Development and Testing of a New Method for Velocity-selecting White Dwarfs from Gaia by Galactic Population

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (143 download)

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Book Synopsis Development and Testing of a New Method for Velocity-selecting White Dwarfs from Gaia by Galactic Population by : Joseph Hammill

Download or read book Development and Testing of a New Method for Velocity-selecting White Dwarfs from Gaia by Galactic Population written by Joseph Hammill and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The detailed processes by which spiral galaxies form remains an open question in modern cosmology. Observations of the current configuration of spiral galaxies including the Milky Way reveal thin and thick disk and halo populations which must all be accounted for in formation theories and likely have distinct ages. Using the Milky Way as an example to probe this question, we are studying the formation history of these structures.

Population Synthesis Studies of the White Dwarfs of the Galactic Disk and Halo

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ISBN 13 :
Total Pages : 157 pages
Book Rating : 4.:/5 (112 download)

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Book Synopsis Population Synthesis Studies of the White Dwarfs of the Galactic Disk and Halo by : Elena-Ruxandra Cojocaru

Download or read book Population Synthesis Studies of the White Dwarfs of the Galactic Disk and Halo written by Elena-Ruxandra Cojocaru and published by . This book was released on 2017 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the evolutionary end-point of most main-sequence stars, white dwarfs can be used to infer important properties concerning the formation and evolution of the different Galactic stellar populations. Population synthesis methods, when correlated with the excellent quality of modern white dwarf cooling tracks, can prove to be a powerful tool for further exploring the information offered by observed samples of white dwarfs. Possible applications may include estimating the age and history of stellar populations, measuring the local stellar formation rate and stellar density, constraining the local content of baryonic matter, examining intrinsic aspects of single and binary stellar evolution and exploring different progenitor scenarios for type Ia supernovae. In this thesis we studied the white dwarf populations of the Galactic disk and halo and our work was focused on four main objectives. The first was to analyze the effects of stellar metallicity on the white dwarf luminosity function of the Galactic disk. We use our Monte Carlo population synthesis code to produce synthetic samples of white dwarfs which we later compare to two relatively large observational samples, from the Sloan Digital Sky Survey (SDSS) and SuperCosmos Sky Survey (SSS). For each of the two cases, we implement the corresponding observational selection criteria. We first explore the impact of varying the fraction of white dwarfs with hydrogen-deficient atmospheres and of using alternative sets of cooling tracks. We then test different age-metallicity relations, considering the impact of progenitor metallicity throughout the entire evolution of the star. Our second objective was to determine the luminosity, mass and cumulative age functions derived from a sample of disk white dwarfs identified by the LAMOST Sky Survey of the Galactic Anti-Center. We initially compute the observed functions and then the theoretical ones, according to series of initial assumptions, using our population synthesis code. We derive values for the local space density and formation rate of hydrogen-rich white dwarfs and analyze the possible causes behind the apparent excess of massive white dwarfs identified in the observed mass function. The next objective of this thesis was to revisit the halo white dwarf luminosity function, modeling the halo white dwarf population using a self-consistent prescription for very low metallicity progenitors. We pass the synthetic sample through a series of filters that reproduce the selection criteria employed in culling the observed sample of halo white dwarfs from the SSS. Given that for very low-metallicity progenitors residual hydrogen burning can become a significant source of energy, we test two different sets of cooling tracks, one that incorporates residual hydrogen burning and another where this phenomenon is artificially ignored. Finally, our last study consisted in modeling the sample of white dwarf-main sequence binaries in the Galactic disk. We compare our simulations to the largest and most recent catalog of white dwarf-main sequence binaries from the SDSS and we provide a detailed account of observational biases and errors. We use this sample to constrain several important inputs for binary formation and evolution, namely the initial mass ratio distribution and the common envelope efficiency parameter. To conclude, the work presented in this thesis testifies to the versatility of using white dwarf populations for constraining different properties of the Galactic disk and halo. The methodology described here can be used in future studies of this kind, with a myriad of new applications, especially given than in the near future a noticeable improvement in terms of the size and quality of observed white dwarf catalogs is expected.

White Dwarfs and the Ages of Stellar Populations

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ISBN 13 :
Total Pages : 270 pages
Book Rating : 4.:/5 (782 download)

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Book Synopsis White Dwarfs and the Ages of Stellar Populations by : Steven Andrew De Gennaro

Download or read book White Dwarfs and the Ages of Stellar Populations written by Steven Andrew De Gennaro and published by . This book was released on 2009 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our group has developed a Bayesian modeling technique to determine the ages of stellar populations (in particular, open and globular clusters) using white dwarf (WD) cooling physics. As the theory of WD cooling is both simpler than, and essentially independent of, main sequence evolutionary theory, white dwarfs provide an independent measure of the ages of Galactic populations. We have developed a Bayesian technique that objectively incorporates our prior knowledge of stellar evolution, star cluster properties, and data quality estimates to derive posterior probability distributions for a cluster's age, metallicity, distance, and line-of-sight absorption, as well as the individual stellar parameters of mass, mass ratio (for unresolved binaries) and cluster membership probability. The key advantage of our Bayesian method is that we can calculate probability distributions for cluster and stellar parameters with reference only to known, quantifiable, objective, and repeatable quantities. In doing so, we also have more sensitivity to subtle changes in cluster isochrones than traditional "chi-by-eye'" cluster fitting methods. As a critical test of our Bayesian modeling technique, we apply it to Hyades UBV photometry, with membership priors based on proper motions and radial velocities, where available. We use secular parallaxes derived from Hipparcos proper motions via the moving cluster method to put all members of the Hyades at a common distance. Under the assumption of a particular set of WD cooling and atmosphere models, we estimate the age of the Hyades based on cooling white dwarfs to be 610 ± 110 Myr, consistent with the best prior analysis of the cluster main-sequence turn-off age (Perryman, et al. 1998). Since the faintest white dwarfs have most likely evaporated from the Hyades, prior work provided only a lower limit to the cluster's white dwarf age. Our result demonstrates the power of the bright white dwarf technique for deriving ages (Jeffery, et al. 2007) and further demonstrates complete age consistency between white dwarf cooling and main-sequence turn-off ages for seven out of seven clusters analyzed to date, ranging from 150 Myr to 4 Gyr. We then turn our attention to the white dwarf luminosity function. We use Sloan Digital Sky Survey (SDSS) data to create a white dwarf luminosity function with nearly an order of magnitude (3,358) more spectroscopically confirmed white dwarfs than any previous work. We determine the completeness of the SDSS spectroscopic white dwarf sample by comparing a proper-motion selected sample of WDs from SDSS imaging data with a large catalog of spectroscopically determined WDs. We derive a selection probability as a function of a single color (g-i) and apparent magnitude (g) that covers the range -1.0

Gravitational Dynamics

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

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Book Synopsis Gravitational Dynamics by : Ofer Lahav

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

White Dwarfs

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Publisher : Springer Science & Business Media
ISBN 13 : 9781402013645
Total Pages : 470 pages
Book Rating : 4.0/5 (136 download)

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Book Synopsis White Dwarfs by : Domitilla de Martino

Download or read book White Dwarfs written by Domitilla de Martino and published by Springer Science & Business Media. This book was released on 2003-07-31 with total page 470 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Research Workshop, held in Naples, Italy, 24-28 June 2002

The Origin and Evolution of Galaxies

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Publisher : Springer Science & Business Media
ISBN 13 : 9400979398
Total Pages : 359 pages
Book Rating : 4.4/5 (9 download)

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Book Synopsis The Origin and Evolution of Galaxies by : J.T. Jones

Download or read book The Origin and Evolution of Galaxies written by J.T. Jones and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Origin and Evolution of Galaxies is the outstanding problem of modern cosmology. Fortunately. we have a firm cosmological framework on which to base our theories (the hot big bang) and recently there has been substantial progress in providing observations which potentially can constrain these theories. The problem of galaxy formation is. as a consequence. one involving many diverse branches of physics and astrophysics. It has been the aim of the school. and this compendium of lectures and seminars. to bring together these diverse aspects at a level enabling research workers to understand what is going on in other corners of the subject and to see how progress in each area impinges on the others. We are grateful to the contributors to this volume for allowing us considerable editorial license with their articles. We have attempted to provide a representative sample of the talks that were given at the school besides the texts of the invited lecturers. It is regrettable that for reasons of space we have had to leave out a number of other contributions.

Developing New Tools and Techniques to Probe the M Dwarf Planet Population

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ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)

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Book Synopsis Developing New Tools and Techniques to Probe the M Dwarf Planet Population by : Shubham Kanodia

Download or read book Developing New Tools and Techniques to Probe the M Dwarf Planet Population written by Shubham Kanodia and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: We do not understand the largest planets around the smallest and most numerous stars in the Galaxy. M dwarfs are the most common type of stars in the Galaxy. Empirical studies show that they also play host to more inner planets than FGK stars, despite this, of the currently $\sim 5000$ confirmed exoplanets, only about 250 orbit M dwarfs, of which only $\sim 65$ have precise mass and radii measurements! The population of planets around M dwarfs is poorly understood. In this thesis I will discuss our efforts to detect and obtain precise measurements for planets around M dwarfs, and then to place this sample of M dwarfs in context of the larger sample of planets around FGK stars. The first part of my dissertation focusses on the instrumentation efforts for the Habitable zone Planet Finder (HPF), and NEID. HPF is a stabilized near-infrared (NIR) fiber-fed radial velocity (RV) spectrograph at the 10 m Hobby Eberly Telescope (HET) at McDonald Observatory, Texas, USA, while NEID is a new high-precision spectrograph in the red-optical installed at the 3.5 m WIYN telescope at Kitt Peak, Arizona, USA. I was in charge of developing, integrating and testing the fiber-feed for HPF, as well as the optical simulations to verify the alignment of the instrument. For NEID, not only did I lead a similar effort for the fiber-feed and simulations, but was also responsible for the chromatic exposure meter which is essential to measure exposure midpoints for barycentric corrections. In conjunction, I developed the algorithm for performing these corrections, which are now used in HPF, NEID and numerous other RV spectrographs. HPF with its large aperture and near-infrared bandpass, and NEID with its red-optical coverage have already started to enable the RV follow up of planets around mid-to-late and early M dwarfs respectively. I then discuss some results from the HPF RV survey, where first I test the scrambling performance of HPF on the fixed altitude HET using on-sky data on an M dwarf. Then I present the results of a serendipitous observation of a flare around the ultracool dwarf vB 10. The HPF spectra taken during the flare show a red excess in the He 10830 \AA~triplet which is similar to observations of coronal rain for the Sun, while also placing a limit on the atmospheric mass loss from flares for planets orbiting such stars. Alongside the instrumentation and observational efforts, I also built upon a nonparametric framework to model exoplanet masses and radii (M-R), which was then applied to a sample of planets around M dwarfs. By comparing the results for M dwarf planets with those from FGK stars we notice some systemic differences in their distributions. However, further inferences were deterred by the small sample of transiting M dwarf planets with mass measurements. I then discuss the efforts to use HPF and NEID to follow up on M dwarf planet candidates discovered by TESS. Not only do these planets help fill in the M-R plane for M dwarfs, but also highlight interesting correlations with stellar properties. Finally, I conclude by giving an overview of how my work on instrumentation, algorithms and novel statistical frameworks has helped develop our understanding of the M dwarf planet population. The ongoing transiting gas giant follow-up will be continued in the future, which will help us shed further light on how these giant planets form around the smallest stars.

Fundamentals of Galaxy Dynamics, Formation and Evolution

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

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

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

Galaxy Formation and Evolution

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Publisher : Cambridge University Press
ISBN 13 : 0521857937
Total Pages : 841 pages
Book Rating : 4.5/5 (218 download)

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Book Synopsis Galaxy Formation and Evolution by : Houjun Mo

Download or read book Galaxy Formation and Evolution written by Houjun Mo and published by Cambridge University Press. This book was released on 2010-05-20 with total page 841 pages. Available in PDF, EPUB and Kindle. Book excerpt: A coherent introduction for researchers in astronomy, particle physics, and cosmology on the formation and evolution of galaxies.

From Pulsations to Planetary Debris

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ISBN 13 :
Total Pages : 390 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis From Pulsations to Planetary Debris by : Zachary Philip Vanderbosch

Download or read book From Pulsations to Planetary Debris written by Zachary Philip Vanderbosch and published by . This book was released on 2021 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: The final fates of stars and their planetary systems are in most cases embodied by white dwarfs. These are the compact remnants of stellar evolution for all low- to intermediate-mass stars in our Galaxy, including the Sun. The relative simplicity of white dwarfs makes them valuable tools in a variety of astrophysical contexts, from placing limits on the age of our Galaxy, to measuring the bulk abundances of exoplanets via the presence of actively accreted metals in their atmospheres. White dwarfs can also exhibit photometric variability for a variety of reasons, both as isolated stars and in binary systems, providing insights into white dwarf structure and circumstellar environments. In this dissertation we first present novel techniques to identify variable white dwarfs in modern time-domain photometric surveys. We then focus on identifying and characterizing two types of variable white dwarfs: those that pulsate and those being transited by circumstellar planetary debris. Using the unprecedented number of white dwarfs observed by Gaia and the Zwicky Transient Facility (ZTF), we define a set of variability metrics based on these publicly available catalogues to efficiently identify variable white dwarfs across the Gaia color magnitude diagram. We then present a dedicated search for pulsating He-atmosphere white dwarfs (DBVs) using McDonald Observatory follow-up observations, in an attempt to better define the observed extent of the helium-atmosphere white dwarf instability strip. We increase the number of DBVs from 28 to 47 using Sloan Digital Sky Survey spectroscopy to initially identify candidate DBVs. We find the observed blue and red edges of the DB instability strip are still hotter than theoretical expectations by about 1500K and 600K, respectively. Using our set of Gaia and ZTF variability metrics, we identify and characterize the second and third cases of white dwarfs with recurring planetary debris transits, with debris orbital periods differing by more than two orders of magnitude. These objects, in combination with the first known system, probe a unique parameter space constraining earlier stages of the planetary debris disruption and migration process

New Worlds, New Horizons in Astronomy and Astrophysics

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

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

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

New Spectroscopic Tools and Techniques for Characterizing M Dwarfs and Discovering Their Planets in the Near-infrared

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (943 download)

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Book Synopsis New Spectroscopic Tools and Techniques for Characterizing M Dwarfs and Discovering Their Planets in the Near-infrared by : Ryan Terrien

Download or read book New Spectroscopic Tools and Techniques for Characterizing M Dwarfs and Discovering Their Planets in the Near-infrared written by Ryan Terrien and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: M dwarfs are the least massive and most common stars in the Galaxy. Due to their prevalence and long lifetimes, these diminutive stars play an outsize role in several fields of astronomical study. In particular, it is now known that they commonly host planetary systems, and may be the most common hosts of Earth-size, rocky planets in the habitable zone. A comprehensive understanding of M dwarfs is crucial for understanding the origins and conditions of their planetary systems, including their potential habitability. Such an understanding depends on methods for precisely and accurately measuring their properties. These tools have broader applicability as well, underlying the use of M dwarfs as fossils of Galactic evolution, and helping to constrain the structures and interiors of these stars.The measurement of the fundamental parameters of M dwarfs is encumbered by their spectral complexity. Unlike stars of spectral type F, G, or K that are similar to our G type Sun, whose spectra are dominated by continuum emission and atomic features, the cool atmospheres of M dwarfs are dominated by complex molecular absorption. Another challenge for studies of M dwarfs is that these stars are optically faint, emitting much of their radiation in the near-infrared (NIR). The availability and performance of NIR spectrographs have lagged behind those of optical spectrographs due to the challenges of producing low-noise, high-sensitivity NIR detector arrays, which have only recently become available.This thesis discusses two related lines of work that address these challenges, motivated by the development of the Habitable Zone Planet Finder (HPF), a NIR radial velocity (RV) spectrograph under development at Penn State that will search for and confirm planets around nearby M dwarfs. This work includes the development and application of new NIR spectroscopic techniques for characterizing M dwarfs, and the development and optimization of new NIR instrumentation for HPF.The first line of work is centered on a large NIR spectroscopic survey of nearby M dwarfs, undertaken to characterize potential targets for HPF. This survey, and new techniques for measuring M dwarf metallicity, are the subject of Chapter 2. These data will provide crucial information to assess planetary composition, and the stellar metallicities will help us understand the process of planet formation around M dwarfs. These techniques have also enabled strong tests of low-mass stellar models in the benchmark eclipsing binary system CM Draconis, and have helped identify potential directions for improvement in the models, as presented in Chapter 3. The development of new spectroscopic indices for measuring M dwarf luminosity, radius, and potentially [alpha]-element abundance is discussed in Chapter 4. Finally, Chapter 5 presents a synthesis of these M dwarf characterization techniques and radial velocity (RV) measurements from the SDSS-III APOGEE spectrograph, which we applied to confirm and characterize the first M dwarfs in the nearby Coma Berenices cluster.The second line of work relates to the optimization of HPF. By targeting M dwarfs, HPF will take advantage of the large signal induced by an Earth-mass planet orbiting an M dwarf compared to the same planet orbiting an FGK star. Chapter 6 discusses a number of design trades and parameter optimizations undertaken in order to ensure the best sensitivity to Earth-mass planets. These subtopics include the optimization of the HPF resolution, bandpass, operating temperature, and vacuum phase holographic cross-disperser, as well as prediction of anticipated HPF performance, and the development of an HPF software simulator tool.In carrying out NIR detector tests for HPF, we have also tested an optical filter that selectively blocks long-wavelength thermal background radiation. This type of contamination is a perennial source of noise for NIR instruments, and typically forces these instruments to operate fully cryogenically. The complexity and cost of this approach may be avoided: for instruments operating in the H-band or bluer, the thermal background can be optically filtered, freeing the instrument to operate at warmer temperatures. Chapter 7 details our characterization and application of an interference filter that effectively blocks thermal background when used with a 1.7[mu]m-cutoff HAWAII-2RG NIR detector array. By effectively filtering the thermal background with a single coated optic, this filter offers the potential for simple, cost-effective, warm-pupil NIR astronomical instruments, which can take advantage of the increasing availability of low-noise, high-efficiency NIR detectors.

The Star Formation History and the Stellar Initial Mass Function of the Milky Way Disc

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Publisher :
ISBN 13 :
Total Pages : 142 pages
Book Rating : 4.:/5 (122 download)

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Book Synopsis The Star Formation History and the Stellar Initial Mass Function of the Milky Way Disc by : Roger Mor Crespo

Download or read book The Star Formation History and the Stellar Initial Mass Function of the Milky Way Disc written by Roger Mor Crespo and published by . This book was released on 2019 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: "AIMS: We develop a new theoretical framework to generate Besançon Galaxy Model Fast Approximate Simulations (BGM FASt) to address fundamental questions of the Galactic structure and evolution performing multi-parameter inference. The flexibility of BGM FASt allows the inference of fundamental parameters related to the stellar initial mass function (IMF), the star formation history (SFH), the density distribution, the kinematics and the chemo-dynamics, among others. BGM FASt allows the study of different Milky Way (MW) components. In this thesis we are focused in a first application of our strategy to simultaneously infer the IMF and the SFH of the MW disc.METHOD: BGM FASt is based on a reweighing scheme, that uses a specific pre-sampled simulation. We use BGM FASt together with an approximate Bayesian computation algorithm to obtain the posterior probability distribution function of the inferred parameters, by automatically comparing synthetic versus observed data. Our full strategy is codified to run on Apache Spark and Hadoop, suited to deal with large surveys. BGM FASt is implemented in the big data infrastructure known as Gaia Data Analytics Framework (GDAF) at the University of Barcelona.To evaluate the performance of BGM FASt we execute a set of validation tests comparing density, colour, mass and age distributions of BGM FASt versus BGM standard simulations. We present two scientific cases that compare synthetic versus Tycho-2 colour-magnitude diagrams. We obtain for the first time using BGM an IMF and SFH of the thin disc by exploring a 6-Dimensional parameter space.We use Gaia data-release 2 magnitudes, colours, and parallaxes for stars with G

The Exoplanet Handbook

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Publisher : Cambridge University Press
ISBN 13 : 1108419771
Total Pages : 973 pages
Book Rating : 4.1/5 (84 download)

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Book Synopsis The Exoplanet Handbook by : Michael Perryman

Download or read book The Exoplanet Handbook written by Michael Perryman and published by Cambridge University Press. This book was released on 2018-08-30 with total page 973 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete and in-depth review of exoplanet research, covering the discovery methods, physics and theoretical background.

Planets, Stars and Stellar Systems

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Publisher : Springer
ISBN 13 : 9789400756113
Total Pages : 0 pages
Book Rating : 4.7/5 (561 download)

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Book Synopsis Planets, Stars and Stellar Systems by : Gerard Gilmore

Download or read book Planets, Stars and Stellar Systems written by Gerard Gilmore and published by Springer. This book was released on 2013-02-23 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is volume 5 of Planets, Stars and Stellar Systems, a six-volume compendium of modern astronomical research, covering subjects of key interest to the main fields of contemporary astronomy. This volume on “Galactic Structure and Stellar Populations”, edited by Gerard F. Gilmore, presents accessible review chapters on Stellar Populations, Chemical Abundances as Population Tracers, Metal-Poor Stars and the Chemical Enrichment of the Universe, The Stellar and Sub-Stellar Initial Mass Function of Simple and Composite Populations, The Galactic Nucleus, The Galactic Bulge, Open Clusters and Their Role in the Galaxy, Star Counts and the Nature of Galactic Thick Disk, The Infrared Galaxy, Interstellar PAHs and Dust, Galactic Neutral Hydrogen, High-Velocity Clouds, Magnetic Fields in Galaxies, Astrophysics of Galactic Charged Cosmic Rays, Gamma-Ray Emission of Supernova Remnants and the Origin of Galactic Cosmic Rays, Galactic Distance Scales, Globular Cluster Dynamical Evolution, Dynamics of Disks and Warps, Mass Distribution and Rotation Curve in the Galaxy, Dark Matter in the Galactic Dwarf Spheroidal Satellites, and History of Dark Matter in Galaxies. All chapters of the handbook were written by practicing professionals. They include sufficient background material and references to the current literature to allow readers to learn enough about a specialty within astronomy, astrophysics and cosmology to get started on their own practical research projects. In the spirit of the series Stars and Stellar Systems published by Chicago University Press in the 1960s and 1970s, each chapter of Planets, Stars and Stellar Systems can stand on its own as a fundamental review of its respective sub-discipline, and each volume can be used as a textbook or recommended reference work for advanced undergraduate or postgraduate courses. Advanced students and professional astronomers in their roles as both lecturers and researchers will welcome Planets, Stars and Stellar Systems as a comprehensive and pedagogical reference work on astronomy, astrophysics and cosmology.

Galactic Astronomy

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Publisher : Princeton University Press
ISBN 13 : 0691233322
Total Pages : 818 pages
Book Rating : 4.6/5 (912 download)

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Book Synopsis Galactic Astronomy by : James Binney

Download or read book Galactic Astronomy written by James Binney and published by Princeton University Press. This book was released on 2021-07-13 with total page 818 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the definitive treatment of the phenomenology of galaxies--a clear and comprehensive volume that takes full account of the extraordinary recent advances in the field. The book supersedes the classic text Galactic Astronomy that James Binney wrote with Dimitri Mihalas, and complements Galactic Dynamics by Binney and Scott Tremaine. It will be invaluable to researchers and is accessible to any student who has a background in undergraduate physics. The book draws on observations both of our own galaxy, the Milky Way, and of external galaxies. The two sources are complementary, since the former tends to be highly detailed but difficult to interpret, while the latter is typically poorer in quality but conceptually simpler to understand. Binney and Merrifield introduce all astronomical concepts necessary to understand the properties of galaxies, including coordinate systems, magnitudes and colors, the phenomenology of stars, the theory of stellar and chemical evolution, and the measurement of astronomical distances. The book's core covers the phenomenology of external galaxies, star clusters in the Milky Way, the interstellar media of external galaxies, gas in the Milky Way, the structure and kinematics of the stellar components of the Milky Way, and the kinematics of external galaxies. Throughout, the book emphasizes the observational basis for current understanding of galactic astronomy, with references to the original literature. Offering both new information and a comprehensive view of its subject, it will be an indispensable source for professionals, as well as for graduate students and advanced undergraduates.

The Impact of Binary Stars on Stellar Evolution

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Publisher : Cambridge University Press
ISBN 13 : 1108428584
Total Pages : 359 pages
Book Rating : 4.1/5 (84 download)

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Book Synopsis The Impact of Binary Stars on Stellar Evolution by : Giacomo Beccari

Download or read book The Impact of Binary Stars on Stellar Evolution written by Giacomo Beccari and published by Cambridge University Press. This book was released on 2019-04-18 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: An advanced review of how binary stars affect stellar evolution, presenting results from state-of-the art models and recent observations.