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Center for Astrophysics
The mission of the Harvard-Smithsonian Center for Astrophysics (CfA) is to advance our knowledge and understanding of the universe through research and education in astronomy and astrophysics.
American Astronomical Society | Advocates for science since 1899
The American Astronomical Society (AAS), established 1899, is the major organization of professional astronomers in North America. The membership (~7,700) also includes physicists, mathematicians, geologists, engineers and others whose research interests lie within the broad spectrum of subjects now comprising contemporary astronomy. The mission of the American Astronomical Society is to enhance and share humanity's scientic understanding of the Universe
Solar Cycle Linked to Global Climate, Drives Events Similar to El Niño, La Niña - News Release
Guest Post: Evalyn Gates on Cosmic Magnification (or — Invasion of the Giant Blue Space Amoebas) | Cosmic Variance | Discover Magazine
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This galaxy has been lensed by the warp in spacetime created by the cluster. Light from the galaxy, which lies almost directly behind the center of the cluster but much farther away from us, travels along several curved paths through the cluster lens, producing multiple magnified images of the galaxy. The inset box shows a computer generated model of the unlensed source galaxy, enlarged by a factor of four so that the details, including the spiral arm structure, are visible. Without the lensing power of the cluster, we would see this galaxy as a single small blue smudge.
In general, lensing will both magnify and distort (shear) images of a background source. This lens is fairly unique in that we see large but relatively intact images of the spiral galaxy, which implies that the mass distribution in the central region of the cluster must be nearly uniform.
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This is not just a pretty picture, however – the image packs a lot of scientific information. The authors extract the mass distribution in the cluster (which has implications for cosmological models), measure the mass-to-light ratio of the bright galaxy in the center of the cluster, and use the magnifying power of the lens to search for even more distant galaxies.
The basic idea is to construct a model of the lens, starting with the cluster galaxies and a dark matter halo; then refine the model to reproduce the multiple images that are seen. Using this refined model it’s possible to predict the location of additional images of a given source, and to identify regions of high magnification that can then be examined for multiple images of other sources. Any additional images that are found can be used to further refine the model and so on.
ESO - ESO 24/09 - Astronomer's new guide to the galaxy: largest map of cold dust revealed
This new guide for astronomers, known as the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) shows the Milky Way in submillimetre-wavelength light (between infrared light and radio waves [1]). Images of the cosmos at these wavelengths are vital for studying the birthplaces of new stars and the structure of the crowded galactic core.
Technology Review: Blogs: arXiv blog: Why ET's genetic code could be just like ours
"The combined actions of thermodynamics and subsequent natural selection suggest that the genetic code we observe on the Earth today may have significant features in common with life throughout the cosmos."
[0903.4849] Dark Matter Candidates
An overview is given of various dark matter candidates. Among the many suggestions given in the literature, axions, inert Higgs doublet, sterile neutrinos, supersymmetric particles and Kaluza-Klein particles are discussed.
FQXi Community: Articles, Forums, Blogs, News - Judgment Day at the End of Time (the Essay Contest)
list of winning essays for the Foundational Questions in Physics and Cosmology Institute
the physics arXiv blog » Blog Archive » The puzzle of planet formation
"At the heart of the problem is the fascinating question: why are all the planets different?
The ones in our solar system ought to have formed out of the same stuff at more or less the same time and yet no two are alike. And now the extrasolar planets seem to be demonstrating a similar variety."
[astro-ph/0511440] Varying Constants
We review properties of theories for the variation of the gravitation and fine structure 'constants'. We highlight some general features of the cosmological models that exist in these theories with reference to recent quasar data that are consistent with time-variation in the fine structure 'constant' since a redshift of 3.5. The behaviour of a simple class of varying-alpha cosmologies is outlined in the light of all the observational constraints.
Sloan Survey Expands to Explore Larger Universe in 3D
And though we may be away from those holographic representations, the Sloan Digital Sky Survey will soon be entering its third phase, in an attempt to create the biggest 3D map of the universe created so far.
[0807.3697] Stars In Other Universes: Stellar structure with different fundamental constants
[0806.0377] A Hemispherical Power Asymmetry from Inflation
Measurements of temperature fluctuations by the Wilkinson Microwave Anisotropy Probe (WMAP) indicate that the fluctuation amplitude in one half of the sky differs from the amplitude in the other half. We show that such an asymmetry cannot be generated during single-field slow-roll inflation without violating constraints to the homogeneity of the Universe. In contrast, a multi-field inflationary theory, the curvaton model, can produce this power asymmetry without violating the homogeneity constraint. The mechanism requires the introduction of a large-amplitude superhorizon perturbation to the curvaton field, possibly a pre-inflationary remnant or a superhorizon curvaton-web structure. The model makes several predictions, including non-Gaussianity and modifications to the inflationary consistency relation, that will be tested with forthcoming CMB experiments.
SkyandTelescope.com - News from Sky & Telescope - Solar Curveballs: Sun Puts a Twist on Its Pitches
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New observations with the X-Ray Telescope (XRT) on Japan's Hinode solar spacecraft captured an unprecedentedly detailed view of a coronal mass ejection (CME) on April
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