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Lyman-alpha as an Astrophysical and Cosmological Tool

2019-11-12 Science
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Release : 2019-11-12
Genre : Science
Kind : eBook
Book Rating : 237/5 ( reviews)

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Book Synopsis Lyman-alpha as an Astrophysical and Cosmological Tool by : Mark Dijkstra

Download or read book Lyman-alpha as an Astrophysical and Cosmological Tool written by Mark Dijkstra. This book was released on 2019-11-12. Available in PDF, EPUB and Kindle. Book excerpt: The hydrogen Lyman-alpha line is of utmost importance to many fields of astrophysics. This UV line being conveniently redshifted with distance to the visible and even near infrared wavelength ranges, it is observable from the ground, and provides the main observational window on the formation and evolution of high redshift galaxies. Absorbing systems that would otherwise go unnoticed are revealed through the Lyman-alpha forest, Lyman-limit, and damped Lyman-alpha systems, tracing the distribution of baryonic matter on large scales, and its chemical enrichment. We are living an exciting epoch with the advent of new instruments and facilities, on board of satellites and on the ground. Wide field and very sensitive integral field spectrographs are becoming available on the ground, such as MUSE at the ESO VLT. The giant E-ELT and TMT telescopes will foster a quantum leap in sensitivity and both spatial and spectroscopic resolution, to the point of being able, perhaps, to measure directly the acceleration of the Hubble flow. In space, the JWST will open new possibilities to study the Lyman-alpha emission of primordial galaxies in the near infrared. As long as the Hubble Space Telescope will remain available, the UV-restframe properties of nearby galaxies will be accessible to our knowledge. Therefore, this Saas-Fee course appears very timely and should meet the interest of many young researchers.

Lyman-[alpha] Radiative Transfer in Cosmological Simulations and Applications to a Z[asymptotically Equal To]8 LY-[alpha] Emitter

2005 Cosmology
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Release : 2005
Genre : Cosmology
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Book Synopsis Lyman-[alpha] Radiative Transfer in Cosmological Simulations and Applications to a Z[asymptotically Equal To]8 LY-[alpha] Emitter by : Argyro Tasitsiomi

Download or read book Lyman-[alpha] Radiative Transfer in Cosmological Simulations and Applications to a Z[asymptotically Equal To]8 LY-[alpha] Emitter written by Argyro Tasitsiomi. This book was released on 2005. Available in PDF, EPUB and Kindle. Book excerpt:

An Analysis of Astrophysics and Fundamental Physics from the Lyman-alpha Forest

2013
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Release : 2013
Genre :
Kind : eBook
Book Rating : 484/5 ( reviews)

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Book Synopsis An Analysis of Astrophysics and Fundamental Physics from the Lyman-alpha Forest by : Aaron Joseph Day

Download or read book An Analysis of Astrophysics and Fundamental Physics from the Lyman-alpha Forest written by Aaron Joseph Day. This book was released on 2013. Available in PDF, EPUB and Kindle. Book excerpt: The Lyman-alpha forest, made up of the cosmologically redshifted hydrogen Lyman-alpha absorption lines in the spectra of distant quasars, is a sensitive probe of cosmology and astrophysics. The shape and distribution of the Lyman-alpha absorption lines is deter- mined by the column densities, peculiar velocities, redshifts, turbulent velocities, temperatures, and the distribution of systems of neutral hydrogen in the space between galaxies known as the intergalactic medium. The Lyman-alpha forest is sensitive to the total cosmological matter power spectrum at the smallest available scales. It provides a long lever arm for constraints on the shape of the matter power spectrum when used in conjunction with measurements at large scales, such as the cosmic microwave background. It also has the potential to be used to detect the small scale matter power suppression caused by the free streaming of fundamental particles including known active light neutrinos or potential warm dark matter candidates. Focusing on the line widths, optical depth, and the power spectrum of the flux of the Lyman-alpha forest, we find that previously published observations do not match the outputs of fully hydrodynamic cosmological computer simulations. We present a new measurement of the power spectrum of the flux of the Lyman-alpha forest, using 91 quasar spectra taken with the Keck HIRES spectrograph. This is the largest high resolution data set to date by a factor of about 3. The high resolution of our data sample gives fully resolved absorption lines. Compared to the low resolution data set from SDSS, the HIRES data allows for more accurate subtraction of metal line contamination, as well as a measurement of the flux power at the smallest scales. Finally, we run a suite of 44 new computer simulations, varying cosmological and astrophysical parameters in an attempt to find a model that matches our observational data. We find that no standard cosmological or astrophysical parameters provide an acceptable match. This calls into question previous constraints on cosmological parameters made from Lyman-alpha forest data sets

The Lyman Alpha Forest in Hierarchical Structure Formation Models

1998 Astrophysics
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Release : 1998
Genre : Astrophysics
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Book Synopsis The Lyman Alpha Forest in Hierarchical Structure Formation Models by : Romeel S Davé

Download or read book The Lyman Alpha Forest in Hierarchical Structure Formation Models written by Romeel S Davé. This book was released on 1998. Available in PDF, EPUB and Kindle. Book excerpt:

Understanding the Epoch of Cosmic Reionization

2015-11-28 Science
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Release : 2015-11-28
Genre : Science
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Book Rating : 57X/5 ( reviews)

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Book Synopsis Understanding the Epoch of Cosmic Reionization by : Andrei Mesinger

Download or read book Understanding the Epoch of Cosmic Reionization written by Andrei Mesinger. This book was released on 2015-11-28. Available in PDF, EPUB and Kindle. Book excerpt: The dawn of the first stars, galaxies and black holes signaled a fundamental milestone in our Universe’s evolution: the Epoch of Reionization. The light from these galactic ancestors began spreading out, ionizing virtually every atom in existence. Our Universe transitioned from darkness to light, from cold to hot, from simple and boring to the wondrous cosmic zoo we see around us today. Despite its importance, observations of reionization have been few, and their interpretation has been highly controversial. Fortunately, this is rapidly changing. We will soon enter the "Big Data” era of this mysterious epoch, driven by an upcoming wave of observations with state-of-the-art telescopes as well as new sophisticated analysis tools. The aim of this volume is to summarize the current status and future outlook of the reionization field. We bring together leading experts in many sub-disciplines, highlighting the measurements that will illuminate our understanding of reionization and the cosmic dawn: (i) 21cm interferometry; (ii) high-redshift quasar spectra; (iii) high-redshift galaxy surveys; (iv) primary and secondary anisotropies of the Cosmic Microwave Background; (v) high-resolution studies of the metal content of early galaxies. We seek a roadmap to interpreting the wealth of upcoming observations. What is the best use of limited observational resources? How do we develop theoretical tools tailored for each observation? Ultimately, what will we learn about the epoch of reionization and our galactic ancestors?

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