Download or read book Strong Gravitational Lensing in the Era of Big Data IAU S381 written by Hannah Stacey and published by Cambridge University Press. This book was released on 2024-05-02 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: During recent decades, strong gravitational lensing has become a powerful tool to study astronomical objects with widely different physical scales. It has also proven to be a promising diagnostic that can solve outstanding problems in cosmology. Now is a critical time for strong lensing research, as forthcoming large surveys (Euclid, Roman Space Telescope, Rubin Observatory and CSST) will map the entire sky and increase the number of known lenses from a few hundred to around 100,000. Concurrently, observations of lenses with current and forthcoming instruments (ALMA, JWST, E-ELT) will spatially resolve scales that are beyond the reach of telescopes for objects in the distant Universe. These new data will revolutionise our understanding of galaxy and structure formation, and offer unprecedented cosmological applications. In IAU Symposium 381, members of observational and theoretical communities review our preparedness for this new era, to discuss advanced statistical techniques, and to foster new collaborations.
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 552 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 All the Lenses written by Ji Won Park and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Unprecedented volumes of data from upcoming sky surveys will yield precise constraints on parameters governing the evolution history of the Universe. One that has received particular attention over the past decade is the Hubble constant (H0) describing the expansion rate of the Universe. This thesis focuses on measuring H0 from an astrophysical phenomenon called strong gravitational lensing. The Vera Rubin Observatory's Legacy Survey of Space and Time (LSST) will increase the sample size of strong lenses from ~100 to ~100,000. This creates an opportunity to obtain the most precise measurement of H0 to date. Fully realizing the potential of LSST data entails rapidly extracting cosmological information from the images, tables, and time series associated with these lenses. My research has focused on developing analysis techniques using Bayesian deep learning, which combines the efficiency of deep learning with principled uncertainty quantification. The techniques promise to automate the analysis of tens of thousands of strong lensing systems in a robust manner. They constitute core methodology that can combine information from all the LSST lenses -- with varying types and signal-to-noise ratios -- into a large-scale hierarchical inference of H0.
Download or read book Measurement of Gravitational Lens Time Delays with LSST SULI Paper written by Lowry Anna Kirkby and published by . This book was released on 2006 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proposed Large Synoptic Survey Telescope will be the first to explore multiple dark energy probes simultaneously, including baryon acoustic oscillations, weak lensing, and strong gravitational lensing. The large data sample, covering the entire visible sky every few nights, will allow an unprecedented survey of deep supernova sources and their lensed images. The latter have not yet been observed. Notably, LSST will measure the time delays between different strong-lensed images of the same supernova. This will provide a unique probe of dark matter, dark energy, and the expansion rate of the Universe. By simulating LSST observations under realistic conditions, we determined the time delay precision of multiple images from a representative strong-lensed Type Ia supernova. The output of the simulation was a set of light curves according to field and filter, which were subsequently analyzed to determine the experimental time delays. We find that a time delay precision of better then 10% can be achieved under suitable conditions. Firstly, a minimum observed peak-magnitude of 22 is required for the lensed image, corresponding to an intrinsic source magnitude of about 24. The number of such supernova sources expected for LSST is under investigation, but it could amount to several thousand. Secondly, a minimum of about 50 visits per field is required, and, moreover, these visits must be evenly distributed over the duration of the event. The visit frequency should be approximately once per week, or better. Thirdly, the sky brightness should be below 21 magnitude arcsec{sup -2} to allow sufficient sensitivity to distance sources. Under the nominal LSST visiting schedule and field conditions, 15% of all fields satisfy these criteria, and allow time delay measurements of better than 10% precision. This performance can be further improved by fitting the predicted supernova light curves to the observations, rather than using the simple weighted mean as in the present study. Of the well-measured fields, 85% involve observations taken with the r filter, which has a wavelength acceptance that is well-matched to supernova spectra. This filter therefore represents the best choice for strong gravitational lens observations with LSST. Our primary conclusion is that the visiting schedule is the single most important parameter to optimize for time delay measurements, and, once a lensed supernova has been detected, that frequent, regular observations should be scheduled to search with the highest sensitivity for multiple, delayed lensed images.
Download or read book Gravitational Lenses written by Peter Schneider and published by Springer. This book was released on 2011-09-17 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The theory, observations, and applications ofgravitational lensingconstitute one ofthe most rapidly growing branches ofextragalactic astrophysics. The deflection of light from very distant sources by intervening masses provides a unique possibility for the investigation of both background sources and lens mass distributions. Gravitational lensing manifestsitselfmost distinctly through multiply imaged QSOs and the formation of highly elongated im ages of distant galaxies ('arcs') and spectacular ring-like images of extra galactic radio sources. But the effects of gravitational light deflection are not limited to these prominent image configurations; more subtle, since not directly observable, consequences of lensing are the, possibly strong, mag nification of sources, which may permit observation of intrinsically fainter, or more distant, sources than would be visible without these natural tele scopes. Such light deflection can also affect the source counts of QSOs and of other compact extragalactic sources, and can lead to flux variability of sources owing to propagation effects. Trying to summarizethe theory and observationalstatus ofgravitational lensing in a monograph turned out to be a bigger problem than any of the authors anticipated when we started this project at the end of 1987, encour aged by Martin Harwit, who originally approached us. The development in the field has been very rapid during the last four years, both through the ory and through observation, and many sections have been rewritten several times, as the previous versions became out of date.
Download or read book Strong Gravitational Lensing and Dark Energy Complementarity written by and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the search for the nature of dark energy most cosmological probes measure simple functions of the expansion rate. While powerful, these all involve roughly the same dependence on the dark energy equation of state parameters, with anticorrelation between its present value w0 and time variation w{sub a}. Quantities that have instead positive correlation and so a sensitivity direction largely orthogonal to, e.g., distance probes offer the hope of achieving tight constraints through complementarity. Such quantities are found in strong gravitational lensing observations of image separations and time delays. While degeneracy between cosmological parameters prevents full complementarity, strong lensing measurements to 1 percent accuracy can improve equation of state characterization by 15-50 percent. Next generation surveys should provide data on roughly 105 lens systems, though systematic errors will remain challenging.
Download or read book Gravitational Lensing written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Planetary Nebulae IAU S323 written by Xiaowei Liu and published by Cambridge University Press. This book was released on 2017-09-28 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Planetary nebulae, glowing shells of ionized gas, are the spectacular products of the evolution of low- and intermediate-mass stars. For astrophysicists, they are important laboratories for the understanding of atomic, molecular, dust, and plasma processes in different cosmic environments; they enable the exploration of the fundamental physics of single and binary star evolution including nucleosynthesis, rotation, mass transfer and loss, and magnetic fields; and they help trace stellar populations, the kinematics, and chemistry of galaxies including our own galaxy, the Milky Way. This volume reviews the current status of this vibrant research field in the form of invited reviews, contributed talks, and posters presented at the IAU Symposium 323. It should be of interest to researchers and advanced students interested in this field and in related fields, including stellar physics, the interstellar medium, and Galactic and extragalactic astronomy.
Download or read book Practical Functional Urology written by John Heesakkers and published by Springer. This book was released on 2016-02-24 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Functional urology is that part of urological practice which deals with functional disorders of the lower urinary tract. Among the diseases that cause functional disorders are spina bifida, spinal cord injury, pelvic organ prolapse, and urethral strictures. This book on practical functional urology will help urologists, urogynecologists, and others to diagnose and treat these functional disorders. The theoretical background and scientific basis are summarized, but the emphasis is very much on clinical practice. Diagnosis and treatment are presented for a variety of conditions, including overactive bladder, detrusor underactivity, painful bladder syndrome/interstitial cystitis, prostatitis, stress urinary incontinence, pelvic organ prolapse, urinary tract infections, and urethral disorders. The content is based on the EAU guidelines, and for each disorder, helpful tips and tricks are highlighted.
Download or read book Education and Heritage in the Era of Big Data in Astronomy IAU S367 written by Rosa M. Ros and published by Cambridge University Press. This book was released on 2022-03-24 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: For thousands of years people have looked to the skies to better understand the universe and our place within it. Crucially it is the role of teachers and experts to make astronomical concepts accessible to the next generation, and to pass on our collective knowledge for others to build on. This volume brings together contributions from modern pioneers in astronomy education, as presented at the online IAU Symposium 367 on 'Education and Heritage in the Era of Big Data in Astronomy'. Topics covered include cultural astronomy and heritage, technological advances, citizen science, inclusivity initiatives, interdisciplinary science education and open astronomy. Particular focus is given to how emerging technologies provide new opportunities to connect with budding astronomers. Many of the techniques discussed can be applied by educators at different levels and in a range of settings, from school classrooms and lecture halls to informal public spaces such as museums and planetariums.
Download or read book White Dwarfs as Probes of Fundamental Physics IAU S357 written by Martin A. Barstow and published by Cambridge University Press. This book was released on 2020-09-30 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: White dwarfs are the most numerous members of the stellar graveyard. More than ninety percent of all stars will end their lives as white dwarfs. Research on these objects is fascinating in its own right, requiring developments in atomic data and the study of properties of matter under extreme conditions. However, these studies also have enormous impact on other areas of astrophysics, including: cosmology, the composition of extrasolar planets and fundamental physics. The proceedings of IAU Symposium 357 bring together experts from different branches of science working on white dwarfs, but also astronomers with expertise in a wide range of relevant disciplines. The resulting papers are organized around several key themes: SN Ia progenitors, debris from extrasolar planetary systems, fundamental physics, precision studies of white dwarf structure and stellar physics and Galactic evolution. They provide a framework for guiding the direction of white dwarf research for the next decade.
Download or read book Nuclear Activity in Galaxies Across Cosmic Time IAU S356 written by Mirjana Pović and published by Cambridge University Press. This book was released on 2020-11-30 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: IAU Symposium 356 summarises the most recent results in the field of active galaxies and active galactic nuclei (AGN). These are some of the most luminous sources in the Universe, also the most distant ones that we can observe, so they are very important for understanding the early Universe and its evolution through cosmic time. This volume gives an overview of the current status in the field of active galaxies including: AGN multiwavelength observations; different AGN types and their properties; AGN variability; active supermassive black holes and properties of galaxies in which they reside; triggering, feedback and shutting off AGN activity; relativistic jets and environments of active galaxies; and AGN evolution. IAU S356 was the third IAU symposium organised in Africa in the past 100 years since the IAU was established, and the first one organised in Ethiopia, highlighting current developments in astronomical research in Africa.
Download or read book Solar and Stellar Magnetic Fields IAU S354 written by Alexander G. Kosovichev and published by Cambridge University Press. This book was released on 2020-10-31 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent observational results from space- and ground-based telescopes have demonstrated that a unified approach to the relationships between solar and stellar magnetism is necessary to advance our understanding of magnetic fields. The Proceedings of IAU Symposium 354 present recent results and discussions of emerging topics, including: magnetic field diagnostics using high-resolution observation; initial data from ALMA, Chinese Radio Spectroheliograph and other instruments; the detection of stellar magnetospheres; and the detailed mapping of magnetic fields on the surface of stars using new unique instrumentation. These observations stimulate comparisons of solar and stellar results, and improve our understanding of how surface magnetic structures and their evolution are related to the generation of magnetic fields by dynamos in solar and stellar interiors. This volume benefits graduate students and researchers interested in the recent advances and key problems of solar and stellar magnetic fields, and their impacts on planetary atmospheres.
Download or read book Under One Sky The IAU Centenary Symposium IAU S349 written by Christiaan Sterken and published by Cambridge University Press. This book was released on 2019-03-31 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: The IAU Centenary Symposium was held at its General Assembly in Vienna in 2018. It starts with plenary lectures, by Malcolm Longair on 100 years of astronomy, astrophysics and cosmology, and by Catherine Cesarsky, who reflects on a century of IAU history. There follows reminiscences from past IAU presidents and general secretaries and presentations on various aspects of IAU history, including some of the famous astronomers who served the Union. The volume then examines the relations between the IAU and different geographical regions, including the issues relating to the Central Powers after World War I, and the "China crisis", when China withdrew from the Union in 1960 and was absent for two decades. The IAU's internal structures and organization are reviewed, along with trends in astronomical publishing and astronomical education. IAU S349 finishes with a vision of the IAU's future from its current president, Ewine van Dishoeck.
Download or read book Astronomy in Focus XXX written by Maria Teresa Lago and published by Cambridge University Press. This book was released on 2020-04-16 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astronomy in Focus presents the most relevant contributions from the Focus Meetings included during the XXX IAU General Assembly held in Vienna, Austria, from 20-31 August 2018. Focus meetings are proposed by groups of scientists with aims to promote cross-disciplinary interactions while maintaining a well-defined focus on a particular topic. They usually address a new scientific area or an emerging field that is not well, or in some cases not at all, represented under the IAU's existing Commission structure. The XXX IAU General Assembly included six scientific symposia, a special symposium focused on the IAU's centenary and fifteen Focus Meetings. The latter comprised twelve scientific Focus Meetings plus two on the mission and activities of the IAU Offices of Astronomy Outreach and Astronomy for Development and the final one promoted by the Working Group on Global Coordination of Ground and Space Astrophysics.
Download or read book Near Field Cosmology with Dwarf Elliptical Galaxies IAU C198 written by International Astronomical Union. Colloquium and published by Cambridge University Press. This book was released on 2005 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of IAUC 198, covering important issues related to near-field cosmology with dwarf elliptical galaxies.
