... Credit: NASA , ESA , H. Lee H. Ford ( Johns Hopkins U. ) Explanation: What are those strange blue objects? Many of the brightest blue images are of a single, unusual, beaded, blue, ring-like galaxy which just happens to line-up behind a giant cluster of galaxies. ... A blue smudge near the cluster center is likely another image of the same background galaxy. In all, a recent analysis postulated that at least 33 images of 11 separate background galaxies are discernable. ...

... 2001 April 16 . The Hydra Cluster of Galaxies . ... Explanation: The Hydra Cluster of Galaxies contains well over 100 bright galaxies - but perhaps fewer galaxies than might be expected from its mass. ... Most of a cluster's mass , however, appears to be in a form too dark to see , as analyses of the distribution of X-ray light , gravitational lensing , and internal motions indicate. ... The Hydra Cluster of Galaxies, named for its home constellation , spans about ten million light years . ...

... Gravitational microlensing of giant luminous arcs: . a test for compact dark matter in clusters of galaxies . ... This paper discusses a new test for the detection of stellar mass compact dark matter in galaxy clusters by observing its gravitational lensing influence on the surface brightness of giant luminous arcs. ... With the advent of the Next Generation Space Telescope, cluster dark matter in the form of compact objects will induce a ubiquitous `shimmering' of the giant arcs. ... Giant Arcs . ...

... These Frontier Fields will combine the power of HST with the natural gravitational telescopes of high-magnification clusters of galaxies. ... We are soliciting gravitational lensing maps for the last four Hubble Frontier Fields clusters (MACSJ0717.5+3745, MACSJ1149.5+2223, AbellS1063, and Abell 370) based upon the exceptionally deep HST FF imaging and other new ancillary data. ... For the full set of proposal instructions and requirements, see the FY16 Frontier Fields Lensing Map Call for Proposals....

... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

home publications > mercury . ... Big Clusters, Tiny Galaxies . ... Astronomers struggle to understand why giant star clusters form in the tiniest of galaxies . ... These clusters are probably young versions of globular clusters, but they are commonly called super star clusters. Seven dwarf galaxies within 16 million light-years have formed super star clusters, with one of these galaxies, NGC 1569, possessing two young clusters. ... Super star clusters have a lot to tell us about star formation. ...

The Astronomical Society of Australia has been asked by STANDARDS AUSTRALIA to compile a list of "designated" optical observatories that are valuable resources for (i) research, (ii) education and (iii) community use. The ASA is the final arbiter of whether any particular observatory is so designated. ... Upon receipt of your application form, your observatory will be entered on a list of "Pending Designated Observatories" on the ASA Home Page. ... It will be emailed for you. ... Email . ...

... Tonight's Sky . ... Sky this Month . ... space physics . ... The Sky This Week: April 1 - 10 . ... Sky this Week . ... Sky Events . Get to Know the Night Sky . Tour the Deep Sky . Sky Guide . ... Observing springtime deep-sky objects with a large telescope . ... Johns Hopkins University Applied Physics Lab, Laurel, Maryland . ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. ...

... Reconstruction of peculiar velocities of galaxies from large-scale redshift catalogues provides an exemplary application of optimal transport. ... U Frisch, S. Matarrese, R. Mohayaee, A. Sobolevsky, A reconstruction of the initial conditions of the Universe by optimal mass transportation , Nature, 417 (2002) 260-262 ( arXiv:astro-ph/0109483 ) . ... R. Mohayaee, A. Sobolevskii, The Monge Amp re Kantorovich approach to reconstruction in cosmology , Physica D (2008) accepted ( arXiv:0712.2561 ) . ...

M1 image More About M1 Nice Color Picture . ... M16 image More About M16 HST image . ... M31 image More About M31 Nice Color Picture . ... M42 image ; M43 image More About M42/43 Nice Color CCD Picture . M51 image More About M51 Color Image of M51 M51 Supernova . M57 image More About M57 Nice Color CCD Picture Very Deep M57 Image . ... M81 image More About M81 M81 Supernova Ultraviolet Image of M81 More about Ultraviolet Imaging . M82 image More About M82 M82 False Color M82 True Color . ...

... Science . ... Science Users Information > Science and Technical Meetings > Conferences 2011 > Dynamics of Low-Mass Stellar Systems: From Star Clusters to Dwarf Galaxies . ... Science Users Information . ... Observing with ESO Telescopes . ... Science Software . ... ESO-MIDAS . ... Science Data Products Forum . ... ESO Data . ... ESO Science Newsletter . ... We aim at bringing together a mix of astronomers from both observations and theory that work on the dynamics of dwarf galaxies and star clusters...

Astronotes Armagh Planetarium's Stellar Blog! ... Stars . ... Starbursts are short-lived events, stars are forming so quickly that the reservoirs of interstellar gas from which stars are coalescing would be used up on a timescale much shorter than the age of the galaxy . ... Strong stellar winds from giant new stars in the starburst region combine with the blasts of supernovae to push a mighty flood of extremely hot gas, a ?superwind? from the galaxy thousands of light years into intergalactic space. ...