Download or read book Toward a New Level of Modeling of Environmental Effects on Galaxies written by Manuel Duarte and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Toward a New Level of Modeling of Environmental Effects on Galaxies written by Manuel Duarte and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxies lie in a large panel of environments from isolated galaxies, to pairs, groups or clusters. The environment is expected to have an impact on galaxy properties such as morphology, stellar formation, metallicity\ldots. Some studies already tried to quantify the importance of the global environment (linked to the dark matter halo mass) and the local environment (galaxy position in the group). These studies have shown that the environment plays a minor role except for low mass galaxies. But the quantification of the environment is difficult since detected groups in redshift space (the only one accessible by the observer) are very elongated, making it difficult to extract spherical groups in real space. If these quantification errors are too important, environment effects will not be measured correctly. Moreover, other physical processes are at work inside groups whose relative roles are not well understood. For example, major or minor mergers (rich or poor in gas, between satellite galaxies, or after the decay of the orbit of a satellite onto the central galaxy by dynamical friction), rapid flybys harassing galaxies, stripping of the interstellar gas by ram pressure or of the gaseous reservoir by tidal forces. Although semi-analytical codes of galaxy formation from initial conditions of a LambdaCDM Universe fit well a large set of observed relations, there are still some discrepancies that might be possibly explained by a lack of correct physical recipes of environmental effects in these models. Our goal with this thesis is to have a detailed comprehension of the role of environment on galaxy properties, and finally determine the major physical processes in the modulation of these properties with both local and global environment. For this, an optimal extraction of galaxy groups from the projected phase space is necessary. We performed a study and re-implementation of some existing group finder to estimate their strengths and weaknesses in the detection of galaxy groups. A galaxy mock catalogue in redshift space, designed to mimic the primary spectroscopic sample of the SDSS survey was created to apply several galaxy group algorithms. An advantage is the already known membership that we can compare to galaxy groups extracted from redshift space. Semi-analytical codes of galaxy formation give us such galaxy catalogs we transformed to be coherent with the vision of an observer. With these mock catalogues, we tested the very popular Friends-of-Friends grouping algorithm. We determined the optimal linking lengths against the set of tests and optimal criterion we developed to judge the efficiency of an algorithm. It appears that this choice of linking lengths depends on the scientific goal to do with the group catalogue. A large part of the thesis consisted on the realization of a new grouping algorithm called MAGGIE (Models and Algorithm for Galaxy Groups, Interlopers and Environment), Bayesian and probabilistic. MAGGIE uses our priors acquired with analysis of cosmological simulations for large scale structure and of observations obtained from large galaxy surveys, to better constrain the selection of galaxy groups from redshift space. Comparison of MAGGIE with the FoF algorithm shows that MAGGIE is superior in avoiding the fragmentation of real space groups, the membership selection (completeness, reliability) and in the group properties (group mass, luminosity). The better performance of MAGGIE comes from its probabilistic nature, the use of astrophysical and cosmological priors, and the use of halo abundance matching technique linking central galaxy distributions (stellar mass or luminosity) to physical properties of dark matter halos. The future application of MAGGIE on galaxy surveys such as the Sloan Digital Sky Survey or the deeper Galaxy and Mass Assembly, taking care of their own observational problems, should improve our understanding of the modulation of galaxy properties with their global and local environments and physical processes operating inside galaxy groups.
Download or read book Toward a New Level of Modeling of Environmental Effects on Galaxies written by Manuel Duarte and published by . This book was released on 2014 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxies lie in a large panel of environments from isolated galaxies, to pairs, groups or clusters. The environment is expected to have an impact on galaxy properties such as morphology, stellar formation, metallicity\ldots. Some studies already tried to quantify the importance of the global environment (linked to the dark matter halo mass) and the local environment (galaxy position in the group). These studies have shown that the environment plays a minor role except for low mass galaxies. But the quantification of the environment is difficult since detected groups in redshift space (the only one accessible by the observer) are very elongated, making it difficult to extract spherical groups in real space. If these quantification errors are too important, environment effects will not be measured correctly. Moreover, other physical processes are at work inside groups whose relative roles are not well understood. For example, major or minor mergers (rich or poor in gas, between satellite galaxies, or after the decay of the orbit of a satellite onto the central galaxy by dynamical friction), rapid flybys harassing galaxies, stripping of the interstellar gas by ram pressure or of the gaseous reservoir by tidal forces. Although semi-analytical codes of galaxy formation from initial conditions of a LambdaCDM Universe fit well a large set of observed relations, there are still some discrepancies that might be possibly explained by a lack of correct physical recipes of environmental effects in these models. Our goal with this thesis is to have a detailed comprehension of the role of environment on galaxy properties, and finally determine the major physical processes in the modulation of these properties with both local and global environment. For this, an optimal extraction of galaxy groups from the projected phase space is necessary. We performed a study and re-implementation of some existing group finder to estimate their strengths and weaknesses in the detection of galaxy groups. A galaxy mock catalogue in redshift space, designed to mimic the primary spectroscopic sample of the SDSS survey was created to apply several galaxy group algorithms. An advantage is the already known membership that we can compare to galaxy groups extracted from redshift space. Semi-analytical codes of galaxy formation give us such galaxy catalogs we transformed to be coherent with the vision of an observer. With these mock catalogues, we tested the very popular Friends-of-Friends grouping algorithm. We determined the optimal linking lengths against the set of tests and optimal criterion we developed to judge the efficiency of an algorithm. It appears that this choice of linking lengths depends on the scientific goal to do with the group catalogue. A large part of the thesis consisted on the realization of a new grouping algorithm called MAGGIE (Models and Algorithm for Galaxy Groups, Interlopers and Environment), Bayesian and probabilistic. MAGGIE uses our priors acquired with analysis of cosmological simulations for large scale structure and of observations obtained from large galaxy surveys, to better constrain the selection of galaxy groups from redshift space. Comparison of MAGGIE with the FoF algorithm shows that MAGGIE is superior in avoiding the fragmentation of real space groups, the membership selection (completeness, reliability) and in the group properties (group mass, luminosity). The better performance of MAGGIE comes from its probabilistic nature, the use of astrophysical and cosmological priors, and the use of halo abundance matching technique linking central galaxy distributions (stellar mass or luminosity) to physical properties of dark matter halos. The future application of MAGGIE on galaxy surveys such as the Sloan Digital Sky Survey or the deeper Galaxy and Mass Assembly, taking care of their own observational problems, should improve our understanding of the modulation of galaxy properties with their global and local environments and physical processes operating inside galaxy groups.
Download or read book Star Formation Rates of Galaxies written by Andreas Zezas and published by Cambridge University Press. This book was released on 2021-04-29 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Star-formation is one of the key processes that shape the current state and evolution of galaxies. This volume provides a comprehensive presentation of the different methods used to measure the intensity of recent or on-going star-forming activity in galaxies, discussing their advantages and complications in detail. It includes a thorough overview of the theoretical underpinnings of star-formation rate indicators, including topics such as stellar evolution and stellar spectra, the stellar initial mass function, and the physical conditions in the interstellar medium. The authors bring together in one place detailed and comparative discussions of traditional and new star-formation rate indicators, star-formation rate measurements in different spatial scales, and comparisons of star-formation rate indicators probing different stellar populations, along with the corresponding theoretical background. This is a useful reference for students and researchers working in the field of extragalactic astrophysics and studying star-formation in local and higher-redshift galaxies.
Download or read book Rising stars in Environmental psychology written by Giuseppe Carrus and published by Frontiers Media SA. This book was released on 2023-06-09 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Secular Evolution of Galaxies written by Jesús Falcón-Barroso and published by Cambridge University Press. This book was released on 2012 with total page 657 pages. Available in PDF, EPUB and Kindle. Book excerpt: The formation and evolution of galaxies is one of the most important topics in modern astrophysics. Secular evolution refers to the relatively slow dynamical evolution due to internal processes induced by a galaxy's spiral arms, bars, galactic winds, black holes and dark matter haloes. It plays an important role in the evolution of spiral galaxies with major consequences for galactic bulges, the transfer of angular momentum, and the distribution of a galaxy's constituent stars, gas and dust. This internal evolution is in turn the key to understanding and testing cosmological models of galaxy formation and evolution. Based on the twenty-third Winter School of the Canary Islands Institute of Astrophysics, this volume presents reviews from nine world-renowned experts on the observational and theoretical research into secular processes, and what these processes can tell us about the structure and formation of galaxies. The volume provides a firm grounding for graduate students and early career researchers working on galactic dynamics and galaxy evolution.
Download or read book Educational and Cultural Challenges of the European Sustainability Model written by María Dolores Sánchez Galera and published by Springer Nature. This book was released on 2020-03-11 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book provides a comprehensive overview of the European Sustainability Model which cannot be properly understood without taking into account the global governance trends surrounding the topic. The author offers a fresh analysis of both theory and praxis of sustainable development in the open-ended process of EU integration by shedding new light on the often-overlooked role that law and legal science should have within the educational and cultural domains. The monograph explores the necessity of new conceptual and methodological approaches in order to understand the emerging educational and cultural challenges when it comes to their integration and intersection with sustainability in today’s society, which desperately claims systemic transformations.
Download or read book Understanding and Solving Environmental Problems in the 21st Century written by R. Costanza and published by Elsevier. This book was released on 2002-06-05 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this book is to encourage integration of the natural and social sciences with the policy and design-making community, and thereby develop a deeper understanding of complex environmental problems. Its fundamental themes are: • integrated modeling and assessment • complex, adaptive, hierarchical systems • ecosystem services • science and decision-making • ecosystem health and human health • quality of life and the distribution of wealth and resources. This book will act as a state of the art assessment of integrated environmental science and its relation to real world problem solving. It is aimed not only at the academic community, but also as a sourcebook for managers, policy makers, and the informed public. It deals both with the state of the science and the level of consensus among scientists on key environmental issues. The concepts underlying this book were developed at the 2nd EcoSummit workshop held in Halifax, Nova Scotia, June, 2000, with active participation from all delegates, and attempts to present their collective view.
Download or read book The Sciencebook written by National Geographic and published by National Geographic Books. This book was released on 2011-08 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: Natural phenomena, revolutionary inventions, scientific facts, and the most up-to-date questions are all explained in detailed text that is complemented by visually arresting graphics. Six major sections are further broken down into subsections that encompass everything from microscopic life to nuclear power.
Download or read book Literature 1997 Part 1 written by Astronomisches Rechen-InstitutARI and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 1746 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astronomy and Astrophysics Abstracts is devoted to the recording, summarizing and indexing of astronomical publications throughout the world. Two volumes are scheduled to appear per year. Volume 67 records 10,903 papers covering besides the classical fields of astronomy and astrophysics such matters as space flights related to astronomy, lunar and planetary probes and satellites, meteorites and interplanetary matter, X rays and cosmic rays, quasars and pulsars. The abstracts are classified under more than one hundred subject categories thus permitting quick surveying of the bulk of material published on the same topic within six months. For instance, this volume records 119 papers on minor planets, 155 papers on supernovae, and 554 papers on cosmology.
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 998 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of Research of the National Bureau of Standards written by United States. National Bureau of Standards and published by . This book was released on 1979 with total page 1132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Galaxy Formation and Evolution written by Houjun Mo and published by Cambridge University Press. This book was released on 2010-05-20 with total page 841 pages. Available in PDF, EPUB and Kindle. Book excerpt: A coherent introduction for researchers in astronomy, particle physics, and cosmology on the formation and evolution of galaxies.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976-05 with total page 912 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book INIS Atomindex written by and published by . This book was released on 1983 with total page 1566 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Spatial Grasp Model written by Peter Simon Sapaty and published by Emerald Group Publishing. This book was released on 2023-01-30 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Spatial Grasp Model suggests uses beyond the theoretical, including the examination of hurricanes and forest fires. Investigating group behaviour of ocean animals, discovery of unknown terrain features, and path-findings in large transport networks truly demonstrates the real-world application of SGL.
Download or read book Laudato Si written by Pope Francis and published by Our Sunday Visitor. This book was released on 2015-07-18 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: “In the heart of this world, the Lord of life, who loves us so much, is always present. He does not abandon us, he does not leave us alone, for he has united himself definitively to our earth, and his love constantly impels us to find new ways forward. Praise be to him!” – Pope Francis, Laudato Si’ In his second encyclical, Laudato Si’: On the Care of Our Common Home, Pope Francis draws all Christians into a dialogue with every person on the planet about our common home. We as human beings are united by the concern for our planet, and every living thing that dwells on it, especially the poorest and most vulnerable. Pope Francis’ letter joins the body of the Church’s social and moral teaching, draws on the best scientific research, providing the foundation for “the ethical and spiritual itinerary that follows.” Laudato Si’ outlines: The current state of our “common home” The Gospel message as seen through creation The human causes of the ecological crisis Ecology and the common good Pope Francis’ call to action for each of us Our Sunday Visitor has included discussion questions, making it perfect for individual or group study, leading all Catholics and Christians into a deeper understanding of the importance of this teaching.
