The first data from H.E.S.S. II show the pulsed gamma-ray signal
The Vela pulsar provided a successful premiere for the new 28-metre Cherenkov telescope in Namibia. The pulsed radiation from Vela is the first to be measured in the southern sky and the performance of the High Energy Spectroscopic System (H.E.S.S.) has been proved once again.
Successful novice: The 28-metre H.E.S.S. II telescope integrated into the H.E.S.S. Cherenkov telescope array.
© MPIK/Christian Föhr
The celestial body in the Vela (sail) constellation is thus only the second pulsar ever from which gamma rays have been detected by a ground-based telescope. The construction and set-up of the 28-metre telescope was led by the Max Planck Institute for Nuclear Physics in Heidelberg.
This discovery has been accessible by the operation of the new 28-meter diameter telescope. Construction of the telescope structure has been led by the Max-Planck-Institute for Nuclear Physics (MPIK). Michael Panter, the coordinator of the telescope construction said:
“Building the largest telescope of its kind was very challenging. We had to mount 600 tons of steel with high precision. This telescope will enable us to study new source types and explore a wide range of astrophysical phenomena.” About 50% of the project’s funding was granted by the Max Planck Society. The instrumentation of the focal plane was developed in France.
Since the upgrade of the H.E.S.S. experiment in Namibia in 2012, H.E.S.S. II with its fifth and larger Cherenkov telescope CT5 is the first Cherenkov telescope system with telescopes of different sizes detecting cosmic TeV gamma rays in sync. CT5 is placed in the centre of the system, extends the energy range to lower energies and allows for the detection of cosmic particle accelerators down to 30 GeV.
In cooperation with scientists throughout Europe, a tailor-made reconstruction analysis was developed for these low-energy gamma rays. With this, H.E.S.S. scientists were able to detect a pulsed, repeating gamma-ray signal in the energy range of 30 GeV and attribute it to the Vela pulsar. This opens the door to new observation possibilities of the inner Galaxy. The first results presented at a conference on June 23 2014 by Christian Stegmann, spokesperson of the H.E.S.S. collaboration.
Besides intensive efforts in the construction and calibration of CT5, two years of intensive software development determined this success. “For the reconstruction of the data from CT5, we elaborated a highly sensitive analysis based on extremely complex statistical algorithms.
This allows us to detect gamma radiation of only 30 GeV from ground level,” explains Wilfried Domainko, from the local H.E.S.S. experimental group at MPIK. “Since we are able to survey a projected area of 10 hectares in the atmosphere, we have a considerably higher yield of gamma rays than for example satellite experiments like Fermi LAT.” From some sources, it is possible to spot up to one gamma per second – a record.
The data reveal regular gamma ray pulses, repeating every 89 milliseconds, coming exactly from the direction of the Vela pulsar. The reconstructed energies of these gamma rays are in the range of 30 GeV. This shows that H.E.S.S. for the first time successfully measured pulsed radiation in the southern sky.
“The whole Milky Way is full of pulsars and from Namibia we can exactly see into its centre. The H.E.S.S. data show that, with Cherenkov telescopes, we will still discover quite a number of mysteries in the universe,” beams Werner Hofmann, director at the MPIK in Heidelberg.
Cherenkov telescope systems consist of large segmented mirrors which focus optical Cherenkov light flashes. These flashes are generated in the atmosphere, last only a few nanoseconds and are invisible for the human eye. They are generated by cascades of elementary particles triggered by cosmic radiation. With highly sensitive cameras, Cherenkov telescopes take pictures of events which allow to identify gamma radiation to construct images of cosmic particle accelerators which emit this kind of gamma radiation.
The H.E.S.S. telescopes are operated by an international collaboration including a strong involvement of German universities and more than 30 institutions in 11 countries: Germany, France, United Kingdom, Namibia, South Africa, Ireland, Armenia, Poland, Australia, Austria and Sweden. H.E.S.S. is the only such system in the southern hemisphere and the only one with different reflector sizes. Therefore, H.E.S.S. ideally paves the way for the Cherenkov Telescope Array CTA, planned in international collaboration, which as from 2017 will be built with a total of about 100 Cherenkov telescopes of three sizes, distributed over two sites.
Dr. Bernold Feuerstein | Max-Planck-Institute
Climate cycles may explain how running water carved Mars' surface features
02.12.2016 | Penn State
What do Netflix, Google and planetary systems have in common?
02.12.2016 | University of Toronto
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy