Download or read book Probing the Effects of a Mixed Dark Matter Scenario Using Weak Gravitational Lensing and Cosmic Microwave Background Observations written by Fabian Hervas Peters and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probing Cosmic Dark Matter and Dark Energy with Weak Gravitational Lensing Statistics written by Masato Shirasaki and published by Springer. This book was released on 2015-11-18 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book the applicability and the utility of two statistical approaches for understanding dark energy and dark matter with gravitational lensing measurement are introduced. For cosmological constraints on the nature of dark energy, morphological statistics called Minkowski functionals (MFs) to extract the non-Gaussian information of gravitational lensing are studied. Measuring lensing MFs from the Canada–France–Hawaii Telescope Lensing survey (CFHTLenS), the author clearly shows that MFs can be powerful statistics beyond the conventional approach with the two-point correlation function. Combined with the two-point correlation function, MFs can constrain the equation of state of dark energy with a precision level of approximately 3–4 % in upcoming surveys with sky coverage of 20,000 square degrees. On the topic of dark matter, the author studied the cross-correlation of gravitational lensing and the extragalactic gamma-ray background (EGB). Dark matter annihilation is among the potential contributors to the EGB. The cross-correlation is a powerful probe of signatures of dark matter annihilation, because both cosmic shear and gamma-ray emission originate directly from the same dark matter distribution in the universe. The first measurement of the cross-correlation using a real data set obtained from CFHTLenS and the Fermi Large Area Telescope was performed. Comparing the result with theoretical predictions, an independent constraint was placed on dark matter annihilation. Future lensing surveys will be useful to constrain on the canonical value of annihilation cross section for a wide range of mass of dark matter annihilation. Future lensing surveys will be useful to constrain on the canonical value of annihilation cross section for a wide range of mass of dark matter.
Download or read book Detecting Gravitational Lensing from the Cosmic Microwave Background written by Chang Feng and published by . This book was released on 2014 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gravitational lensing of the Cosmic Microwave Background (CMB) measures all the matter content in the Universe. It can be used to constrain neutrino masses, calibrate biased tracers for large scale structure, and remove contamination of primordial B-modes. The theoretical framework, which includes simulations and reconstruction of gravitational lensing effects from CMB observations, has been established and applied through this dissertation. From observations of the CMB's temperature anisotropy, WMAP datasets are used to probe gravitational lensing effects. It is found that the lensing signal can not be directly detected from WMAP alone but can be indirectly detected at >3[sigma] if WMAP's CMB observations are cross-correlated with galaxy surveys. Other than the CMB temperature, the CMB polarization is of great importance because the CMB's polarization is more sensitive than its temperature to probing lensing effects. From the ground-based small-scale polarization experiment, POLARBEAR, we (for the first time) measure polarization lensing and lensing B-modes from different types of correlation functions. The B-mode power spectrum is measured, showing the evidence for lensing B-modes at the 2[sigma] level. Lensing reconstruction with B-modes is also performed. From the auto-correlation of the lensing reconstruction with B-modes, the polarization lensing and lensing B-mode signal is measured at the 4.2[sigma] level, including systematics. This signal measures dark matter fluctuations with 27% uncertainty. The matter structure seen in the lensing reconstruction is further validated by the cross-correlation with cosmic infrared background, which shows evidence for polarization lensing at 4[sigma]. This state-of-the-art technique is capable of mapping all gravitating matter in the Universe, is sensitive to the sum of neutrino masses, and is essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.
Download or read book Dark Matter and Dark Energy written by Sabino Matarrese and published by Springer Science & Business Media. This book was released on 2011-02-10 with total page 413 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book brings together reviews from leading international authorities on the developments in the study of dark matter and dark energy, as seen from both their cosmological and particle physics side. Studying the physical and astrophysical properties of the dark components of our Universe is a crucial step towards the ultimate goal of unveiling their nature. The work developed from a doctoral school sponsored by the Italian Society of General Relativity and Gravitation. The book starts with a concise introduction to the standard cosmological model, as well as with a presentation of the theory of linear perturbations around a homogeneous and isotropic background. It covers the particle physics and cosmological aspects of dark matter and (dynamical) dark energy, including a discussion of how modified theories of gravity could provide a possible candidate for dark energy. A detailed presentation is also given of the possible ways of testing the theory in terms of cosmic microwave background, galaxy redshift surveys and weak gravitational lensing observations. Included is a chapter reviewing extensively the direct and indirect methods of detection of the hypothetical dark matter particles. Also included is a self-contained introduction to the techniques and most important results of numerical (e.g. N-body) simulations in cosmology. " This volume will be useful to researchers, PhD and graduate students in Astrophysics, Cosmology Physics and Mathematics, who are interested in cosmology, dark matter and dark energy.
Download or read book Progress in Dark Matter Research written by J. Val Blain and published by Nova Publishers. This book was released on 2005 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is generally believed that most of the matter in the universe is dark, i.e. cannot be detected from the light which it emits (or fails to emit). Its presence is inferred indirectly from the motions of astronomical objects, specifically stellar, galactic, and galaxy cluster/supercluster observations. It is also required in order to enable gravity to amplify the small fluctuations in the cosmic microwave background enough to form the large-scale structures that we see in the universe today. For each of the stellar, galactic, and galaxy cluster/supercluster observations the basic principle is that if we measure velocities in some region, then there has to be enough mass there for gravity to stop all the objects flying apart. Dark matter has important consequences for the evolution of the Universe and the structure within it. According to general relativity, the Universe must conform to one of three possible types: open, flat, or closed. The total amount of mass and energy in the universe determines which of the three possibilities applies to the Universe. In the case of an open Universe, the total mass and energy density (denoted by the Greek letter Omega) is less than unity. If the Universe is closed, Omega is greater than unity. For the case where Omega is exactly equal to one the Universe is "flat". This book details leading-edge research from around the globe.
Download or read book Constraining Equation of State of Dark Matter Including Weak Gravitational Lensing Supported by the National Natural Science Foundation of China Under Grant written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : Usually the equation of state (EoS) of dark matter is zero when it is cold, however there exists the possibility of a (effective) nonzero EoS of dark matter due to its decay and interaction with dark energy. In this work, we try to constrain the EoS of dark matter wdm using the currently available cosmic observations which include the geometrical and dynamical measurements. For the geometrical measurements, the luminosity distance of type Ia supernovae, the angular diameter distance and comoving sound horizon from baryon acoustic oscillations and the cosmic microwave background radiation will be employed. The data points from the redshift-space distortion and weak gravitational lensing will be taken as dynamical measurements. Using the Markov chain Monte Carlo method, we obtain a very tight constraint on the EoS of dark matter: w dm = 0.0000532 - 0.000686 - 0.00136 - 0.00177 + 0.000692 + 0.00136 + 0.00183 .
Download or read book Dark Matter in the Universe written by John N. Bahcall and published by World Scientific. This book was released on 2004 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: If standard gravitational theory is correct, then most of the matterin the universe is in an unidentified form which does not emit enoughlight to have been detected by current instrumentation. This book isthe second editon of the lectures given at the 4th Jerusalem WinterSchool for Theoretical Physics, with new material added. The lecturesare devoted to the missing matter problem in the universe, thesearch to understand dark matter. The goal of this volume is to makecurrent research work on unseen matter accessible to students withoutprior experience in this area and to provide insights for experts inrelated research fields. Due to the pedagogical nature of the originallectures and the intense discussions between the lecturers and thestudents, the written lectures included in this volume often containtechniques and explanations not found in more formal journalpublications.
Download or read book Illuminating the Universe written by Stephen John Osborne and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The cosmic microwave background (CMB) provides a backlight that allows us to probe structure out to the last scattering surface. We exploit observations of the sky at microwave and sub-mm wavelengths to measure properties of galaxies and galaxy clusters, as well as to search for possible pre-inflationary signals. In Chapters 2--4 we measure the correlation between the dark matter distribution and the microwave and sub-mm emission from galaxies to probe the connection between dark and luminous matter at redshifts ~1-3. CMB photons are gravitationally deflected by dark matter overdensities, with the majority of the ~3 arcminute RMS deflection occurring between redshift 2 and 3. The dark matter structures that lens the CMB are traced by dusty star-forming galaxies that emit strongly in the infrared, and have a redshift distribution that peaks between redshift 1 and 3. We use observations of the CMB from the Planck satellite to reconstruct the deflection angles with statistical estimators, and we correlate the deflections with observations of the infrared background light at 100-850 GHz. We find that the two signals are strongly correlated, with a correlation coefficient of approximately 0.8, and we use the measured cross spectrum to estimate the minimum mass scale at which dark matter halos host a CIB source, as well as the star formation rate density in three redshift bins between redshift 1 and 7. In Chapter 5 we use the Doppler shift of CMB light scattered by moving galaxy clusters, known as the kinetic Sunyaev-Zeldovich (kSZ) effect, to put a limit on the large-scale velocity distribution of a sample of galaxy clusters observed in WMAP CMB data. On 100 Mpc scales cluster velocities relative to the CMB are expected to be small, originating from gravitational instabilities. Larger motions could be generated by pre-inflationary inhomogeneities that leave a "tilt" across our horizon, resulting in a uniform matter flow across the horizon. The kSZ effect is sensitive to such a flow, and we use it to constrain the radial and dipole velocity of a sample of 736 clusters with mean redshift 0.12, finding no evidence for either. In Chapters 6 and 7 we search for a possible pre-inflationary signal in CMB data. Models of inflation suggest that our current patch of the universe could have been created as a nucleation bubble from a phase of false vacuum eternal inflation. If additional bubbles are produced, then it is possible that one of them intersected our past lightcone at the time of decoupling, imprinting a disk-shaped signal in the CMB. We have searched for this signal in the WMAP data using optimal algorithms that evaluate the exact posterior likelihood in an efficient and computationally fast way. We find no evidence for the signal, and place limits on the curvature perturbation generated by a collision intersecting the last scattering surface.
Download or read book An Investigation of Cosmological Dark Matter Using Weak Gravitational Lensing written by R. Michael Jarvis and published by . This book was released on 2002 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probing the Dark Universe with Gravitational Lensing written by Mansour Karami and published by . This book was released on 2018 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its early success as an experimental test of the theory of general relativity in 1919, gravitational lensing has come a long way and is firmly established as an indispensable element for many astrophysical applications. In this thesis, we explore novel applications of gravitational lensing that further our understanding of the dark sectors of the cosmos and other astrophysical objects, namely dark matter nanostructure, black holes and the Galactic disk. We pay particular attention to developing concrete and optimal statistical methodologies and numerical implemen- tations for these novel probes. We start by developing a statistical framework to measure the dark matter power spectrum in the deep nonlinear regime, using transient weak lensing, and simultaneously measure the time delays for strongly lensed quasars. We then outline how observations of microlensing in optical and radio can unravel the structure, dynamics, and content of the Galactic disk, and in particular, be used to detect stellar mass black holes. Lastly, using the shadow images of the super-massive black holes caused by extreme lensing effect, we can learn about the structure of space-time, accretion flows and astrophysical jets. We present a Bayesian framework for analyzing the data from the Event Horizon Telescope Collaboration.
Download or read book Connecting Quarks with the Cosmos written by National Research Council and published by National Academies Press. This book was released on 2003-03-12 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances made by physicists in understanding matter, space, and time and by astronomers in understanding the universe as a whole have closely intertwined the question being asked about the universe at its two extremesâ€"the very large and the very small. This report identifies 11 key questions that have a good chance to be answered in the next decade. It urges that a new research strategy be created that brings to bear the techniques of both astronomy and sub-atomic physics in a cross-disciplinary way to address these questions. The report presents seven recommendations to facilitate the necessary research and development coordination. These recommendations identify key priorities for future scientific projects critical for realizing these scientific opportunities.
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.
Download or read book Constraining Cosmological Parameters with Gravitational Lensing of the Cosmic Microwave Background written by Gabrielle Simard and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "The cosmic microwave background (CMB) anisotropies are a direct probe of early Universe physics. They also carry information about the late Universe through different secondary effects, including gravitational lensing. Propagating away from the last scattering surface, the primary CMB photons are deflected by the intervening large-scale structure, creating slight distortions in the CMB radiation temperature and polarization patterns that can be detected statistically. In this thesis, we present constraints on the parameters describing our Universe on cosmological scales obtained with the use of CMB gravitational lensing measurements. We begin with a description of the current cosmological model and follow with a review of gravitational lensing effects on the CMB observables.We then present bounds on cosmological parameters set by the lensing power spectrum estimated from a combined SPT+Planck CMB temperature map on the SPT-SZ 2500 square-degrees patch of sky.Adding lensing information to primary CMB data helps tightening constraints on cosmological parameters affecting late-time growth, such as the matter fluctuation amplitude today, the spatial curvature and the sum of neutrino masses.Measurements of the CMB polarization sourced in the early Universe are hindered by the additional polarization created by the gravitational lensing deflections; this contaminating lensing signal can be estimated and removed. We discuss projected constraints on the scale-dependence of the primordial CMB polarization signal assuming that the lensing induced contamination can be subtracted through different scenarios." --
Download or read book A Measurement of the Cosmic Microwave Background Gravitational Lensing Potential and Its Power Spectrum from 500 Deg2 of SPTpol Data written by Laura Monica Mocanu and published by . This book was released on 2017 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Matter Dark Matter and Anti Matter written by Alain Mazure and published by Springer Science & Business Media. This book was released on 2011-11-16 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: For over ten years, the dark side of the universe has been headline news. Detailed studies of the rotation of spiral galaxies, and 'mirages' created by clusters of galaxies bending the light from very remote objects, have convinced astronomers of the presence of large quantities of dark (unseen) matter in the cosmos. The most striking fact is that they seem to compromise about 95% of the matter/energy content of the universe. As for ordinary matter, although we are immersed in a sea of dark particles, including primordial neutrinos and photons from fossil cosmological radiation, both we and our environment are made of ordinary, 'baryonic' matter. Authors Mazure and Le Brun present the inventory of matter, baryonic and exotic, and investigating the nature and fate of matter's twin, anti-matter. They show how technological progress has been a result of basic research, in tandem with the evolution of new ideas, and how the combined effect of these advances might help lift the cosmic veil.
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.
Download or read book Constraining Dark Matter Through the Study of Merging Galaxy Clusters written by William Anthony Dawson and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The majority (~85%) of the matter in the universe is composed of dark matter, a mysterious particle that does not interact via the electromagnetic force yet does interact with all other matter via the gravitational force. Many direct detection experiments have been devoted to finding interactions of dark matter with baryonic matter via the weak force. To date only tentative and controversial evidence for such interactions has been found. While such direct detection experiments have ruled out the possibility that dark matter interacts with baryonic matter via a strong scale force, it is still possible that dark matter interacts with itself via a strong scale force and has a self-scattering cross-section of ~0.5 cm2g−1. In fact such a strong scale scattering force could resolve several outstanding astronomical mysteries: a discrepancy between the cuspy density profiles seen in [Lambda]CDM simulations and the cored density profiles observed in low surface brightness galaxies, dwarf spheroidal galaxies, and galaxy clusters, as well as the discrepancy between the significant number of massive Milky Way dwarf spheroidal halos predicted by [Lambda]CDM and the dearth of observed Milky Way dwarf spheroidal halos. Need: While such observations are in conflict with [Lambda]CDM and suggest that dark matter may self-scatter, each suffers from a baryonic degeneracy, where the observations might be explained by various baryonic processes (e.g., AGN or supernove feedback, stellar winds, etc.) rather than self-interacting dark matter (SIDM). In fact, the important scales of these observations often coincide with baryonic scales (e.g., the core size in clusters is few factors smaller than the radius of the brightest cluster galaxy). What is needed is a probe of SIDM where the expected effect cannot be replicated by the same processes responsible for the baryonic degeneracy in the aforementioned probes. Merging galaxy clusters are such a probe. During the merging process the effectively collisionless galaxies (~2% of the cluster mass) become dissociated from the collisional intracluster gas (~15% of the cluster mass). A significant fraction of the gas self-interacts during the merger and slows down at the point of collision. If dark matter lags behind the effectively collisionless galaxies then this is clear evidence that dark matter self-interacts. The expected galaxy-dark matter offset is typically >25 kpc (for cross-sections that would explain the other aforementioned issues with [Lambda]CDM), this is larger than the scales of that are plagued by the baryonic degeneracies. Task: To test whether dark matter self-interacts we have carried out a comprehensive survey of the dissociative merging galaxy cluster DLSCL J0916.2+2951 (also known as the Musket Ball Cluster). This survey includes photometric and spectroscopic observations to quantify the position and velocity of the cluster galaxies, weak gravitational lensing observations to map and weigh the mass (i.e., dark matter which comprises ~85% of the mass) of the cluster, Sunyaev-Zel'dovich effect and X-ray observations to map and quantify the intracluster gas, and finally radio observations to search for associated radio relics, which had they been observed would have helped constrain the properties of the merger. Using this information in conjunction with a Monte Carlo analysis model I quantify the dynamic properties of the merger, necessary to properly interpret constraints on the SIDM cross-section. I compare the locations of the galaxies, dark matter and gas to constrain the SIDM cross-section. This dissertation presents this work. Findings: We find that the Musket Ball is a merger with total mass of 4.8(+3.2)(-1.5) x 1014M(sun). However, the dynamic analysis shows that the Musket Ball is being observed 1.1(+1.3)(-0.4) Gyr after first pass through and is much further progressed in its merger process than previously identified dissociative mergers (for example it is 3.4(+3.8)(1.4) times further progressed that the Bullet Cluster). By observing that the dark matter is significantly offset from the gas we are able to place an upper limit on the dark matter cross-section of [sigma](SIDM)m−1(DM)
