Constraining the intergalactic medium at z ≈ 9.1 using LOFAR Epoch of Reionization observations
Monthly Notices of the Royal Astronomical Society, vol. 493, pp. 4728–4747
Abstract
ABSTRACT We derive constraints on the thermal and ionization states of the intergalactic medium (IGM) at redshift ≈ 9.1 using new upper limits on the 21-cm power spectrum measured by the LOFAR radio telescope and a prior on the ionized fraction at that redshift estimated from recent cosmic microwave background (CMB) observations. We have used results from the reionization simulation code grizzly and a Bayesian inference framework to constrain the parameters which describe the physical state of the IGM. We find that, if the gas heating remains negligible, an IGM with ionized fraction ≳0.13 and a distribution of the ionized regions with a characteristic size ≳ 8 h−1 comoving megaparsec (Mpc) and a full width at half-maximum (FWHM) ≳16 h−1 Mpc is ruled out. For an IGM with a uniform spin temperature TS ≳ 3 K, no constraints on the ionized component can be computed. If the large-scale fluctuations of the signal are driven by spin temperature fluctuations, an IGM with a volume fraction ≲0.34 of heated regions with a temperature larger than CMB, average gas temperature 7–160 K, and a distribution of the heated regions with characteristic size 3.5–70 h−1 Mpc and FWHM of ≲110 h−1 Mpc is ruled out. These constraints are within the 95 per cent credible intervals. With more stringent future upper limits from LOFAR at multiple redshifts, the constraints will become tighter and will exclude an increasingly large region of the parameter space.
Authors 22
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Raghunath Ghara corresponding
Stockholm University · Open University of Israel · Technion – Israel Institute of Technology · AlbaNova
Affiliation as printed
Department of Natural Sciences, The Open University of Israel, 1 University Road, PO Box 808, Ra’anana 4353701, Israel
Department of Physics, Technion, Haifa 32000, Israel
The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE-10691 Stockholm, Sweden
Department of Natural Sciences, The Open University of Israel, 1 University Road, PO Box 808, Ra'anana 4353701, Israel
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Sambit K. Giri corresponding
Stockholm University · University of Zurich · AlbaNova
Affiliation as printed
Institute for Computational Science, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE-10691 Stockholm, Sweden
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Stockholm University · AlbaNova
Affiliation as printed
The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, SE-10691 Stockholm, Sweden
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Max Planck Institute for Astrophysics
Affiliation as printed
Max-Planck Institute for Astrophysics, Karl-Schwarzschild-Straße 1, D-85748 Garching, Germany
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Open University of Israel · University of Groningen · Technion – Israel Institute of Technology
Affiliation as printed
Department of Natural Sciences, The Open University of Israel, 1 University Road, PO Box 808, Ra’anana 4353701, Israel
Department of Physics, Technion, Haifa 32000, Israel
Kapteyn Astronomical Institute, University of Groningen, PO Box 800, NL-9700AV Groningen, the Netherlands
Department of Natural Sciences, The Open University of Israel, 1 University Road, PO Box 808, Ra'anana 4353701, Israel
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Affiliation as printed
Astronomy Centre, Department of Physics and Astronomy, Pevensey II Building, University of Sussex, Brighton BN1 9QH, UK
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Affiliation as printed
Kapteyn Astronomical Institute, University of Groningen, PO Box 800, NL-9700AV Groningen, the Netherlands
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Affiliation as printed
Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ, UK
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Affiliation as printed
Kapteyn Astronomical Institute, University of Groningen, PO Box 800, NL-9700AV Groningen, the Netherlands
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University of Groningen · Arizona State University
Affiliation as printed
Kapteyn Astronomical Institute, University of Groningen, PO Box 800, NL-9700AV Groningen, the Netherlands
School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA
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South African Radio Astronomy Observatory · Banwarilal Bhalotia College · University of the Western Cape
Affiliation as printed
Department of Physics, Banwarilal Bhalotia College, Asansol, West Bengal, India
Department of Physics, University of the Western Cape, Cape Town 7535, South Africa
SARAO, 2 Fir Street, Black River Park, Observatory, Capetown, South Africa
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Affiliation as printed
Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
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Centre National de la Recherche Scientifique · University of Groningen · Université Paris Sciences et Lettres · Observatoire de Paris · Sorbonne Université · Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères
Affiliation as printed
Kapteyn Astronomical Institute, University of Groningen, PO Box 800, NL-9700AV Groningen, the Netherlands
LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, F-75014 Paris, France
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Affiliation as printed
Astronomy Centre, Department of Physics and Astronomy, Pevensey II Building, University of Sussex, Brighton BN1 9QH, UK
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Leiden University · Leiden Observatory
Affiliation as printed
Leiden Observatory, Leiden University, PO Box 9513, NL-2300RA Leiden, the Netherlands
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Affiliation as printed
Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029 Blindern, N-0315 Oslo, Norway
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Independent University, Bangladesh
Affiliation as printed
Independent University Bangladesh, Plot 16, Block B, Aftabuddin Ahmed Road, Bashundhara R/A, Dhaka, Bangladesh
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Kavli Institute for the Physics and Mathematics of the Universe · University of Groningen · The University of Tokyo
Affiliation as printed
Kapteyn Astronomical Institute, University of Groningen, PO Box 800, NL-9700AV Groningen, the Netherlands
Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan
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Netherlands Institute for Radio Astronomy
Affiliation as printed
ASTRON, PO Box 2, NL-7990 AA Dwingeloo, the Netherlands
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University of Groningen · Netherlands Institute for Radio Astronomy
Affiliation as printed
ASTRON, PO Box 2, NL-7990 AA Dwingeloo, the Netherlands
Kapteyn Astronomical Institute, University of Groningen, PO Box 800, NL-9700AV Groningen, the Netherlands
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University of Groningen · Netherlands Institute for Radio Astronomy
Affiliation as printed
ASTRON, PO Box 2, NL-7990 AA Dwingeloo, the Netherlands
Kapteyn Astronomical Institute, University of Groningen, PO Box 800, NL-9700AV Groningen, the Netherlands
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Netherlands Institute for Radio Astronomy
Affiliation as printed
ASTRON, PO Box 2, NL-7990 AA Dwingeloo, the Netherlands
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