Galaxy IC 1613

IFAE Research Groups

Observational Cosmology Group

  • Observational Cosmology

    Shedding light on the nature of the mysterious dark energy, responsible for the current accelerated expansion of the universe.

    Starry Night
    • Hardware contributions to large international collaborations: DES, PAU, Euclid, DESI
      • The group led the development and production of the read-out electronics for the DES Camera, DECam, the leading astronomical camera at the time (2012).
      • The group led the construction of the innovative PAU astronomical camera, installed (2015) at the William Herschel 4-meter Telescope in the Canary Islands
      • The group designed and built the Filter Wheel Assembly for the ESA Euclid mission (2018).
      • The group designed and built the 10 Guiding, Focusing and Aligning (GFA) cameras for DESI (2019)
    • Leading role in state-of-the-art analyses of international collaborations
      The group has played a leading role in the analyses of the data of the two leading cosmological surveys of the 2010s. In DES, the leading photometric galaxy survey, IFAE has led photometric redshift calibration and galaxy-galaxy lensing in the analysis of the first (DES-Y1) and first-to-third (DES-Y3) year data. Furthermore, IFAE led the paper that presents the measurement and calibration of the shapes of over 100 million distant galaxies, which is the basis of all DES-Y3 weak lensing measurements and cosmological inference. Finally, an IFAE researcher co-led the 2021 paper presenting the final cosmological results of 20 years of observation by the SDSS Collaboration and its successors BOSS and eBOSS, the leading spectroscopic surveys of the last two decades.
    • Pioneer of a new cosmological probe, 3D correlations in the Lyman-α forest
      The Lyman-α forest is a unique window to study the expansion of the Universe at high redshift, during the matter-dominated era. The excellence and international leadership of Dr. Andreu Font-Ribera in this field has been recently recognised with an ERC Consolidator Grant, and his group is currently leading the Lyman-α analyses with the first data from DESI.
    Papers led or co-led by a group member in the period 2015-2022
    33
    Competitive funding raised by the group in the period 2015-2022
    5M€+
    highly cited papers (10%, WOS)
    147
  • Observational Cosmology Group

    The main goal of the Observational Cosmology group at IFAE is to study the origin, evolution, and fate of the universe, and, in particular, to shed light on the nature of the mysterious dark energy, responsible for the current accelerated expansion of the universe.

    The Observational Cosmology Group is led by R. Miquel.

    The Dark Energy Survey (DES)

    In 2005, IFAE joined the preparations for the Dark Energy Survey (DES), the current leading imaging galaxy survey, and designed and built most of the readout electronics of DECam, the DES camera. DES started taking data in 2012 and has now finished its observations. The group has concentrated on the measurements and data analysis of the weak gravitational lensing effect, potentially the most powerful probe of dark energy, and related important measurements such as those of galaxy redshift distributions, achieving very high impact and leading key DES publications.

    In particular, DES has so far had two main analyses, using data from the first year of observations (DES-Y1) and the first three years (DES-Y3). For the Y1 analysis, IFAE PhD students led two of the 12 so-called “essential” papers that led to the “key” paper with the cosmological constraints from the first year of DES observations published in 2018, which has already amassed over 1000 citations. Furthermore, with DES Year 1 data, IFAE’s group led analyses in a number of cutting-edge topics: galaxy-galaxy lensing; photometric redshifts, including using a new technique based on angular cross-correlations; cosmic void science, including void lensing and cross-correlations with the cosmic microwave background (CMB) temperature and lensing maps; etc.

    Dark Energy Camera (DECam) on Blanco Telescope, Cerro Tololo Observatory, Chile Credit: Reidar Hahn, Fermilab

    For the analysis of DES-Y3 data, IFAE’s group co-led several essential projects as part of the main cosmological analysis released in 2021, including the test and calibration of the measurements of the galaxy shapes for the weak lensing cosmological probe (probably the most crucial measurement in DES), mass mapping from weak lensing, cosmology from the moments of the mass distribution, and, again, photometric redshift calibration, using both unsupervised learning techniques and cross-correlations, and cross-correlations between DES voids and CMB lensing. The DES-Y3 cosmological analysis represents the state-of-the-art in weak lensing cosmology.

    Currently, the group is heavily involved in the analysis of the final DES data set (DES-Y6). In terms of management, a group member chairs the DES Builders Committee, while two group members are co-leads of two of the most important working groups (Redshifts and Large-Scale Structure), and are also members of the Science Committee, the highest scientific organ in DES. In terms of analysis, three PhD students are leading crucial bits of the analysis, namely the calibration of the redshift distributions of weak lensing galaxies, using again both unsupervised learning and cross-correlation techniques, and that of the weak lensing magnification effect and the galaxy-galaxy lensing signal.

    Blanco Telescope, Cerro Tololo Observatory, Chile Credit: DES Collaboration

    The Legacy Survey of Space and Time (LSST)

    The Legacy Survey of Space and Time (LSST) at the new Vera C. Rubin Observatory in Chile is the natural continuation of DES and will become the preeminent imaging galaxy survey of this decade, being faster, wider and deeper than DES. Using a gigantic 3-billion-pixel camera, LSST will repeatedly scan half of the sky (20,000 sq. deg.) to reach a magnitude limit about iAB < 26 after 10 years of observations. This will provide a sample of over 3 billion galaxies for cosmological studies, particularly galaxy clustering and weak lensing, in which IFAE has a recognized expertise. Originally, IFAE joined LSST in 2016. A drastic change in admission conditions in 2019 brought a long and protracted negotiation that has just culminated in 2023. IFAE provides LSST with a data access center at PIC as well as significant software contributions, and it is participating in the commissioning of the camera, which is expected to start observations in late 2024.

    Credit: LSST

    The Dark Energy Spectroscopic Instrument (DESI)

    In May 2021, the Dark Energy Spectroscopic Instrument (DESI) started a 5-year campaign to obtain optical spectra of 40 million galaxies and quasars. These catalogs will enable precise measurements of the expansion rate of the Universe from z=0 to z=3.5, using the technique of Baryon Acoustic Oscillations (BAO). The same dataset will also be used to study the growth of structure across cosmic time, using the technique of Redshift Space Distortions (RSD). DESI is an international collaboration led by Berkeley Lab, that has built a multi object spectrograph for the Mayall 4-meter telescope, at Kitt Peak National Observatory (Arizona, US). DESI has an important hardware contribution from IFAE: the design, production and commissioning of the 10 Guiding, Focusing and Alignment (GFA) cameras, the only imaging instrument in DESI.

    Kitt Peak National Observatory
    Star trails over the Nicholas U. Mayall 4-meter Telescope on Kitt Peak National Observatory near Tucson, Arizona Credit: KPNO/NOIRLab/NSF/AURA/P. Marenfeld

    The first results using data from DESI are expected for Spring 2023, with two publications led by members of our group (Ramírez-Pérez et al. 2023, Gordon et al. 2023). The first BAO results are expected by the end of 2023, and the measurement at highest redshift will be co-led by Andreu Font-Ribera.

    Extended Baryon Oscillation Spectroscopic Survey (eBOSS)

    Prior to DESI, the state-of-the-art in BAO measurements from spectroscopic surveys were those from the extended Baryon Oscillation Spectroscopic Survey (eBOSS). Andreu Font-Ribera co-led the final BAO measurement at z>2 from eBOSS (du Mas de Bourboux et al. 2020) and was one of the 5 co-leads of the legacy cosmological analyses presented in eBOSS Collaboration et al. (2021). This last publication has already been cited more than 500 times. The important contributions of eBOSS to our understanding of the Universe were recently recognised by the European Physical Society (EPS) with the 2023 Giuseppe and Vanna Cocconi Prize.

    Kitt Peak National Observatory
    Nicholas U. Mayall 4-meter Telescope on Kitt Peak National Observatory near Tucson, Arizona Credit: KPNO/NOIRLab/NSF/AURA/P. Marenfeld

    Euclid

    Euclid is the first satellite mission dedicated to the study of the large-scale structure of the Universe, and it includes a photometric survey to study weak lensing (similar to DES and LSST), and a spectroscopic survey to measure BAO and RSD (similar to eBOSS and DESI). Euclid will dominate the field of dark-energy studies from space by measuring the shapes of over 1.5 billion galaxies down to magnitude 24.5 and the precise redshifts of over 50 million emission line galaxies. Euclid is expected to improve our knowledge on the cosmological model by an order of magnitude with respect to current constraints. IFAE led the development, construction and characterization of the Filter-Wheel Assembly (FWA) of the Near Infrared Spectrometer and Photometer (NISP), IFAE’s first flight-model space hardware. IFAE is currently involved in the redshift task force and weak lensing groups in Euclid.

    Artist's impression of the Euclid spacecraft.
    Artist's impression of the Euclid spacecraft. Credit: ESA/ATG medialab (spacecraft); NASA, ESA, CXC, C. Ma, H. Ebeling and E. Barrett (University of Hawaii/IfA), et al. and STScI (background)

    The PAU Survey (PAUS)

    The group also led the construction, commissioning and operation of PAUCam, a novel narrow-band imager with quasi-spectroscopical resolution installed at the William Herschel Telescope (WHT) in La Palma in 2015. Since then, the camera has surveyed the sky for 216 nights with an operation efficiency higher than 98%. The group has led several key publications of the PAU Survey (PAUS), demonstrating that PAUCam achieves the expected photo-z resolution. PAU was an entirely Spanish project until it started operations at the WHT. Since then, 5 groups in 4 European countries have joined, providing funds for operations in exchange for data rights.

    PAUCam
    The PAU camera installed on the William Herschel telescope at the Roque de los Muchachos Observatory in La Palma, Canary Islands. Credit: IFAE
  • Group Members

    Observational Cosmology Group

    Staff Researchers

    Postdoc Researchers

    • Santiago Avila

      Santiago Avila

    • Jonás Chaves

      Jonás Chaves

    • Hui Kong

      Hui Kong

    • Martine Lokken

      Martine Lokken

    • Carles Sánchez

      Carles Sánchez

    PhD Students

    • Laura Casas

      Laura Casas

    • Dane Cross

      Dane Cross

    • William d’Assignies D.

      William d’Assignies D.

    • Umut Demirbozan

      Umut Demirbozan

    • Calum Gordon

      Calum Gordon

    • Elisa Legnani

      Elisa Legnani

    • César Ramírez

      César Ramírez

    • Lucy Reynolds

      Lucy Reynolds

  • International Collaborations

    Observational Cosmology Group

    DES

    The Dark Energy Survey

    The Dark Energy Survey (DES) is a visible and near-infrared survey that aims to probe the dynamics of the expansion of the Universe and the growth of large-scale structure. The last data from DES were obtained in 2019, and we are currently working on the final analyses.

      Victor Blanco Telescope in Coquimbo, Chile
    Mayall

    DESI

    The Dark Energy Spectroscopic Instrument

    The Dark Energy Spectroscopic Instrument is a scientific research instrument for conducting a spectrographic astronomical surveys of distant galaxies. Its main components are a focal plane containing 5,000 fiber-positioning robots, and a bank of spectrographs which are fed by the fibers. DESI started its 5-year survey on May 2021, and we are currently working on the analysis of the first year of data.

      Kitt Peak, Arizona, USA
    Artist's impression of the Euclid spacecraft.

    Euclid

    Euclid

    Euclid is a visible to near-infrared space telescope led by the European Space Agency and the Euclid Consortium. The objective of the Euclid mission is to better understand dark energy and dark matter by accurately measuring the acceleration of the universe. The launch of the satellite is expected for July 2023.

     

    LSST

    Legacy Survey of Space and Time

    The Legacy Survey of Space and Time (LSST) at the new Vera C. Rubin Observatory in Chile will become the preeminent imaging galaxy survey of this decade. Using a gigantic 3-billion-pixel camera, LSST will repeatedly scan half of the sky (20,000 sq. deg.) to reach a magnitude limit about iAB < 26 after 10 years of observations.

      Cerro Pachon, Chile
    PAUCam

    PAU

    Physics of the Accelerating Universe

    The PAU (Physics of the Accelerating Universe) Survey goal is to obtain photometric redshifts (photo-z) and Spectral Energy Distribution (SED) of astronomical objects with a resolution roughly one order of magnitude better than current broad band photometric surveys.

      WHT Telescope, ORM, La Palma
  • Research Projects

    Observational Cosmology Group

    ERC-Consolidator, 2021

    A Cosmological Lever Arm for Fundamental Physics (COSMO-LYA)

    COSMO-LYA is a ERC Consolidator project that will use innovative techniques and new data from the Dark Energy Spectroscopic Instrument (DESI) to address some of the open questions in fundamental physics.COSMO-LYA will allow Andreu Font-Ribera and his team to use a large dataset of distant quasars to study some of the mysteries of our Universe: dark energy, inflation, and the mass of neutrinos.

    DES

    Proyectos I+D Generación de Conocimiento, 2021

    Cosmology and Fundamental Physics with Extragalactic Surveys - COSMOFUN

    This project aims to understand the nature of dark energy through the analysis of data from extragalactic surveys such as DES, PAU, DESI, Euclid, and LSST. The group works on basic science related to these surveys, develops analysis tools, and uses cosmological simulations to test and verify the programs. The project seeks funding to obtain scientific results from DES data and contribute to the scientific analysis of PAU and DESI. Project coordinated by IFAE. Project coordinated by IFAE.

      Starry Night

      Plan Complementario, 2021

      Tecnologías avanzadas para la exploración del universo

      The main objective of this proposal is to make a qualitative leap in Spanish participation in the next generation of leading international projects in astrophysics and high energy physics, with an emphasis particularly in the most technological aspects. The Institut de Física d’ALtes Energies (IFAE) has been chosen to be the national coordinator of the Plan Complementario for Astrophysics and High Energy Physics, a strategic program that aims to develop advanced technologies for the exploration of the Universe and its components.

      Artist's impression of the Euclid spacecraft.

      Programa Estatal de I+D+i Orientada a los Retos de la Sociedad, 2019

      Cartografiados Extragalacticos para el estudio de la Energia Oscura, preparacion para Euclid y futuras misiones

      The Euclid mission is an extragalactic survey from space approved by the European Space Agency to understand the matter and energy content of the Universe and the nature of cosmic accelerated expansion. This project aims to fulfill Spanish commitments to the Euclid mission and involves investigating basic science related to the survey, developing analysis tools, contributing to the Euclid payload and the Science Ground Segment, and leading the Euclid Simulations Working Group, among other tasks. project Coordinated by IFAE.

        Programa Estatal de I+D+i Orientada a los Retos de la Sociedad, 2019

        Centro de Datos para Cosmologia de Energia Oscura - Euclid

        The "Data Center for Dark Energy Cosmology - Euclid" sub-project provides data production, processing, and analysis for DES, PAU, and Euclid, with a focus on developing and maintaining SIM pipelines for Euclid simulations. PIC plays a pivotal role in producing synthetic galaxy catalogs and supports PAU as its reference data center while also providing infrastructure and developing science pipelines for DES, LSST, and other relevant projects. project coordinated by IFAE.

          Asteroid

          H2020-COMPET, 2018

          ASTronomy EuROpean Infrared Detection (Asteroid)

          ASTEROID is an EU funded H2020-COMPET project whose main objective is to provide Europe with the capability to manufacture high performance infrared 2k2 Focal Plane Arrays of 15 µm pitch pixels that can be used in scientific and astronomical space and ground telescope missions.

          DES

          Proyectos I+D Generación de Conocimiento, 2018

          Cosmology and Fundamental Physics with Extragalactic Surveys - COSMOFUN

          This project aims to understand the nature of dark energy through the analysis of data from extragalactic surveys such as DES, PAU, DESI, Euclid, and LSST. The group works on basic science related to these surveys, develops analysis tools, and uses cosmological simulations to test and verify the programs. The project seeks funding to obtain scientific results from DES data and contribute to the scientific analysis of PAU and DESI. Project coordinated by IFAE. Project coordinated by IFAE.

            EWC

            H2020-COMPET, 2018

            Enabling Weak lensing Cosmology (EWC)

            Enabling Weak lensing Cosmology (EWC) is a team of cosmologists working across Europe to prepare for the next generation of astronomical data that will come from the European Space Agency Euclid mission.

          • Publications

            Observational Cosmology Group

          • Instrumentation Projects

            Observational Cosmology Group

            PAUCam

            PAUCam

            IFAE led the construction of the innovative PAU astronomical camera, PAUCam, that operates as a Visitor’s Instrument at the prime focus of the William Herschel Telescope (WHT) in the Canary Island of La Palma. The distinctive feature of PAUS is the ability to measure redshift of galaxies by photometric methods, with roughly an order of magnitude higher accuracy than that provided by other past and existing photometric surveys.

            Dark Energy Camera (DECam)

            The Dark Energy Camera (DECam) is mounted on the Victor M. Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory (CTIO) in the Chilean Andes. IFAE led the development and production of the read-out electronics for the DECam, the leading astronomical camera at the time (2012).

          • Group News

            New Member

            New Member in the Cosmology group

            November 1, 2023

            Martine Lokken has just joined the Observational Cosmology group as Postdoc researcher.

            New Member

            New Member in the Theory group

            November 1, 2023

            Juan Sebastián Valbuena has just joined the Theory group as Postdoc researcher.

            New Member

            New Member in the Cosmology group

            October 4, 2023

            Laura Casas has just joined IFAE as a PhD student in the Observational Cosmology Group.

            Outreach

            New Planetarium show - '5000 Eyes: Mapping the Universe with DESI'

            June 13, 2023

            A stunning documentary film featuring recent discoveries from the Dark Energy Spectroscopic Instrument (DESI) has been released to planetariums worldwide. A catalan version of this new documentary has been produced by the ERC COSMO-LYA project in collaboration with the UAB.

            Visit

            IFAE members visit Euclid at Thales Cannes

            March 1, 2023

            Cristobal Padilla and PhD student William d’Assignies, visited the Euclid space telescope at Thales Cannes on February 22, with eighty members of the European collaboration.

            New Publication

            New Cosmology group paper

            January 12, 2023

            Cosmological Fisher forecasts for next-generation spectroscopic surveys ” by William Doumerg and collaborators has been uploaded to arXiv.