Matthias Bergmann

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: 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.

Bokeh mirror alignment for Cherenkov telescopes

Segmented imaging reflectors are a great choice for Imaging Atmospheric Cherenkov Telescopes (IACTs). However, the alignment of the individual mirror facets is challenging. We align a segmented reflector by observing and optimizing its Bokeh function. Bokeh alignment can already be done with very little resources and little preparation time. Further, Bokeh alignment can be done anytime, even during the day. We present a first usage of Bokeh alignment on FACT, a 4m IACT on Canary Island La Palma, Spain and further a first Bokeh alignment test on the CTA MST IACT prototype in Brelin Adlershof.