Tracing the Peculiar Dark Matter Structure in the Galaxy Cluster CL 0024+17 with Intracluster Stars and Gas

ICL is believed to originate from the stars stripped from cluster galaxies. They are no longer gravitationally bound to individual galaxies, but to the cluster, and their smooth distribution potentially makes them serve as much denser tracers of the cluster dark matter than the sparsely distributed cluster galaxies. We present our study of the ICL in Cl 0024+17 using both ACS and Subaru data, where we previously reported discovery of a ringlike dark matter structure with gravitational lensing. The ACS images provide much lower sky levels than ground data, and enable us to measure relative variation of surface brightness reliably. This analysis is repeated with the Subaru images to examine if consistent features are recovered despite different reduction scheme and instrumental characteristics. We find that the ICL profile clearly resembles the peculiar mass profile, which stops decreasing at r~50" (~265 kpc) and slowly increases until it turns over at r~75" (~397 kpc). This feature is seen in both ACS and Subaru images for nearly all available passband images while the features are stronger in red filters. The consistency across different filters and instruments strongly rules out the possibility that the feature might come from any residual, uncorrected calibration errors. In addition, our re-analysis of the cluster X-ray data shows that the peculiar mass structure is also indicated by a non-negligible bump in the intracluster gas profile when the geometric center of the dark matter ring, not the peak of the X-ray emission, is chosen as the center of the radial bin. The location of the gas ring is closer to the center by ~15" (~80 kpc), raising an interesting possibility that the ring-like structure is expanding and the gas ring is lagging behind perhaps because of the ram pressure if both features in mass and gas share the same dynamical origin.Comment: Accepted to ApJ for publicatio

Comprehensive aerodynamic and dynamic study of independence of ukraine monument

Розглянуто результати комплексних досліджень вирішення інженерної проблеми створення висотного монумента колонного типу в Києві, динамічних досліджень моделі в масштабі 1:25 та аеродинамічних досліджень великомасштабної моделі (1:8) в аеродинамічній трубі ТАД-2 Національного авіаційного університету. Наведено процедуру визначення на натурному об’єкті реальних динамічних характеристик та забезпечення ефективності демпфіруванняРассмотрены результаты комплексных исследований решения инженерной задачи создания высотного монумента колонного типа в Киеве, динамических исследований модели в масштабе 1:25 и аэродинамических испытаний крупномасштабной (1:8) модели в аэродинамической трубе ТАД-2 Национального авиационного университета. Приведена процедура определения на натурном объекте реальных динамических характеристик и обеспечения эффективности демпфированияComprehensive approach for solution the engineering problems o f creation the high-rise extended pillartype Monument in Kiyv is described. The results o f dynamic tests o f 1:25 scale model and aerodynamictests o f 1:8 scale model o f the Monument in TAD-2 wind tunnel are given. The procedures fordetermination o f actual dynamic characteristics and assurance the efficiency o f damping on the siteare describe

The magnetic field and geometry of the oblique shock in the jet of 3C 346

We investigate the brightest regions of the kpc-scale jet in the powerful radio galaxy 3C 346, using new optical HST ACS/F606W polarimetry together with Chandra X-ray data and 14.9 GHz and 22.5 GHz VLA radio polarimetry. The jet shows a close correspondence in optical and radio morphology, while the X-ray emission shows an 0.80 +/- 0.17 kpc offset from the optical and radio peak positions. Optical and radio polarimetry show the same apparent magnetic field position angle and fractional polarization at the brightest knot, where the jet undergoes a large kink of almost 70 degrees in the optical and radio images. The apparent field direction here is well-aligned with the new jet direction, as predicted by earlier work that suggested the kink was the result of an oblique shock. We have explored models of the polarization from oblique shocks to understand the geometry of the 3C 346 jet, and find that the upstream flow is likely to be highly relativistic (0.91 +0.05 / -0.07 c), where the plane of the shock front is inclined at an angle of 51 (+/- 11) degrees to the upstream flow which is at an angle 14 (+8 / -7) degrees to our line of sight. The actual deflection angle of the jet in this case is only 22 degrees.Comment: 11 pages, 5 figures. Accepted by MNRA

Ancient stars beyond the Local Group: RR Lyrae variables and Blue Horizontal Branch stars in Sculptor Group Dwarf Galaxies

We have used Hubble Space Telescope ACS images to generate color-magnitude diagrams that reach below the magnitude of the horizontal branch in the Sculptor Group dwarf galaxies ESO294-010 and ESO410-005. In both diagrams blue horizontal branch stars are unambiguously present, a signature of the existence of an ancient stellar population whose age is comparable to that of the Galactic halo globular clusters. The result is reinforced by the discovery of numerous RR Lyrae variables in both galaxies. The occurrence of these stars in the first direct confirmation of the existence of ancient stellar populations beyond the Local Group and indicates that star formation can occur at the earliest epochs even in low density environments.Comment: 11 pages, 2 figures, accepted for publication in Astrophysical Journal Letter

Efficacy and safety of dasatinib vs. Imatinib in Latin american subpopulation from the dasision trial in patients with newly diagnosed chronic myeloid leukemia (CML) in chronic phase (CP)

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