The Milky Way’s Tumultuous Heart Revealed In X-Rays

 

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This new image of powerful remnants of dead stars and their mighty action on the surrounding gas from the European Space Agency’s XMM-Newton X-ray satellite observatory reveals some of the most intense processes taking place at the centre of our galaxy, the Milky Way.

The bright, point-like sources that stand out across the image trace binary stellar systems in which one of the stars has reached the end of its life, evolving into a compact and dense object — a neutron star or black hole. Because of their high densities, these compact remnants devour mass from their companion star, heating the material up and causing it to shine brightly in X-rays.

The central region of our galaxy also contains young stars and stellar clusters, and some of these are visible as white or red sources sprinkled throughout the image, which spans about one thousand light-years.

Most of the action is occurring at the centre, where diffuse clouds of gas are being carved by powerful winds blown by young stars, as well as by supernovae, the explosive demise of massive stars.

The supermassive black hole sitting at the centre of the Galaxy is also responsible for some of this action. Known as Sagittarius A*, this black hole has a mass a few million times that of our Sun, and it is located within the bright, fuzzy source to the right of the image centre.

While black holes themselves do not emit light, their immense gravitational pull draws in the surrounding matter that, in the process, emits light at many wavelengths, most notably X-rays. In addition, two lobes of hot gas can be seen extending above and below the black hole.

Astronomers believe that these lobes are caused either directly by the black hole, which swallows part of the material that flows onto it but spews out most of it, or by the cumulative effect of the numerous stellar winds and supernova explosions that occur in such a dense environment.

This image, showing us an unprecedented view of the Milky Way’s energetic core, was put together in a new study by compiling all observations of this region that were performed with XMM-Newton, adding up to about one and a half months of monitoring in total.

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The central regions of our galaxy, the Milky Way, seen in X-rays by ESA’s XMM-Newton X-ray observatory. This image combines data collected at energies that correspond to the light emitted by heavy elements such as silicon and argon, which are produced primarily in supernova explosions, as well as other narrow energy bands. It spans about 2.5° across, equivalent to about one thousand light-years. Image credits: © ESA/XMM-Newton/G. Ponti et al. 2015.

The large, elliptical structure to the lower right of Sagittarius A* is a super-bubble of hot gas, likely puffed up by the remnants of several supernovae at its centre. While this structure was already known to astronomers, this study confirms for the first time that it consists of a single, gigantic bubble rather than the superposition of several, individual supernova remnants along the line of sight.

Another huge pocket of hot gas, designated the ‘Arc Bubble’ due to its crescent-like shape, can be seen close to the image centre, to the lower left of the supermassive black hole. It is being inflated by the forceful winds of stars in a nearby stellar cluster, as well as by supernovae; the remnant of one of these explosions, a candidate pulsar wind nebula, was detected at the core of the bubble.

The rich data set compiled in this study contains observations that span the full range of X-ray energies covered by XMM-Newton; these include some energies corresponding to the light emitted by heavy elements such as silicon, sulphur and argon, which are produced primarily in supernova explosions. By combining these additional information present in the data, the astronomers obtained another, complementary view of the Galactic Centre, which reveals beautifully the lobes and bubbles described earlier on.

In addition, this alternative view also displays the emission, albeit very faint, from warm plasma in the upper and lower parts of the image. This warm plasma might be the collective macroscopic effect of outflows generated by star formation throughout this entire central zone.

Another of the possible explanations for such emission links it to the turbulent past of the now not-so-active supermassive black hole. Astronomers believe that, earlier on in the history of our galaxy, Sagittarius A* was accreting and ejecting mass at a much higher rate, like the black holes found at the centre of many galaxies, and these diffuse clouds of warm plasma could be a legacy of its ancient activity.

 

Alaa Murabit: What my religion really says about women

About the Speaker:

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Alaa Murabit (born October 26, 1989) is a Canadian physician who became a women’s rights activist in Libya in 2011. She has since become a leading international advocate for women’s rights and their inclusion in peace processes and conflict resolution.

Murabit founded The Voice of Libyan Women in August 2011 and has been president ever since. She has explained that VLW “was founded following the 2011 Libyan Revolution. I was in my final year of medical school at the time, and found out that there was a window of opportunity for women in Libya.

She has maintained that peace is achievable through communities, The only real solution, the only way to get that grenade or gun put down safely is the very spirit of this Forum. It is by filling his hands and head with something else.

Becci Manson: Re(touching) lives through Photos

Becci Manson participated in Re(touching) the photos found in the debris of the damage in Japan in 2011 due to earthquakes and tsunami. She made a campaign in which she invited everyone to join from across the globe and participate with full enthusiasm. They were successful in their work by giving happiness to the people who needed the most and who lost their home in this disaster. Hope it will inspire our young youth and will contribute to the world through their amazing talent..!!

 

About the Speaker:

becci_manson-default[1] Becci Manson is a high-end photographic retoucher who works with client like fashion magazines to tart up glamorous images. You can visit her website: http://www.rebeccamanson.com/

Ramesh Raskar: Imaging at a trillion frames per second

Ramesh Raskar presents femto-photography, a new type of imaging so fast it visualizes the world one trillion frames per second, so detailed it shows light itself in motion. This technology may someday be used to build cameras that can look “around” corners or see inside the body without X-rays.

About the Speaker: Associate Professor at MIT Media Lab, Ramesh Raskar is known for his work in Femto-photography (trillion frames per second imaging, cameras to see around corners), eyeNETRA ( eye tests on mobile phones) and Computational Photography.

In 2004, Raskar received the TR100 Award from Technology Review, which recognizes top young innovators under the age of 35, and in 2003, the Global Indus Technovator Award, instituted at MIT to recognize the top 20 Indian technology innovators worldwide. In 2009, he was awarded a Sloan Research Fellowship. In 2010, he received the Darpa Young Faculty award. Other awards include Marr Prize honorable mention 2009, LAUNCH Health Innovation Award, presented by NASA, USAID, US State Dept and NIKE, 2010, Vodafone Wireless Innovation Project Award (first place), 2011. He holds over 40 US patents and has received four Mitsubishi Electric Invention Awards. He is currently co-authoring a book on Computational Photography.