A shallow slope for the stellar mass-angular momentum relation of star-forming galaxies at 1.5 < <i>z</i> < 2.5

Juan M. Espejo Salcedo, Karl Glazebrook, Deanne B. Fisher, Sarah M. Sweet, Danail Obreschkow, N. M. Foerster Schreiber

Research output: Contribution to journalArticlepeer-review

Abstract

We present measurements of the specific angular momentum j(star) of 41 star-forming galaxies at 1.5 < z < 2.5. These measurements are based on radial profiles inferred from near-infrared Hubble Space Telescope photometry, along with multiresolution emission-line kinematic modelling using integral field spectroscopy (IFS) data from K-band multi-object spectrograph, Spectrograph for Integral Field Observations in the Near Infrared, and OH-Suppressing Infra-Red Imaging Spectrograph. We identified 24 discs (disc fraction of 58.6 +/- 7.7 per cent) and used them to parametrize the j(star) versus stellar mass M-star relation (Fall relation) as j(star) proportional to M-star(beta). We measure a power-law slope beta=0.25 +/- 0.15, which deviates by approximately 3 sigma from the commonly adopted local value beta=0.67, indicating a statistically significant difference. We find that two key systematic effects could drive the steep slopes in previous high-redshift studies: first, including irregular (non-disc) systems due to limitations in spatial resolution and second, using the commonly used approximation (j) over tilde (star) approximate to k(n)v(s)r(eff), which depends on global unresolved quantities. In our sample, both effects lead to steeper slopes of beta=0.48 +/- 0.21 and 0.61 +/- 0.21, respectively. To understand the shallow slope, we discuss observational effects and systematic uncertainties and analyse the retention of j(star) relative to the angular momentum of the halo j(h) (angular momentum retention factor f(j) = j(star)/j(h)). For the M-star range covered by the sample 9.5 < log(10) (M-star/M-circle dot) < 11.5 (halo mass 11.5 < log(10) (M-h/M-circle dot) < 14), we find large f(j) values (>1 in some cases) in low-mass haloes that decrease with increasing mass, suggesting a significant role of efficient angular momentum transport in these gas-rich systems, aided by the removal of low-j(star) gas via feedback-driven outflows in low-mass galaxies.
Original languageEnglish
Pages (from-to)1188-1216
Number of pages29
JournalMonthly Notices of the Royal Astronomical Society
Volume536
Issue number2
DOIs
Publication statusPublished - Jan 2025

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