Peering into the dark (ages) with low-frequency space interferometers: Using the 21-cm signal of neutral hydrogen from the infant universe to probe fundamental (Astro)physics

Léon V E Koopmans; Rennan Barkana; Mark Bentum; Gianni Bernardi; Albert-Jan Boonstra; Judd Bowman; Jack Burns; Xuelei Chen; Abhirup Datta; Heino Falcke; Anastasia Fialkov; Bharat Gehlot; Leonid Gurvits; Vibor Jelić; Marc Klein-Wolt; Joseph Lazio; Daan Meerburg; Garrelt Mellema; Florent Mertens; Andrei Mesinger; André Offringa; Jonathan Pritchard; Benoit Semelin; Ravi Subrahmanyan; Joseph Silk; Cathryn Trott; Harish Vedantham; Licia Verde; Saleem Zaroubi; Philippe Zarka

doi:10.1007/s10686-021-09743-7

Peering into the dark (ages) with low-frequency space interferometers: Using the 21-cm signal of neutral hydrogen from the infant universe to probe fundamental (Astro)physics

Exp Astron (Dordr). 2021;51(3):1641-1676. doi: 10.1007/s10686-021-09743-7. Epub 2021 Sep 3.

Authors

Léon V E Koopmans¹, Rennan Barkana², Mark Bentum^{3

4}, Gianni Bernardi^{5

6}, Albert-Jan Boonstra⁴, Judd Bowman⁷, Jack Burns⁸, Xuelei Chen⁹, Abhirup Datta¹⁰, Heino Falcke¹¹, Anastasia Fialkov¹², Bharat Gehlot⁷, Leonid Gurvits¹³, Vibor Jelić¹⁴, Marc Klein-Wolt¹¹, Joseph Lazio¹⁵, Daan Meerburg¹⁶, Garrelt Mellema¹⁷, Florent Mertens^{1

18}, Andrei Mesinger¹⁹, André Offringa⁴, Jonathan Pritchard²⁰, Benoit Semelin¹⁸, Ravi Subrahmanyan²¹, Joseph Silk^{22

23}, Cathryn Trott²⁴, Harish Vedantham⁴, Licia Verde²⁵, Saleem Zaroubi^{1

26}, Philippe Zarka¹⁸

Affiliations

¹ Kapteyn Astronomical Institute, University of Groningen, Groningen, Netherlands.
² Tel-Aviv University, Tel Aviv, Israel.
³ Eindhoven University of Technology, Eindhoven, Netherlands.
⁴ ASTRON, Dwingeloo, Netherlands.
⁵ INAF, Bologna, Italy.
⁶ SKAO-SA, Cape Town, South Africa.
⁷ Arizona State University, Tempe, AZ USA.
⁸ University of Colorado Boulder, Boulder, CO USA.
⁹ NAOC, Beijing, China.
¹⁰ IIT Indore, Indore, India.
¹¹ Radboud University, Nijmegen, Netherlands.
¹² IoA, University of Cambridge, Cambridge, UK.
¹³ JIVE and Delft University of Technology, Delft, Netherlands.
¹⁴ Institut Ruđer Bošković, Zagreb, Croatia.
¹⁵ JPL, Caltech, Pasadena, CA USA.
¹⁶ VSI, University of Groningen, Groningen, Netherlands.
¹⁷ Stockholm University, Stockholm, Sweden.
¹⁸ Observatoire de Paris, Paris, France.
¹⁹ Scuola Normale Superiore, Pisa, Italy.
²⁰ Imperial College, London, UK.
²¹ Raman Research Institute, Bengaluru, India.
²² Institut d'astrophysique de Paris, Paris, France.
²³ University of Oxford, Oxford, UK.
²⁴ Curtin University, Perth, Australia.
²⁵ Institute of Cosmological Sciences, Barcelona, Spain.
²⁶ Open University of Israel, Ra'anana, Israel.

Abstract

The Dark Ages and Cosmic Dawn are largely unexplored windows on the infant Universe (z ~ 200-10). Observations of the redshifted 21-cm line of neutral hydrogen can provide valuable new insight into fundamental physics and astrophysics during these eras that no other probe can provide, and drives the design of many future ground-based instruments such as the Square Kilometre Array (SKA) and the Hydrogen Epoch of Reionization Array (HERA). We review progress in the field of high-redshift 21-cm Cosmology, in particular focussing on what questions can be addressed by probing the Dark Ages at z > 30. We conclude that only a space- or lunar-based radio telescope, shielded from the Earth's radio-frequency interference (RFI) signals and its ionosphere, enable the 21-cm signal from the Dark Ages to be detected. We suggest a generic mission design concept, CoDEX, that will enable this in the coming decades.

Keywords: 21-cm cosmology; Cosmic dawn; Dark ages; Epoch of reionization; Space or lunar-based radio telescopes.