Thomas was awarded the H.E.S.S. prize for his numerous and highly valuable contributions to H.E.S.S. in the past few years. He played, in particular, a major role in the maintenance of the H.E.S.S. data acquisition system (DAQ), and contributed to the development and implementation of a mono classification scheme for the large telescope (CT5), which is the basis of the low-energy real-time analysis (RTA). This classification provides the fast and reliable backbone for the mono RTA, used to trigger follow-up observations of known variable sources like Active Galactic Nuclei (AGN) or the recently detected Gamma Ray Burst GRB 190829A, and to search for emission from new transients.
In addition to his technical contributions to the H.E.S.S. collaboration, he participated in the data analysis and interpretation of several astrophysical sources, such as the binary system PSR B1259-63 with H.E.S.S.-I and H.E.S.S.-II data. His most significant achievement in the past months was his role in the successful implementation of the HESS DAQ cluster upgrade, which will ensure continued stable and reliable operation of H.E.S.S. in the coming years.
H.E.S.S. Prize Hall of Fame
The H.E.S.S. Prize
With the H.E.S.S. Prize, the collaboration acknowledges young scientists (PhD, postdoc, junior staff) who made outstanding service contributions to the experiment. Such contributions might range from hardware maintenance to various aspects of data handling including outstanding analyses (the development of a new analysis technique allowing a measurement not possible before) or a key contribution to an important scientific discovery. The prize is awarded at every collaboration meeting through a confidential vote by the Collaboration Board.
List of H.E.S.S. Prize Winners
Lars Mohrmann
Lars has been awarded the H.E.S.S. prize for outstanding contributions to characterising the HESS-II instrument and shaping the reconstruction and analysis pipeline of the array. He served as one of the key developers of the H.E.S.S. analysis pipeline HAP, coordinating the implementation and systematic testing. It is to a large extend his achievement that HAP keeps staying one of two competitive analysis frameworks to produce high-impact science results. Lars was also one of the main contributors to an upcoming publication on the performance of the HESS-II array. In this effort, many spin-off developments, from which the whole collaboration benefits every day, were driven by him, including the combined analysis in HAP and a new standard tool for data quality selection.
Besides these activities, he is one of the key persons preparing for the analysis of H.E.S.S. data with open source tools such as gammalib/ctools and gammapy. Accompanying his many technical contributions are numerous analysis tasks which he is actively involved in like the search for Galactic PeVatrons and the discovery of TeV pulsed emission from the Vela pulsar.
Jean-Philippe Lenain has always dedicated a significant part of his time to maintain and develop general tools for HESS collaboration and, this way, provided excellent support to the collaboration. He had transferred the HESS simulation framework to the international EGI GRID computing facility, and supports the production of simulated data. In parallel, he created programs dedicated to the automated survey of Fermi-LAT data for triggering target-of-opportunity HESS observations. As a service task more closely related to the detector, Jean-Philippe always scrutinized the quality of the collected data and contributed deeply to their calibration. He has supervised the development of tools dedicated to the survey of the performance of the real time analysis pipeline. He made a significant contribution to the development of run wise simulations which boosted the reliability of our physics results. He was also actively involved at the startup of CT5 and pushed the analysis teams to obtain the first HESS publication with this new instrument with a minimal time delay from the start of CT5 operations. More recently, Jean-Philippe has adapted simulation tools to take into account the new setup of the HESS 1 telescopes, and he is preparing the simulations for the eventual installation of the FlashCam prototype in the CT5 focal plane. His very strong and continuous support to the HESS collaboration is a key ingredient of our ability to publish high impact papers.
Clemens Hoischen
Clemens Hoischen has been awarded the H.E.S.S. Prize for his path-finding leadership of the H.E.S.S. transients program. Clemens designed and implemented a new, more flexible transient alert system, which is based on the VO standard and replaced the old GCN alerter in September 2016. The VO alert system receives external alerts, processes and filters them, and initiates prompt follow-ups of the alerts. Clemens connected H.E.S.S. to multiple sources of alarms (IceCube and Antares for neutrinos, Ligo/Virgo for gravitational waves), opening up completely new possibilities for the transients physics programs, which resulted in 2017 in the follow-up observations of the gravitational wave neutron star-neutron star merger and the follow up of the neutrino event IC-EHE-170922. In both cases, H.E.S.S. was the first VHE instrument to be on target. Thanks to Clemens, today H.E.S.S. has a modern and flexible transient system, unparalleled in ground-based Cherenkov astronomy and state-of-the-art compared to other wavelengths. In addition, Clemens also developed and established data unblinding and analysis strategies for transient sources, and initiated the systematic analysis and planned publication of all GRB data that has been taken since 2012. Since 2017 he leads the H.E.S.S. transients envelope task, which is responsible for the coordination of all transient-related activities.
During his time as a Ph.D. student in Tübingen, Daniel has been responsible for the actuator system of the large (28 m) H.E.S.S. II telescope, CT5, including maintenance, tests and alignment campaigns, and the corresponding analysis activities. He also prepared and performed all necessary actions concerning the mirror alignment system so that the collaboration can now point CT5 in reverse mode significantly faster to a new source than in traditional slewing modes. This is of great value specifically for GRB observations. Daniel also happily took over the task of monitoring the point spread function of the 12-m telescpoes CT1-4 after the University of Hamburg stepped down from that responsibility. In 2017, Daniel took over the responsibility of leading the effort to exchange all mirrors of CT3 with spare mirrors. This comprised both the on-site hardware as well as the control and analysis software of the alignment system. He furthermore led the maintenance of the mirror test facility, and, in addition, contributed significantly to analysis tasks for the H.E.S.S. I legacy paper on TeV supernova remnant shell candidates.
Markus Holler
Markus Holler’s most outstanding contribution to H.E.S.S. was the tremendous work he did in the development of a new paradigm, namely the Run Wise Simulations. This new simulation framework not only paves the way towards improved control of systematic effects, thereby opening new science cases such as the measurement of the extension of the Crab Nebula, but will very likely have a very large impact on the future of VHE gamma‐ray astronomy in general. Markus Holler was hired primarily for an ambitious project aiming at measuring the Galactic Diffuse Emission in VHE gamma‐rays. This is very challenging and requires in particular to significantly improve the understanding the of instrumental background systematics, and thus to develop new background determination/subtraction techniques. A more precise simulation of the instrument was quickly identified as the central element in these investigations. Markus led this task with enthusiasm, pertinacity and efficiency, and with a great care of precision. He successively incorporated many effects such as non‐operational pixels, actual calibration, effect of telescope dead‐time on event multiplicity, and actual tracking of the telescopes. He devoted a huge amount of work on the comparison between Monte Carlo and real data. At the end, we have now a much more precise simulation of the instrument, which opens up new possibilities previously out of reach: the almost perfect understanding of the PSF, for instance, enables extension measurements with great confidence (e.g. Crab Nebula). Last but not least, the success of this approach raised large interest in the community, as future instruments such as CTA will probably have to adopt Run Wise Simulations for optimal scientific return. In addition, Markus is serving as deputy‐convener of the Analysis & Reconstruction WG. He provided many cross‐check analyses and contributed to an incredibly large number of tasks. He is also very well considered in the collaboration for his kindness, his abilities to share his work and willingness to help.