Latest Galaxy formation and evolution Stories

2009-08-31 12:05:00

 As scientists attempt to learn more about how galaxies evolve, an open question has been whether collisions with our dwarf galactic neighbors will one day tear apart the disk of the Milky Way.That grisly fate is unlikely, a new study now suggests.While astronomers know that such collisions have probably occurred in the past, the new computer simulations show that instead of destroying a galaxy, these collisions "puff up" a galactic disk, particularly around the edges, and produce...

2009-08-19 14:05:00

For decades, astronomers have gone about their business of studying the cosmos with the assumption that stars of certain sizes form in certain quantities. Like grocery stores selling melons alone, and blueberries in bags of dozens or more, the universe was thought to create stars in specific bundles. In other words, the proportion of small to big stars was thought to be fixed. For every star 20 or more times as massive as the sun, for example, there should be 500 stars with the sun's mass or...

2009-08-05 15:54:52

Galaxies of today are bigger and denser than the most massive galaxies of the universe in its early days, U.S. astronomers said. Recent observations of very distant massive galaxies -- located so far away that their light left them more than 10 billion years ago -- suggested that the galaxies were about five times smaller than similar galaxies of today even though they contain roughly the same amount of stars, researchers from Yale University and Swinburne University of Technology in...

2009-08-05 13:55:00

Looking almost 11 billion years into the past, astronomers have measured the motions of stars for the first time in a very distant galaxy and clocked speeds upwards of one million miles per hour, about twice the speed of our Sun through the Milky Way. The fast-moving stars shed new light on how these distant galaxies, which are a fraction the size of our Milky Way, may have evolved into the full-grown galaxies seen around us today. The results will be published in the August 6, 2009 issue of...

2009-07-09 15:40:00

The tight cluster of stars surrounding a supermassive black hole after it has been violently kicked out of a galaxy represents a new kind of astronomical object and a fossil record of the kick. A paper published in the July 10 issue of The Astrophysical Journal discusses the theoretical properties of "hypercompact stellar systems" and suggests that hundreds of these faint star clusters might be detected at optical wavelengths in our immediate cosmic environment. Some of these objects may...

2009-07-01 06:35:22

UC Riverside astronomer leads international team studying galaxy formation and evolution in early history of the universe An international team of researchers led by a UC Riverside astronomer has completed the largest ever survey designed to find very distant clusters of galaxies. Named the Spitzer Adaptation of the Red-sequence Cluster Survey, "SpARCS" detects galaxy clusters using deep ground-based optical observations from the CTIO 4m and CFHT 3.6m telescopes, combined with Spitzer Space...

2009-07-01 06:30:00

Our Milky Way galaxy only survived because it was already immersed in a large clump of dark matter which trapped gases inside it, scientists led by Durham University's Institute for Computational Cosmology (ICC) found. The research, to be presented at an international conference today (Wednesday, July 1), also forms a core part of a new ICC movie charting the evolution of the Milky Way to be shown at the Royal Society. The researchers said that the early Milky Way, which had begun forming...

2009-06-24 12:45:00

The "coming of age" of galaxies and black holes has been pinpointed, thanks to new data from NASA's Chandra X-ray Observatory and other telescopes. This discovery helps resolve the true nature of gigantic blobs of gas observed around very young galaxies. About a decade ago, astronomers discovered immense reservoirs of hydrogen gas -- which they named "blobs" "“ while conducting surveys of young distant galaxies. The blobs are glowing brightly in optical light, but the source of immense...

2009-06-09 16:15:00

Some of the black holes nearest to Earth may be larger than previously believed. A re-examination of the vast black hole at the core of the nearby M87 galaxy indicates it could have 6.4 billion times the mass of the Sun, two to three times larger than previous studies had suggested.The reassessment has led scientists to speculate that many other black holes are also under-recorded, said Dr. Karl Gebhardt in remarks made at a meeting of the American Astronomical Society (AAS) in Pasadena,...

2009-04-30 16:02:58

A U.S. astronomer says he discovered a galaxy in which gas is distributed over a much larger area than researchers expected to find. Macalester College Professor John Cannon said the giant disk dwarf galaxy he discovered has the largest size difference between stars and gas of any known galaxy. That finding, he said, is important for furthering the understanding of how galaxies form and how they remain stable over time. Cannon said data from the Kitt Peak National Observatory in Arizona and...

Latest Galaxy formation and evolution Reference Libraries

2010-09-13 16:56:08

The Coma Cluster (Abell 1656), along with the Leo Cluster, is one of two major clusters compromising the Coma Supercluster. It contains over 1000 identified galaxies. Most of the galaxies in the center of the Coma Cluster are elliptical galaxies including both dwarf and giant. However the center is dominated by NGC 4874 and NGC 4889, two giant elliptical galaxies. The brightest galaxies are visible, a few degrees north of the galactic pole, with an amateur telescope larger than 20 cm. The...

2010-09-07 17:03:18

The Abell 520 galaxy cluster is an strange structure formed by a major merger. Due to its odd and chaotic nature it has been given the nick-name the Train Wreck Cluster. The Dark Matter within the cluster does not act as expected like it does in other clusters, therefore, Abell 520 creates problems for many of the prevailing theories about Dark Matter. It also disrupts many alternative theories of modified gravity. Similar to the Bullet Cluster the gas contents and galaxies within the...

2004-10-19 04:45:42

Ring Galaxy -- A subclass of interacting galaxies, ring galaxies, provides a unique laboratory for studying unusually large bursts of non-nuclear star formation. The rings in these systems are often large (10s of kiloparsecs) and contain what appear to be associations of giant H{\small II} regions. As a basis for future modeling of star forming regions in observed ring galaxies we present a series of combined n-body/gas numerical experiments on ring formation and evolution. Three...

2004-10-19 04:45:41

Molecular Cloud -- Molecular clouds are interstellar nebulae that have a density and size sufficient to permit the formation of H2, molecular hydrogen. However, this molecule is difficult to detect, and the molecule most used to trace the H2 is CO (carbon monoxide). The ratio between CO luminosity and H2 mass is roughly constant, although there are reasons to doubt this assumption in observations of some other galaxies. In the Milky Way, molecular clouds account for roughly one-half...

2004-10-19 04:45:41

Globular Cluster -- A globular cluster is a cluster of stars that is spherical in shape and extremely dense towards its core. Globular clusters are usually composed of hundreds of thousands of old stars, similar to the bulge of a spiral galaxy but confined to a volume of only a few cubic parsecs. Some globular clusters (like Omega Centauri in our Milky Way, and G1 in M31) are truly massive clusters, with several million times the mass of our Sun. Such globular clusters may be the...

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