Voyages of Discovery: Copernicus to the Big Bang http://edu-observatory.org/olli/VD-C2BB/Week6.html Runaway Universe 58:30 http://www.pbs.org/wgbh/nova/transcripts/2713universe.html http://www.pbs.org/wgbh/nova/universe/ Type Ia Supernovae http://www.astro.uiuc.edu/~pmricker/research/type1a/ http://www.pbs.org/wgbh/nova/universe/supernova1a_nf_01.html http://hyperphysics.phy-astr.gsu.edu/hbase/astro/snovcn.html Adaptive Optics http://www.eso.org/projects/aot/introduction.html http://cfao.ucolick.org/ao/ SN 1987A in the Large Magellanic Cloud http://heritage.stsci.edu/1999/04/sn1987anino.html Supernova 1987A exploded on 1987 February 23, in the Large Magellanic Cloud. Because of its relative proximity to us (a mere 168,000 light years) SN 1987A is by far the best-studied supernova of all time. Immediately after the discovery was announced, literally every telescope in the southern hemisphere started observing this exciting new object. In addition to light, particle emission was detected from the supernova. "Kamiokande II" is a neutrino telescope whose heart is a huge cylindrical tub, 52 feet in diameter and 53 feet high, containing about 3000 metric tons of water; it is located in the Kamioka mine in Japan, 3,300 feet underground. On February 23, around 7:36 am Greenwich time, the Kamiokande II recorded the arrival of 9 neutrinos within an interval of 2 seconds, followed by 3 more neutrinos 9 to 13 seconds later. Simultaneously, the same event was revealed by the IMB detector (located in the Morton-Thiokol salt mine near Faiport, Ohio), counted 8 neutrinos within about 6 seconds. A third neutrino telescope (the "Baksan" telescope, located in the North Caucasus Mountains of Russia, under Mount Andyrchi) also recorded the arrival of 5 neutrinos within 5 seconds from each other. This makes a total of 25 neutrinos detected on Earth, out of the 10^54 of them produced in the explosion! Neutron Stars & Black Holes http://edu-observatory.org/eo/black_holes.html Black Holes http://scienceworld.wolfram.com/physics/BlackHole.html http://scienceworld.wolfram.com/physics/topics/BlackHoles.html http://www.gothosenterprises.com/black_holes/static_black_holes.html http://www.gothosenterprises.com/black_holes/rotating_black_holes.html What is the dark matter? http://www.astro.ucla.edu/~wright/cosmolog.htm#News 21 Aug 2006 - NASA announced updated information about the "bullet cluster" 1E0657-56 today. Two clusters of galaxies have recently collided in this X-ray source. This cluster is filled with hot gas so X-ray observations by the Chandra X-ray Observatory show where the ordinary matter is located. 90% of the ordinary matter (the "baryonic" matter) is hot gas. The new results [Clowe et al., Bradac et al.] use gravitational lensing of background galaxies to show where the sources of gravity are located. The sources of gravity in the cluster are not located where the ordinary matter is located, so this cluster is a counter-example to MOND. All of this was known in 2003 but with less precision. A direct empirical proof of the existence of dark matter http://arxiv.org/abs/astro-ph/0608407 From: Marusa Bradac [view email] Date: Sat, 19 Aug 2006 17:51:03 GMT (119kb) Authors: Douglas Clowe (1), Marusa Bradac (2), Anthony H. Gonzalez (3), Maxim Markevitch (4), Scott W. Randall (4), Christine Jones (4), Dennis Zaritsky (1) ((1) Steward Observatory, Tucson, (2) KIPAC, Stanford, (3) Department of Astronomy, Gainesville, (4) CfA, Cambridge) Comments: Accepted for publication in ApJL We present new weak lensing observations of 1E0657-558 (z=0.296), a unique cluster merger, that enable a direct detection of dark matter, independent of assumptions regarding the nature of the gravitational force law. Due to the collision of two clusters, the dissipationless stellar component and the fluid-like X-ray emitting plasma are spatially segregated. By using both wide-field ground based images and HST/ACS images of the cluster cores, we create gravitational lensing maps which show that the gravitational potential does not trace the plasma distribution, the dominant baryonic mass component, but rather approximately traces the distribution of galaxies. An 8-sigma significance spatial offset of the center of the total mass from the center of the baryonic mass peaks cannot be explained with an alteration of the gravitational force law, and thus proves that the majority of the matter in the system is unseen. Strong and weak lensing united III: Measuring the mass distribution of the merging galaxy cluster 1E0657-56 http://arxiv.org/abs/astro-ph/0608408 From: Marusa Bradac [view email] Date: Fri, 18 Aug 2006 20:06:48 GMT (373kb) Authors: Marusa Bradac (1,2), Douglas Clowe (3), Anthony H. Gonzalez (4), Phil Marshall (1), William Forman (5), Christine Jones (5), Maxim Markevitch (5), Scott Randall (5), Tim Schrabback (2), Dennis Zaritsky (3) ((1) KIPAC, Stanford, (2) AIfA, Bonn, (3) Steward Observatory, Tucson, (4) Department of Astronomy, Gainesville, (5) CfA, Cambridge) Comments: Accepted for publication in ApJ; Version with full-resolution figures available at this http URL The galaxy cluster 1E0657-56 (z = 0.296) is remarkably well-suited for addressing outstanding issues in both galaxy evolution and fundamental physics. We present a reconstruction of the mass distribution from both strong and weak gravitational lensing data. Multi-color, high-resolution HST ACS images allow detection of many more arc candidates than were previously known, especially around the subcluster. Using the known redshift of one of the multiply imaged systems, we determine the remaining source redshifts using the predictive power of the strong lens model. Combining this information with shape measurements of "weakly" lensed sources, we derive a high-resolution, absolutely-calibrated mass map, using no assumptions regarding the physical properties of the underlying cluster potential. This map provides the best available quantification of the total mass of the central part of the cluster. We also confirm the result from Clowe et al. (2004,2006a). swormley1@mchsi.com