39 research outputs found
The Distance to the Coma Cluster from Surface Brightness Fluctuations
We report on the first determination of the distance to the Coma Cluster
based on surface brightness fluctuation (SBF) measurements obtained from Hubble
Space Telescope WFPC2 observations of the bright E0 galaxy NGC 4881 in the Coma
Cluster and ground-based observations of the standard E1 galaxy NGC 3379 in the
Leo-I group. Relative distances based on the I-band fluctuation magnitude,
I(SBF), are strongly dependent on metallicity and age of the stellar
population. However, the radial changes in the stellar populations of the two
giant ellipticals, NGC 3379 and NGC 4881, are well described by published Mg_2
gradients, and the ground-based measurements of I(SBF) at several radial points
in NGC 3379 are used to calibrate I(SBF) in terms of the Mg_2 index. The
distance to NGC 3379, assumed to be identical to the average SBF distance of
the Leo-I group, is combined with the new SBF measurements of NGC 4881 to
obtain a Coma Cluster distance of 102+-14 Mpc. Combining this distance with the
cosmic recession velocity of Coma (7186+-428 km/s), we find the Hubble constant
to be H_0 = 71+-11 km/s/Mpc.Comment: 12 pages, LaTex, includes aaspp4.sty and 3 eps figures. To appear in
ApJ Letter
Anomalous Surface Brightness Fluctuations in NGC 4489
Anomalously high K-band surface brightness fluctuations (SBF) have been
reported in NGC 4489 by Pahre & Mould (1994), Jensen et al. (1996) and Jensen
et al. (1998). However, these conclusions were uncertain because of relatively
low signal-to-noise data. New high signal-to-noise data for NGC 4489 have been
obtained at the NOAO/KPNO 2.1m and the ESO/La Silla 3.5m NTT telescopes.
Adopting the I-band SBF distance modulus determined by Tonry et al. (1990) and
the M_I versus (V-I) calibration of Tonry et al. (2000), a value of M_K =-6.18
+/-0.09 mag was derived. Relative to the average empirical M_K derived for
giant ellipticals by Jensen et al. (1998) (M_K=-5.61 +/- 0.12 mag), the
detection of an anomalous K-band SBF in NGC 4489 is confirmed at the two sigma
level. Such anomalous fluctuations could be caused by an extended giant branch,
consisting of either intermediate-age AGB stars above the tip of the
first-ascent giant branch or high-metallicity first-ascent giants, or by lack
of a full understanding of the K-band SBF calibration. This result raises
questions about the accuracy of K-band SBF distance measurements for elliptical
galaxies with unknown stellar composition and underscores the need for M_K
measurements over a larger range of color and luminosity.Comment: A&A, in pres
Asteroids. From Observations to Models
We will discuss some specific applications to the rotation state and the
shapes of moderately large asteroids, and techniques of observations putting
some emphasis on the HST/FGS instrument.Comment: to appear in LNP; 28pages; written in 2003; Winter School "Dynamique
des Corps Celestes Non Ponctuels et des Anneaux", Lanslevillard (FRANCE
Solar System Objects Observed in the SDSS Commissioning Data
We discuss measurements of the properties of about 10,000 asteroids detected
in 500 deg2 of sky in the Sloan Digital Sky Survey (SDSS) commissioning data.
The moving objects are detected in the magnitude range 14 < r < 21.5, with a
baseline of 5 minutes. Extensive tests show that the sample is at least 98%
complete, with the contamination rate of less than 3%.
We find that the size distribution of asteroids resembles a broken power-law,
independent of the heliocentric distance: D^{-2.3} for 0.4 km < D < 5 km, and
D^{-4} for 5 km < D < 40 km. As a consequence of this break, the number of
asteroids with r < 21.5 is ten times smaller than predicted by extrapolating
the power-law relation observed for brighter asteroids (r < 18). The observed
counts imply that there are about 530,000 objects with D>1 km in the asteroid
belt, or about four times less than previous estimates.
The distribution of main belt asteroids in the 4-dimensional SDSS color space
is bimodal, and the two groups can be associated with S (rocky) and C
(carbonaceous) asteroids. A strong bimodality is also seen in the heliocentric
distribution of asteroids and suggests the existence of two distinct belts: the
inner rocky belt, about 1 AU wide (FWHM) and centered at R~2.8 AU, and the
outer carbonaceous belt, about 0.5 AU wide and centered at R~3.2 AU. The colors
of Hungarias, Mars crossers, and near-Earth objects are more similar to the
C-type than to S-type asteroids, suggesting that they originate in the outer
belt. (abridged).Comment: 89 pages, 31 figures, submitted to A
Inside Post-Socialist Courts: The Determinants of Adjudicatory Outcomes in Slovenian Commercial Disputes
Despite the judiciary's central role in the capitalist market system, micro-level empirical analyses of courts in post-socialist countries are remarkably rare. This paper draws on a unique hand-collected dataset of commercial claims filed at Slovenian courts to examine the determinants of two salient adjudicatory outcomes: whether a case was resolved via trial or settlement and if the case was tried, whether the plaintiff was awarded the initial claim. Consistent with the divergent expectations theory of litigation, we find that trial-based resolution is more likely when the case is complex and less likely when parties use mediation. Addressing sample selection and endogeneity concerns, we show that defendant's legal representation, plaintiff's profitability, and, importantly, court identity are robust predictors of plaintiff victory at trial. Thus, more than two decades after the start of transition in Slovenia, the judicial system is still a source of legal inconsistency and uncertainty
Corporealities : Dancing Knowledge, Culture and Power
"The contributors look at bodies engaged in practices as varied as pageantry, physical education, festivals and exhibitions, tourism, and social and theatrical dance. Thy succeed in bringing these bodies to life with all the political, gendered, racial and aesthetic resonances of which bodily motion is capable. Dance is used in this volume as a theoretical framework to assist the reader in understanding the body's permanent transience, and in the task of transposing its movements into words and its choregraphy into theory. " -- p. [4] of cover