Final Report Summary - PHYS.LSS (Cosmological Physics with future large-scale structure surveys)
The goal of cosmology is to understand the origin, composition and evolution of the Universe. The extremely successful standard cosmological model with only few parameters describes very well our Universe but leaves us with little understanding and with many open questions (what is dark energy? Is Einstein’s theory of gravity correct? What is the dark matter and what are its properties? Etc.)
These open questions have deep connections to fundamental physics, and even they may indicate that our theory of particles and field is incorrect or incomplete.
A huge experimental effort is both under way and being planned to address these questions. Most of the current effort is going towards large-scale structure surveys . In particular, three-dimensional maps of the galaxy (and dark matter via gravitational lensing) distribution covering a sizeable fraction of the volume of the observable Universe are being carried out and planned. One of these is the Sloan digital sky survey III, and in particular its sub-project called BOSS survey another one is DESI the Dark Energy Spectroscopic Instrument survey.
To extract the maximum information from these data sets and ensure scientific exploitation of these data requires also a theoretical effort, in modeling , model building, data analysis etc. This project aims at developing the necessary modeling to ensure the best scientific exploitation of these data with particular emphasis on what cosmology can teach us about fundamental physics.
To this end we have developed new techniques to simulate the distribution of dark matter from different types of initial conditions both standard and not (in particular we can now model massive neutrinos and their hierarchy as predicted by neutrino oscillations experiments and non-gaussianity motivated by inflationary models). We have also developed new statistical tools to analyze these surveys and new ways of modeling and interpreting the observations.
We have measured properties of neutrinos demonstrating that cosmology provides information on the nature of neutrinos that is highly competitive and complementary to particle physics/accelerator experiments. We have explored the synergy.
We have explored what constraints current and forthcoming data can impose on the nature of initial conditions (gaussianity, adiabaticity) and the nature of dark energy and how (wrong or incomplete) assumptions about the nature of initial conditions or the nature of dark energy might invalid the interpretation of current and future data. We have started proposing new ways to interpret observations as to protect oneself from this.
We have contributed to several data releases and analyses of the SDSS-III's Baryon Oscillation Spectroscopic Survey (BOSS) survey, which is mapping the spatial distribution of luminous red galaxies (LRGs) to detect the characteristic scale imprinted by baryon acoustic oscillations in the early universe. Sound waves that propagate in the early universe, like spreading ripples in a pond, imprint a characteristic scale on cosmic microwave background fluctuations and on the galaxy distribution. These fluctuations have evolved into today's walls and voids of galaxies, making this baryon acoustic oscillation (BAO) scale (about 150 Mpc) visible among galaxies today. This has been used to measure the expansion history of the Universe, and so to determine the properties of dark energy. BOSS data have also been used to constrain the growth of cosmological structures in different ways. We have been leading the work on one of these approaches. Puzzlingly enough, dark energy is still consistent with being a cosmological constant.
We have entered the DESI collaboration and started developing the tools to maximize the scientific return from this forthcoming , exceptional, data.
* Please, notice that this summary will be published
These open questions have deep connections to fundamental physics, and even they may indicate that our theory of particles and field is incorrect or incomplete.
A huge experimental effort is both under way and being planned to address these questions. Most of the current effort is going towards large-scale structure surveys . In particular, three-dimensional maps of the galaxy (and dark matter via gravitational lensing) distribution covering a sizeable fraction of the volume of the observable Universe are being carried out and planned. One of these is the Sloan digital sky survey III, and in particular its sub-project called BOSS survey another one is DESI the Dark Energy Spectroscopic Instrument survey.
To extract the maximum information from these data sets and ensure scientific exploitation of these data requires also a theoretical effort, in modeling , model building, data analysis etc. This project aims at developing the necessary modeling to ensure the best scientific exploitation of these data with particular emphasis on what cosmology can teach us about fundamental physics.
To this end we have developed new techniques to simulate the distribution of dark matter from different types of initial conditions both standard and not (in particular we can now model massive neutrinos and their hierarchy as predicted by neutrino oscillations experiments and non-gaussianity motivated by inflationary models). We have also developed new statistical tools to analyze these surveys and new ways of modeling and interpreting the observations.
We have measured properties of neutrinos demonstrating that cosmology provides information on the nature of neutrinos that is highly competitive and complementary to particle physics/accelerator experiments. We have explored the synergy.
We have explored what constraints current and forthcoming data can impose on the nature of initial conditions (gaussianity, adiabaticity) and the nature of dark energy and how (wrong or incomplete) assumptions about the nature of initial conditions or the nature of dark energy might invalid the interpretation of current and future data. We have started proposing new ways to interpret observations as to protect oneself from this.
We have contributed to several data releases and analyses of the SDSS-III's Baryon Oscillation Spectroscopic Survey (BOSS) survey, which is mapping the spatial distribution of luminous red galaxies (LRGs) to detect the characteristic scale imprinted by baryon acoustic oscillations in the early universe. Sound waves that propagate in the early universe, like spreading ripples in a pond, imprint a characteristic scale on cosmic microwave background fluctuations and on the galaxy distribution. These fluctuations have evolved into today's walls and voids of galaxies, making this baryon acoustic oscillation (BAO) scale (about 150 Mpc) visible among galaxies today. This has been used to measure the expansion history of the Universe, and so to determine the properties of dark energy. BOSS data have also been used to constrain the growth of cosmological structures in different ways. We have been leading the work on one of these approaches. Puzzlingly enough, dark energy is still consistent with being a cosmological constant.
We have entered the DESI collaboration and started developing the tools to maximize the scientific return from this forthcoming , exceptional, data.
* Please, notice that this summary will be published