Universe

[lukman]

Elegant Universe 3/1 <br /><br /> Elegant Universe 3/2 <br /><br /> Elegant Universe 3/3 <br /><br /> Elegant Universe 3/4 <br /><br /> Elegant Universe 3/5 <br /><br /> Elegant Universe 3/6 <br /><br /> Elegant Universe 3/7 <br /><br /> Elegant Universe 3/8 <div class="Discussion_UserSignature"> </div>

 

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Great job lukman. Thanks <img src="/images/icons/wink.gif" />

 

[lukman]

You are welcome, got the link from another physics forum <img src="/images/icons/laugh.gif" />. Please cross check the link, i may had made typing mistakes. <div class="Discussion_UserSignature"> </div>

 

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X-rays Reveal What Makes the Milky Way Move<br />With the galaxy cluster population mapped over the entire sky for the first time, Kocevski analyzed how all the clusters surrounding the Milky Way would affect it and found that only 44% of our galaxy's motion through space is due to the gravitational pull of galaxies in the nearby Great Attractor region. The remaining portion is the result of a large-scale flow in which much of the local Universe, including perhaps the Great Attractor itself, is being pulled toward the Shapley Supercluster.<br /><br />The results confirm previous work, which suggested the Milky Way's motion was influenced by structures more distant than the Great Attractor, but this study is the first to reach this conclusion after having fully mapped the Great Attractor and regions behind it.<br /><br />http://arxiv.org/abs/astro-ph/0510106<br />We aim to settle the debate regarding the fraction of the Local Group's peculiar velocity that is induced by structures beyond the Great Attractor by calculating the dipole anisotropy of the largest, all-sky, truly X-ray selected cluster sample compiled to date. The sample is the combination of the REFLEX catalog in the southern hemisphere, the eBCS sample in the north, and the CIZA survey in the Galactic plane. The composite REFLEX+eBCS+CIZA sample overcomes many of the problems inherent to previous galaxy and cluster catalogs which limited their effectiveness in determining the origin of the Local Group's motion. From the dipole anisotropy present in the cluster distribution we determine that 44% of the Local Group's peculiar velocity is due to infall into the GA region, while 56% is in the form of a large-scale flow induced by more distant overdensities between 130 and 180 h^-1 Mpc away. In agreement with previous analyses, we find that the Shapley superclust

 

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<br />Andromeda is the only big spiral galaxy galaxy moving towards the Milky Way.<br /><br />Collision Simulation

 

[alokmohan]

Is there a great attractor region?Possibly it deos not have the same name now,I don see the name anywhere.

 

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That is the point of the post above. <br /><br />Great Attractor<br />The Great Attractor is located in a region of the universe that is obscured from observers in the Solar System by the dust of the Milky Way's disk<br /><br />The Great Attractor is apparently pulling in millions of galaxies in a region of the universe that includes the Milky Way, the surrounding Local Group of 15 to 16 nearby galaxies and larger Virgo Supercluster, and the nearby Hydra-Centaurus Supercluster, at velocities of around 600 (in the Local Group) to thousands of kilometers (or miles) per second (Lynden-Bell et al, 1988; and Dressler et al, 1987). Based on the observed galactic velocities, the unseen mass inhabiting the voids between the galaxies and clusters of galaxies is estimated to total around 10 times more than the visible matter in this region of the universe and so must be composed of mostly dark matter. Calculations indicate that the Great Attractor has perhaps around 5.4 times 1016 Solar-masses. Galaxies located on the other side of the Great Attractor are also being pulled in its direction, so that they were being held back very slightly from expanding as fast as rest of the universe, by the gravitational pull of the Great Attractor (Renée C. Kraan-Korteweg, 2000).

 

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From the Kocevski study:<br />Kocevski and collaborators report finding far fewer massive cluster systems near the Great Attractor than would be expected given the region's proposed mass. "One of our goals was to uncover the true mass of the Great Attractor. What we found is that it is not that great after all," says Kocevski.<br /><br />Before this study the Great Atractor was predicted like this (see image):<br />

 

[MeteorWayne]

GREAT STUFF SEARCH!!!!<br /><br />Thankyouverymuch <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

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You are welcome. It is amazing stuff.<br />The Shapley Supercluster<br />"<br />The Scientific Study of the Shapley Supercluster<br /><br />In the Harvard Observatory Bulletin in 1930, Harlow Shapley published a Note on a Remote Cloud of Galaxies in Centaurus. He described "a cloud of galaxies in Centaurus that appears to be one of the most populous yet discovered". He did not actually discover the entire supercluster. His map showing the cloud corresponds to the row of clusters in the centre of the supercluster including A3556, A3558 and A3562. In 1933, Harlow Shapley included A3558 in a list of 25 rich clusters of galaxies.<br /><br />It required a long time for astronomers to rediscover the Shapley supercluster. In the late 1970's astronomers began to notice strong X-ray sources in this part of the sky. J Melnick and H Quintana rediscovered the A3558 cluster in 1981 which they called 2A1326-311 (from a catalogue of X-ray sources) and they mentioned that it was in "an area of the sky extremely rich in galaxies", thus repeating Harlow Shapley's observation from 51 years earlier. In 1987, Jorge Melnick and Mariano Moles published the first major evidence that there is a massive supercluster here.<br /><br />The publication of the southern extension of the Abell catalogue by G Abell, H Corwin and R Olowin in 1989 was very important because it gave astronomers a full list of the rich clusters in this region. R Scaramella, G Baiesi-Pillastrini, G Chincarini, G Vettolani and G Zamorani announced in a paper in 1989 and in another paper in 1990 that they had also discovered this supercluster (which they called the alpha region) while searching for the Great Attractor (see the page on the Centaurus supercluster). S Raychaudhury also noticed the supercluster in a paper in 1989, but he concluded that it was too far to be the Great Attractor. S Raychaudhury was one of the first people to use the name Sha

 

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Core of the Great Attractor<br /><br />The core of the Great Attractor lies within the so-called "Centaurus Wall" of galaxies. From the perspective of observers in the Solar System, this Great Wall-like structure is viewed edge-on (Woudt and Kraan-Korteweg, 2000). The intersection of the Centaurus Wall and the Great Attractor includes the Norma Cluster or Supercluster -- ACO 3627, Abell 3627, or A3627 (Woudt et al, 2000, 1999a, and 1999b). Indeed, the Milky Way, the Local Group, and the surrounding Virgo Supercluster, as well as the Hydra-Centaurus Supercluster, appear to be part (or at least "appendages") of the sheet of ordinary and dark matter that forms the Centaurus Wall. [More discussion and color images of the Virgo Supercluster and the Centaurus Wall are available from Professor Anthony P. Fairall's lecture on "Large-Scale Structures in the Universe.")

 

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AN ATLAS OF NEARBY LARGE-SCALE STRUCTURES<br />Anthony Fairall

 

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NED Image Data Atlas<br /><br />The NASA/IPAC Extragalactic Database (NED) is built around a master list of extragalactic objects for which cross identifications of object names and positions are established using data published in journal articles and survey catalogs covering all wavelengths. Detailed photometry, positions, and redshift data are assimilated, entered with uncertainties when available, and linked to bibliographic references, abstracts and online literature. NED also maintains an image archive that currently contains over 1.9 million images, maps and links to external images. NED's image archive focuses on unique FITS images acquired from authors of journal articles, but also includes cut-outs from very large sky surveys such as 2MASS and the Digitized Sky Survey. NED currently contains data for over 7.5 million objects, and the content is continually being updated. Revised versions of the public database are released every few months.<br />Images in NED are represented above as overlays in red on the 2MASS all-sky image above. Either type in a coordinate or click on any red region to get a close-up of the area; the size of the search region is adjustable. Please note that the above all-sky grid is in Galactic coordinates, however, the default coordinate search is done using Equatorial J2000, unless specified otherwise within the coordinate input string. This service is a collaborative project between the NED group and the Infrared Science Archive (IRSA) group at the Infrared Processsing and Analysis Center (IPAC).<br /><br />How to use Atlas