Extending the supernova Hubble diagram to z ~ 1.5 with the Euclid space mission

¹ LPNHE, CNRS/IN2P3, Université Pierre et Marie Curie Paris 6, Université Denis Diderot Paris 7, 4 place Jussieu, 75252 Paris Cedex 5, France
e-mail: pierre.astier@in2p3.fr
² INAF, Capodimonte Astronomical Observatory, via Moiariello 16, 80131 Naples, Italy
³ INAF–Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
⁴ Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto ON M5S 3H4, Canada
⁵ Dept. of Physics, University Federico II, via Cinthia, 80126 Naples, Italy
⁶ International Center for Relativistic Astrophysics, Piazza Repubblica, 10, 65122 Pescara, Italy
⁷ Clermont Université, Université Blaise Pascal, CNRS/IN2P3, Laboratoire de Physique Corpusculaire, BP 10448, 63000 Clermont-Ferrand, France
⁸ Albanova University Center, Department of Physics, Stockholm University, Roslagstullsbacken 21, 106 91 Stockholm, Sweden
⁹ Department of Physics (Astrophysics), University of Oxford, DWB, Keble Road, Oxford OX1 3RH, UK
¹⁰ INAF–Osservatorio Astronomico di Roma, via Frascati 33, 00040 Monteporzio ( RM), Italy
¹¹ Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA
¹² Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue Chicago, IL 60637, USA
¹³ LBNL, 1 Cyclotron Rd, Berkeley CA 94720, USA
¹⁴ University of California Berkeley, CA 94720 USA
¹⁵ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
¹⁶ INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
¹⁷ Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, 21500 Piikkiö, Finland
¹⁸ Institute of Cosmology & Gravitation, University of Portsmouth, Portsmouth PO1 3FX, UK
¹⁹ School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, UK
²⁰ CPPM, Université Aix-Marseille, CNRS/IN2P3, Case 907, 13288 Marseille Cedex 9, France
²¹ Tsinghua center for astrophysics, Physics department, Tsinghua University, 100084 Beijing, PR China
²² PITT PACC, Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh PA 15260, USA

Received: 31 January 2014
Accepted: 26 September 2014

Abstract

We forecast dark energy constraints that could be obtained from a new large sample of Type Ia supernovae where those at high redshift are acquired with the Euclid space mission. We simulate a three-prong SN survey: a z < 0.35 nearby sample (8000 SNe), a 0.2 < z < 0.95 intermediate sample (8800 SNe), and a 0.75 < z < 1.55 high-z sample (1700 SNe). The nearby and intermediate surveys are assumed to be conducted from the ground, while the high-z is a joint ground- and space-based survey. This latter survey, the “Dark Energy Supernova Infra-Red Experiment” (DESIRE), is designed to fit within 6 months of Euclid observing time, with a dedicated observing programme. We simulate the SN events as they would be observed in rolling-search mode by the various instruments, and derive the quality of expected cosmological constraints. We account for known systematic uncertainties, in particular calibration uncertainties including their contribution through the training of the supernova model used to fit the supernovae light curves. Using conservative assumptions and a 1D geometric Planck prior, we find that the ensemble of surveys would yield competitive constraints: a constant equation of stateparameter can be constrained to σ(w) = 0.022, and a Dark Energy Task Force figure of merit of 203 is found for a two-parameter equation of state. Our simulations thus indicate that Euclid can bring a significant contribution to a purely geometrical cosmology constraint by extending a high-quality SN Ia Hubble diagram to z ~ 1.5. We also present other science topics enabled by the DESIRE Euclid observations.