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  • INSTITUTE OF SPACE SCIENCES25 6 DES • Senior institute members involved: E Gaztañaga, F Castander, M Crocce, P Fosalba • Department: Department of Cosmology and Fundamental Physics The Dark Energy Survey is an international astronomical collaboration with more than 400 scientists from 25 institutions. It designed, built and operated a state-of-the-art imaging camera (DECam) to produce the largest survey of galaxies in the Universe, more than 500 million objects over 5000 deg2 of the southern sky, and spanning the last 10 billion years of cosmic history. The goal is to trace the large-scale structure of the Universe to study some major issues in observational cosmology, in particular the late time cosmic acceleration. Now at its peak scientific return, it probes the growth of structure by combining clustering and lensing, in addition to baryon acoustic oscillations (BAO), SNIa and Clusters. Recent developments From 2014 until now, DES has published over 326 papers, collecting well over 17000 citations. In particular, the cosmological results from the analysis of the 3rd year of observations (DES-Y3) were published in summer 2021 in a series of 27 papers culminating in (DES; Abbott et al. 2021 arxiv 2105.13549), which combines galaxy clustering and weak lensing from over 100 million galaxies to constrain some cosmological parameters to a precision comparable to that of the CMB (see Figure), yielding dark energy consistent with a cosmological constant within 3% when combined. The cosmology group at ICE in collaboration with the Spanish Excellent Network (SPADES) have led several DES papers in the past years, in particular 9 of the recent 27 papers presenting the latest cosmology results. We also had a major contribution leading the full BAO analysis presented in (DES; Abbott et al. 2021 arxiv 2107.04646 ). All these results were presented to the broader scientific community and the general public in a webinar (available at YouTube) with an audience of over 700 viewers. Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile. Reidar Hahn, Fermilab.
  • Blanco Telescope Dome and Milky Way. Credits: Reidar Hahn, Fermilab.

Uncovering the nature of dark energy

The Dark Energy Survey (DES) is an international, collaborative effort to map hundreds of millions of galaxies, detect thousands of supernovae, and find patterns of cosmic structure that will reveal the nature of the mysterious dark energy that is accelerating the expansion of our Universe. DES began searching the Southern skies on August 31, 2013.

Surveying the sky

DES is an international collaboration involving 10 institutions from the US, and  six international consortia from Brazil, the UK, Germany, Switzerland, Australia and a consortium from Spain (CIEMAT, IFAE and ICE-CSIC). The collaboration will carry out a very large and deep photometric survey of 5000 deg2 of the southern sky in five bands in the visible and near infrared (g, r, i, Z, Y), with the aim of producing the first precise characterisation of the properties of dark energy. To perform the survey, the DES Collaboration has built a wide-field (3 deg2) CCD camera (DECam), which is mounted at the prime focus of the 4-metre Blanco Telescope, located in Cerro Tololo (Chile).

Elliptical galaxy NGC 474 with star shells. Credit: DES/NOIRLab/NSF/AURA.

ICE-CSIC's participation

DES-Spanish groups (ICE-CSIC, IFAE and CIEMAT/UAM) were funded by Plan Nacional since 2006 to participate in DES. The Spanish groups have collaborated very effectively and, acting as a single institution, have been able to take important responsibilities in the collaboration:

  • DES-Spain had the responsibility for the design on most of, and the production and testing of all, the front-end electronics of the camera. Now we keep the responsibility of its operation and maintenance. The main responsibility was for IFAE and CIEMAT.
  • The ICE-CSIC provides some of the production electronics and contributes to the test-bench and test-camera to test CCD and electronics.
  • The ICE-CSIC has been responsible for production and testing of the star guider software.
  • The ICE-CSIC is responsible for the production of the N-body dark matter simulations (MICE) used in the DES Data Challenges and science analysis

The above tasks make our contribution to DES very visible within the collaboration. Consequently, DES-Spain is well represented in all committees governing and making decisions for DES: Management Committee (E. Gaztañaga and R. Miquel), Membership Committee (E. Sánchez), Publications Committee (R. Miquel), Science Committee (F. Castander, M. Crocce, E. Gaztañaga), DES Builders Committee (E. Fernández), Co-coordination of Large Scale Structure Working Group (E. Gaztañaga, M. Crocce), Co-coordination of Photo-z Working Group (F. Castander, E.Gaztanaga), etc. Six members of ICE-CSIC have the status of being DES builders. The Spanish institutions were the first to join the DES Collaboration from outside the US, following a procedure that has become the model for other institutions, in particular for those of the UK, Brazil, Germany, Switzerland and Australia.

Senior institute members involved

Meet the senior researchers who lead our participation in the DES mission.

  • Enrique Gaztañaga

    Enrique Gaztañaga

  • Francisco Javier Castander

    Francisco J. Castander

  • Martin Crocce

    Martin Crocce

  • Pablo Fosalba

    Pablo Fosalba