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Abstract We present the construction of a deep multiwavelength point-spread-function-matched photometric catalog in the Ultra-Deep Survey (UDS) field following the final UKIDSS UDS release. The catalog includes photometry in 24 filters, from the MegaCam-uS0.38μm band to the Spitzer-IRAC 8μm band, over ∼0.9 deg²and with a 5σdepth of 25.3 AB in theK-band detection image. The catalog, containing ≈188,564 (136,235) galaxies at 0.2 <z< 8.0 with stellar mass $\log \left(M_{*}/M_{\odot }\right)>8$andK-band total magnitudeK< 25.2 (24.3) AB, enables a range of extragalactic studies. We also provide photometric redshifts, corresponding redshift probability distributions, and rest-frame absolute magnitudes and colors derived using the template-fitting codeeazy-py. Photometric redshift errors are less than 3%−4% atz< 4 across the full brightness range in theKband and stellar mass range $8<\log \left(M_{*}/M_{\odot }\right)<12$. Stellar population properties (e.g., stellar mass, star formation rate, dust extinction) are derived from the modeling of the spectral energy distributions using the codesFASTand Dense Basis. 

Abstract In this work, we publish stellar velocity dispersions, sizes, and dynamical masses for eight ultramassive galaxies (UMGs; $\log \left(M_{*}/M_{\odot }\right)$> 11),z≳ 3) from the Massive Ancient Galaxies Atz> 3 NEar-infrared (MAGAZ3NE) Survey, more than doubling the number of such galaxies with velocity dispersion measurements at this epoch. Using the deep Keck/MOSFIRE and Keck/NIRES spectroscopy of these objects in theHandKbandpasses, we obtain large velocity dispersions of ∼400 km s⁻¹for most of the objects, which are some of the highest stellar velocity dispersions measured and ∼40% larger than those measured for galaxies of similar mass atz∼ 1.7. The sizes of these objects are also smaller by a factor of 1.5–3 compared to this samez∼ 1.7 sample. We combine these large velocity dispersions and small sizes to obtain dynamical masses. The dynamical masses are similar to the stellar masses of these galaxies, consistent with a Chabrier initial mass function (IMF). Considered alongside previous studies of massive quiescent galaxies across 0.2 <z< 4.0, there is evidence for an evolution in the relation between the dynamical mass–stellar mass ratio and velocity dispersion as a function of redshift. This implies an IMF with fewer low-mass stars (e.g., Chabrier IMF) for massive quiescent galaxies at higher redshifts in conflict with the bottom-heavy IMF (e.g., Salpeter IMF) found in their likelyz∼ 0 descendants, though a number of alternative explanations such as a different dynamical structure or significant rotation are not ruled out. Similar to data at lower redshifts, we see evidence for an increase of IMF normalization with velocity dispersion, though thez≳ 3 trend is steeper than that forz∼ 0.2 early-type galaxies and offset to lower dynamical-to-stellar mass ratios.