Rubin-Euclid Derived Data Products:Initial Recommendations

This report is the result of a joint discussion between the Rubin and Euclid scientific communities. The work presented in this report was focused on designing and recommending an initial set of Derived Data products (DDPs) that could realize the science goals enabled by joint processing. All interested Rubin and Euclid data rights holders were invited to contribute via an online discussion forum and a series of virtual meetings. Strong interest in enhancing science with joint DDPs emerged from across a wide range of astrophysical domains: Solar System, the Galaxy, the Local Volume, from the nearby to the primaeval Universe, and cosmology

Ricostruzione delle condizioni iniziali per la formazione delle strutture cosmiche

In questa tesi verranno presentati i vari metodi utilizzati per affrontare il problema di ricostruzione delle condizioni iniziali che hanno condotto alla formazione delle strutture cosmiche osservate. Verranno prima presentati due metodi storicamente importanti, il principio variazionale di Peebles e il metodo Potent, e si passerà poi ad una riformulazione del problema che garantisca l'unicità della soluzione. Si esaminerà infine il metodo Monge-Ampère-Kantorovich mostrando come esso fornisca una soluzione unica al di fuori delle regioni di multistreaming

Campo di velocità e densità su scala cosmologica : modellizzazione via tecniche di ricostruzione non lineare e applicazione a survey cosmologiche

Un nouvel algorithme de reconstruction entièrement non-linéaire, basé sur le principe de moindre action, extension du Fast Action Minimization method (Nusser & Branchini, 2000), conçu pour applications aux sondages spectroscopiques de galaxies, est présenté. Sa capacité de reconstruire le champ de vitesse à partir du champ de densité observé et testée sur des catalogues de halo de matière noire: les trajectoires de 10^6 halos sont tracées en arrier dans le temps, bien au-delà de l'approximation lagrangienne du premier ordre. Les vittes propres sont modélisées avec succès à la fois dans l'espace réel et dans l'espace du redshift. Le nouvel algorithme est utilisé pour déterminer avec plud grande précision l'échelle des Oscillations Acoustiques de Baryons (BAO) à partir de la fonction de corrélation à deux points. Des tests sur des catalogues de halos de matière montrent comment le nouvel algorithme récupère avec succès les BAO dans l'espace réel et du redshift, également pour des catalogues synthétiques (mocks) exceptionnelles où la signature des BAO est à la mauvaise échelle où absent. Cette technique se révèle plus puissante que l'approximation linéaire, en fournissant une mesure non baiaisée de l'échelle BAO. L'algorithme est ensuite testée sur des mocks de galaxies à faible redshift spécifiquement conçues pour correspondre au functions de corrélation des galaxies lumineuses rouges du catalogue SDSS-DR12. Enfin, l'application à l'analyse des vides cosmiques est présentée, montrant la grande potentialité d'une modélisation non-linéaire du champ de vitesse pour restaurer l'isotropie intrinsèque des videsA new fully non-linear reconstruction algorithm, based on the least-action principle and extending the Fast Action Minimisation method by is presented, intended for applications with the next-generation massive spectroscopic surveys. Its capability of recovering the velocity field starting from the observed density field is tested on dark-matter halo catalogues simulation to trace the trajectories of up to 10^6 haloes backward-in-time. Both in real and redshift-space it successfully recovers the peculiar velocities. The new algorithm is first employed for the accurate recovery of the Baryonic Acoustic Oscillations (BAO) scale in two-point correlation functions. Tests on dark-matter halo catalogues show how the new algorithm successfully recovers the BAO feature in real and redshift-space, also for anomalous samples showing misplaced or absent signature of BAO. A comparison with the first-order Lagrangian reconstruction is presented, showing that this techniques outperforms the linear approximation in recovering an unbiased measurement of the BAO scale. A second version of the algorithm accounting for the survey geometry and the bias of tracers is finally tested on low-redshift galaxy samples extracted form mocks specifically designed to match the SDSS-DR12 LRG clustering. The analysis of the anisotropic clustering indicates the non-linear reconstruction as a fundamental tool to brake the degeneracy between redshift-space distortion and the Alcock-Paczynski effect. Finally the application to the cosmic voids analysis is introduced, showing the great potentiality of a non-linear modelling of the velocity field in restoring the intrinsic isotropy of void

BAO reconstruction: a swift numerical action method for massive spectroscopic surveys

none4A new fully non-linear reconstruction algorithm for the accurate recovery of the baryonic acoustic oscillations (BAO) scale in two-point correlation functions is proposed, based on the least action principle and extending the Fast Action Minimisation method by Nusser & Branchini (2000). Especially designed for massive spectroscopic surveys, it is tested on dark matter halo catalogues extracted from the DEUS-FUR Lambda cold dark matter simulation (Reverdy et al. 2015) to trace the trajectories of up to {˜ }207 000 haloes backward in time, well beyond the first-order Lagrangian approximation. The new algorithm successfully recovers the BAO feature in real and redshift space in both the monopole and the anisotropic two-point correlation function, also for anomalous samples showing misplaced or absent signature of BAO. In redshift space, the non-linear displacement parameter ΣNL is reduced from 11.8± 0.3 h^{-1} Mpc at redshift z = 0 to 4.0± 0.5 h^{-1} Mpc at z ≃ 37 after reconstruction. A comparison with the first-order Lagrangian reconstruction is presented, showing that these techniques outperform the linear approximation in recovering an unbiased measurement of the acoustic scale.mixedSarpa, E; Schimd, C; Branchini, E; Matarrese, SSarpa, E; Schimd, C; Branchini, E; Matarrese,

Tracing the environmental history of observed galaxies via extended fast action minimization method

We present a novel application of the extended Fast Action Minimization method (eFAM) aimed at assessing the role of the environment in shaping galaxy evolution. We validate our approach by testing eFAM predictions against the Magneticum hydrodynamical simulation. We consider the z~0 snapshot of the simulation as our observed catalogue and use the reconstructed trajectories of galaxies to model the evolution of cosmic structures. At the statistical level, the fraction of volume (VFF) occupied by voids, sheets, filaments, and clusters in the reconstructed catalogues agrees within $1\sigma$ with the VFF estimated from the high-redshift snapshots of the simulation. The local accuracy of eFAM structures is evaluated by computing their purity with respect to the simulated catalogues, P, at the cells of a regular grid. Up to z=1.2, clusters have 0.58<P<0.93, filaments vary in 0.90<P<0.99, sheets show 0.78<P<0.92, and voids are best identified with 0.90<P<0.92. As redshift increases, comparing reconstructed tracers and simulated galaxies becomes more difficult due to their different biases and number densities and the purity decreases to P~0.6. We retrieve the environmental history of individual galaxies by tracing their trajectories through the cosmic web and relate their observed gas fraction, $f_\mathrm{gas}$, with the time spent within different structures. For galaxies in clusters and filaments, eFAM reproduces the variation of $f_\mathrm{gas}$ as a function of the redshift of accretion/infall as traced by the simulations with a 1.5 $\sigma$ statistical agreement (which decreases to 2.5 $\sigma$ statistical agreement for low-mass galaxies in filaments). These results support the application of eFAM to observational data to study the environmental dependence of observed galaxy properties, offering a complementary approach to that based on light-cone observations

Tracing the environmental history of observed galaxies via extended fast action minimization method

We present a novel application of the extended Fast Action Minimization method (eFAM) aimed at assessing the role of the environment in shaping galaxy evolution. We validate our approach by testing eFAM predictions against the Magneticum hydrodynamical simulation. We consider the z~0 snapshot of the simulation as our observed catalogue and use the reconstructed trajectories of galaxies to model the evolution of cosmic structures. At the statistical level, the fraction of volume (VFF) occupied by voids, sheets, filaments, and clusters in the reconstructed catalogues agrees within $1\sigma$ with the VFF estimated from the high-redshift snapshots of the simulation. The local accuracy of eFAM structures is evaluated by computing their purity with respect to the simulated catalogues, P, at the cells of a regular grid. Up to z=1.2, clusters have 0.58<P<0.93, filaments vary in 0.90<P<0.99, sheets show 0.78<P<0.92, and voids are best identified with 0.90<P<0.92. As redshift increases, comparing reconstructed tracers and simulated galaxies becomes more difficult due to their different biases and number densities and the purity decreases to P~0.6. We retrieve the environmental history of individual galaxies by tracing their trajectories through the cosmic web and relate their observed gas fraction, $f_\mathrm{gas}$, with the time spent within different structures. For galaxies in clusters and filaments, eFAM reproduces the variation of $f_\mathrm{gas}$ as a function of the redshift of accretion/infall as traced by the simulations with a 1.5 $\sigma$ statistical agreement (which decreases to 2.5 $\sigma$ statistical agreement for low-mass galaxies in filaments). These results support the application of eFAM to observational data to study the environmental dependence of observed galaxy properties, offering a complementary approach to that based on light-cone observations

Tracing the environmental history of observed galaxies via extended fast action minimization method

International audienceWe present a novel application of the extended Fast Action Minimization method (eFAM) aimed at assessing the role of the environment in shaping galaxy evolution. We validate our approach by testing eFAM predictions against the Magneticum hydrodynamical simulation. We consider the z~0 snapshot of the simulation as our observed catalogue and use the reconstructed trajectories of galaxies to model the evolution of cosmic structures. At the statistical level, the fraction of volume (VFF) occupied by voids, sheets, filaments, and clusters in the reconstructed catalogues agrees within $1\sigma$ with the VFF estimated from the high-redshift snapshots of the simulation. The local accuracy of eFAM structures is evaluated by computing their purity with respect to the simulated catalogues, P, at the cells of a regular grid. Up to z=1.2, clusters have 0.58<P<0.93, filaments vary in 0.90<P<0.99, sheets show 0.78<P<0.92, and voids are best identified with 0.90<P<0.92. As redshift increases, comparing reconstructed tracers and simulated galaxies becomes more difficult due to their different biases and number densities and the purity decreases to P~0.6. We retrieve the environmental history of individual galaxies by tracing their trajectories through the cosmic web and relate their observed gas fraction, $f_\mathrm{gas}$, with the time spent within different structures. For galaxies in clusters and filaments, eFAM reproduces the variation of $f_\mathrm{gas}$ as a function of the redshift of accretion/infall as traced by the simulations with a 1.5 $\sigma$ statistical agreement (which decreases to 2.5 $\sigma$ statistical agreement for low-mass galaxies in filaments). These results support the application of eFAM to observational data to study the environmental dependence of observed galaxy properties, offering a complementary approach to that based on light-cone observations

Tracing the environmental history of observed galaxies via extended fast action minimization method

We present a novel application of the extended Fast Action Minimization method (eFAM) aimed at assessing the role of the environment in shaping galaxy evolution. We validate our approach by testing eFAM predictions against the Magneticum hydrodynamical simulation. We consider the z~0 snapshot of the simulation as our observed catalogue and use the reconstructed trajectories of galaxies to model the evolution of cosmic structures. At the statistical level, the fraction of volume (VFF) occupied by voids, sheets, filaments, and clusters in the reconstructed catalogues agrees within $1\sigma$ with the VFF estimated from the high-redshift snapshots of the simulation. The local accuracy of eFAM structures is evaluated by computing their purity with respect to the simulated catalogues, P, at the cells of a regular grid. Up to z=1.2, clusters have 0.58<P<0.93, filaments vary in 0.90<P<0.99, sheets show 0.78<P<0.92, and voids are best identified with 0.90<P<0.92. As redshift increases, comparing reconstructed tracers and simulated galaxies becomes more difficult due to their different biases and number densities and the purity decreases to P~0.6. We retrieve the environmental history of individual galaxies by tracing their trajectories through the cosmic web and relate their observed gas fraction, $f_\mathrm{gas}$, with the time spent within different structures. For galaxies in clusters and filaments, eFAM reproduces the variation of $f_\mathrm{gas}$ as a function of the redshift of accretion/infall as traced by the simulations with a 1.5 $\sigma$ statistical agreement (which decreases to 2.5 $\sigma$ statistical agreement for low-mass galaxies in filaments). These results support the application of eFAM to observational data to study the environmental dependence of observed galaxy properties, offering a complementary approach to that based on light-cone observations