Constraints on the Hubble constant from supernova Refsdal’s reappearance
Patrick L. Kelly, S. Rodney, Tommaso Treu, Masamune Oguri, Wenlei Chen, Adi Zitrin, Simon Birrer, V. Bonvin, Luc Dessart, J. M. Diego, A. V. Filippenko, R. J. Foley, Daniel Gilman, J. Hjorth, Mathilde Jauzac, Kaisey S. Mandel, Martin Millon, Justin Pierel, Keren Sharon, Stephen Thorp, Liliya L. R. Williams, Tom Broadhurst, Alan Dressler, Or Graur, Saurabh W. Jha, C. McCully, Marc Postman, Kasper Borello Schmidt, B. Tucker, Anja von der Linden
Abstract
The gravitationally lensed supernova Refsdal appeared in multiple images produced through gravitational lensing by a massive foreground galaxy cluster. After the supernova appeared in 2014, lens models of the galaxy cluster predicted that an additional image of the supernova would appear in 2015, which was subsequently observed. We use the time delays between the images to perform a blinded measurement of the expansion rate of the Universe, quantified by the Hubble constant ( H 0 ). Using eight cluster lens models, we infer <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>H</mml:mi> <mml:mn>0</mml:mn> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>64.8</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>4.3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>4.4</mml:mn> </mml:mrow> </mml:msubsup> <mml:mtext> kilometers per second per megaparsec</mml:mtext> </mml:mrow> </mml:math> . Using the two models most consistent with the observations, we find <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:msub> <mml:mi>H</mml:mi> <mml:mn>0</mml:mn> </mml:msub> <mml:mo>=</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>66.6</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3.3</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>4.1</mml:mn> </mml:mrow> </mml:msubsup> <mml:mtext> kilometers per second per megaparsec</mml:mtext> </mml:mrow> </mml:math> . The observations are best reproduced by models that assign dark-matter halos to individual galaxies and the overall cluster.