Kai Brügge

Online analysis of high-volume data streams in astroparticle physics

Experiments in high-energy astroparticle physics produce large amounts of data as continuous high-volume streams. Gaining insights from the observed data poses a number of challenges to data analysis at various steps in the analysis chain of the experiments. Machine learning methods have already cleaved their way selectively at some particular stages of the overall data mangling process. In this paper we investigate the deployment of machine learning methods at various stages of the data analysis chain in a gamma-ray astronomy experiment. Aiming at online and real-time performance, we build up on prominent software libraries and discuss the complete cycle of data processing from raw-data capturing to high-level classification using a data-flow based rapid-prototyping environment. In the context of a gamma-ray experiment, we review user requirements in this interdisciplinary setting and demonstrate the applicability of our approach in a real-world setting to provide results from high-volume data streams in real-time performance.

FACT - Calibration of Imaging Atmospheric Cerenkov Telescopes with Muon Rings

M. Nothe∗, a M. L. Ahnen b, M. Balbo c, M. Bergmann d , C. Bockermann e, A. Biland b, T. Bretz b, K. A. Brugge a, J. Buss a, D. Dorner d , S. Einecke a, J. Freiwald a, C. Hempfling d , D. Hildebrand b, G. Hughes b, W. Lustermann b, K. Mannheim d , K. Meier d , K. Morik e, S. Muller b, D. Neise b, A. Neronov c, A.-K. Overkemping a, A. Paravac d , F. Pauss b, W. Rhode a, F. Temme a, J. Thaele a, S. Toscano c, P. Vogler b, R. Walter c, and A. Wilbert d Email: maximilian.noethe@tu-dortmund.de

FACT-Tools: Streamed Real-Time Data Analysis

K. A. Brügge b∗, M. L. Ahnena, M. Balboc, M. Bergmannd , A. Bilanda, C. Bockermanne, T. Bretza, J. Bussb, D. Dornerd , S. Eineckeb, J. Freiwaldb, C. Hempflingd , D. Hildebranda, G. Hughesa, W. Lustermanna, K. Mannheimd , K. Meierd , K. Morike, S. Müllera, D. Neisea, A. Neronovc, M. Nötheb, A.-K. Overkempingb, A. Paravacd , F. Paussa, W. Rhodeb, F. Temmeb, J. Thaeleb, S. Toscanoc, P. Voglera, R. Walterc, and A. Wilbertd Email: kai.bruegge@tu-dortmund.de

FACT - Status and Experience from Three Years Operation of the First SiPM Camera

A. Biland∗a, M. L. Ahnena, M. Balbob, M. Bergmannc, T. Bretza,1, K. A. Brugged , J. Bussd , D. Dornerc, S. Einecked , J. Freiwaldd , C. Hempflingc, D. Hildebranda, G. Hughesa, W. Lustermanna, K. Mannheimc, K. Meierc, S. Mullera, D. Neisea, A. Neronovb, M. Nothed , A.-K. Overkempingd , A. Paravacc, F. Paussa, W. Rhoded , F. Temmed , J. Thaeled , S. Toscanob, P. Voglera, R. Walterb, and A. Wilbertc aETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich, Switzerland bUniversity of Geneva, ISDC Data Center for Astrophysics Chemin d’Ecogia 16, 1290 Versoix, Switzerland cUniversitat Wurzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Wurzburg, Germany dTU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund, Germany 1also at RWTH Aachen E-mail: biland@phys.ethz.ch

FACT - TeV Flare Alerts Triggering Multi-Wavelength Observations

D. Dorner∗a, M. L. Ahnenb, M. Balbod , M. Bergmanna, A. Bilandb, T. Bretzb1, K. A. Bruggec, J. Bussc, S. Eineckec, J. Freiwaldc, C. Hempflinga, D. Hildebrandb, G. Hughesb, W. Lustermannb, K. Mannheima, K. Meiera, S. Mullerb, D. Neiseb, A. Neronovd , M. Nothec, A.-K. Overkempingc, A. Paravaca, F. Paussb, W. Rhodec, F. Temmec, J. Thaelec, S. Toscanod , P. Voglerb, R. Walterd , and A. Wilberta aUniversitat Wurzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Wurzburg, Germany bETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich, Switzerland cTU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund, Germany dUniversity of Geneva, ISDC Data Center for Astrophysics Chemin d’Ecogia 16, 1290 Versoix, Switzerland 1also at RWTH Aachen E-mail: dorner@astro.uni-wuerzburg.de

First study of combined blazar light curves with FACT and HAWC

For studying variable sources like blazars, it is crucial to achieve unbiased monitoring, either with dedicated telescopes in pointing mode or survey instruments. At TeV energies, the High Altitude Water Cherenkov (HAWC) observatory monitors approximately two thirds of the sky every day. It uses the water Cherenkov technique, which provides an excellent duty cycle independent of weather and season. The First G-APD Cherenkov Telescope (FACT) monitors a small sample of sources with better sensitivity, using the imaging air Cherenkov technique. Thanks to its camera with silicon-based photosensors, FACT features an excellent detector performance and stability and extends its observations to times with strong moonlight, increasing the duty cycle compared to other imaging air Cherenkov telescopes. As FACT and HAWC have overlapping energy ranges, a joint study can exploit the longer daily coverage given that the observatories’ locations are offset by 5.3 hours. Furthermore, the better sensitivity of FACT adds a ...

FACT - Novel mirror alignment using Bokeh and enhancement of the VERITAS SCCAN alignment method

S. Muller∗a, M. L. Ahnena, M. Balbob, M. Bergmannc, A. Bilanda, T. Bretza,1, K. A. Brugged , J. Bussd , D. Dornerc, S. Einecked , J. Freiwaldd , C. Hempflingc, D. Hildebranda, G. Hughesa, W. Lustermanna, K. Mannheimc, K. Meierc, D. Neisea, A. Neronovb, M. Nothed , A.-K. Overkempingd , A. Paravacc, F. Paussa, W. Rhoded , F. Temmed , J. Thaeled , S. Toscanob, P. Voglera, R. Walterb, and A. Wilbertc aETH Zurich, Institute for Particle Physics Otto-Stern-Weg 5, 8093 Zurich, Switzerland bUniversity of Geneva, ISDC Data Center for Astrophysics Chemin d’Ecogia 16, 1290 Versoix, Switzerland cUniversitat Wurzburg, Institute for Theoretical Physics and Astrophysics Emil-Fischer-Str. 31, 97074 Wurzburg, Germany dTU Dortmund, Experimental Physics 5 Otto-Hahn-Str. 4, 44221 Dortmund, Germany 1also at RWTH Aachen E-mail: sebmuell@phys.ethz.ch

FACT – Influence of SiPM Crosstalk on the Performance of an Operating Cherenkov Telescope

J. Buß∗b, M. L. Ahnen a, M. Balbo c, M. Bergmann d , A. Biland a, C. Bockermann e, T. Bretz a, K. A. Brügge b, D. Dorner d , S. Einecke b, J. Freiwald b, C. Hempfling d , D. Hildebrand a, G. Hughes a, W. Lustermann a, K. Mannheim d , K. Meier d , K. Morik d , S. Müller a, D. Neise a, A. Neronov c, M. Nöthe b, A.-K. Overkemping b, A. Paravac d , F. Pauss a, W. Rhode b, F. Temme b, J. Thaele b, S. Toscano c, P. Vogler a, R. Walter c, and A. Wilbert d E-mail: jens.buss@tu-dortmund.de

Open high-level data formats and software for gamma-ray astronomy

In gamma-ray astronomy, a variety of data formats and proprietary software have been traditionally used, often developed for one specific mission or experiment. Especially for ground-based imaging atmospheric Cherenkov telescopes (IACTs), data and software are mostly private to the collaborations operating the telescopes. However, there is a general movement in science towards the use of open data and software. In addition, the next-generation IACT instrument, the Cherenkov Telescope Array (CTA), will be operated as an open observatory. We have created a Github organisation at this https URL where we are developing high-level data format specifications. A public mailing list was set up at this https URL and a first face-to-face meeting on the IACT high-level data model and formats took place in April 2016 in Meudon (France). This open multi-mission effort will help to accelerate the development of open data formats and open-source software for gamma-ray astronomy, leading to synergies in the development of analysis codes and eventually better scientific results (reproducible, multi-mission). This write-up presents this effort for the first time, explaining the motivation and context, the available resources and process we use, as well as the status and planned next steps for the data format specifications. We hope that it will stimulate feedback and future contributions from the gamma-ray astronomy community.

FACT: status and experience from four years of operation of the first G-APD Cherenkov Telescope

The First G-APD Cherenkov Telescope (FACT) is pioneering the usage of novel Geiger-mode operated Avalanche Photo Diodes (G-APD, nowadays usually called SiPM) for Cherenkov Telescopes. The camera consists of 1440 pixels with dedicated electronics operated at 2 GHz and is installed on a refurbished telescope with a mirror area of ≈ 9:5 m2 at the Canary Island La Palma. The camera was installed in October 2011, and data are taken almost every night since then. The very stable and reliable operation allows to operate FACT from remote without the need of a data taking crew on-site. Over the years, operation became more and more automatic, and the next step will be to switch to fully automatic operation. This results in a very high data taking efficiency. The operation of FACT allows monitoring the long-term behavior of few variable extra-galactic very-high energy sources with unprecedented sampling density as well as testing the behavior of the sensors under harsh conditions. Despite operating also under strong moonlight conditions and therefore collecting far more signals than during dark nights, the G-APDs show no change in their performance or any indication for ageing. Understanding the behavior of the G-APDs under all the varying conditions allows to operate FACT without the need of any external calibration device. The properties of the sensors themselves allow for a high precision self-calibration of the camera.