Gravitational lensing reveals ionizing ultraviolet photons escaping from a distant galaxy

T Emil Rivera-Thorsen; Håkon Dahle; John Chisholm; Michael K Florian; Max Gronke; Jane R Rigby; Michael D Gladders; Guillaume Mahler; Keren Sharon; Matthew Bayliss

doi:10.1126/science.aaw0978

Gravitational lensing reveals ionizing ultraviolet photons escaping from a distant galaxy

Science. 2019 Nov 8;366(6466):738-741. doi: 10.1126/science.aaw0978.

Authors

T Emil Rivera-Thorsen¹, Håkon Dahle², John Chisholm^{3 4}, Michael K Florian⁵, Max Gronke⁶, Jane R Rigby⁵, Michael D Gladders^{7 8}, Guillaume Mahler⁹, Keren Sharon⁹, Matthew Bayliss^{10 11}

Affiliations

¹ Institute of Theoretical Astrophysics, University of Oslo, 0315 Oslo, Norway. trive@astro.su.se.
² Institute of Theoretical Astrophysics, University of Oslo, 0315 Oslo, Norway.
³ Observatoire de Genève, Université de Genève, 1290 Versoix, Switzerland.
⁴ Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA.
⁵ Observational Cosmology Lab, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.
⁶ Department of Physics, University of California, Santa Barbara, CA 93106, USA.
⁷ Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637, USA.
⁸ Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637, USA.
⁹ Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA.
¹⁰ Massachusetts Institute of Technology-Kavli Center for Astrophysics and Space Research, Cambridge, MA 02139, USA.
¹¹ Department of Physics, University of Cincinnati, Cincinnati, OH 45221, USA.

PMID: 31699936
DOI: 10.1126/science.aaw0978

Abstract

During the epoch of reionization, neutral gas in the early Universe was ionized by hard ultraviolet radiation emitted by young stars in the first galaxies. To do so, ionizing ultraviolet photons must escape from the host galaxy. We present Hubble Space Telescope observations of the gravitationally lensed post-reionization galaxy PSZ1-ARC G311.6602-18.4624 (nicknamed the "Sunburst Arc"), revealing bright, multiply imaged ionizing photon escape from a compact star-forming region through a narrow channel in an optically thick gas. The gravitational lensing magnification shows how ionizing photons escape this galaxy, contributing to the reionization of the Universe. The multiple sight lines to the source probe absorption by intergalactic neutral hydrogen on a scale of less than a few hundred parsecs.