Letter to the Editor

The angular momentum of disc galaxies at z = 1

¹ Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands
e-mail: marasco@astro.rug.nl
² ASTRON, Netherlands Institute for Radio Astronomy, Oude Hoogeveensedijk 4, 7991 PD Dwingeloo, The Netherlands
³ Research School of Astronomy and Astrophysics – The Australian National University, Canberra, ACT 2611, Australia

Received: 18 October 2018
Accepted: 20 December 2018

Abstract

We investigate the relation between stellar mass (M_⋆) and specific stellar angular momentum (j_⋆), or “Fall relation”, for a sample of 17 isolated, regularly rotating disc galaxies at z ∼ 1. All galaxies have rotation curves determined from Hα emission-line data; HST imaging in optical and infrared filters; and robust determinations of their stellar masses. We use HST images in f814w and f160w filters, roughly corresponding to rest-frames B and I bands, to extract surface-brightness profiles for our systems. We robustly bracket j_⋆ by assuming that rotation curves beyond the outermost Hα rotation point stay either flat or follow a Keplerian fall-off. By comparing our measurements with those determined for disc galaxies in the local universe, we find no evolution in the Fall relation in the redshift range 0 <  z <  1, regardless of the band used and despite the uncertainties in the stellar rotation curves at large radii. This result holds unless stellar masses at z = 1 are systematically underestimated by ≳50%. Our findings are compatible with expectations based on a ΛCDM cosmological framework and support a scenario where both the stellar Tully–Fisher and mass-size relations for spirals do not evolve significantly in this redshift range.