Gravitational Dynamics Of Halo Formation In A Collisional Versus Collisionless Cold Dark Matter Universe

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Gravitational Dynamics of Halo Formation in a Collisional Versus Collisionless Cold Dark Matter Universe

Author : Jun Koda
Publisher :
ISBN 13 :
Total Pages : 322 pages
Book Rating : 4.:/5 (698 download)

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Book Synopsis Gravitational Dynamics of Halo Formation in a Collisional Versus Collisionless Cold Dark Matter Universe by : Jun Koda

Download or read book Gravitational Dynamics of Halo Formation in a Collisional Versus Collisionless Cold Dark Matter Universe written by Jun Koda and published by . This book was released on 2009 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flat cosmology with collisionless cold dark matter (CDM) and cosmological constant ([Lambda]CDM cosmology) may have some problems on small scales, even though it has been very successful on large scales. We study the effect of Self-Interacting Dark Matter (SIDM) hypothesis on the density profiles of halos. Collisionless CDM predicts cuspy density profiles toward the center, while observations of low mass galaxies prefer cored profiles. SIDM was proposed by Spergel & Steinhardt [161] as a possible solution to this cuspy profile problem on low-mass scales. On the other hand, observations and collisionless CDM agree on mass scales of galaxy clusters. It is also known that the SIDM hypothesis would contradict with X-ray and gravitational lensing observations of cluster of galaxies, if the cross section were too large. Our final goal is to find the range of SIDM scattering cross section models that are consistent with those astrophysical observations in two different mass scales. There are two theoretical approaches to compute the effect of self-interacting scattering -- Gravitational N-body simulation with Monte Carlo scattering and conducting fluid model; those two approaches, however, had not been confirmed to agree with each other. We first show that two methods are in reasonable agreement with each other for both isolated halos and for halos with realistic mass assembly history in an expanding [Lambda]CDM universe; the value of cross section necessary to have a maximally relaxed low-density core in [Lambda]CDM is in mutual agreement. We then develop a semianalytic model that predicts the time evolution of SIDM halo. Our semianalytic relaxation model enables us to understand how a SIDM halo would relax to a cored profile, and obtain an ensemble of SIDM halos from collisionless simulations with reasonable computational resources. We apply the semianalytic relaxation model to CDM halos, and compare the resulting statistical distribution of SIDM halos with astrophysical observations. We show that there exists a range of scattering cross sections that simultaneously solve the cuspy core problem on low-mass scales and satisfy the galaxy cluster observations. We also present that other potential conflicts between [Lambda]CDM and observations could be resolved in Part II and III.

Fundamentals of Galaxy Dynamics, Formation and Evolution

Author : Ignacio Ferreras
Publisher : UCL Press
ISBN 13 : 1911307614
Total Pages : 200 pages
Book Rating : 4.9/5 (113 download)

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Book Synopsis Fundamentals of Galaxy Dynamics, Formation and Evolution by : Ignacio Ferreras

Download or read book Fundamentals of Galaxy Dynamics, Formation and Evolution written by Ignacio Ferreras and published by UCL Press. This book was released on 2019-04-02 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxies, along with their underlying dark matter halos, constitute the building blocks of structure in the Universe. Of all fundamental forces, gravity is the dominant one that drives the evolution of structures from small density seeds at early times to the galaxies we see today. The interactions among myriads of stars, or dark matter particles, in a gravitating structure produce a system with fascinating connotations to thermodynamics, with some analogies and some fundamental differences. Ignacio Ferreras presents a concise introduction to extragalactic astrophysics, with emphasis on stellar dynamics, and the growth of density fluctuations in an expanding Universe. Additional chapters are devoted to smaller systems (stellar clusters) and larger ones (galaxy clusters). Fundamentals of Galaxy Dynamics, Formation and Evolution is written for advanced undergraduates and beginning postgraduate students, providing a useful tool to get up to speed in a starting research career. Some of the derivations for the most important results are presented in detail to enable students appreciate the beauty of maths as a tool to understand the workings of galaxies. Each chapter includes a set of problems to help the student advance with the material.

The Role of Halo Substructure in Gamma-Ray Dark Matter Searches

Author : Miguel A. Sánchez-Conde
Publisher : MDPI
ISBN 13 : 3039360442
Total Pages : 220 pages
Book Rating : 4.0/5 (393 download)

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Book Synopsis The Role of Halo Substructure in Gamma-Ray Dark Matter Searches by : Miguel A. Sánchez-Conde

Download or read book The Role of Halo Substructure in Gamma-Ray Dark Matter Searches written by Miguel A. Sánchez-Conde and published by MDPI. This book was released on 2020-05-28 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important, open research topic today is to understand the relevance that dark matter halo substructure may have for dark matter searches. In the standard cosmological model, halo substructure or subhalos are predicted to be largely abundant inside larger halos, for example, galaxies such as ours, and are thought to form first and later merge to form larger structures. Dwarf satellite galaxies—the most massive exponents of halo substructure in our own galaxy—are already known to be excellent targets for dark matter searches, and indeed, they are constantly scrutinized by current gamma-ray experiments in the search for dark matter signals. Lighter subhalos not massive enough to have a visible counterpart of stars and gas may be good targets as well, given their typical abundances and distances. In addition, the clumpy distribution of subhalos residing in larger halos may boost the dark matter signals considerably. In an era in which gamma-ray experiments possess, for the first time, the exciting potential to put to test the preferred dark matter particle theories, a profound knowledge of dark matter astrophysical targets and scenarios is mandatory should we aim for accurate predictions of dark matter-induced fluxes for investing significant telescope observing time on selected targets and for deriving robust conclusions from our dark matter search efforts. In this regard, a precise characterization of the statistical and structural properties of subhalos becomes critical. In this Special Issue, we aim to summarize where we stand today on our knowledge of the different aspects of the dark matter halo substructure; to identify what are the remaining big questions, and how we could address these; and, by doing so, to find new avenues for research.

The Dynamics of Satellite and Dark Matter Halo Interactions on Galaxy Formation and Evolution

Author : Jun-Hwan Choi
Publisher : ProQuest
ISBN 13 : 9780549330585
Total Pages : 226 pages
Book Rating : 4.3/5 (35 download)

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Book Synopsis The Dynamics of Satellite and Dark Matter Halo Interactions on Galaxy Formation and Evolution by : Jun-Hwan Choi

Download or read book The Dynamics of Satellite and Dark Matter Halo Interactions on Galaxy Formation and Evolution written by Jun-Hwan Choi and published by ProQuest. This book was released on 2007 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Effects of Inelastic Self-interacting Dark Matter on Galactic Halo Properties V

Author : Karia Radh Dibert
Publisher :
ISBN 13 :
Total Pages : 40 pages
Book Rating : 4.:/5 (18 download)

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Book Synopsis The Effects of Inelastic Self-interacting Dark Matter on Galactic Halo Properties V by : Karia Radh Dibert

Download or read book The Effects of Inelastic Self-interacting Dark Matter on Galactic Halo Properties V written by Karia Radh Dibert and published by . This book was released on 2018 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-interacting dark matter, which serves as an alternative to collisionless cold dark matter, may be useful for solving the small-scale galaxy formation problems present in the Lambda-Cold Dark Matter model. So far, most self-interacting dark matter simulations have considered only elastic collisions between particles. Using the results of a numerical implementation in the AREPO code, the effects of two-state inelastic dark matter on the density profiles, velocity dispersions, pseudo-phase-space density profiles, orbital anisotropy parameter profiles, and principal axis ratios of galactic halos are examined. We find that inelastic self-interacting dark matter halos differ from both cold dark matter halos and elastic self-interacting dark matter halos in density profiles, in velocity dispersion profiles, in pseudo-phase-space density profiles, and in orbital anisotropy parameter profiles, while the shapes of the halos generated by elastic and inelastic self-interacting dark matter models are relatively similar.

Investigating the Nature of Dark Matter with Strong Gravitational Lensing

Author : Daniel Alejandro Gilman
Publisher :
ISBN 13 :
Total Pages : 257 pages
Book Rating : 4.:/5 (116 download)

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Book Synopsis Investigating the Nature of Dark Matter with Strong Gravitational Lensing by : Daniel Alejandro Gilman

Download or read book Investigating the Nature of Dark Matter with Strong Gravitational Lensing written by Daniel Alejandro Gilman and published by . This book was released on 2020 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dark matter makes up most of the mass in the Universe, and yet its particle nature remains unknown. Structure formation arguments provide a promising avenue to address this confounding mystery, as the mass and formation mechanism of the dark matter manifests in the abundance and density profiles of dark matter halos. Measurements of the halo mass function and the mass-concentration relation can therefore be cast as direct constraints on the particle nature of dark matter itself. Strong gravitational lensing by galaxies offers a unique probe of dark matter structure across cosmological distance, circumventing the use of luminous matter to trace the underlying dark matter. Observables from strong lens systems, particularly the image magnifications in quadruply-imaged quasars, probe the halo mass function directly on sub-galactic scales, below $10^8$ solar masses. In this low-mass regime, where halos become devoid of stars and gas, various dark matter models make unique predictions that lensing can constrain. In this dissertation, I present the development and implementation of a forward modeling framework that constrains any model based on dark matter theory, provided the model predicts the form of the halo mass function, and the density profile of individual halos. Using the framework I developed, my thesis presents an unprecedented constraint on the free-streaming length of dark matter that corresponds to a lower limit of $5.2 \rm{keV}$ on the mass of a thermal relic dark matter particle. In addition, I present the first constraint on the mass-concentration relation of Cold Dark Matter halos on sub-galactic scales across cosmological distance. The flexibility of the framework I developed broadens the scope of strong-lensing analyses to any structure formation model based on dark matter theory, underscoring the power of strong gravitational lensing as a probe of fundamental physics.

Dark Matter Halos and Tidal Effects in Parabolic Galaxy Encounters

Author : John David Capriotti
Publisher :
ISBN 13 :
Total Pages : 130 pages
Book Rating : 4.:/5 (319 download)

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Book Synopsis Dark Matter Halos and Tidal Effects in Parabolic Galaxy Encounters by : John David Capriotti

Download or read book Dark Matter Halos and Tidal Effects in Parabolic Galaxy Encounters written by John David Capriotti and published by . This book was released on 1998 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Modern Cosmology

Author : Scott Dodelson
Publisher : Academic Press
ISBN 13 : 0122191412
Total Pages : 462 pages
Book Rating : 4.1/5 (221 download)

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Book Synopsis Modern Cosmology by : Scott Dodelson

Download or read book Modern Cosmology written by Scott Dodelson and published by Academic Press. This book was released on 2003-03-13 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced text for senior undergraduates, graduate students and physical scientists in fields outside cosmology. This is a self-contained book focusing on the linear theory of the evolution of density perturbations in the universe, and the anisotropiesin the cosmic microwave background.

At the Heart of Darkness

Author : Matthew William Craig
Publisher :
ISBN 13 :
Total Pages : 314 pages
Book Rating : 4.:/5 (34 download)

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Book Synopsis At the Heart of Darkness by : Matthew William Craig

Download or read book At the Heart of Darkness written by Matthew William Craig and published by . This book was released on 1997 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Interplay Between Massive Star Formation, the ISM and Galaxy Evolution

Author : D. Kunth
Publisher : Atlantica Séguier Frontières
ISBN 13 : 9782863321942
Total Pages : 668 pages
Book Rating : 4.3/5 (219 download)

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Book Synopsis The Interplay Between Massive Star Formation, the ISM and Galaxy Evolution by : D. Kunth

Download or read book The Interplay Between Massive Star Formation, the ISM and Galaxy Evolution written by D. Kunth and published by Atlantica Séguier Frontières. This book was released on 1996 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Secondary Infall Model of Galactic Halo Formation and the Spectrum of Cold Dark Matter Particles on Earth

Author :
Publisher :
ISBN 13 :
Total Pages : 39 pages
Book Rating : 4.:/5 (16 download)

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Book Synopsis The Secondary Infall Model of Galactic Halo Formation and the Spectrum of Cold Dark Matter Particles on Earth by :

Download or read book The Secondary Infall Model of Galactic Halo Formation and the Spectrum of Cold Dark Matter Particles on Earth written by and published by . This book was released on 1996 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Gravitational Dynamics

Author : Ofer Lahav
Publisher : Cambridge University Press
ISBN 13 : 9780521563277
Total Pages : 286 pages
Book Rating : 4.5/5 (632 download)

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Book Synopsis Gravitational Dynamics by : Ofer Lahav

Download or read book Gravitational Dynamics written by Ofer Lahav and published by Cambridge University Press. This book was released on 1996-07-13 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gravity plays a central role in the dynamics of all astrophysical systems - from stars to the Universe as a whole. This timely volume examines all aspects of gravitational dynamics - from stellar systems and galaxy disks, to the dynamics of the Local Group, large scale structures and motions, galaxy formation and general relativity. Each chapter is written by a world expert renowned for original contributions to the field. The authors are: James Binney, Roger Blandford, David Burstein, Tim de Zeeuw, George Efstathiou, Steve Gull, Nick Kaiser, J. Katz, Donald Lynden-Bell, Ruth Lynden-Bell, Douglas Lin, Jeremiah Ostriker, T. Padmanabhan, J. Papaloizou, Jim Peebles, Jim Pringle, Martin Rees, Maarteen Schmidt, Scott Tremaine and Simon White. This volume provides a broad, pedagogical introduction to gravitational dynamics for graduate students, and an up-to-date review for researchers in cosmology, astrophysics, mathematical physics and applied mathematics.

Galaxy Formation by Gravitational Collapse in a Universe Dominated by Cold Dark Matter

Author : Barbara Sue Ryden
Publisher :
ISBN 13 :
Total Pages : 230 pages
Book Rating : 4.:/5 (31 download)

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Book Synopsis Galaxy Formation by Gravitational Collapse in a Universe Dominated by Cold Dark Matter by : Barbara Sue Ryden

Download or read book Galaxy Formation by Gravitational Collapse in a Universe Dominated by Cold Dark Matter written by Barbara Sue Ryden and published by . This book was released on 1987 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Halo Cold Dark Matter and Microlensing

Author :
Publisher :
ISBN 13 :
Total Pages : 13 pages
Book Rating : 4.:/5 (16 download)

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Book Synopsis Halo Cold Dark Matter and Microlensing by :

Download or read book Halo Cold Dark Matter and Microlensing written by and published by . This book was released on 1993 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is good evidence that most of the baryons in the Universe are dark and some evidence that most of the matter in the Universe is nonbaryonic with cold dark matter (cdm) being a promising possibility. We discuss expectations for the abundance of baryons and cdm in the halo of our galaxy and locally. We show that in plausible cdm models the local density of cdm is at least $10{̂-25}\gcmm3$. We also discuss what one can learn about the the local cdm density from microlensing of stars in the LMC by dark stars in the halo and, based upon a suite of reasonable two-component halo models, conclude that microlensing is not a sensitive probe of the local cdm density.

Principles of Star Formation

Author : Peter Bodenheimer
Publisher : Springer Science & Business Media
ISBN 13 : 3642150632
Total Pages : 352 pages
Book Rating : 4.6/5 (421 download)

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Book Synopsis Principles of Star Formation by : Peter Bodenheimer

Download or read book Principles of Star Formation written by Peter Bodenheimer and published by Springer Science & Business Media. This book was released on 2011-07-10 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding star formation is one of the key fields in present-day astrophysics. This book treats a wide variety of the physical processes involved, as well as the main observational discoveries, with key points being discussed in detail. The current star formation in our galaxy is emphasized, because the most detailed observations are available for this case. The book presents a comparison of the various scenarios for star formation, discusses the basic physics underlying each one, and follows in detail the history of a star from its initial state in the interstellar gas to its becoming a condensed object in equilibrium. Both theoretical and observational evidence to support the validity of the general evolutionary path are presented, and methods for comparing the two are emphasized. The author is a recognized expert in calculations of the evolution of protostars, the structure and evolution of disks, and stellar evolution in general. This book will be of value to graduate students in astronomy and astrophysics as well as to active researchers in the field.

New Worlds, New Horizons in Astronomy and Astrophysics

Author : National Research Council
Publisher : National Academies Press
ISBN 13 : 0309157994
Total Pages : 324 pages
Book Rating : 4.3/5 (91 download)

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Book Synopsis New Worlds, New Horizons in Astronomy and Astrophysics by : National Research Council

Download or read book New Worlds, New Horizons in Astronomy and Astrophysics written by National Research Council and published by National Academies Press. This book was released on 2011-02-04 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Driven by discoveries, and enabled by leaps in technology and imagination, our understanding of the universe has changed dramatically during the course of the last few decades. The fields of astronomy and astrophysics are making new connections to physics, chemistry, biology, and computer science. Based on a broad and comprehensive survey of scientific opportunities, infrastructure, and organization in a national and international context, New Worlds, New Horizons in Astronomy and Astrophysics outlines a plan for ground- and space- based astronomy and astrophysics for the decade of the 2010's. Realizing these scientific opportunities is contingent upon maintaining and strengthening the foundations of the research enterprise including technological development, theory, computation and data handling, laboratory experiments, and human resources. New Worlds, New Horizons in Astronomy and Astrophysics proposes enhancing innovative but moderate-cost programs in space and on the ground that will enable the community to respond rapidly and flexibly to new scientific discoveries. The book recommends beginning construction on survey telescopes in space and on the ground to investigate the nature of dark energy, as well as the next generation of large ground-based giant optical telescopes and a new class of space-based gravitational observatory to observe the merging of distant black holes and precisely test theories of gravity. New Worlds, New Horizons in Astronomy and Astrophysics recommends a balanced and executable program that will support research surrounding the most profound questions about the cosmos. The discoveries ahead will facilitate the search for habitable planets, shed light on dark energy and dark matter, and aid our understanding of the history of the universe and how the earliest stars and galaxies formed. The book is a useful resource for agencies supporting the field of astronomy and astrophysics, the Congressional committees with jurisdiction over those agencies, the scientific community, and the public.

A Philosophical Approach to MOND

Author : David Merritt
Publisher : Cambridge University Press
ISBN 13 : 1108665683
Total Pages : 285 pages
Book Rating : 4.1/5 (86 download)

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Book Synopsis A Philosophical Approach to MOND by : David Merritt

Download or read book A Philosophical Approach to MOND written by David Merritt and published by Cambridge University Press. This book was released on 2020-04-30 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dark matter is a fundamental component of the standard cosmological model, but in spite of four decades of increasingly sensitive searches, no-one has yet detected a single dark-matter particle in the laboratory. An alternative cosmological paradigm exists: MOND (Modified Newtonian Dynamics). Observations explained in the standard model by postulating dark matter are described in MOND by proposing a modification of Newton's laws of motion. Both MOND and the standard model have had successes and failures – but only MOND has repeatedly predicted observational facts in advance of their discovery. In this volume, David Merritt outlines why such predictions are considered by many philosophers of science to be the 'gold standard' when it comes to judging a theory's validity. In a world where the standard model receives most attention, the author applies criteria from the philosophy of science to assess, in a systematic way, the viability of this alternative cosmological paradigm.