The CTA project is an initiative to build the next generation ground-based very high-energy gamma-ray instrument. The success of the precursor projects (i.e. MAGIC, VERITAS and H.E.S.S.) motivated the construction of this large infrastructure that is included in the roadmap of the ESFRI projects since 2008. CTA is in construction phased and is planned to start in late-2017. It will consist of two arrays of Cherenkov telescopes operated as a proposal-driven open observatory. To view the full sky, two CTA sites are foreseen at southern and northern hemispheres, with three telescopes types (Large, Medium and Small - LST, MST, SST). The northern observatory will be built in La Palma, in the Canary Island, whereas the southern one will be placed in Chile in the Atacama desert.
CTA foresees a factor of 5-10 improvement in sensitivity above 20 GeV and up to 300 TeV, extending the accessible energy range to explore the lowest and highest energy limits with unprecedented sensitivity. CTA will boost the field of Galactic and extragalactic sources, increasing the number of detected sources and the quality of the gamma-ray results by at least a factor 10.
The CTA observatory will have to deal with a large variety of observation modes and will have to operate tens of telescopes with a highly efficient and reliable control. The control software is required to operate with an idle time shorter than 10 s, which is a hard requirement for the control applications. A well-designed, failure-tolerant software system must be developed to control all the CTA observatory systems. Moreover, a complex and intelligent scheduling application and control system have been identified as critical ingredients for the efficient and reliable operation of the facility. The Institute is responsible for the development of the scheduler since 2010. This task is included in the CTA Array Control (ACTL) work package and is a key element in the control layer for the observatory time optimisation. Our institute is also committed to develop and install the central control for the LST prototype, that will manage the operation and communication between the telescope different subsystems, and that will be extended to the rest of the telescopes units.
Aim of our participation
The Institute has been involved in the CTA Project from 2006 in both the technical, as part of the Array Control and DAQ System (ACTL) working group and leading the scheduler team and in preparing the scientific exploitation of the observatory. Concerning the scientific exploitation, our institute is leading a number of the 'Key Science Programs', putting an effort of maximising the physic output of the observatory. Our team is responsible for designing the Galactic observations of CTA. We are also in charge of coordinating the studies for the first light Galactic observations of CTA and its pathfinders, and of coordinating the necessary multi-wavelength activities (such MoU with other large installations). This follows our earlier efforts: we have been the global Science Coordinator of the whole collaboration for 8 years in the period 2007-2014, having responsibilities in the scientific definition of the experiment, up to Technical Design Report.
Concerning the technological contribution to the CTA observatory, our team achieved several goals related to the scheduler software and telescope central control tools. During 2016 the first multi-telescope planning tool for scheduling the future gamma ray observations of different parts of the sky with CTA was developed. The CTA collaboration has compiled a number of science cases, which are described in Key Science Projects (KSP). The first scheduler prototype that we developed in collaboration with an industrial partner, GTD (Spain/Germany), has been used to evaluate the feasibility of the proposed science cases within 3 years and 1 year. Our team also obtain a first version of the LST central control sofware, which should be install in the first telescope in La Palma during 2017. On the scientific preparation of the observatory, we prepared a complete document on the Key Science Project.
The Cherenkov Telescope Array Observatory: top level use cases. ?Bulgarelli et al. Proceedings of the SPIE, Volume 9913, id. 991331 12 pp. (2016).
On the potential of atmospheric Cherenkov telescope arrays for resolving TeV gamma-ray sources in the Galactic plane Ambrogi et al. Astroparticle Physics, Volume 80, p. 22-33.
On the sensitivity of atmospheric Cherenkov telescope arrays for regions with presence of multiple gamma-ray sources Ambrogi et al. Journal of Physics: Conference Series, Volume 718, Issue 5, article id. 052002 (2016).
Status of the array control and data acquisition system for the Cherenkov Telescope Array Fuessling et al. Proceedings of the SPIE, Volume 9913, id. 99133C 12 pp. (2016).
The software architecture to control the Cherenkov Telescope Array Oya et al. Proceedings of the SPIE, Volume 9913, id. 991303 15 pp. (2016).
Senior Institute members involved
E. de Oña
, D. F. Torres, J. Colomé