Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

GROND Takes Off

09.07.2007
A new instrument has seen First Light at the ESO La Silla Observatory. Equipping the 2.2-m MPI/ESO telescope, GROND takes images simultaneously in seven colours. It will be mostly used to determine distances of gamma-ray bursts.

Taking images in different filters simultaneously is important for the study of many astrophysical sources, and in particular of variable sources, such as close binaries or active galactic nuclei. But it is most crucial in the follow-up of gamma-ray bursts. Gamma-ray bursts (GRBs) are short flashes of energetic gamma-rays lasting from less than a second to several minutes. They release a tremendous quantity of energy in this short time making them the most powerful events since the Big Bang.

Gamma-ray bursts, which are invisible to our eyes, are discovered by telescopes in space. After releasing their intense burst of high-energy radiation, they become detectable for a fleeting moment in the optical and in the near-infrared. This 'afterglow' fades very rapidly, making detailed analysis possible for only a few hours after the gamma-ray detection. This analysis is important in particular in order to determine the GRB's distance and, hence, intrinsic brightness.

A first determination of the distance can be done by taking images through different filters, using the so-called photometric redshift [1]. Because a typical GRB afterglow becomes 15 times fainter after just 10 minutes, and over 200 times fainter after an hour, it is important to observe the object in as many filters as possible simultaneously.

"To make the determination of distance of far-away objects as accurate as possible, we decided to use four different filters in the optical and three different filters in the near-infrared," says Jochen Greiner, who led the development of the GROND instrument. GROND stands for Gamma-Ray burst Optical/Near-Infrared Detector.

GROND takes thus images of the same region of the sky in 7 different filters. The field of view in the near-infrared is 10 times 10 arcminutes, or 1/7th the area of the Full Moon. It is smaller in the visible, slightly above 5 x 5 arcmin.

GROND is presently in its commissioning phase and its first science demonstration has been achieved, showing that all technical systems work properly. In particular, GROND observed a quasar located more than 12 billion light-years away.

As for many instruments specialising in the follow-up of gamma-ray bursts (see e.g. ESO 17/07 and 26/07), GROND can also be activated with a Rapid Response Mode (RRM): GRB alerts will be automatically fed into the system thus minimising the delay between the gamma-ray burst detection by a satellite and its observation by GROND.

"The implementation of the RRM at the 2.2-m telescope is done in exactly the same way as for the VLT, and boosts ESO's leadership to offer observing systems with ultra fast response time towards GRB follow-up," says Michael Sterzik, Head of Science Operations Department at ESO La Silla.

A dedicated data analysis pipeline is also being tested which will provide the distance of the burst a few minutes after the first observations.

"Ultimately, the goal is to trigger ESO's VLT to perform spectroscopy of the source with fine-tuned settings, thereby maximising the scientific return of GRB follow-up observations of the VLT," says Greiner.

GROND has been built by the Max-Planck Institute for Extraterrestrial Physics in collaboration with the Thüringer Landessternwarte Tautenburg.

Note
[1] The photometric redshift method makes it possible to judge the distance to a remote celestial object (a galaxy, a quasar, a gamma-ray burst afterglow) from its measured colours. It is based on the proportionality between the distance and the velocity along the line of sight (Hubble's law) that reflects the expansion of the Universe. The larger the distance of an object is, the larger is its velocity and, due to the Doppler effect, the spectral shift of its emission towards longer (redder) wavelengths. Thus, the measured colour provides a rough indication of the distance.

Henri Boffin | alfa
Further information:
http://www.eso.org/public/outreach/press-rel/pr-2007/pr-30-07.html

More articles from Physics and Astronomy:

nachricht Nanostructures taste the rainbow
29.06.2017 | California Institute of Technology

nachricht X-ray photoelectron spectroscopy under real ambient pressure conditions
28.06.2017 | National Institutes of Natural Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making Waves

Computer scientists use wave packet theory to develop realistic, detailed water wave simulations in real time. Their results will be presented at this year’s SIGGRAPH conference.

Think about the last time you were at a lake, river, or the ocean. Remember the ripples of the water, the waves crashing against the rocks, the wake following...

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Cystic fibrosis alters the structure of mucus in airways

29.06.2017 | Health and Medicine

New Headlamp Dimension: Fully Adaptive Light Distribution in Real Time

29.06.2017 | Automotive Engineering

Turning the Climate Tide by 2020

29.06.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>