14 January 2016

On 12 January 2016, the Japan Aerospace Exploration Agency (JAXA) presented their ASTRO-H satellite to the media at the Tanegashima Space Center, situated on a small island in the south of Japan. The satellite, developed with institutions in Japan, the US, Canada and Europe, is now ready to be mounted on an H-IIA rocket for launch on 12 February.

ASTRO-H is a new-generation satellite, designed to study some of the most powerful phenomena in the Universe by probing the sky in the X-ray and gamma-ray portions of the electromagnetic spectrum. Scientists will investigate extreme cosmic environments ranging from supernova explosions to supermassive black holes at the centres of distant galaxies, and the hot plasma permeating huge clusters of galaxies.

ESA contributed to ASTRO-H by partly funding various elements of the four science instruments, by providing three European scientists to serve as science advisors and by contributing one scientist to the team in Japan. In return for ESA’s contribution, European scientists will have access to the mission’s data.

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15. November 2015 von Markus Pössel in Astronomie, Kosmologie

Dieser Tage befinden wir uns mitten im 100jährigen Jubiläum von Albert Einsteins Allgemeiner Relativitätstheorie, also von Einsteins Theorie von Raum, Zeit und Gravitation. Wer meinen Jubiläumsvortrag dazu noch mitbekommen möchte, hat am 25. November in Berlin im Planetarium am Insulaner dazu Gelegenheit; in Heidelberg habe ich ihn letzte Woche bereits zweimal gehalten, und eine Hauptbotschaft bei meinem Überblick über die letzten hundert relativistischen Jahre lautet: Wo sich die Beobachter und Experimentatoren anfangs sehr abmühen mussten, um die von Einstein vorhergesagten Effekte wie Lichtablenkung im Schwerefeld oder Gravitations-Rotverschiebung nachzuweisen, sind dieselben Effekte heutzutage längst entweder Störeffekte bei anderen Messungen oder aber Werkzeuge, die sich beispielsweise für astronomische Messungen nutzen lassen.

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The Dark Energy Survey has now mapped one-eighth of the full sky (red shaded region) using the Dark Energy Camera on the Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile (foreground). This map has led to the discovery of 17 dwarf galaxy candidates in the past six months (red dots), including eight new candidates just announced. Several of the candidates are in close proximity to the two largest dwarf galaxies orbiting the Milky Way, the Large and Small Magellanic Clouds, both of which are visible to the unaided eye. By comparison, the new stellar systems are so faint that they are difficult to “see” even in the deep DES images and can be more easily visualised using maps of the stellar density (inset). Fourteen of the dwarf galaxy candidates found in DES data are visible in this particular image. Illustration credit: Dark Energy Survey Collaboration.

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• A clump of material has been jettisoned from a double star system at incredibly high speeds.
• X-rays from Chandra reveal that a pulsar in orbit around a massive star punched through a circumstellar disk of material.
• Three Chandra observations of the system were taken between December 2011 and February 2014.
• The data suggest the clump may even be accelerating due to the pulsar's powerful winds.

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In this short post series I try to tackle one of the biggest questions out there: Are we alone? The reasoning leads to some radical implications for the very near future of humankind. Read till the end and feel free to comment as you go. Hopefully this will spark interesting discussions.

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Zeuthen, Germany – On 15 and 16 July 2015, the Cherenkov Telescope Array (CTA) Resource Board decided to enter into detailed contract negotiations for hosting CTA on the European Southern Observatory (ESO) Paranal grounds in Chile and at the Instituto de Astrofisica de Canarias (IAC), Roque de los Muchachos Observatory in La Palma, Spain.

The Board, composed of representatives of ministries and funding agencies from Austria, Brazil, the Czech Republic, France, Germany, Italy, Namibia, the Netherlands, Japan, Poland, South Africa, Spain, Switzerland and the UK, decided after months of negotiations and careful consideration of extensive studies of the environmental conditions, simulations of the science performance and assessments of construction and operation costs to start contract negotiations with ESO and Spain. The Namibian and Mexican sites will be kept as viable alternatives.

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Sharpest View Ever of Star Formation in the Distant Universe

ALMA’s Long Baseline Campaign has produced a spectacular image of a distant galaxy being gravitationally lensed. The image shows a magnified view of the galaxy’s star-forming regions, the likes of which have never been seen before at this level of detail in a galaxy so remote. The new observations are far sharper than those made using the NASA/ESA Hubble Space Telescope, and reveal star-forming clumps in the galaxy equivalent to giant versions of the Orion Nebula in the Milky Way.

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 Black holes create and destroy galaxies, like this spiral galaxy in the constellation Dorado. (Roberto Colombari/Stocktrek Images/Corbis)

Much has been made of the mind-bending visual effects in Interstellar. But the methods created by the film’s Oscar-nominated visual effects team may have more serious applications than wowing movie audiences—they could actually be useful to scientists, too. A new paper in Classical and Quantum Gravity tells how the Interstellar team turned science fiction towards the service of scientific fact and produced a whole new picture of what it might look like to orbit around a spinning black hole.

Director Christopher Nolan and executive producer (and theoretical physicist) Kip Thorne wanted to create a visual experience that was immersive and credible. When they began to construct images of a black hole within an accretion disk, they realized that existing visual effects technology wouldn’t cut it—it created a flickering effect that would have looked bad in IMAX theaters. So the team turned to physics to create something different.

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Modern cosmology is dominated by two fundamental theories: general relativity, which describes the structure of space and time as manifold that interacts with mass/energy (aka gravity), and quantum theory, which describes the fundamental interactions of protons, electrons, light, etc. (aka quanta). Both models are strongly supported by experimental and observational evidence. The problem is that each theory makes fundamental assumptions about the way the universe works, and they contradict each other at a basic level. This isn’t a problem if you are interested in things on a large scale, such as planets and galaxies (general relativity), or things on a small scale such as nuclear fusion (quantum theory). The contradiction arises when you want to understand objects that are both very dense and interact at high energies, such as black hole interiors, the big bang, etc. So one of the challenges of modern cosmology is to develop a unified theory of quantum gravity, which would combine the predictions of general relativity and quantum theory in a consistent way.

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