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2 Justification and benefits in joining TMT
2 Justification and benefits in joining TMT

... reveal that the Universe is dominated by dark matter and dark energy. The nature of these two dark components is the most fundamental question in (astro-)physics today. The discovery of more than 400 extrasolar planet systems indicates that our solar system may be the exception rather than the norm; ...
Science with the Constellation
Science with the Constellation

... Since their discovery, quasars and active galactic nuclei (AGN) have stood out as uniquely luminous objects in the Universe. Today we are confident that their ultimate power source is the release of gravitational energy sustained by an accretion disk, which is feeding matter directly into a central ...
The Terrestrial Planet Finder Mission
The Terrestrial Planet Finder Mission

... ing through the pupil plane from a plane pupil plane given direction at a certain point on the focal plane, say (0, 0). However, the wave nature of light makes it impossible to concentrate all of the light at a point. Instead, a small disk, called the Airy disk, with diffraction rings around it appe ...
The Habitability of Proxima Centauri b I: Evolutionary Scenarios
The Habitability of Proxima Centauri b I: Evolutionary Scenarios

... Centauri are known, the mass MP rox , age, effective temperature T , and composition are not. The spectra and luminosity suggest the mass of Proxima is ∼ 0.12 M (Delfosse et al. 2000). If we adopt this value, then the semi-major axis of b’s orbit is 0.0485 AU and the planet receives 65% of the inst ...
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A New Science Strategy for Space Astronomy and Astrophysics
A New Science Strategy for Space Astronomy and Astrophysics

... The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the respo ...
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... handful of hot planet systems, namely, WASP-12 b (Fossati et al. 2010), HD 189733 b (Ben-Jaffel & Ballester 2013; Bourrier et al. 2013; Cauley et al. 2015), and GJ 436 b (Ehrenreich et al. 2015; see Section 1 of Cauley et al. 2015, for a brief overview). Most recently, Ehrenreich et al. (2015) repor ...
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... Almost all Galactic black hole (BH) binaries with low mass donors are transient X-ray sources; we expect most of the X-ray transients (XRTs) observed in external galaxies to be BH binaries also. Obtaining period estimates for extra-galactic XRTs is challenging, but the resulting period distribution ...
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... libraries contain models with burst fractions very close to zero, which are essentially identical to the models in the continuous library, so the new minimum χ2 is guaranteed to be equal to or smaller than the old one. If the new χ2min /Nd lies in the range 2.37-6.25, the probability that the model ...
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... ago, the time delay required for SMBHs to merge (Begelman et al. 1984). This is also comparable to the timescale for driving gas to the center of the merger suggested by other simulations (Di Matteo et al. 2005, 2008; Hopkins et al. 2005; Springel et al. 2005a, 2005b). While this timescale supports ...
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... phase of early stellar evolution. As many as 50 per cent of all members of a young cluster may have lost their discs and any other accretion signatures at an age of 2–3 Myr. Observations made from space with X-ray observatories, such as the Chandra X-ray Observatory, have shown that young stars emit ...
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The Origin of Comets and the Oort Cloud

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... PAPER I: I contributed to the preparation of the proposal to NRAO, as well as the full procedure for preparing and performing the observations, together with Aage Sandqvist, John Whiteoak and Frank Gardner. The post-observational calibration of the data was made at the VLA together with Aage Sandqvi ...
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... while a star like the Sun keeps burning its hydrogen nuclear fuel for about 10 billion years, one hundred thousand times longer. Thus, about one million years or so after the end of the star formation, when all the massive stars have died out, the luminosity of the galaxy eventually becomes again do ...
Galaxy Evolution
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... while a star like the Sun keeps burning its hydrogen nuclear fuel for about 10 billion years, one hundred thousand times longer. Thus, about one million years or so after the end of the star formation, when all the massive stars have died out, the luminosity of the galaxy eventually becomes again do ...
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... dominated by poorly understood dark matter and a mysterious vacuum energy density. This progress poses new, and more fundamental, questions, the answers to some of which will perhaps unite astrophysics with elementary particle physics in a new approach to the nature of matter. Some discoveries, made ...
Rest-frame Optical Spectra: A Window into Galaxy Formation at z~2
Rest-frame Optical Spectra: A Window into Galaxy Formation at z~2

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N-Body/SPH simulations of induced star formation in dwarf galaxies

... out that dark matter is necessary to explain large scale structure formation and the origin of galaxies. Structure in the universe is believed to originate hierarchically. Primarily, small density perturbations arise. Pressureless dark matter clumps together in these density perturbations and dark m ...
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Nebular hypothesis

The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System. It suggests that the Solar System formed from nebulous material. The theory was developed by Immanuel Kant and published in his Universal Natural History and Theory of the Heaven. Originally applied to our own Solar System, this process of planetary system formation is now thought to be at work throughout the universe. The widely accepted modern variant of the nebular hypothesis is the solar nebular disk model (SNDM) or simply solar nebular model. This nebular hypothesis offered explanations for a variety of properties of the Solar System, including the nearly circular and coplanar orbits of the planets, and their motion in the same direction as the Sun's rotation. Some elements of the nebular hypothesis are echoed in modern theories of planetary formation, but most elements have been superseded.According to the nebular hypothesis, stars form in massive and dense clouds of molecular hydrogen—giant molecular clouds (GMC). These clouds are gravitationally unstable, and matter coalesces within them to smaller denser clumps, which then rotate, collapse, and form stars. Star formation is a complex process, which always produces a gaseous protoplanetary disk around the young star. This may give birth to planets in certain circumstances, which are not well known. Thus the formation of planetary systems is thought to be a natural result of star formation. A Sun-like star usually takes approximately 1 million years to form, with the protoplanetary disk evolving into a planetary system over the next 10-100 million years.The protoplanetary disk is an accretion disk that feeds the central star. Initially very hot, the disk later cools in what is known as the T tauri star stage; here, formation of small dust grains made of rocks and ice is possible. The grains eventually may coagulate into kilometer-sized planetesimals. If the disk is massive enough, the runaway accretions begin, resulting in the rapid—100,000 to 300,000 years—formation of Moon- to Mars-sized planetary embryos. Near the star, the planetary embryos go through a stage of violent mergers, producing a few terrestrial planets. The last stage takes approximately 100 million to a billion years.The formation of giant planets is a more complicated process. It is thought to occur beyond the so-called frost line, where planetary embryos mainly are made of various types of ice. As a result, they are several times more massive than in the inner part of the protoplanetary disk. What follows after the embryo formation is not completely clear. Some embryos appear to continue to grow and eventually reach 5–10 Earth masses—the threshold value, which is necessary to begin accretion of the hydrogen–helium gas from the disk. The accumulation of gas by the core is initially a slow process, which continues for several million years, but after the forming protoplanet reaches about 30 Earth masses (M⊕) it accelerates and proceeds in a runaway manner. Jupiter- and Saturn-like planets are thought to accumulate the bulk of their mass during only 10,000 years. The accretion stops when the gas is exhausted. The formed planets can migrate over long distances during or after their formation. Ice giants such as Uranus and Neptune are thought to be failed cores, which formed too late when the disk had almost disappeared.
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