Thursday, 26 March 2015

Surprising gamma ray signal in satellite galaxy could come from WIMPs

Like moons orbiting a planet, there are smaller bodies circling the Milky Way. Known as dwarf galaxies, they can be dim enough to escape detection—it’s not known how many there are in total, and new dwarfs are still being detected. One such dwarf galaxy was discovered within the last few weeks using data from the Dark Energy Survey, an experiment that scans the southern sky in order to learn about the accelerating expansion of the Universe (the experiment’s name comes from the mysterious dark energy that causes that acceleration).

The dwarf, known as Reticulum 2, is about 98,000 light-years from Earth, making it one of the Milky Way’s closest discovered satellites. But that’s not its most exciting feature. The mini-galaxy seems to be emitting a strong gamma ray signal, a research team concludes in a paper submitted to the journal Physical Review Letters. That’s surprising for a dwarf, since they tend to be mostly devoid of the objects that typically produce gamma rays. While it’s too early to say for sure what the source of the gamma rays is, the authors have tentatively come to a very intriguing conclusion: dark matter annihilation.

Dwarfs and dark matter

Like their larger counterparts, dwarf galaxies rest within a spherical blob, or halo, of dark matter that accounts for most of the galaxy’s mass. In the case of the Milky Way’s satellites, their halos rest within the Milky Way’s own larger halo, making them subhalos.

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#NYFW: Mark & Estel Fall 2015

When Mark & Estel show started I was wondering how their rock star would look on the runway this Fall 2015. This collection "Stairways to the stars" is for the duo Estel Day and Mark Tango a continuation of the saga, their fourth collection at New York Fashion Week. They wanted to create a kind of "royal" collection because they believe that everybody can be royal!

I liked this fashion show, its energy. It started with the very first model  while the song "she's dancing" was playing.

On the runway, there was a combination of leather and plaid. The Californian designers have reinvented plaid so that instead of being the standard thick fabric it was thinner with some transparency at times. Plaid brings colors to the looks, mainly a flamboyant red giving the models a fierce attitude. A red perfect for Valentine's Day! There were also colors also on hosiery. Colors constitute a nice addition in comparison with previous collections where black & white were dominant. 

I noticed a trend in several shows regarding socks: wearing them with dresses and here too with dresses we could see socks with platforms. 

The designers have used a lot of silk and wool with printed pattern and actually they even launched printed fabrics by Mark & Estel as well as hosiery and silk chiffon scarves.

The Finale was indeed royal! Mark & Estel performed the song "Stairway to the stars" and rocked the Lincoln Center. You can feel that they especially love that moment of the show. What a contrast with all the other designers who make the shortest possible appearance, often looking shy and clumsy. Mark & Estel own the catwalk/stage and really sing or shout to the photographers and the audience. It seems that they wish the audience in New York were more rock 'n' roll. To conclude, they screamed "You're a fashion rock star"!

Reported by Geraldine Trippitelli of Mazette Media, a full-service marketing agency
Photos by Mariana Leung
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Unusually Beautiful Architectural Collages by Matthias Jung


German graphic artist Matthias Jung creates collages of fictional structures that seemingly turn the logic of architecture upside down. Buildings sprout mountains populated by livestock, homes hover in mid-air, and contrasting architectural styles are fused together in strangely harmonious ways like something straight out of a Terry Gilliam movie. You can see more of Jung’s work on his website where he also has a number of prints availble. (via iGNANT)








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Black holes and the dark sector explained by quantum gravity

Ask any theoretical physicist on what are the most profound mysteries in physics and you will be surprised

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Electron spins controlled using sound waves

The ability to control the intrinsic angular momentum of individual electrons – their “spins” – could lead to

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Why is the Rosetta mission so important? A short history of comet exploration.

The Conversation

Exciting as it is (and it is incredibly exciting), the Rosetta mission is just the latest in a history of comet exploration that has added to our knowledge of these icy dirtballs.

Comets are usually just a few kilometres across and consist of a mixture of ice, carbon-based material, and rock dust. A comet can develop a spectacular million kilometer-long tail of gas and dust when its elongated orbit brings it close to the sun.

The warmth of the sun vaporizes water, carbon monoxide, and other volatile substances that are otherwise held as ice. Jets of gas escape from the solid part of the comet (its nucleus) to feed the growing tail. However, for most of the time a comet is far from the sun, and it is simply a dark, dusty object too faint to detect using even the largest telescopes.

It is hoped that access to a comet will provide a pristine, deep-frozen sample of the material from which planets were built. Comets have been hitting the Earth since the Earth was formed. We currently do not know what fraction of the Earth's ocean water was delivered to the surface by comets after the Earth was formed, as opposed to water that escaped from inside and condensed on the early Earth.

Comets also carry organic molecules — and one theory has it that these building blocks for life on Earth were delivered by comets rather than forming here. Recent observations by the ALMA telescope in Chile revealed very simple organic molecules — two sorts of hydrogen cyanide and also formaldehyde — being made in comets today.

Missions to comets
Small wonder, then, that comets have been the targets of several space missions. To date, eight comets have been visited over the course of 10 successful missions. In 1982, a probe called ISEE-3, which had already been in space for four years, was renamed International Cometary Explorer (ICE) and re-tasked to fly past comet Giacobini-Zinner, at a minimum distance of 7,862km. The probe had no cameras on board, but other sensors gathered data on the interplay between the solar wind and the comet's atmosphere. ICE subsequently joined a fleet of two Soviet, two Japanese, and one European Space Agency probe that studied Halley's comet in 1986. ESA's mission, Giotto, was the best equipped. It got to within nearly 600km, and sent back the first close-up pictures of a comet's nucleus.

(The Conversation UK)

The most spectacular mission before Rosetta was NASA's Deep Impact, which in 2005 dropped an impactor into the nucleus of comet Tempel 1, while the mother-ship watched. The impact excavated more dust and less ice than had been expected. Another surprise was that much of this material was clays and carbonates, which usually require liquid water for their formation.

Only one mission has brought back samples from a comet. This was NASA's Stardust, which in 2003 collected dust that was escaping from comet Wild 2. The sample return capsule made it back in 2006 and included grains that seemed to have formed at high temperatures in the inner solar system before heading out to the cold comet-forming region. There were also traces of an amino acid — glycine — adding weight to the idea that comets could be source of the building blocks of life. Remarkably, the Stardust mother-ship was redirected to Tempel 1, the only comet to have been visited on two different occasions. In 2011, it sent back pictures of the crater that had been made by Deep Impact's impactor.

Rosetta images
It is early days for Rosetta, and the team have yet to release more than a few images and other data from the main instruments. However, navigation camera images reveal a startling landscape in far greater detail than has previously been achieved. There are boulders up to several meters in size, patchily distributed across the surface.

A view from Rosetta's navigation camera on 26 October, about 8 km above the comet's surface, from which range the field of view is less than 1 km across. (ESA/The Conversation UK)

Are they pure ice? Dust cemented by ice? Will the apparently smooth areas turn out to be just as rugged on a smaller scale when the Philae lander gets close enough to see finer detail? What are the exposed layers that can be seen in some areas, and how did they form? And how is all this compatible with the extremely low-bulk density of the comet, which Rosetta's orbit and shape-mapping have revealed to be only about 40 percent the density of solid ice? The interior must be porous, but there's precious little sign of that at the surface.

More from The Conversation UK...

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After Ebola, measles may follow

The Ebola crisis in West Africa is one of the most striking public health emergencies in recent years. According to the Centers for Disease Control, this fast-spreading virus has killed over 9,951 people since the start of the outbreak in December of 2013. Currently, there are no FDA-approved vaccines or antiviral treatments for Ebola, and patients’ survival depends on their own immune response and the supportive care they receive. The mortality rate for this disease is currently estimated to be approximately 70 percent by the World Health Organization.

Now a new study published in the journal Science suggests that the Ebola crisis could leave countries vulnerable to epidemics of a more common virus, measles, due to its disruption of routine health care services in affected areas.

The authors of this study are affiliated with some of the most prominent public health institutions in the world, including Princeton University, Johns Hopkins’ Bloomberg School of Public Health, and the National Institutes of Health. They project that due to the loss of healthcare workers caused by the Ebola crisis, a cluster of children unvaccinated for measles will accumulate in Guinea, Liberia, and Sierra Leone. Because of the susceptibility of this population, the investigators expect a regional measles outbreak of 127,000 to 227,000 cases after 18 months, which will result in 2,000 to 16,000 measles-related deaths in the region.

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Between Micro and Macro, Mathematicians Model Fluids at the Mesoscale

When it comes to boiling water—or the phenomenon of applying heat to a liquid until it transitions to

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Sponsor // PurePhoto Installs Photographic World of Wonder at LA Boutique Hotel


Fine art photography gallery PurePhoto and Farmer’s Daughter Hotel owner Ellen Picataggio—an avid art collector—recently collaborated on a custom photography installation by conceptual artist Matthew Carden.

LA’s best kept secret, this charming 60-room boutique hotel in Hollywood boasts world-class comfort food, a relaxed, unpretentious atmosphere, and best of all an art gallery spanning the property featuring work by local artists.

Carden painstakingly creates exotic worlds of miniature figures that live amongst food-based landscapes. The photographs line Farmer’s Daughter’s hallways, and are also included in Picataggio’s art box project, which features over 40 local artists; one per room.

Carden’s full body of work can be seen on PurePhoto, which represents over 300 additional photographers. PurePhoto’s clients include top interior designers and collectors, and the gallery specializes in printing large-scale works and custom installations. The PurePhoto collection offers open and limited edition photographs, which range from $200 – $15,000.

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Rosetta blog: Waiting patiently for Philae

For the past eight days, Rosetta has been sending signals to Philae and listening for a response, but

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Hot Spots, Cold Spots: When Temperature Goes Quantum

Imagine setting a frying pan on the stove and cranking up the heat, only to discover that in

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