News

First Light for MUSE

MUSE at the VLT. (Credit: Ghaouti Hansali, Maître de Conférences à l'ENISE)

First Light for MUSE

5 March 2014. A new innovative instrument called MUSE (Multi Unit Spectroscopic Explorer) has been successfully installed on ESO’s Very Large Telescope (VLT) at the Paranal Observatory in norther...

Following testing and preliminary acceptance in Europe in September 2013, MUSE was shipped to ESO’s Paranal Observatory in Chile.

The leader of the team and principal investigator for the instrument, Roland Bacon from the Centre de Recherche Astrophysique de Lyon expressed his feelings: "It has taken a lot of work by many people over many years, but we have done it! It seems strange that this seven-tonne collection of optics, mechanics and electronics is now a fantastic time machine for probing the early Universe. We are very proud of the achievement — MUSE will remain a unique instrument for years to come.”

MUSE’s science goals include delving into the early epochs of the Universe to probe the mechanisms of galaxy formation and studying both the motions of material in nearby galaxies and their chemical properties. It will have many other applications, ranging all the way from studies of the planets and satellites in the Solar System, through the properties of star-forming regions in the Milky Way and out to the distant Universe.

++ For the full text version please refer to the ESO website ++


Science contact AIP:

Dr. Andreas Kelz (MUSE local project manager), akelz@aip.de, +49 331-7499-640

Prof. Dr. Lutz Wisotzki (MUSE instrument scientist), lwisotzki@aip.de

 

Media contact AIP:

Kerstin Mork, presse@aip.de, +49 331-7499-469

 

Further information:

 

The key topics of the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. Since 1992 the AIP is a member of the Leibniz Association

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Dwarfs of the Milky Way

The Cosmic Web.

Dwarfs of the Milky Way

25 February 2014. Noam Libeskind, scientist of the Leibniz Institute for Astrophysics Potsdam (AIP), explains in an article in the latest issue of “Scientific American”, why dwarf galaxies (als...

Noam Libeskind: “Most galaxies like the Milky Way are surrounded by dozens of small “satellite galaxies” that orbit around them. In the case of our Milky Way these satellite galaxies don’t just fly around haphazardly - instead the satellites are all arranged on a plane. Surprisingly, this situation has just been discovered in our closest neighbor Andromeda, as well. What’s more, at least in the Milky Way’s case, this plane is roughly perpendicular to the disc of our Galaxy.”

“The problem is simple:” he continues,  “if the universe is dominated by dark matter (which we believe it is), satellites should be randomly distributed about the Milky Way, not sitting on a thin plane. The origin of this alignment has thus puzzled astronomers for at least four decades, and computational cosmologists have been attempting to model the dynamics for many years. In fact, many cosmologists think that the distribution of the satellites encodes information about the mechanics of the very formation and origin of the Milky Way. Recent work, including my own research, proposes a compelling solution to this problem: the satellite galaxies did not flock to the Milky Way from all directions, but were shot towards it along cosmic superhighways of Dark Matter, thus giving the satellites a preferred direction and alignment.”

The article “How The Milky Way Got Its Dwarf Galaxies” was published in the March issue of Scientific American.

 

Picture: When examined on the largest possible scales, matter in the universe segments into a filamentary network of bridges as shown here in this computer simulation. The brighter tendrils in the image represent regions where the density of matter is high and where galaxies are expected to reside. It is along these dark matter cosmic superhighways along which satellite galaxies are thought to travel.  (Credit: S Gottloeber and tthe MultiDark collaboration)

Science contact: Dr. Noam I. Libeskind, nlibeskind@aip.de, +49 331-74 99-641

 

The key topics of the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. Since 1992 the AIP is a member of the Leibniz Association.

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Milky Way shaken... and stirred

Three stages of the evolution of the galaxy simulation used to model the Milky Way. (Credit: AIP)

Milky Way shaken... and stirred

20 January 2014. A team of scientists headed by Ivan Minchev from the Leibniz Institute for Astrophysics Potsdam (AIP) has found a way to reconstruct the evolutionary history of our galaxy, the Mil...

The astronomers studied how the vertical motions of stars - in the direction perpendicular to the galactic disc - depend on their ages. Because a direct determination of the age of stars is difficult, the astronomers instead analyzed the chemical composition of stars: an increase in the ratio of magnesium to iron ([Mg/Fe]) points to a great age. For this study, Ivan Minchev’s team took advantage of high-quality data regarding stars close to the Sun from the RAdial Velocity Experiment (RAVE). The scientists found that the rule of thumb “the older a star is, the faster it moves up and down through the disc” did not apply to the stars with the highest magnesium-to-iron ratios. Contrary to expectations, scientists observed an extreme drop in the vertical speed for these stars.

To understand these surprising observations, the scientists ran a computer model of the Milky Way, which allowed them to examine the origin of these slow-moving, old stars. After studying the computer model, they found that small galactic collisions might be responsible. It is thought that the Milky Way has undergone hundreds of such collisions with smaller galaxies in the course of its history. These collisions are not very effective at shaking up the massive regions near the galactic center. However they can trigger the formation of spiral arms and as a consequence move stars from the center of the Galaxy to the outer parts, where the Sun is. This “radial migration” process is able to transport outward old stars (with high values of magnesium-to-iron ratio) and with low up-and-down velocities. Therefore, the best explanation for why the oldest stars near our Sun have such small vertical velocities is that they were forced out of the galactic center by galactic collisions. The difference in speed between those stars and the ones born close to the Sun thereby betray how massive and how numerous the merging satellite galaxies were.

AIP scientist Ivan Minchev: “Our results will enable us to trace the history of our home Galaxy more accurately than ever before. By looking at the chemical composition of stars around us, and how fast they move, we can deduce the properties of satellite galaxies interacting with the Milky Way throughout its lifetime. This can lead to an improved understanding of how the Milky Way may have evolved into the Galaxy we see today.”

The article “A new stellar chemo-kinematic relation reveals the merger history of the Milky Way disc” was published in the Astrophysical Journal Letters on January 20.

 

Caption: Three stages of the evolution of the galaxy simulation used to model the Milky Way. Face-on (top) and edge-on (bottom) stellar density contours are shown for each time. Each square panel has a side of about 117,500 light years. The mass and frequency of satellites galaxies interacting with the disc decrease with time. (Credit: AIP)

 

Science contact: Dr. Ivan Minchev, +49 331-7499 454, iminchev@aip.de

Media contact: Kerstin Mork, +49 331-7499 469, presse@aip.de

 

The key topics of the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. Since 1992 the AIP is a member of the Leibniz Association.

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Technology from Potsdam for the World’s Largest Telescope

The PFUs are mounted at the LBT. (Credit: AIP)

Technology from Potsdam for the World’s Largest Telescope

19 November 2013. Two high performance instruments from Potsdam-Babelsberg arrived at the Large Binocular Telescope (LBT) in Arizona, the largest reflector telescope in the world. The so-called PFU...

The PFUs were developed and constructed entirely by scientists, engineers and technicians of the Leibniz Institute for Astrophysics Potsdam (AIP) in Babelsberg. The two car-sized control elements were installed on the observation platform of the telescope following their successful transport and delivery to the 3,200-meter altitude location in Arizona. At the end of November, the highly sensitive optics will receive their “first light”. The PFUs will allow the spectrograph PEPSI, which is still being constructed at the AIP workshop, to be operational and available for research from around the world for the first time.

Professor Klaus G. Strassmeier, Head of Project PEPSI & PFU and one of the directors of the AIP: “The two PFUs are designed to lead the starlight from the two 8.4 meter diameter LBT primary mirrors into two microscopically thin fiber optic cables with a diameter of only 0.1 millimeter. In all telescope positions and all weather conditions, every spectrum of light, from ultraviolet to infrared, will flow through the PFUs throughout the entire night without losing a photon – or at least far fewer.”

Three different fiber optic bundles are available for use by researchers and in the end determine the resolution of the PEPSI spectrograph. PEPSI and the two PFUs are able to reach a resolution corresponding to one one-hundredth of the diameter of an atom.

Thanks to the electronic and optical composition of the PFU’s interior, it is also possible to compensate for aberrations caused by the gravitational and thermic deformation of the two large primary mirrors (the so-called “Active Optics”). Additionally, the Potsdam instruments improve the tracking of the telescopes. It is necessary to adjust telescopes, compensating for the rotation of the Earth in order to keep observed objects in focus. PEPSI project scientist Dr. Ilya Ilyin: “In order to guarantee accurate tracing, the PFUs transmit a portion of the collected starlight through an assortment of special beam splitters to two CCD Sensors (Charged Coupled Device)”. The CCD Sensor is a highly sensitive light sensor, which can detect minute changes in brightness and shifts in position and thereby keep the object of stellar observation in focus in “real time”.

 

Scientific contact: Prof. Dr. Klaus G. Strassmeier, +49 331-7499 223, kstrassmeier@aip.de

Media contact: Kerstin Mork, +49 331-7499 469, presse@aip.de

 

The Large Binocular Telescope (LBT) is located at the Mt. Graham International Observatory in Arizona, USA. The telescope is of a novel design collecting simultaneously the light from the Universe with two circular mirrors, each 8.4m in diameter. The total collecting area of the telescope corresponds to a single circular mirror with a diameter of 11.8m. This makes the LBT the most powerful single mount telescope in the world when it comes to light collection ability. There are also several instruments under development to combine the light from the two mirrors in what is called 'interferometric mode'. This will eventually allow the LBT to achieve images with a resolution about ten times better than the Hubble Space Telescope.

 

The key topics of the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. Since 1992 the AIP is a member of the Leibniz Association.

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The Galactic Mosh Pit

Velocity map, see below. (Credit: AIP)

The Galactic Mosh Pit

22 October 2013. Astronomers have discovered that our Galaxy wobbles. An international team of astronomers around Mary Williams from the Leibniz Institute for Astrophysics Potsdam (AIP) detected an...

It is common knowledge that our Galaxy is permanently in motion. Being a barred spiral galaxy it rotates around the Galactic centre. It has now been discovered that our Galaxy, the Milky Way, also makes small wobbling or squishing movements. It acts like a Galactic mosh pit or a huge flag fluttering in the wind, north to south, from the Galactic plane with forces coming from multiple directions, creating a chaotic wave pattern. The source of the forces is still not understood however: possible causes include spiral arms stirring things up or ripples caused by the passage of a smaller galaxy through our own.

In this study, RAVE stars were used to examine the kinematics (velocities) of stars in a large, 3D region around the Sun - the region surveys 6500 light years above and below the Sun's position as well as inwards and outwards from the Galactic centre, reaching a quarter of the way to the centre. Using a special class of stars, red clump stars, which all have about the same brightness, mean distances to the stars could be determined. This was important as then the velocities measured with RAVE, combined with other survey data, could be used to determine the full 3D velocities (up-down, in-out and rotational). The RAVE red clump giants gave an unprecedented number of stars with which it is possible to study 3D velocities in a large region around the Sun.

The 3D movement patterns obtained showed highly complex structures. The aim was then to untangle these structures, concentrating on differences between the north and south of the Galactic plane. From these velocities it was seen that our Galaxy has a lot more going on than previously thought. The velocities going upwards and downwards show that there is a wave-like behaviour, with stars sloshing in and out. The novel element in our approach was true 3D observation, showing how complex the velocity landscape of the Galaxy really is. Modellers now have the challenge of understanding this behaviour, be it from ripples from an eaten galaxy or the wake from spiral arms. These new findings will make it possible to make 3D models of our Galaxy much more precise.

The publication can be found online at http://arxiv.org/abs/1302.2468 and was published this month in Monthly Notices of the Royal Astronomical Society (MNRAS).

 

Science contact: Dr. Mary Williams, mary@aip.de

Media contact: Kerstin Mork, +49 331-7499 469, presse@aip.de

 

Caption: Velocity map of the extended solar neighbourhood as seen by RAVE. Shown is a slice cut perpendicular to the plan of the Milky Way through the position of the Sun. Arrows indicate the streaming motions of the stars, the colour indicates the velocity perpendicular to the plane of the Milky Way (Credit: AIP).

 

RAVE is a multinational project with participation of scientists from Australia, Germany, France, UK, Italy, Canada, the Netherlands, Slovenia and the USA, coordinated by the Leibniz Institute for Astrophysics Potsdam (AIP), Germany. Funding of RAVE which guarantees extensive data, telescope and instrument access is provided by the participating institutions and the national research foundations.

 

The key topics of the Leibniz Institute for Astrophysics Potsdam (AIP) are cosmic magnetic fields and extragalactic astrophysics. A considerable part of the institute's efforts aim at the development of research technology in the fields of spectroscopy, robotic telescopes, and e-science. The AIP is the successor of the Berlin Observatory founded in 1700 and of the Astrophysical Observatory of Potsdam founded in 1874. The latter was the world's first observatory to emphasize explicitly the research area of astrophysics. Since 1992 the AIP is a member of the Leibniz Association.

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