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1. The Massive and Distant Clusters of WISE Survey. V. Extended Radio Sources in Massive Galaxy Clusters at z ∼ 1

   https://doi.org/10.3847/1538-4357/aaf569  

   Moravec, Emily ; Gonzalez, Anthony H. ; Stern, Daniel ; Brodwin, Mark ; Clarke, Tracy ; Decker, Bandon ; Eisenhardt, Peter R. ; Mo, Wenli ; O’Donnell, Christine ; Pope, Alexandra ; et al ( February 2019 , The Astrophysical Journal)
2. Dynamical masses and mass-to-light ratios of resolved massive star clusters – II. Results for 26 star clusters in the Magellanic Clouds

   https://doi.org/10.1093/mnras/stab1065  

   Song, Ying-Yi ; Mateo, Mario ; Bailey, John I ; Walker, Matthew G ; Roederer, Ian U ; Olszewski, Edward W ; Reiter, Megan ; Kremin, Anthony ( May 2021 , Monthly Notices of the Royal Astronomical Society)

   null (Ed.)

   ABSTRACT We present spectroscopy of individual stars in 26 Magellanic Cloud (MC) star clusters with the aim of estimating dynamical masses and V-band mass-to-light (M/LV) ratios over a wide range in age and metallicity. We obtained 3137 high-resolution stellar spectra with M2FS on the Magellan/Clay Telescope. Combined with 239 published spectroscopic results of comparable quality, we produced a final sample of 2787 stars with good quality spectra for kinematic analysis in the target clusters. Line-of-sight velocities measured from these spectra and stellar positions within each cluster were used in a customized expectation-maximization (EM) technique to estimate cluster membership probabilities. Using appropriate cluster structural parameters and corresponding single-mass dynamical models, this technique ultimately provides self-consistent total mass and M/LV estimates for each cluster. Mean metallicities for the clusters were also obtained and tied to a scale based on calcium IR triplet metallicities. We present trends of the cluster M/LV values with cluster age, mass, and metallicity, and find that our results run about 40 per cent on average lower than the predictions of a set of simple stellar population (SSP) models. Modified SSP models that account for internal and external dynamical effects greatly improve agreement with our results, as can models that adopt a strongly bottom-light IMF. To the extent that dynamical evolution must occur, a modified IMF is not required to match data and models. In contrast, a bottom-heavy IMF is ruled out for our cluster sample as this would lead to higher predicted M/LV values, significantly increasing the discrepancy with our observations. 

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3. Galaxy populations in the most distant SPT-SZ clusters: II. Galaxy structural properties in massive clusters at 1.4 ≲ z ≲ 1.7

   https://doi.org/10.1051/0004-6361/202245268  

   Strazzullo, V. ; Pannella, M. ; Mohr, J. J. ; Saro, A. ; Ashby, M. L. ; Bayliss, M. B. ; Canning, R. E. ; Floyd, B. ; Gonzalez, A. H. ; Khullar, G. ; et al ( January 2023 , Astronomy & Astrophysics)

   We investigate structural properties of massive galaxy populations in the central regions (< 0.7  r 500 ) of five very massive ( M 200  > 4 × 10 14   M ⊙ ), high-redshift (1.4 ≲  z  ≲ 1.7) galaxy clusters from the 2500 deg 2 South Pole Telescope Sunyaev Zel’dovich effect (SPT-SZ) survey. We probe the connection between galaxy structure and broad stellar population properties at stellar masses of log( M / M ⊙ ) > 10.85. We find that quiescent and star-forming cluster galaxy populations are largely dominated by bulge- and disk-dominated sources, respectively, with relative contributions being fully consistent with those of field counterparts. At the same time, the enhanced quiescent galaxy fraction observed in these clusters with respect to the coeval field is reflected in a significant morphology-density relation, with bulge-dominated galaxies already clearly dominating the massive galaxy population in these clusters at z  ∼ 1.5. At face value, these observations show no significant environmental signatures in the correlation between broad structural and stellar population properties. In particular, the Sersic index and axis ratio distribution of massive, quiescent sources are consistent with field counterparts, in spite of the enhanced quiescent galaxy fraction in clusters. This consistency suggests a tight connection between quenching and structural evolution towards a bulge-dominated morphology, at least in the probed cluster regions and galaxy stellar mass range, irrespective of environment-related processes affecting star formation in cluster galaxies. We also probe the stellar mass–size relation of cluster galaxies, and find that star-forming and quiescent sources populate the mass–size plane in a manner largely similar to their field counterparts, with no evidence of a significant size difference for any probed sub-population. In particular, both quiescent and bulge-dominated cluster galaxies have average sizes at fixed stellar mass consistent with their counterparts in the field. 

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4. The Massive and Distant Clusters of WISE Survey. VII. The Environments and Properties of Radio Galaxies in Clusters at z ∼ 1

   https://doi.org/10.3847/1538-4357/ab5af0  

   Moravec, Emily ; Gonzalez, Anthony H. ; Stern, Daniel ; Clarke, Tracy ; Brodwin, Mark ; Decker, Bandon ; Eisenhardt, Peter R. ; Mo, Wenli ; Pope, Alexandra ; Stanford, Spencer A. ; et al ( January 2020 , The Astrophysical Journal)
5. The Massive and Distant Clusters of WISE Survey. IV. The Distribution of Active Galactic Nuclei in Galaxy Clusters at z ∼ 1

   https://doi.org/10.3847/1538-4357/aaef83  

   Mo, Wenli ; Gonzalez, Anthony ; Stern, Daniel ; Brodwin, Mark ; Decker, Bandon ; Eisenhardt, Peter ; Moravec, Emily ; Stanford, S. A. ; Wylezalek, Dominika ( December 2018 , The Astrophysical Journal)