Measurements of the dependence of stellar specific angular momentum (j∗) on stellar mass (M∗) are presented for large samples of ALFALFA galaxies spanning the stellar mass range ∼108-1011 M⊙. Accurate estimates of j∗ are generated using measurements of I-band effective radius and velocity width of the HI line profile. While the full sample (N=3 607) of galaxies yields a j∗-M∗ relation with power-law index α=0.404±0.03, it is shown that various sub-samples have indices that are very similar to the best literature results, yet with comparatively lower intrinsic scatters. A galaxy’s mean I-band surface brightness within its effective radius (<μeff>) is shown to significantly correlate with j∗-M∗ scatter. A 3D plane fit to all N=3 607 galaxies in log10j∗-log10M∗-<μeff> space yields j∗∝M0.589±0.002∗<μeff>0.193±0.002 with scatter σ=0.089 dex. <μeff>-selected sub-samples of size up to N=1 450 yield power-law j∗-M∗ relations mostly consistent with α=0.55±0.02 from the literature and with intrinsic scatter ranging from 0.083 to 0.129 dex. Thus, this paper presents new, highly accurate measurements of the j∗-M∗ relation that can be used to better understand the important roles played by angular momentum in the formation and evolution of galaxies.
Reference: On the existence of a tight planar relation between stellar specific angular momentum, mass and effective surface brightness for ALFALFA galaxies, E. Elson, Submitted on MNRAS, arXiv:2310.17916