The flare model for X-ray variability of NGC 4258

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Authors: T. Trze?niewski, B. Czerny, V. Karas, T. Pechá?ek, M. Dov?iak, R. Goosmann and M. Niko?ajuk.<br />Astronomy & Astrophysics Vol. 530 , page A136<br />Published online: 25/05/2011<br />
Keywords:
accretion, accretion disks ; galaxies: active ; galaxies: Seyfert ; X-rays: galaxies.

The VLT-FLAMES Tarantula Survey

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Authors: J. M. Bestenlehner, J. S. Vink, G. Gräfener, F. Najarro, C. J. Evans, N. Bastian, A. Z. Bonanos, E. Bressert, P. A. Crowther, E. Doran, K. Friedrich, V. Hénault-Brunet, A. Herrero, A. de Koter, N. Langer, D. J. Lennon, J. Maíz Apellániz, H. Sana, I. Soszynski and W. D. Taylor.<br />Astronomy & Astrophysics Vol. 530 , page L14<br />Published online: 25/05/2011<br />
Keywords:
stars: Wolf-Rayet ; stars: early-type ; stars: atmospheres ; stars: mass-loss ; stars: fundamental parameters.

Ammonia Cloud on Saturn

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Cassini view of an ammonia cloud on Saturn. Click for larger. Credit: NASA/JPL/Univ. of Arizona

 

From JPL’ s Photojournal:

This false-color infrared image, obtained by NASA’s Cassini spacecraft, shows clouds of large ammonia ice particles dredged up by a powerful storm in Saturn’s northern hemisphere. Large updrafts dragged ammonia gas upward more than 30 miles (50 kilometers) from below. The ammonia then condensed into large crystals in the frigid upper atmosphere. This storm is the most violent ever observed at Saturn by an orbiting spacecraft.

Cassini’s visual and infrared mapping spectrometer obtained these images on Feb. 24, 2011. Scientists colorized the image by assigning red to brightness detected from the 4.08-micron wavelength, green to brightness from the 0.90-micron wavelength, and blue to brightness from the 2.73-micron wavelength. Large particles (red) reflect sunlight well at 4.08 microns. Particles at high altitude (green) reflect sunlight well at 0.9 microns. Particles comprised of ammonia — especially large ones — do not reflect 2.73-micron sunlight well, but instead absorb light at this wavelength.

The storm here shows up as yellow, demonstrating that it has a large signal in both red and green colors. This indicates the cloud has large particles and extends upward to relatively high altitude. In addition, the lack of blue in the feature indicates that the storm cloud has a substantial component of ammonia crystals. The head of the storm is particularly rich in such particles, as created by powerful updrafts of ammonia gas from depth in the throes of Saturn’s thunderstorm. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency (ASI). NASA’s Jet Propulsion Laboratory in Pasadena, Calif., manages the mission for NASA’s Science Mission Directorate at the agency’s headquarters in Washington. The Cassini orbiter was designed, developed and assembled at JPL. The visual and infrared mapping spectrometer was built by JPL, with a major contribution by ASI. The visual and infrared mapping spectrometer science team is based at the University of Arizona, Tucson. JPL is a division of the California Institute of Technology in Pasadena.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov or http://www.nasa.gov/cassini . The Cassini imaging team homepage is at http://ciclops.org . Full-Res: PIA14119 Credit: NASA/JPL/Space Science Institute

Cat’s Eyes During a Midnight Solar Eclipse

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A Midnight eclipse gives us cat's eyes. Click for larger. Credit: B.Art Braafhart via spaceweather.com

 

What a grand picture!  This is a solar eclipse of the midnight sun that occurred last night taken by B.Art Braafhart, Sallatunturi, Finnish Lapland, ca. 35km north of Arctic Circle.

No you read right and I’m not (too) crazy, the midnight solar eclipse.

First go to to Spaceweather.com where I got this image and see other pictures, plus you can figure out how the cat’s eyes happened.

Then you can go to NASA Science News to learn more about the eclipse (it’s also linked off the Spaceweather site).

Landing in the Early Morning

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STS-134 Landing (Endeavour)

Current Status (1st opportunity @ KSC): GO

Deorbit Burn: 01:29 EST

Landing: 02:35 EST


NASA TV Stills reload page to refresh image Webcam Image courtesy: NASA/Kennedy Space Center

NOAA’s Forecast:

Tonight: Isolated showers after 2am. Partly cloudy, with a low around 71. East northeast wind between 5 and 15 mph, with gusts as high as 20 mph. Chance of precipitation is 20%..

To keep current with the news about the landing, I recommend you go to NASA-TV.

Image Credits: NASA / NOAA

This is the last mission for Endeavour and there is one more mission to go.  The last shuttle to be launched is Atlantis and it will begin the trip to the launch pad at 8pm tonight.  Yes we can continue down the path of being beholding to everybody else for our needs, at least in this particular case sooner or later private industry will be geared up and ready.  Interestingly enough, when private industry does finally get “there” the advances will boggle our minds.

The Eyes To The Skies

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It seems as if man has always looked to the skies, and not just for answers to its own inherent mystery, either.  We told stories about the pictures we seemed to see in the stars.  We believed that close study of the positions of the celestial bodies could predict future events.  The night sky showed the homes and areas of influence of a whole flock of deities.  The more we could see, the more intriguing became the sight.

On October 2, 1608, application was made for a patent for a device which allowed “for seeing things far away as if they were nearby“.  Before that there was a rich history of men using lenses, mirrors, even rock crystals to see things far away as if they were nearby.  Aristophanes mentions the use of a “burning glass” (convex glass – a magnifying lens) in his 424 BCE play “The Clouds”.

Emblemata of zinne-werck, Johan de Brune 1624

Telescopes advanced through the centuries (the original had about a 3X magnification), first by stacking lenses together to create more powerful magnification, or variations of the same general idea (as with aerial telescopes).  There were reflecting telescopes (using parabolic mirrors), achromatic refracting telescopes (using different types of lenses to form a refracting telescope with a twist), giant reflecting telescopes like the Leviathan of Parsonstown, and adaptive optics, like those used on the Gemini telescopes.  You remember us talking about adaptive optics, right?  That’s where your telescope is, essentially, wearing glasses.

Woodcut 140 ft Johann Hevelius telescope, ca 1673

The twentieth century, beginning about 1931, ushered in radio astronomy and radio telescopes.  Arecibo and the Very Large Array are radio telescopes.  In addition to radio astronomy, we’ve had advancements with the light spectrum telescopes; the infrared, far infrared, ultraviolet, X-ray, and gamma ray telescopes.  Out of advances in these modern telescopes comes the hulking astronomical interferometer, in which an array of telescopes thousands of kilometers distant takes the shape of a single parabolic lens.  The Fast Fourier Transform telescope is an interferometer.

In a class by themselves are the space telescopes like the Hubble and the soon-to-be-launched James Webb telescope.  Space telescopes (or observatories) have the advantage of not having to work around and with the distortions caused by Earth’s atmosphere.  In addition, space based astronomy has a much wider range of frequencies with which to work.  X-ray astronomy is nearly impossible from the Earth, while infrared and ultraviolet are significantly limited.

NASA STS-82, Hubble Space Telescope

We’ve come a long way from being gobsmacked by a 3X magnification.  As advances in telescope design and technique continue exponentially, there is no telling what (or who) we’ll see in the telescopes of the future.  Imagine if Galileo and Newton could have had access to modern telescopes.

Imagine what the Newtons of tomorrow will discover.

New Apps Reinforce U.S. Troops

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Three years in the making, an ammunition app provides all kinds of info on new ammunition, inspection, and training via virtual reality. Since Army personnel can't haul around manuals in the field, it makes sense. What other apps do you think would be useful for smartphone access?

The preceding art

Class of 1986 – Mercedes-Benz 300E

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We previously took a look at another Mercedes-Benz in the Class of 1986, the 560SL, a new car for that year, though one based on an aged chassis. In the same year, Mercedes-Benz also introduced another new car, but this one entirely new: the 300E.

Based on the W124 chassis, the 300E brought t

Does Amazon's Glitch Call Clouds into Question?

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The concept of cloud computing has attracted the attention of a growing number of companies. But Amazon's recent problems with its Elastic Compute Cloud (EC2) service — perhaps the leading cloud offering — took many third-party Internet companies that depended on the service off-line. Do