CTA: the world’s leading gamma-ray observatory

High-Throughput Compute and Storage solutions for CTA’s computational challenges

The Cherenkov Telescope Array (CTA) brings together 1350 scientists and engineers from 32 countries with the goal of building the world’s largest and most sensitive very high-energy gamma-ray observatory.

The CTA will be used to understand the role of high-energy particles in the most violent phenomena of the Universe and to search for annihilating dark matter particles.

The computational challenges

The CTA will be a distributed array of more than 100 telescopes built in La Palma in Spain and the European Space Observatory site in Paranal, Chile, and is expected to produce up to 27 Petabytes per year for long term archive.

The computational challenges start right there: how to transfer all this data from the telescopes to scientists across the world? Then, the CTA infrastructure needs space to archive the data and enough processing power for data reduction and large-scale Monte Carlo simulations.

CTA aims to be the first ground-based gamma-ray public observatory. This means that a fraction of the observation time will be opened to the whole scientific community. Any scientist in the world will be able to submit an observation proposal to CTA and will have access to the corresponding data, which after a proprietary period, will become public.

This collaborative model, with the participation of the scientific community, implies other major challenges: “we need to make sure we have the capability to provide a unified and efficient access to data, which will follow the common standards of the Virtual Observatory”, explains Luisa Arrabito, the CTA computing grid technical coordinator, based at the Laboratoire Univers et Particules de Montpellier.

Why EGI services?

CTA relies on EGI’s High-Throughput Compute and Online Storage services to manage its computational challenges during the project’s preparatory phase. The benefits according to Arrabito are:

  • The possibility to aggregate resources from several sites, benefiting also of opportunistic resources
  • The long term reliability of storage resources provided by the main sites supporting CTA
  • Common and transparent data access for all CTA members

The compute and storage services are provided to the consortium via the CTA Virtual Organisation (vo.cta.in2p3.fr), one of the most active user groups of EGI.

Since 2012 the consortium has used EGI services to guide the choice of the best sites to host CTA telescopes in the North and in the South hemispheres. Once La Palma and Paranal sites were selected, “CTA also performed additional Monte Carlo simulation campaigns to determine the optimal array geometry” concludes Arrabito.

More information

Cherenkov Telescope Array

CTA EGI usage (2013-2016)
  • 360 million HS06 CPU hours
  • 11 Petabytes of data transferred
  • 2 Petabytes currently in storage
  • 11 million computation jobs

The data centres providing the most computing and storage resources to CTA are:

  • CC-IN2P3
  • GRIF
  • IN2P3-LAPP
  • CYFRONET-LCG2
  • DESY-ZN
  • INFN-T1

The CTA also benefits from resources provided by the National e-Infrastructures of the Czech Republic, France, Germany, Italy, Poland and Spain.