Download or read book Improving the Precision of Type I A Supernova Cosmology written by Jing Lu and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Type Ia supernovae (SNe Ia) mark the beginning and the end of stellar evolution. They are one of the most powerful cosmological probes in our universe thanks to their high intrinsic luminosities and standardizable properties. In the 1990s, the observation of SNe Ia led to the discovery of the accelerating cosmic expansion that was awarded the Nobel Prize in 2011. Despite decades of advancements, the exact details of progenitor systems (id est what exploded), explosion mechanisms (id est, how they exploded), and evolution effect (id est are the nearby population the same as those in the early universe?) are still not fully understood yet. With more advanced observation surveys forthcoming in the near future, such as those on board the Vera C. Rubin Observatory and the Nancy Grace Roman Space Telescope, the systematic uncertainties of SNe Ia observations will continue to dominate the error budget of their distance measurements. This dissertation is motivated to improve the precision of SN~Ia cosmology by understanding the physics and diversity and SNe Ia, as well as improving the astronomical tools needed for cosmological purposes. Photometric and spectroscopic observational studies of the first homogenous sample of the peculiar 03fg-like SNe Ia obtained by the Carnegie Supernovae Project (CSP) are conducted to investigate the physics of SNe Ia. 03fg-like events are usually more luminous than the normal SNe Ia and exhibit peculiar light-curve shapes in the redder filters, such as the weak or missing secondary maxima and the delayed peak time in iYJH bands. Spectroscopically, 03fg-like SN Ia show peculiar features in both optical and near-infrared (NIR) regions, such as the stronger C, slower Si, and the lack of the H-band break. One of the most extreme objects within this subgroup, ASASSN-15hy, is used for the case study of an envelope model that could potentially explain all 03fg-like SNe~Ia. It is found that a core degenerate scenario, an explosion of a degenerate white dwarf core inside a nondegenerate envelope, with a transition from deflagration to detonation can explain the observed peculiar properties. In the case of ASASSN-15hy, the low metallicity of the progenitor is a key aspect of the model explanation. In fact, a low-metallicity host environment is a shared preference among these 03fg-like SNe~Ia. Such host environment is more common in the early universe, which brings up the concern that 03fg-like SNe~Ia may be a problem for high-redshift SN~Ia cosmology due to detection bias and potential evolution preference. Therefore, more detailed observational and theoretical studies of these events are strongly recommended. Another main focus of this dissertation is on the development of a new NIR spectral template of SNe Ia that captures the feature variations that are correlated with the light-curve shapes. Compared to optical observations, NIR observations of SN Ia are less sensitive to dust and have more uniform peak luminosities, which are beneficial for cosmological purposes. A spectral template is usually needed to fit the light curves of SNe Ia accurately in order to estimate the distance. However, the NIR part of the existing spectral templates lacks an accurate description of the intrinsic spectral variations. Using the largest and most homogeneous collection of NIR spectra of SNe Ia to date collected by CSP-II, we are able to explore the NIR spectral diversity of SNe Ia and build a new NIR spectra template. Principal component analysis and Gaussian process regression are used for the template construction, which reduces data dimensionality and models the parameter dependence, respectively. Using the new template reduces the systematic uncertainties in K-corrections by ~90% compared to those from the Hsiao template. Furthermore, this template can serve as the baseline spectral energy distribution for various light-curve fitters and can identify peculiar spectral features that might point to compelling physics. The NIR spectra data and template presented in this work will substantially improve future SN Ia cosmological experiments, for both nearby and distant samples.

Download or read book Type Ia Supernovae written by Jens C. Niemeyer and published by Cambridge University Press. This book was released on 2000-05 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: A unique and wide-ranging review of one of the most dramatic research results in astronomy in recent decades.

Download or read book In Pursuit of Dark Energy written by Bradley Elton Tucker and published by . This book was released on 2013 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Equation of State SuperNova trace Cosmic Expansion (ESSENCE) was a 6 year survey which discovered and followed 228 type Ia supernova (SN Ia). The primary goal of ESSENCE was to characterize the dark energy equation-of-state, w. However, due to limitations in the knowledge of the SN Ia progenitor system and systematic errors related to influences of the host galaxies on SN Ia distances and the photometric calibrations of the survey, the measurements are only accurate to approximately 10%. Combining the 228 SN Ia light-curves with published data, we used a set of 695 SN Ia to search for progenitor signatures in SN Ia light-curves SN Ia. Kasen 2010 predicted that the companion star in a SN Ia would create a hole in the ejecta, allowing heated emission to escape, producing a strong signature in the early phases of a SN Ia light-curve. Using Monte-Carlo simulations, we examine the 695 SN Ia light-curves, searching for the peak flux in the ultra-violet (UV) and blue filters, expected from a red giant companion. Using both the frequency of these progenitor scenarios and viewing angles of the shock break-out, 4-5 detections are predicted. Our analysis yields zero detections, with a 98.2% confidence. We explain that the SN Ia scenario involving accretion from a red giant onto a white dwarf can not make up a significant fraction of the SN Ia population and better models are needed. Also using the ESSENCE survey, we develop a new method for determining the Spectral Energy Distribution (SED) and rest-frame magnitudes of the host galaxies from the UV to the infrared (IR) and use empirical relations to derive galaxy properties. We also calculate the normalized separation of the SN Ia from the center of the host galaxy. We find a substantial amount of UV emission in our passive galaxies, suggesting star-formation in these galaxies. Additionally we find an approximately 4 sigma correlation of the rest-frame Far UV (FUV) - V host galaxy color and distance residuals from best fitting cosmology (Hubble residual) when the sample is divided by host galaxy type. Lastly, we find SN Ia greater than 2 effective radii occur in low-extinction environments, producing a uniform sample of SN Ia for cosmological measurements. SN Ia at these distances have noticeable offsets in SN color and Hubble residual from the entire sample, suggesting improper SN Ia light-curve fitting, potentially biasing SN Ia distance measurements. Finally, we discuss improvements in the photometric calibration of the SN Ia photometry to reduce the systematic errors in distance measurements. We produced a photometrically flat image with less than 1% illumination gradient across the images. We also detail our automated procedure for correcting the flux of the SN Ia in a given aperture. These two improvements, along with a few other implementations, produce SN Ia photometry with approximately 1% accuracy. We compare our SN Ia photometry and light-curves to that of Wood-Vasey et al. 2007 illustrating the full extent of our improvements.

Download or read book Bayesian Methods in Cosmology written by Michael P. Hobson and published by Cambridge University Press. This book was released on 2010 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive introduction to Bayesian methods in cosmological studies, for graduate students and researchers in cosmology, astrophysics and applied statistics.

Download or read book Improving Type Ia Supernova Standard Candle Cosmology Measurements Using Observations of Early Type Host Galaxies written by Joshua Evan Meyers and published by . This book was released on 2012 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: Type Ia supernovae (SNe Ia) are the current standard-bearers for dark energy but face several hurdles for their continued success in future large surveys. For example, spectroscopic classification of the myriad SNe soon to be discovered will not be possible, and systematics from uncertainties in dust corrections and the evolution of SN demographics and/or empirical calibrations used to standardize SNe Ia must be studied. Through the identification of low-dust host galaxies and through increased understanding of both the SN -- progenitor connections and empirical calibrations, host galaxy information may offer opportunities to improve the cosmological utility of SNe Ia. The first half of this thesis analyzes the sample of SNe~Ia discovered by the Hubble Space Telescope (HST) Cluster Supernova Survey augmented with {\it HST}-observed SNe~Ia in the Great Observatories Origins Deep Survey (GOODS) fields. Correlations between properties of SNe and their host galaxies are examined at high redshift. Using galaxy color and quantitative morphology to determine the red sequence in 25 clusters, a model is developed to distinguish passively evolving early-type galaxies from star-forming galaxies in both clusters and the field. With this approach, 6 early-type cluster member hosts and 11 SN~Ia early-type field hosts are identified. For the first time at z>0.9, the correlation between host galaxy type and the rise and fall time of SN~Ia light curves is confirmed. The relatively simple spectral energy distributions of early-type galaxies also enables stellar mass measurements for these hosts. In combination with literature host mass measurements, these measurements are used to show, at z>0.9, a hint of the correlation between host mass and Hubble residuals reported at lower redshift. By simultaneously fitting cluster galaxy formation histories and dust content to the scatter of the cluster red sequences, it is shown that dust reddening of early-type cluster SN hosts is likely less than E(B-V)

Download or read book Handbook of Supernovae written by Athem W. Alsabti and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Estimation of the Cosmological Parameters from an Analysis of Type Ia Supernovae with CMAGIC written by Alexander Joseph Conley and published by . This book was released on 2005 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Type Ia Supernovae written by Benjamin M. Rose and published by . This book was released on 2018 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Supernova Cosmology and How to Talk about It written by Rachel Cane Wolf and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The discovery of the accelerating expansion of the Universe launched a new chapter in modern cosmology. Evidence for this accelerating expansion was first observed using Type Ia supernovae, which are brilliant, standardizable explosions that can be detected at large distances and used to infer cosmological parameters. New surveys are being designed to detect thousands of Type Ia supernovae, ushering in an era where parameter inference is no longer limited by statistics, but by systematic uncertainties. One of these systematics which is not well understood is the progenitor and progenitor environment, which can be investigated by studying properties of the supernova host galaxy. In this dissertation, I use the three-year sample of photometrically-classified and spectroscopically-confirmed Type Ia supernovae from Sloan Digital Sky Survey-II Supernova Survey to explore correlations between supernova luminosity and host-galaxy mass, metallicity, and star-formation rate. Observations suggest that such correlations should be incorporated to improve the standardization of Type Ia supernova luminosities. As such, new techniques for parameter inference will need to accommodate increasingly large samples of supernovae and a variety of standardization models. In this dissertation, I also introduce the BAyesian hierarchical Modeling with BIased Simulations (BAMBIS) algorithm, a novel approach to parameter inference using Type Ia supernovae which can, in principle, include systematics such as host-galaxy correlations in a robust statistical framework.In addition to offering new scientific research opportunities, the quest to understand the evolution of the cosmos brings excellent opportunities for astronomers to engage in science education and public outreach (EPO). I present an analysis of the Dark Energy Survey EPO program, a unique large-scale astronomy EPO initiative organized and led entirely by professional astronomers. In this analysis, I detail the development of the EPO program as well as analyze the strengths and weaknesses of a subset of specific initiatives. I also discuss scientists' reported methods of communicating science with the public.

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 Ideal Bandpasses for Type Ia Supernova Cosmology written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To use type Ia supernovae as standard candles for cosmologywe need accurate broadband magnitudes. In practice the observed magnitudemay differ from the ideal magnitude-redshift relationship either throughintrinsic inhomogeneities in the type Ia supernova population or throughobservational error. Here we investigate how we can choose filterbandpasses to reduce the error caused by both these effects. We find thatbandpasses with large integral fluxes and sloping wings are best able tominimise several sources of observational error, and are also leastsensitive to intrinsic differences in type Ia supernovae. The mostimportant feature of a complete filter set for type Ia supernovacosmology is that each bandpass be a redshifted copy of the first. Wedesign practical sets of redshifted bandpasses that are matched totypical high resistivity CCD and HgCdTe infra-red detector sensitivities. These are designed to minimise systematic error in well observedsupernovae, final designs for specific missions should also considersignal-to-noise requirements and observing strategy. In addition wecalculate how accurately filters need to be calibrated in order toachieve the required photometric accuracy of future supernova cosmologyexperiments such as the SuperNova-Acceleration-Probe (SNAP), which is onepossible realisation of the Joint Dark-Energy mission (JDEM). We considerthe effect of possible periodic miscalibrations that may arise from theconstruction of an interference filter.

Download or read book Precision Cosmology written by Bernard J. T. Jones and published by Cambridge University Press. This book was released on 2017-04-20 with total page 1166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cosmology seeks to characterise our Universe in terms of models based on well-understood and tested physics. Today we know our Universe with a precision that once would have been unthinkable. This book develops the entire mathematical, physical and statistical framework within which this has been achieved. It tells the story of how we arrive at our profound conclusions, starting from the early twentieth century and following developments up to the latest data analysis of big astronomical datasets. It provides an enlightening description of the mathematical, physical and statistical basis for understanding and interpreting the results of key space- and ground-based data. Subjects covered include general relativity, cosmological models, the inhomogeneous Universe, physics of the cosmic background radiation, and methods and results of data analysis. Extensive online supplementary notes, exercises, teaching materials, and exercises in Python make this the perfect companion for researchers, teachers and students in physics, mathematics, and astrophysics.

Download or read book Thermonuclear Supernovae written by P. Ruiz-Lapuente and published by Springer Science & Business Media. This book was released on 1997 with total page 920 pages. Available in PDF, EPUB and Kindle. Book excerpt: All theoretical and observational topics relevant to the understanding of the thermonuclear (Type Ia) supernova phenomenon are thoroughly and consistently reviewed by a panel including the foremost experts in the field. The book covers all aspects, ranging from the observations of SNe Ia at all stages and all wavelengths to the 2D and 3D modelling of thermonuclear flames in very dense plasmas. Scenarios for close binary evolution leading to SNe Ia are discussed. Particular emphasis is placed on the homogeneity vs. diversity of SNe Ia and on their use as standard candles to measure cosmological parameters. The book reflects the recent and very significant progress made in both the modelling of the explosions and in the observational field.

Download or read book Verifying the Cosmological Utility of Type Ia Supernovae written by and published by . This book was released on 2008 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: We analyze the mean rest-frame ultraviolet (UV) spectrum of Type Ia Supernovae (SNe) and its dispersion using high signal-to-noise ratio Keck-I/LRIS-B spectroscopy for a sample of 36 events at intermediate redshift (z=0.5) discovered by the Canada-France-Hawaii Telescope Supernova Legacy Survey (SNLS). We introduce a new method for removing host galaxy contamination in our spectra, exploiting the comprehensive photometric coverage of the SNLS SNe and their host galaxies, thereby providing the first quantitative view of the UV spectral properties of a large sample of distant SNe Ia. Although the mean SN Ia spectrum has not evolved significantly over the past 40percent of cosmic history, precise evolutionary constraints are limited by the absence of a comparable sample of high-quality local spectra. The mean UV spectrum of our z~;;=0.5 SNe Ia and its dispersion is tabulated for use in future applications. Within the high-redshift sample, we discover significant UV spectral variations and exclude dust extinction as the primary cause by examining trends with the optical SN color. Although progenitor metallicity may drive some of these trends, the variations we see are much larger than predicted in recent models and do not follow expected patterns. An interesting new result is a variation seen in the wavelength of selected UV features with phase. We also demonstrate systematic differences in the SN Ia spectral features with SN light curve width in both the UV and the optical. We show that these intrinsic variations could represent a statistical limitation in the future use of high-redshift SNe Ia for precision cosmology. We conclude that further detailed studies are needed, both locally and at moderate redshift where the rest-frame UV can be studied precisely, in order that future missions can confidently be planned to fully exploit SNe Ia as cosmological probes.

Download or read book Thirteenth Marcel Grossmann Meeting The On Recent Developments In Theoretical And Experimental General Relativity Astrophysics And Relativistic Field Theories Proceedings Of The Mg13 Meeting On General Relativity In 3 Volumes written by Remo Ruffini and published by World Scientific. This book was released on 2015-01-26 with total page 2807 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Marcel Grossmann Meetings seek to further the development of the foundations and applications of Einstein's general relativity by promoting theoretical understanding in the relevant fields of physics, mathematics, astronomy and astrophysics and to direct future technological, observational, and experimental efforts. The meetings discuss recent developments in classical and quantum aspects of gravity, and in cosmology and relativistic astrophysics, with major emphasis on mathematical foundations and physical predictions, having the main objective of gathering scientists from diverse backgrounds for deepening our understanding of spacetime structure and reviewing the current state of the art in the theory, observations and experiments pertinent to relativistic gravitation. The range of topics is broad, going from the more abstract classical theory, quantum gravity, branes and strings, to more concrete relativistic astrophysics observations and modeling.The three volumes of the proceedings of MG13 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 33 morning plenary talks during 6 days, and 75 parallel sessions over 4 afternoons. Volume A contains plenary and review talks ranging from the mathematical foundations of classical and quantum gravitational theories including recent developments in string/brane theories, to precision tests of general relativity including progress towards the detection of gravitational waves, and from supernova cosmology to relativistic astrophysics including such topics as gamma ray bursts, black hole physics both in our galaxy and in active galactic nuclei in other galaxies, and neutron star and pulsar astrophysics. Volumes B and C include parallel sessions which touch on dark matter, neutrinos, X-ray sources, astrophysical black holes, neutron stars, binary systems, radiative transfer, accretion disks, quasors, gamma ray bursts, supernovas, alternative gravitational theories, perturbations of collapsed objects, analog models, black hole thermodynamics, numerical relativity, gravitational lensing, large scale structure, observational cosmology, early universe models and cosmic microwave background anisotropies, inhomogeneous cosmology, inflation, global structure, singularities, chaos, Einstein-Maxwell systems, wormholes, exact solutions of Einstein's equations, gravitational waves, gravitational wave detectors and data analysis, precision gravitational measurements, quantum gravity and loop quantum gravity, quantum cosmology, strings and branes, self-gravitating systems, gamma ray astronomy, and cosmic rays and the history of general relativity.

Download or read book Precision Cosmology written by and published by Cambridge University Press. This book was released on with total page 777 pages. Available in PDF, EPUB and Kindle. Book excerpt: