Download or read book Precision Cosmology with Time Delay Lenses written by and published by . This book was released on 2016 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Impact of Gravitational Lensing on Cosmology IAU S225 written by International Astronomical Union. Symposium and published by Cambridge University Press. This book was released on 2005-09-05 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains the proceedings of the International Astronomical Union Symposium no. 225, held in July 2004 at the Ecole Polytechnique Federale de Lausanne (EPFL), in Lausanne, Switzerland. The meeting focused on the applications of gravitational lensing to cosmological physics, and this book summarizes the most recent theoretical and observational developments. With chapters written by leading scientists in the field, this is a valuable resource for professional astronomers and graduate students in astronomy, physics and astro-particle physics.
Download or read book Strong Gravitational Lensing as a Probe of Galaxy Evolution and Cosmology written by Kenneth Christopher Wong and published by . This book was released on 2013 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, I explore how the environments of both galaxy and cluster-scale strong gravitational lenses affect studies of cosmology and the properties of the earliest galaxies. Galaxy-scale lenses with measured time delays can be used to determine the Hubble constant, given an accurate lens model. However, perturbations from structures along the line of sight can introduce errors into the measurement. I use data from a survey towards known lenses in group environments to calculate the external shear in these systems, which is typically marginalized over in standard lens analyses. In three of six systems where I compare the independently-calculated environment shear to lens model shears, the quantities disagree at greater than 95% confidence. We explore possible sources of this disagreement. Using these data, I generate fiducial lines of sight and insert mock lenses with assumed input physical and cosmological parameters and find that those parameters can be recovered with {598} 5-10% scatter when uncertainties in my characterization of the environment are applied. The lenses in groups have larger bias and scatter. I predict how well new time delay lenses from LSST will constrain H0 and find that an ensemble of 500 quad lenses will recover H0 with {598} 2% bias with {598} 0.3% precision. On larger scales, galaxy cluster lenses can magnify the earliest galaxies into detectability. While past studies have focused on single massive clusters, I investigate the properties of lines of sight, or "beams", containing multiple cluster-scale halos in projection. Even for beams of similar total mass, those with multiple halos have higher lensing cross sections on average. The optimal configurations for maximizing the cross section are also those that maximize faint z {598} 10 detections. I present a new selection technique to identify beams in wide-area photometric surveys that contain high total masses and often multiple clusters in projection as traced by luminous red galaxies. I apply this technique to the Sloan Digital Sky Survey and present the 200 most promising beams. Several are confirmed spectroscopically to be among the highest mass beams known with some containing multiple clusters. These are among the best fields to search for faint high-redshift galaxies.
Download or read book The Hubble Constant and the lambda CDM Cosmology A Magnified View Using Strong Lensing written by Anowar Jaman Shajib and published by . This book was released on 2020 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, a significant tension has been reported between two measurements of the Hubble constant (H_0) from early-Universe (e.g., cosmic microwave background) and late-Universe probes (e.g., cosmic distance ladder). If systematic errors are ruled out in these measurements, then new physics extending the CDM model will be required to resolve the tension. Therefore, different independent probes of H_0 -- such as the strong-lensing time-delay -- are essential to confirm or resolve the tension. The measured time-delays between the lensed images of a background quasar constrain H_0, as they depend on the absolute physical distances in the lens configuration. I led a team from the STRong-lensing Insights into the Dark Energy Survey (STRIDES) collaboration to analyze the lens DES J0408-5354. I modeled the mass distribution of this lens using Hubble Space Telescope imaging, and combined it with analyses from my collaborators to infer H_0 = 74.2-3.0+2.7 km s^-1 Mpc^-1 with the highest precision (3.9 per cent) from a single lens to date. This measurement agrees well with both the previous sample of six lenses from the H0LiCOW collaboration and other late-Universe probes, thus it increases the aforementioned tension. To confirm or resolve this tension at the 5 level -- the gold standard of detecting new physics -- we need to increase the sample size and improve precision per system while keeping the systematics under control. The large amount of required investigator time (~1 year per lens) is currently the main bottleneck to increase the sample size. I present an automated lens-modeling framework that will enable rapid increment of the sample size in the near future. I also show, through simulation, that incorporating the spatially resolved kinematics of the lensing galaxy improves the precision of H_0 per system. Additionally, I develop the first general method to efficiently compute the lensing properties of any given elliptical mass distribution. By allowing any radial shape of mass profile, this method helps to avoid any systematic that may potentially arise from adopting only a few specific parameterizations. I forecast that a sample of ~40 lenses with spatially resolved kinematics will provide sub-per-cent precision in H_0 within the next decade.
Download or read book Gravitational Lensing Strong Weak and Micro written by Peter Schneider and published by Springer Science & Business Media. This book was released on 2006-12-30 with total page 565 pages. Available in PDF, EPUB and Kindle. Book excerpt: The observation, in 1919 by A.S. Eddington and collaborators, of the gra- tational de?ection of light by the Sun proved one of the many predictions of Einstein’s Theory of General Relativity: The Sun was the ?rst example of a gravitational lens. In 1936, Albert Einstein published an article in which he suggested - ing stars as gravitational lenses. A year later, Fritz Zwicky pointed out that galaxies would act as lenses much more likely than stars, and also gave a list of possible applications, as a means to determine the dark matter content of galaxies and clusters of galaxies. It was only in 1979 that the ?rst example of an extragalactic gravitational lens was provided by the observation of the distant quasar QSO 0957+0561, by D. Walsh, R.F. Carswell, and R.J. Weymann. A few years later, the ?rst lens showing images in the form of arcs was detected. The theory, observations, and applications of gravitational lensing cons- tute one of the most rapidly growing branches of astrophysics. The gravi- tional de?ection of light generated by mass concentrations along a light path producesmagni?cation,multiplicity,anddistortionofimages,anddelaysp- ton propagation from one line of sight relative to another. The huge amount of scienti?c work produced over the last decade on gravitational lensing has clearly revealed its already substantial and wide impact, and its potential for future astrophysical applications.
Download or read book Gravitational Lensing in Standard and Non standard Frameworks as a Probe for Precision Cosmology written by Michael A. Troxel and published by . This book was released on 2014 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gravitational lensing has been identified as a critical cosmological tool in studying the evolution of large scale structure in the universe as well as the nature of dark matter and dark energy. One of the primary physical systematics of weak lensing due to large scale structure (cosmic shear) is the intrinsic alignment (IA) of galaxies, which poses a barrier to precision weak lensing measurements. Methods for identifying and removing its effects on cosmological information are key to the success of weak lensing survey science goals. We have expanded model-independent techniques to isolate and remove the IA contamination from the lensing signal. These self-calibration techniques take advantage of complementary survey information to self-calibrate the lensing signal, which along with unique lensing and IA geometry and separation dependencies, allow us to reconstruct the IA correlations at the level of the spectrum and bispectrum. We have demonstrated that the self-calibration approach can reduce the IA bias over most relevant scale and redshift ranges by up to a factor of 10 or more. This could reduce a potential 10-20% bias in some cosmological information down to the 1-2% level. The self-calibration techniques have the added benefit of preserving the IA signal, which itself provides additional information that can be used in studying the formation and evolution of large scale structure in the universe. We have also identified a new source of intrinsic alignment contamination in cross-correlations with cosmic microwave background lensing and proposed a method to calibrate it, and we explored the potential of future surveys to measure directly various 2- and 3-point intrinsic alignment correlations. Finally, we have investigated the use of exact anisotropic and inhomogeneous models in general relativity for large- and small-scale structures in the universe, developing the frameworks necessary to analyze gravitational lensing in such models, and have compared them to observations, identifying potential sources of bias. We have found, for example, that ignoring substructure level anisotropies in structures could bias the lensing convergence, shear, and kinematic mass estimates by up to 10% or more. We conclude by presenting a numerical code package for calculations in such exact anisotropic and inhomogeneous models.
Download or read book 3K SN s Clusters Hunting the Cosmological Parameters with Precision Cosmology written by Domingos Barbosa and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: A JENAM 2002 Workshop, Porto, Portugal, 3-5 September 2002
Download or read book Singularity Theory and Gravitational Lensing written by Arlie O. Petters and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph is the first to develop a mathematical theory of gravitational lensing. The theory applies to any finite number of deflector planes and highlights the distinctions between single and multiple plane lensing. Introductory material in Parts I and II present historical highlights and the astrophysical aspects of the subject. Part III employs the ideas and results of singularity theory to put gravitational lensing on a rigorous mathematical foundation.
Download or read book Introduction to Gravitational Lensing written by Massimo Meneghetti and published by Springer Nature. This book was released on 2021-12-10 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the phenomenology of gravitational lensing in an accessible manner and provides a thorough discussion of the related astrophysical applications. It is intended for advanced undergraduates and graduate students who want to start working in this rapidly evolving field. This includes also senior researchers who are interested in ongoing or future surveys and missions such as DES, Euclid, WFIRST, LSST. The reader is guided through many fascinating topics related to gravitational lensing like the structure of our galaxy, the searching for exoplanets, the investigation of dark matter in galaxies and galaxy clusters, and several aspects of cosmology, including dark energy and the cosmic microwave background. The author, who has gained valuable experience as academic teacher, guides the readers towards the comprehension of the theory of gravitational lensing and related observational techniques by using simple codes written in python. This approach, beyond facilitating the understanding of gravitational lensing, is preparatory for learning the python programming language which is gaining large popularity both in academia and in the private sector.
Download or read book Gravitational Lenses written by P. Schneider and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: Light observed from distant objects is found to be deflected by the gravitational field of massive objects near the line of sight - an effect predicted by Einstein in his first paper setting forth the general theory of relativity, and confirmed by Eddington soon afterwards. If the source of the light is sufficiently distant and bright, and if the intervening object is massive enough and near enough to the line of sight, the gravitational field acts like a lens, focusing the light and producing one or more bright images of the source. This book, by renowned researchers in the field, begins by discussing the basic physics behind gravitational lenses: the optics of curved space-time. It then derives the appropriate equations for predicting the properties of these lenses. In addition, it presents up-to-date observational evidence for gravitational lenses and describes the particular properties of the observed cases. The authors also discuss applications of the results to problems in cosmology.
Download or read book Measuring and Modeling the Universe Volume 2 Carnegie Observatories Astrophysics Series written by Wendy L. Freedman and published by Cambridge University Press. This book was released on 2004-11-04 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive volume reviews the current theory and measurement of various parameters related to the evolution of the universe. Topics include inflation, string theory and the history of cosmology in the context of current measurements being made of the Hubble constant, matter density, and dark energy. Observational results are included from the Sloan, Digital Sky Survey, Keck, Magellan, cosmic microwave background experiments, Hubble space telescope and Chandra. Featuring chapters by leading authorities in the field, this book is a valuable resource for graduate students and professional research astronomers.
Download or read book A Precise H0 Measurement from Four Time delay Lensed Quasars with Adaptive optics Imaging written by Geoff Chih-Fan Chen and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Hubble constant (H0) is one of the most important parameters in cosmology. Its value directly sets the age, the size, and the critical density of the Universe. Despite the great success of the LCDM model, a stringent challenge to the model comes from a discrepancy between the extremely precise H0 value derived from Planck measurements of the cosmic microwave background (CMB) anisotropies under the assumption of LCDM, and the H0 value from direct measurements of the local Universe. Any deviation, if confirmed,indicates that either there is new physics in the early universe or that we do not fully understand the evolution of the expansion history at later time. The recent direct H0 measurements from Type Ia supernovae (SNe), calibrated by the traditional Cepheid distance ladder [SH0ES collaboration; Riess et al., 2019], show a 4.4 [sigma] tension with the Planck results. On the other hand, a recent measurement of H0 from SNe Ia calibrated by the Tip of the Red Giant Branch (CCHP) agrees with both the Planck and SH0ES results [Freedman et al., 2019]. The spread in these results,whether due to systematic effects or not, clearly demonstrates that it is crucial to test any single methodology by different and independent datasets. Time-delay cosmography provides a technique to constrain H0 at low redshift that is completely independent of the traditional distance ladder approach. When a quasar is strongly lensed by a galaxy, its multiple images have light-curves that are offset by a well defined time delay, which depends on the mass profile of the lens and cosmological distances to the galaxy and the quasar. By measuring the time delays and accurately modeling the lensing galaxy, one can then measure the combined cosmological distances (time-delay distance, Ddt ), from which the cosmological parameters (primarily H0) can be determined. Previous TDC measurements have used Hubble Space Telescope (HST) imaging to constrain the mass distribution of the lensing galaxy. To further exam the robustness of TDC approach, I have led a new approach to enable a completely independent data set, namely adaptive-optics (AO) imaging taken with Keck telescope, to deliver an independent H0 measurement. To achieve this goal, in this thesis my work focused on overcoming the unknown point spread function (PSF) issue in AO imaging, addressing the microlensing time-delay effect, and increasing the sample size of well-constrained time-delay systems. Under the assumption of the LCDM model, I found that the joint result of the three lenses with both AO and HST imaging is H0 = 76.8[superscript +2.6][subscript −2.6] kms−1 Mpc−1, which is in 3.5[sigma] tension with Planck results [Chen et al., 2019].
Download or read book Astrophysical Applications of Gravitational Lensing written by Evencio Mediavilla and published by Cambridge University Press. This book was released on 2016-10-06 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents gravitational lensing as an essential tool in astrophysics for tracking dark matter at all scales in the Universe.
Download or read book Astrophysical Masers IAU S336 written by International Astronomical Union. Symposium and published by Cambridge University Press. This book was released on 2018-09-13 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summarizes state of the art observations and theories pertaining to astrophysical masers and their environments, for graduate students and researchers.
Download or read book Astrophysics written by James Binney and published by Oxford University Press. This book was released on 2016 with total page 177 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astrophysics is said to have been born when Isaac Newton saw an apple drop in his orchard and had the electrifying insight that the Moon falls just like that apple. James Binney shows how the application of physical laws derived on Earth allows us to understand objects that exist on the far side of the Universe.
Download or read book Introduction to Cosmology written by Barbara Ryden and published by Cambridge University Press. This book was released on 2017 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: A substantial update of this award-winning and highly regarded cosmology textbook, for advanced undergraduates in physics and astronomy.
Download or read book Sixteenth Marcel Grossmann Meeting The On Recent Developments In Theoretical And Experimental General Relativity Astrophysics And Relativistic Field Theories Proceedings Of The Mg16 Meeting On General Relativity In 4 Volumes written by Remo Ruffini and published by World Scientific. This book was released on 2022-12-15 with total page 4880 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proceedings of MG16 give a broad view of all aspects of gravitational physics and astrophysics, from mathematical issues to recent observations and experiments. The scientific program of the meeting included 46 plenary presentations, 3 public lectures, 5 round tables and 81 parallel sessions arranged during the intense six-day online meeting. All talks were recorded and are available on the ICRANet YouTube channel at the following link: www.icranet.org/video_mg16.These proceedings are a representative sample of the very many contributions made at the meeting. They contain 383 papers, among which 14 come from the plenary sessions.The material represented in these proceedings cover the following topics: accretion, active galactic nuclei, alternative theories of gravity, black holes (theory, observations and experiments), binaries, boson stars, cosmic microwave background, cosmic strings, dark energy and large scale structure, dark matter, education, exact solutions, early universe, fundamental interactions and stellar evolution, fast transients, gravitational waves, high energy physics, history of relativity, neutron stars, precision tests, quantum gravity, strong fields, and white dwarf; all of them represented by a large number of contributions.The online e-proceedings are published in an open access format.
