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"Pi of the Sky" observation of GRB080319B
2008.03.19 "Pi of the Sky" telescope detected the brightest ever optical outburst from a distant universe. The explosion happened 7.5 billion light years from the Earth, halfway across the visible Universe. The telescope is only 71 mm in diameter.
Birth of a black hole
The outburst was also detected in gamma rays by "Swift" satellite proving that it was so called Gamma Ray Burst denoted as GRB 080319B (2nd one on 2008.03.19). Probably, it was the death of a massive star and the birth of a black hole. Optical observations during the first minute of the burst are crucial to understand the fenomenon. The "Pi of the Sky" observation combined with the Swift gamma-ray data for the first time confirmed with 10s precision that optical and gamma-ray emission start simultaneously.
In the graph, brightness changes with time are expressed in magnitudo units with 0 corresponding to the brightest visible stars and 6 being a naked eye limit. The GRB 080319B was so bright that it could be seen with the naked eye.
Race for the burst
During the night of 2008.03.18/19 the "Swift" satellite was as usually hunting for GRBs.
"Pi of the Sky" telescope was routinely monitoring the sky looking in the same direction as "Swift"
taking 10s long images.
The image stated at 6:12:47 UT showed a new object. It was automatically detected by the burst recognition algorithm.
At 6:12:49 UT "Swift" received the first gamma rays. This moment marked as T=0 stands for the beginning of the burst.
Only two seconds later (T0+2s) another robotic telescope "RAPTOR" took an image of the object.
At T0+16s the object became visible to "TORTORA" camera which made a beautiful movie of the peak of the burst.
At T0+17s "Swift" sent out the alert about the burst and many telescopes on the ground turned towards the target.
"Swift" on-board telescope "UVOT" begin observation at T0+51s.
One hour later the Very Large Telescope in Chile measured the distance to the burst, which was confirmed by
the Hobby-Eberly Telescope in Texas.
Be ready for the next burst
This observation was the proof of the novel concept of the "Pi of the Sky" project. Usually, optical emission from GRB is observed by telescopes listening to alerts from satellite gamma ray detectors. Signal distribution and turning the telescope take some time and the very first minute of the outburst cannot be observed. The principle of the "Pi of the Sky" project is different. The apparatus monitors continuously large fraction of the sky taking 10s exposures and detects optical flashes independently, while the satellite information confirms the origin of the flash.
The project was inspired by Bohdan Paczynski, great astrophysicist who past away last year. He contributed a lot to the understanding of GRBs and he always claimed that small telescopes have large potential.
More cameras - more bursts
Currently "Pi of the Sky" apparatus consists of two cameras installed in Las Campanas Observatory in Chile. They cover 20ox20o of the sky. To increase the chance of observing a GRB 32 new cameras are under construction. They will cover 1/3 of the visible sky continuously. Original plan was to cover pi steradians of the sky, giving the name for the project. The name recalls also the title of John Barrow book "Pi in the sky" arguing that the phenomena we observe are governed by physical laws expressed in mathematical language.
The project is conducted by collaboration of Polish research institutes: Soltan Institute for Nuclear Studies (Warsaw), Center for Theoretical Physics PAS (Warsaw), Warsaw University, Warsaw University of Technology, Space Research Center PAS (Warsaw), University of Cardinal Stefan Wyszynski (Warsaw), Pedagogical University of Cracow
| "Pi of the Sky" cameras in ASAS dome at LCO | "Pi of the Sky" team celebrating the discovery |
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We would like to thank the staff of the Las Campanas Observatory for their help during installation and maintenance of our telescope
We also thank Grzegorz Pojmanski for providing the space in the ASAS dome and for a lot of help in making our apparatus operational.