Welcome

Studying the Sun is a key to understand the physical processes on and in the majority of stars. Moreover, there is also a very practical aspect: the solar activity affects or even damages satellite systems and power networks in some regions on Earth. Knowing more about it may help to mitigate expensive damages.

The inauguration ceremony will take place on May 21, 2012 on Tenerife.

GREGOR is a solar telescope with an aperture of 1.5 meters and has been designed to carry out observations of the solar photosphere and chromosphere in the visible and infrared part of the spectrum. Due to its large diameter it will allow observations with higher resolution than was possible before. A novel “adaptive optics system” is able to compensate for atmospheric disturbances and provides a detailed image of the Sun, similar to what would be achieved if the telescope was in space. The resulting high spatial, spectral, and temporal resolution will allow scientists to follow physical processes on the Sun on spatial scales as small as 70 km.

During night time GREGOR can also observe bright stars. It will mainly be used for long term monitoring of stars in order to find out whether the distant suns show similar cyclic behaviour as our own.

GREGOR’s design is completely open in order to enable wind cooling of the telescope structure and the mirrors. The classical dome has therefore been replaced by a retractable structure which allows natural air flushing. This open structure places high demands on the mechanical stability of the telescope structure in order to eliminate wind-induced vibrations.

The primary mirror is a lightweight filigree structure made of a special material that does not deform under the heat of the bright Sun. Additionally, the mirror is actively cooled from the back in order to prevent the front side from heating up and thus producing internal turbulence.

From the telescope the light is guided into the laboratory rooms where it can be distributed to a number of analyzing instruments:

• An imaging setup produces images of the solar surface at various wavelengths. These images are expected to show an extraordinary richness of details.
• Studying the photosphere and chromosphere of the Sun, analyzing the interaction of the solar magnetic field and the highly dynamic plasma, will be possible thanks to the interferometric setup.
• A spectrograph will analyze the solar atmosphere by looking into the near infrared part of the spectrum. It will be able to produce detailed maps of the solar magnetic field.

GREGOR will be accessible to the international solar physics community and has the potential to provide a significant boost to solar physics worldwide.

The GREGOR solar telescope has been built by a German consortium under the leadership of the Kiepenheuer-Institut für Sonnenphysik in Freiburg with the Leibniz-Institut für Astrophysik Potsdam and the Max-Planck-Institut für Sonnensystemforschung in Katlenburg/Lindau as partners, and with contributions by the Instituto de Astrofísica de Canarias, the Institut für Astrophysik Göttingen, and the Astronomical Institute of the Academy of Sciences of the Czech Republic.

More informationen:

• GREGOR Telescope: http://gregor.kis.uni-freiburg.de/
• Kiepenheuer-Institut für Sonnenphysik Freiburg: www.kis.uni-freiburg.de
• Leibniz Institute for Astrophysics Potsdam (AIP): www.aip.de
• Max-Planck-Institut für Sonnensystemforschung Katlenburg-Lindau (MPS):  http://www.mps.mpg.de/de/aktuelles/
• Observatorio del Teide (engl.): http://www.iac.es/eno.php?op1=3&lang=en

Images:

• Telescope, mirror, building, observatory, Tenerife:
  http://www.kis.uni-freiburg.de/index.php?id=168
• Images of the inaugration will be published after the event on May 21:
  http://www.kis.uni-freiburg.de/index.php?id=788&L=0

Science contact:

• Freiburg/KIS: Dr. Reiner Hammer. Tel.: +49-761-3198-216, E-mail: hammer@kis.uni-freiburg.de
• Potsdam/AIP: apl. Prof. Dr. Carsten Denker, Tel.: +49-331-7499-297, E-mail: cdenker@aip.de
• Katlenburg-Lindau/MPS: Prof. Dr. Sami K. Solanki

Press contact:

• Potsdam/AIP: Dr. Gabriele Schönherr/ Kerstin Mork, Tel.: +49-331-7499-469, E-mail: presse@aip.de
• Katlenburg-Lindau/MPS: Birgit Krummheuer (presseinfo@mps.mpg.de), Tel.: +49-5556-979-462

The key topics of the Leibniz Institute for Astrophysics 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.The AIP is a foundation according to civil law and is a member of the Leibniz Association. The Leibniz Association is a network of 86 independent research institutes and scientific service facilities, which strive for scientific solutions for major social challenges.

In her thesis Meetu Verma explores the "Developement and Erosion of Sunspots“ working in the research section "Physics of the Sun“ at Leibniz Institute for Astrophysics Potsdam (AIP).

To study the decay of sunspots Meetu Verma analyzed time-series of solar images obtained with the Solar Optical Telescope onboard the Japanese space mission "Hinode". As a part of her doctoral work she created a database of velocity fields on the surface of the Sun, which contains hundreds of datasets allowing scientists to study a variety of new phenomena on the Sun.

In a case study Meetu Verma followed the evolution of sunspots, which decayed over the course of a week. One sunspot was surrounded by strong outward motions with a speed of up to 1 km per second appropriately named moat flow. Meetu Verma demonstrated that small concentrations of the magnetic fields do not move randomly, but follow specific paths and contribute to the slow erosion of the sunspot. "The interaction of strong magnetic fields with hot solar plasma," says Meetu Verma, "was previously known only in general terms. The new telescopes on Earth and in space, now allow us to investigate these processes in detail."

In another study, she investigated if photospheric flow fields can trigger solar eruptions. "Shear flows between sunspots of different magnetic polarity tend to increase the energy stored in the magnetic fields, but they are not directly responsible for triggering flares," explains Meetu Verma. Within a few seconds solar eruptions can releases tremendous amounts of energy. These solar outbursts can affect technological assets in space and even influence technical systems on Earth. These effects are also called "space weather".

Meetu Verma holds a scholarship of the German Academic Exchange Service (Deutscher Akademischer Austauschdienst (DAAD)) and is currently working on her thesis at the University of Potsdam and the Leibniz Institute for Astrophysics Potsdam (AIP). The award is shared with Dr. Damaris Zurell, who works at the Institute of Biochemistry and Biology at the University of Potsdam.

Scientific Publications

Verma, M., Denker, C. 2011: Horizontal Flow Fields Observed in Hinode G-Band Images. I. Methods. Astronomy and Astrophysics 529, A153.

Verma, M., Balthasar, H., Deng, N., Liu, C., Shimizu, T., Wang, H., Denker, C. 2012: Horizontal Flow Fields Observed in Hinode G-band Images. II. Flow Fields in the Final Stages of Sunspot Decay. Astronomy and Astrophysics 538, A109.

Beauregard, L., Verma, M., Denker, C. 2012: Horizontal Flows Concurrent with an X2.2 Flare in Active Region NOAA 11158. Astronomische Nachrichten 333, 125.

Scientific Contact

Meetu Verma, 0331-7499-332, mverma@aip.de

Press Contact

Dr. Gabriele Schönherr / Kerstin Mork, 0331-7499-469, presse@aip.de

The key topics of the Leibniz Institute for Astrophysics 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.The AIP is a foundation according to civil law and is a member of the Leibniz Association. The Leibniz Association is a network of 86 independent research institutes and scientific service facilities, which strive for scientific solutions for major social challenges.

4 May 2012. Latest optics for the PEPSI spectrograph at the Large Binocular Telescope (LBT)

The PEPSI spectrograph, being developed and built at the Leibniz Institute for Astrophysics (AIP), will in the future enable astronomers to simultaneously obtain highly resolved spectra in the optical and near infrared light. This is made possible by the employment of special optical components called cross dispersers. The last of a total of six of these dispersers made by the French company Thales SESO has now arrived at the AIP labs for integration into the spectrograph.

Spectrographs are used to decompose white light, for instance the light of stars, into its individual colours. Dark lines appearing in a spectrum can result from the absorption of light by bound electrons in an atom, thus giving a fingerprint of the physical properties of a star and its surface chemistry. The phrase "a spectrum tells us more than a thousand images“ is very appropriate for modern stellar astrophysics.

With a resolution of only 0.002 nanometres – 2 trillionths of metres – the "Potsdam Echelle Polarimetric and Spectroscopic Instrument" (PEPSI) outperforms today’s spectrographs by a factor of five, running in parallel in the full optical and full infrared wavebands. The cross dispersers give this parallel coverage, as they decompose the light not according to its wavelength but rather, according to the geometrical direction which is perpendicular to the light dispersion of the grating. This allows for simultaneous observation of the individual spectra, providing access to all wavelengths at the same time.

The PEPSI cross dispersers are made of three components each: a prism which parallelizes the incoming light, a “volume phase holographic“ (VPH) grating plate which is a hologram in a gelatine layer illuminated by the light installed on two very precise plane-parallel glass plates of pure fused silica which catches the incident light. Finally, a second prism is located at the emission point, connected optically to the VPH grating plate.

After completion in 2013, PEPSI will be shipped to the Large Binocular Telescope on top of the 3200 metre high Mount Graham in Arizona to start science operations in 2014. After 10-years of construction and investments of about five million euro, PEPSI will then be the world’s largest and most powerful spectrograph of its kind, being able to observe magnetic fields of stars other than our Sun.

Scientific Contact

Prof. Dr. Klaus G. Strassmeier, +49 331 7499-295, kstrassmeier@aip.de

Manfred Woche, +49 331 7499-204, mwoche@aip.de

Press Contact

Dr. Gabriele Schönherr / Kerstin Mork, +49 331-7499-469, presse@aip.de

The key topics of the Leibniz Institute for Astrophysics 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.The AIP is a foundation according to civil law and is a member of the Leibniz Association. The Leibniz Association is a network of 86 independent research institutes and scientific service facilities, which strive for scientific solutions for major social challenges.

RR Lyrae stars are bright pulsating stars which are very important standard candles which can be used to determine distances to distant galaxies. Precise knowledge of the properties of RR Lyrae stars is therefore important. An international team of astronomers seeking to improve the accuracy of the extragalactic distance scale believed to have found such a star in a double star system which would allow the very accurate determination of its distance and mass.To their surprise they found that the star was only half as massive as expected and that the star, in spite of its apperance, is not a true RR Lyrae star but rather a new type of pulsating variable star which has lost a large fraction of its mass to the companion in the double star system. The probabilities to find stars in similar constellations which could be mistaken for RR Lyrae stars is luckily very low, such that distance measurements obtained with RR Lyrae stars remain valid.

Jesper  Storm (AIP) is a member of the international team of researchers and a co-author of the publication in the journal Nature. He has been studying the use of pulsationally variable stars as distance indicators for many years.

Link to publication: doi10.1038/nature10966

Scientific Contact: Dr. Jesper Storm – Tel.: 0331 7499 394, E-mail: jstorm[at]aip.de

Press Contact: Dr. Gabriele Schönherr / Kerstin Mork – 0331 7499 383, presse[at]aip.de

Full text of the press release by the SDSS collaboration, including high-resolution image: http://www.sdss3.org/press/20120330.bspec.php

Sebastian Nuza of the Leibniz Institute for Astrophysics Potsdam (AIP) is among the co-authors. His specialization are numerical simulations of cosmological structure formation and predictions of the clustering of galaxies. All published results together allow for the most complete view of the distant Universe and are an important step towards understanding what drives its expansion.

Further Information:

• All six publications have been posted online today at astro.ph: http://arxiv.org
• Previously posted publication by Sebastian Nuza about the clustering of galaxies: http://arxiv.org/abs/1202.6057

Science contact
Dr. Sebastian Nuza snuza@aip.de, +49 331-7499-414

Press contact
Dr. Gabriele Schönherr / Kerstin Mork, presse@aip.de Tel.: +49 331 7499 383

About SDSS-III

Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy Office of Science. The SDSS-III web site is www.sdss3.org. SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, University of Cambridge, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, and Yale University.

About the AIP

The key topics of the Leibniz Institute for Astrophysics 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. The AIP is a foundation according to civil law and is a member of the Leibniz Association. The Leibniz Association is a network of 86 independent research institutes and scientific service facilities, which strive for scientific solutions for major social challenges.