Distances from Surface Brightness Fluctuations

The practice of measuring galaxy distances from their spatial fluctuations in surface brightness is now a decade old. While several past articles have included some review material, this is the first intended as a comprehensive review of the surface brightness fluctuation (SBF) method. The method is conceptually quite simple, the basic idea being that nearby (but unresolved) star clusters and galaxies appear "bumpy", while more distant ones appear smooth. This is quantified via a measurement of the amplitude of the Poisson fluctuations in the number of unresolved stars encompassed by a CCD pixel (usually in an image of an elliptical galaxy). Here, we describe the technical details and difficulties involved in making SBF measurements, discuss theoretical and empirical calibrations of the method, and review the numerous applications of the method from the ground and space, in the optical and near-infrared. We include discussions of stellar population effects and the "universality" of the SBF standard candle. A final section considers the future of the method.Comment: Invited review article to appear in: `Post-Hipparcos Cosmic Candles', A. Heck & F. Caputo (Eds), Kluwer Academic Publ., Dordrecht, in press. 22 pages, including 3 postscript figures; uses Kluwer's crckapb.sty LaTex macro file, enclose

The Distances of the Magellanic Clouds

The present status of our knowledge of the distances to the Magellanic Clouds is evaluated from a post-Hipparcos perspective. After a brief summary of the effects of structure, reddening, age and metallicity, the primary distance indicators for the Large Magellanic Cloud are reviewed: The SN 1987A ring, Cepheids, RR Lyraes, Mira variables, and Eclipsing Binaries. Distances derived via these methods are weighted and combined to produce final "best" estimates for the Magellanic Clouds distance moduli.Comment: Invited review article to appear in ``Post Hipparcos Cosmic Candles'', F. Caputo & A. Heck (Eds.), Kluwer Academic Publ., Dordrecht, in pres

Why is M87 jet one sided in appearance?

The jet in M87 is one sided and knotty. The question of whether the one sidedness is due to relativistic beaming or to intrinsic one sidedness has not yet been resolved. Recently, the knots have been observed in detail at the Very Large Array (VLA) 1; knot A is observed to consist of a thin disk, apparently a shock that is perpendicular to the jet axis and viewed edge-on, where the radio brightness profile has a very sharp gradient, and also of a trail downstream of the disk, that is pointing away from the nucleus. We discuss here the geometric implications of these observations, in particular the sharp edge facing the nucleus. We discuss models that represent the extremes in the apparent motion of the shock, and argue that proper motion measurements of the knot's inner edge would discriminate between them

Determination of the Hubble Constant from Observations of Cepheid Variables in the Galaxy M96

New Hubble Space Telescope observations of Cepheid variable stars in the nearby galaxy M96 give a distance to the host galaxy group, Leo-I, of 11.6+/-0.8 Mpc. This value, used in conjunction with several reliable secondary indicators of relative distance, constrains the distances to more remote galaxy clusters, and yields a value of the Hubble constant (Ho=69+/-8 km/s/Mpc) that is independent of the velocity of the Leo-I group itself.Comment: uuencoded compressed postscript. The preprint is also available at http://www.ast.cam.ac.uk/preprint/PrePrint.htm

Planetary Mapping: A historical overview

The development of the methods of visualization, control, and content of planetary maps goes in parallel with terrestrial ones. Both reflect technological, scientific, sociopolitical, and graphic design changes. However, while terrestrial maps are ubiquitous and show abstract or iconic representations of the Earth features, planetary surfaces are much more frequently represented with uninterpreted images, despite the wealth of planetary spatial data. In this paper, we highlight the key maps and map series made before the space age and the new cartographic methods introduced in the early 1960s when rectified, geologic and airbrush maps, and space-borne planetary photography, revolutionized the way we can look at planetary surfaces. This chapter also highlights the most recent novel approaches in planetary cartography