... In order to obtain a quantitative estimate of the accuracy and reliability of our data reduction procedures and results, we have performed a data reduction pipeline based on the following steps: i) define a set of simulated HST-like images with synthetic globular cluster stellar distributions, which provide the ``true'' data for comparison; ii) convolve these images with appropriate assumptions of PSF and noise in order to construct simulated `` observed '' ... It contains 470 stars. b) ...

... We have made observations of the Perseus cluster with the Westerbork Telescope at 610 MHz. ... Several newly detected sources are identified with cluster galaxies. ... No evidence is found for the existence of the previously reported ~ 65'x25' cluster halo, 3C 84B. Key words: radio galaxies - clusters - tailed radio sources buoyancy The Perseus Cluster of galaxies is one of the most fascinating systems accessible to extragalactic astronomers. ...

. " The Arecibo Observatory is sponsored by the National Science Foundation. Any opinions, findings and conclusions or recommendations . expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation."

... During observations of Sagittarius A* with the orbiting Chandra X-ray Observatory, the bright X-ray source at the very center of our Milky Way brightened dramatically for a few minutes. ... Hot blue stars shine brightly in this beautiful, recently formed galactic or "open" star cluster. ... Moon AND Stars . ... Visible as the central dot is quasar 3C175, the active center of a galaxy so distant that the light we see from it was emitted when the Earth was just forming. 2dF Sees Waves of Galaxies . ...

I will present theresults from a deep, extended, planetary nebulae survey in a 0.5 sqdeg region centered on the brightest cluster galaxy NGC 4486 (M87) in the Virgo cluster core, carried out with SuprimeCam@Subaru and FLAMES-GIRAFFE@VLT. ... A substructure detected in the projected phase-space of the line-of-sight velocity vs. major axis distance for the M87 halo planetary nebulae provides evidence for the recent accretion event of a satellite galaxy with luminosity twice that of M33. ...

... 2.3 Establishing the Extragalactic Distance Scale . ... 2.3.2 The Second Rung: Distances to stellar clusters . ... 2.3.4 Distances to Local Group Galaxies . ... The Luminosity Function of Planetary Nebulae . ... 3.2.2 Clusters of Galaxies . ... 4.2 Evidence for Dark Matter as a Function of Scale Size . ... 4.3 Other Dark Matter Indicators for Galaxies . ... What is the nature of the large-scale distribution of matter in the universe as traced by the three-dimensional galaxy distribution? ...

... MARX includes models of the AXAF mirrors, the low- and high-energy transmission grating assemblies (LETG and HETG), and the HRC and ACIS focal plane detectors. We discuss the role of MARX within the ASC Data System and present sample simulated images and spectra for two typical cosmic X-ray sources. ... A continuous emission measure model was constructed based on the published EUVE data (Dupree 1996); the peak emission occurred near 10 7 K. Simulations were run for both the HETG and LETG . ...

... Subject and Problems of Stellar Astronomy. ... Plane of Galaxy, Methods of Its Location Determination. ... Stars Distances. ... Other Methods of Stars Distances Determination. ... Tangential Velocities, Their Determination by Self-Motions. ... Determination of Solar Apex and Spatial Velocity by Radial and Spatial Velocities of Stars. ... Features of Orientation and Parameters of Peculiar Stellar Velocities Ellipsoid. ... General and Selective Light Absorption in Galaxy. ... Darc Clouds in Galaxy. ...

This image from the NASA/ESA Hubble Space Telescope shows NGC 6388, a dynamically middle-aged globular cluster in the Milky Way. ... A new study using Hubble data has discovered that globular clusters of the same age can have dramatically different distributions of blue straggler stars within them, suggesting that clusters can age at substantially different rates. Credit: NASA/ESA/F. Ferraro (University of Bologna) ...