We present the detection of a large population of ultra diffuse galaxies (UDGs) in two massive galaxy clusters, Abell S1063 at z = 0.348 and Abell 2744 at z = 0.308, based on F814W and F105W images in the Hubble Frontier Fields Program. We find 47 and 40 UDGs in Abell S1063 and Abell 2744, respectively. Color-magnitude diagrams of the UDGs show that they are mostly located at the faint end of the red sequence. From the comparison with simple stellar population models, we estimate their stellar mass to range from 10 8 to 10 9 M ⊙ . Radial number density profiles of the UDGs show a turnover or a flattening in the central region at r < 100 kpc. We estimate the total masses of the UDGs using the galaxy scaling relations. A majority of the UDGs have total masses, M 200 = 10 10 to 10 11 M ⊙ , and only a few of them have total masses, M 200 = 10 11 to 10 12 M ⊙ . The total number of UDGs within the virial radius is estimated to be N(UDG)= 770 ± 114 for Abell S1063, and N(UDG)= 814 ± 122 for Abell 2744. Combining these results with data in the literature, we fit the relation between the total numbers of UDGs and the masses of their host systems for M 200 > 10 13 M ⊙ with a power law, N(UDG) = M 1.05±0.09 200. These results suggest that a majority of the UDGs have a dwarf galaxy origin, while only a small number of the UDGs are massive L * galaxies that failed to form a normal population of stars.

An independent determination of H 0 is crucial given the growing tension between the Hubble constant, H 0, derived locally and that determined from the modeling of the cosmic microwave background (CMB) originating in the early universe. In this work, we present a new determination of H 0 using velocities and tip of the red giant branch (TRGB) distances to 33 galaxies located between the Local Group and the Virgo cluster. We use a model of the infall pattern of the local Hubble flow modified by the Virgo mass, which is given as a function of the cosmological constants (H 0, ΩΛ), the radius of the zero-velocity surface R 0, and the intrinsic velocity dispersion, σ v . Fitting velocities and TRGB distances of 33 galaxies to the model, we obtain H 0 = 65.8 ± 3.5 (stat) ± 2.4 (sys) km s−1 Mpc−1 and R 0 = 6.76 ± 0.35 Mpc. Our local H 0 is consistent with the global H 0 determined from CMB radiation, showing no tension. In addition, we present new TRGB distances to NGC 4437 and NGC 4592, which are located near the zero-velocity surface: D = 9.28 ± 0.39 Mpc and D = 9.07 ± 0.27 Mpc, respectively. Their spatial separation is 0.29 Mpc, suggesting that they form a physical pair.

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We report the discovery of ultra-diffuse galaxies (UDGs) in Abell 370 (A370; z = 0.375). We find 46 UDGs in A370 from the images of the Hubble Frontier Fields. Most UDGs are low-luminosity red sequence galaxies, while a few of them are blue UDGs. We estimate the abundance of UDGs in A370, N(UDG) = 644 ± 104. Combining these results with those of Abell S1063 (z = 0.348) and Abell 2744 (z = 0.308), we derive a mean radial number density profile of UDGs in the three clusters. The number density profiles of UDGs and bright galaxies show a discrepancy in the central region of the clusters: the profile of UDGs shows a flattening as clustercentric distance decreases, while that of bright galaxies shows a continuous increase. This implies that UDGs are prone to disruption in the central region of the clusters. The relation between the abundance of UDGs and virial masses of their host systems is described by a power law with an index of nearly one: for M 200 > 1013 M ⊙. We estimate approximately dynamical masses of UDGs using the fundamental manifold method and find that most UDGs have dwarf-like masses (M 200 < 1011 M ⊙). This implies that most UDGs have a dwarf-like origin and a small number of them could be failed L* galaxies. These results suggest that multiple origins may contribute to the formation and evolution of UDGs in massive galaxy clusters.

Three cyclometalated platinum­(II) β-diketonate complexes were developed to investigate the relationship between intermolecular interactions in the solid state according to the position of a bulky trimethylsilyl (TMS) substituent and organic light-emitting diode performance. A variety of intermolecular interactions was observed (i.e., Pt­(II)···π, Pt···Pt, and π–π interactions) that were dependent on the presence or absence of TMS and its position on the 2′,6′-difluoro-2,3′-bipyridine ligand. Hirshfeld analysis was performed for the quantitative analysis of intermolecular interactions, indicating that the incorporation of TMS at the 4- or 5-position of the ligand results in strong intermolecular interactions between the Pt­(II) complexes. All three complexes show blue to sky blue emissions with high photoluminescent quantum efficiency of ∼0.6–0.8. A relatively remarkable decrease in the highest occupied molecular orbital energy was observed compared to the increase in the lowest unoccupied molecular orbital energy, which is attributed to the stronger electronegativity of difluorinated-bipyridine than phenylpyridine. All complexes effectively formed excimers under low doping concentration, which made it possible to prepare single-doped white organic light-emitting diodes (WOLEDs). WOLEDs were successfully fabricated using the three different Pt­(II) complexes as single dopant materials, resulting in over 10% external quantum efficiency. Moreover, the Pt­(II) complex substituted with TMS at the 5-position was used as a single dopant at 3 wt % in a nonoptimized WOLED, exhibiting an external quantum efficiency of 12.3%, white emission with Commission Internationale de L’Eclairage (1931) coordinates (x, y) of (0.40, 0.42), and good color rendering index (80), providing one of the highest performance results among single-doped WOLEDs.