Periodic Reporting for period 2 - LACEGAL (Latin American Chinese European Galaxy Formation Network)
Reporting period: 2019-03-01 to 2022-09-30
Spectacular breakthroughs in astronomy have been driven by a combination of observational advances and groundbreaking computer simulations. Simulations are now accepted as being essential for the interpretation and exploitation of data. Europe is a world leader in this area. The aim of this RISE project is to build on the highly successful FP7 LACEGAL IRSES to avoid fragmentation of expertise and concentration of supercomputer resources in a few groups. Our research program addresses key questions in galaxy formation and the large-scale structure of the Universe and is divided into 4 scientific work packages, covering different scales and physical processes: 1) Simulations of Milky-Way like galaxies 2) Simulations of the galaxy population 3) Dark matter physics 4) Large-scale structure of the universe/Cosmology.
This is important for society because astronomy has long held an interest for the general public and brings science to new audiences. The scientific focus of this RISE project is computer simulation of the formation of cosmic structures. These provide visually striking media that we have used to engage people at various outreach events. A further benefit for society is the training of early stage researchers in high performance computing and data science; computational cosmology and astronomy are challenging scientific problems that develop computing and analysis skills that are readily transferable outside academia.
The overall objectives of the LACEGAL RISE are to 1) avoid fragmentation of expertise across Europe 2) to build a new state-of-the-art in the simulation of cosmic structures from dwarf galaxies, through Milky Way analogues to the largest structures in the Universe 3) to build new research collaborations between leading European research centres and third countries.
This is important for society because astronomy has long held an interest for the general public and brings science to new audiences. The scientific focus of this RISE project is computer simulation of the formation of cosmic structures. These provide visually striking media that we have used to engage people at various outreach events. A further benefit for society is the training of early stage researchers in high performance computing and data science; computational cosmology and astronomy are challenging scientific problems that develop computing and analysis skills that are readily transferable outside academia.
The overall objectives of the LACEGAL RISE are to 1) avoid fragmentation of expertise across Europe 2) to build a new state-of-the-art in the simulation of cosmic structures from dwarf galaxies, through Milky Way analogues to the largest structures in the Universe 3) to build new research collaborations between leading European research centres and third countries.
Our research program has been underpinned by a vigorous series of secondments. 85 researchers have undertaken secondments for a period of 310 months. We have delivered 291/300 secondment months supported by the EU (97%). In addition, 18 months of secondments of research not funded by the EU have taken place.
The results of the project have been disseminated in 108 papers submitted or published in peer reviewed journals, all of which are available on the open access preprint server arXiv and in two conferences which received significant support from LACEGAL.
The main results so far are:
• An explanation of the origin of the observed decline in [O/Fe] (and [Mg/Fe]) with Galactocentric distance for high-metallicity stars ([Fe/H] > -1.1) based on a sample of halo stars selected within the Apache Point Observatory Galactic Evolution Experiment (APOGEE) fourteenth data release (DR14).
• The use of the state-of-the-art EAGLE simulation to study the oxygen abundance gradients of gas discs in galaxies at z = 0.
• The study of the evolution of assembly bias using a semi-analytical model of galaxy formation implemented in the Millennium-WMAP7 N-body simulation.
•The study of cosmic voids in the normal-branch Dvali-Gabadadze-Porrati (nDGP) braneworld models that are representative of a class of modified gravity theories where deviations from General Relativity are usually hidden by the Vainshtein screening in high-density environments.
•A study of 324 re-simulated clusters, which has investigated a range of properties of the halos that host clusters, the state of the gas in clusters and their galactic content (the Three Hundred project, which has featured in more than 20 papers, and which was supported by a LACEGAL workshop).
•The application of machine learning to decompose simulated galaxies into various components (e.g. thin disk, thick disk) to allow their stellar populations to be compared with observations.
The results of the project have been disseminated in 108 papers submitted or published in peer reviewed journals, all of which are available on the open access preprint server arXiv and in two conferences which received significant support from LACEGAL.
The main results so far are:
• An explanation of the origin of the observed decline in [O/Fe] (and [Mg/Fe]) with Galactocentric distance for high-metallicity stars ([Fe/H] > -1.1) based on a sample of halo stars selected within the Apache Point Observatory Galactic Evolution Experiment (APOGEE) fourteenth data release (DR14).
• The use of the state-of-the-art EAGLE simulation to study the oxygen abundance gradients of gas discs in galaxies at z = 0.
• The study of the evolution of assembly bias using a semi-analytical model of galaxy formation implemented in the Millennium-WMAP7 N-body simulation.
•The study of cosmic voids in the normal-branch Dvali-Gabadadze-Porrati (nDGP) braneworld models that are representative of a class of modified gravity theories where deviations from General Relativity are usually hidden by the Vainshtein screening in high-density environments.
•A study of 324 re-simulated clusters, which has investigated a range of properties of the halos that host clusters, the state of the gas in clusters and their galactic content (the Three Hundred project, which has featured in more than 20 papers, and which was supported by a LACEGAL workshop).
•The application of machine learning to decompose simulated galaxies into various components (e.g. thin disk, thick disk) to allow their stellar populations to be compared with observations.
85 researchers have benefited from the LACEGAL RISE secondments, gaining training in high performance computing and data analysis techniques. The research projects carried out during these secondments have led to progress beyond the current state-of-the-art: 1) the generation of galaxy catalogues from cosmological N-body simulations of standard and modified gravity models. 2) the establishment of the role of the environment in shaping galaxy properties. 3) the public release of a code to model the propagation of Lyman-alpha photons through the interstellar and intergalactic medium 4) the proposal of a new explanation for the magnitude of the cosmological constant 5) the elucidation of the physical process that shape the galaxy population.6) the release of the resimulations of galaxy clusters from the The Hundred Project.