Diffuse Radio Foregrounds

This extensive thesis work covers several topics, including intensity and polarization, focusing on a new polarization bias reduction method. Vidal studied data from the WMAP satellite, which is low signal-to-noise and as such has to be corrected for polarization bias. He presents a new method for correcting the data, based on knowledge of the underlying angle of polarization. Using this novel method, he sets upper limits for the polarization fraction of regions known to emit significant amounts of spinning dust emissions. He also studies the large-scale loops and filaments that dominate the synchrotron sky. The dominant features are investigated, including identification of several new features. For the North Polar Spur, a model of an expanding shell in the vicinity of the Sun is tested, which appears to fit the data. Implications for CMB polarization surveys are also discussed. In addition, Vidal presents interferometric observations of the dark cloud LDN 1780 at 31 GHz and shows that the spinning dust hypothesis can explain the radio properties observed.

This book contains the expanded lecture notes of the 32nd Saas-Fee Advanced Course. The three contributions present the central themes in modern research on the cold universe, ranging from cold objects at large distances to the physics of dust in cold clouds.

New observations of the period between the cosmic recombination and the end of reionization are posing intriguing questions about where the first generations of stars were formed, how the first galaxies were assembled, whether these galaxies have low redshift counterparts, and what role the early galaxies played in the reionization process. Combining the new observational data with theoretical models can shed new light on open issues regarding the star formation process, its role in the reionization of the Universe, and the metal enrichment in galaxies at those early epochs. This volume brings together leading experts in the field to discuss our current level of understanding and what may come in the near future as our observational as well as theoretical tools improve. The book confronts the theory of how the first stars, black holes, and galaxies formed with current and planned observations. This synthesis is very timely, just ahead of the establishment of major new facilities, such as the James Webb Space Telescope (JWST), a next-generation, millimeter/sub-millimeter observatory in the Atacama desert (ALMA), and ground-based Extremely Large Telescopes (ELT). Together, they will revolutionize the study of the most distant objects in the Universe. This volume is aimed at beginning graduate students but can also serve as a reference work for active researchers in the field. Apart from presenting the fundamental concepts involved, it also provides an introduction to the methods and techniques used. The book will also be useful to anyone with an astrophysical background who needs an effective starting point for learning about the first stars and galaxies.

Are we living in the "golden age" of cosmology? Are we close to understanding the nature of the unknown ingredients of the currently most accepted cosmological model and the physics of the early Universe? Or are we instead approaching a paradigm shift? What is dark matter and does it exist? How is it distributed around galaxies and clusters? Is the scientific community open to alternative ideas that may prompt a new scientific revolution - as the Copernican revolution did in Galileo's time? Do other types of supernovae exist that can be of interest for cosmology? Why have quasars never been effectively used as standard candles? Can you tell us about the scientific adventure of COBE? How does the extraction of the Cosmic Microwave Background anisotropy depend on the subtraction of the various astrophysical foregrounds? These, among many others, are the astrophysical, philosophical and sociological questions surrounding modern cosmology and the scientific community that Mauro D'Onofrio and Carlo Burigana pose to some of the most prominent cosmologists of our time. Triggered by these questions and in the spirit of Galileo's book "Dialogue Concerning the Two Chief World Systems" the roughly 40 interview partners reply in the form of essays, with a critical frankness not normally found in reviews, monographs or textbooks.

Now in its 4th edition, this classic text presents a quantitative understanding of a range of astrophysical concepts. Emphasizing physical concepts, the book outlines cosmic events but does not portray them in detail. Instead, it provides a series of astrophysical sketches showing how to obtain quantitative insights into the structure and evolution of stars, the dynamics of cosmic gases, the large-scale behavior of the universe, and the origins of life. Nearly every part of the text has been reconsidered and rewritten for the new edition; new sections cover recent developments, and the remainder has been revised and brought up to date.

The existence of soft excess emission originating from clusters of galaxies, de ned as em- sion detected below 1 keV in excess over the usual thermal emission from hot intracluster gas (hereafter the ICM) has been claimed since 1996. Soft excesses are particularly - portant to detect because they may (at least partly) be due to thermal emission from the Warm-Hot Intergalactic Medium, where as much as half of the baryons of the Universe could be. They are therefore of fundamental cosmological importance. Soft excess emission has been observed (and has also given rise to controversy) in a number of clusters, mainly raising the following questions: (1) Do clusters really show a soft excess? (2) If so, from what spatial region(s) of the cluster does the soft excess or- inate? (3) Is this excess emission thermal, originating from warm-hot intergalactic gas (at 6 temperatures of?10 K), or non-thermal, in which case several emission mechanisms have been proposed. Interestingly, some of the non-thermal mechanisms suggested to account for soft excess emission can also explain the hard X-ray emission detected in some clusters, for example by RXTE and BeppoSAX (also see Petrosian et al. 2008—Chap. 10, this issue; Rephaeli et al. 2008—Chap. 5, this issue).

A comprehensive and up-to-date review of Cygnus A and what it can teach us about other active galaxies - for graduate students and researchers.

A scientist’s inspiring vision of our return to the Moon as humanity’s next thrilling step in space exploration Just over half a century since Neil Armstrong first stepped foot on the lunar surface, a new space race to the Moon is well underway and rapidly gaining momentum. Laying out a vision for the next fifty years, Back to the Moon is astrophysicist Joseph Silk’s persuasive and impassioned case for putting scientific discovery at the forefront of lunar exploration. The Moon offers opportunities beyond our wildest imaginings, and plans to return are rapidly gaining momentum around the world. NASA aims to build a habitable orbiting space station to coordinate lunar development and exploration, while European and Chinese space agencies are planning lunar villages and the mining of precious resources dwindling here on Earth. Powerful international and commercial interests are driving the race to revisit the Moon, but lunar infrastructures could also open breathtaking vistas onto the cosmos. Silk describes how the colonization of the Moon could usher in a thrilling new age of scientific exploration, and lays out what the next fifty years of lunar science might look like. With lunar telescopes of unprecedented size situated in permanently dark polar craters and on the far side of the Moon, we could finally be poised to answer some of the most profound questions confronting humankind, including whether we are alone in the Universe and what our cosmic origins are. Addressing both the daunting challenges and the immense promise of lunar exploration and exploitation, Back to the Moon reveals how prioritizing science, and in particular lunar astronomy, will enable us to address the deepest cosmic mysteries.