scale hosts; reverberation mapping of supermassive black holes in quasars; next generation cosmological surveys using redshift space distortions and peculiar velocities. MSE is an essential follow-up facility to current and next generations of multi-wavelength imaging surveys, including LSST, Gaia, Euclid, ...
Galaxy clusters exhibit a rich morphology during the early and intermediate stages of mass assemb... more Galaxy clusters exhibit a rich morphology during the early and intermediate stages of mass assembly, especially beyond their boundary. A classification scheme based on shapefinders deduced from the Minkowski functionals is examined to fully account for the morphological diversity of galaxy clusters, including relaxed and merging clusters, clusters fed by filamentary structures, and cluster-pair bridges. These configurations are conveniently treated with idealised geometric models and analytical formulae, some of which are novel. Examples from CLASH and LC2 clusters and observed cluster-pair bridges are discussed.
The mean and the scatter of the H i content of a dark matter halo as a function of the halo mass ... more The mean and the scatter of the H i content of a dark matter halo as a function of the halo mass are useful statistics that can be used to test models of structure and galaxy formation. We investigate the possibility of constraining this H i–halo mass relation (HIHMR) from intensity maps of the redshifted 21-cm line. In particular, we use the geometry and topology of the brightness-temperature isocontours in a single frequency channel as quantified by the Minkowski functionals. First, we generate mock maps from a large N-body simulation considering the impact of thermal noise and foreground removal. We then use the Fisher information formalism to forecast constraints on a parametric model for the HIHMR. We consider a 20 000 deg2 survey (originally proposed for dark energy science) conducted with the Square Kilometre Array Phase 1 (SKA-1) MID observatory operating in single-dish mode. For a channel bandwidth of 2 MHz, we show that an integration time of a few$\, \times \, 10^4$ s pe...
ABSTRACT This review surveys the signatures of dark energy on large-scale structures (LSS) at low... more ABSTRACT This review surveys the signatures of dark energy on large-scale structures (LSS) at low redshift, focusing on observables relying on the evolution of matter perturbations, i.e. on the growth of structures. We discuss in particular galaxy clustering, weak-gravitational lensing by LSS, also called cosmic-shear, and Lyman-alpha forest, which respectively describe the 3D, 2D, and 1D power spectrum of matter density fluctuations. We illustrate some example of data analysis for each these observables.
Uploads
Papers