Kinematic scaling relations of disc galaxies from ionised gas at <i>z</i>   ∼  1 and their connection with dark matter haloes

We derive the Tully-Fisher (TFR; M * − V circ, f ) and Fall (FR; j * − M * ) relations at redshift z = 0.9 using a sample of 43 main-sequence disc galaxies with H α IFU data and JWST/HST imaging. The strength of our analysis lies in the use of state-of-the-art 3D kinematic models to infer galaxy rotation curves, the inclusion of near-IR bands and their morphological modelling, and the application of homogeneous spectral energy distribution modelling to our photometry measurements to estimate stellar masses. After correcting the inferred H α velocities for asymmetric drift, we find a TFR of the form log( M * / M ⊙ ) = a log( V circ,f / 150 km s −1 + b , with a = 3.82 −0.40 +0.55 and b = 10.27 −0.07 +0.06 , as well as a FR of the form log( j * /kpc km s −1 ) = a log( M * /10 10.5 M ⊙ )+ b , with a = 0.44 −0.06 +0.06 and b = 2.86 −0.02 +0.02 . Compared with their z = 0 counterparts, we found moderate evolution in the TFR and strong evolution in the FR over the past 8 Gyr. We interpreted our findings in the context of the galaxy-to-halo scaling parameters f M = M * / M vir and f j = j * / j vir . We inferred that f j shows little redshift evolution and depends very weakly on M * , with typical values around f j ∼ 0.8. As for f M , we find it to be higher and less dependent on M * at z = 0.9 than at z = 0. We discuss how interpreting our observed f M − M * relations within the cold dark matter framework implies necessarily that the galaxy populations at z = 0.9 and z = 0 are not the progenitor nor descendant of one another. The alternative scenario is that the z = 0.9 scaling relations are incorrect due to strong selection effects, unidentified systematics, or the possibility that H α kinematics may not be a reliable dynamical tracer. Such problems would affect not only our work but also previous studies on the same subject.