Browsing by Author "Smith, RJ"

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    Streaming motions of galaxy clusters within 12 000 km s-1 -: II.: New photometric data for the Fundamental Plane
    (2001) Smith, RJ; Lucey, JR; Schlegel, DJ; Hudson, MJ; Baggley, G; Davies, RL
    We present new R-band photometric data for 447 galaxies, gathered for the 'Streaming Motions of Abell Clusters' (SMAC) project. The data comprise 629 individual measurements of the Fundamental Plane (FP) parameters effective radius (R-e) and surface brightness derived from r(1/4)-law profile fitting. More than a third of the galaxies were observed more than once. The photometric precision is similar to0.02 mag as judged from comparisons of aperture photometry between repeat observations of galaxies. The combination X-fp = log R-e - 0.33[mu](e), e, which enters into the Fundamental Plane relation, has internal uncertainties of similar to0.008, corresponding to < 2 per cent in estimated distance. Taken individually, the (correlated) internal errors in R-e and [](e) are similar to8 per cent and similar to0.12 mag respectively. Comparisons with literature data constrain the external random errors to less than or similar to5 per cent in distance (per observation), which is small in comparison to the similar to 20 per cent scatter in the FR The data will form part of a merged catalogue of FP parameters, presented in a companion paper.
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    Streaming motions of galaxy clusters within 12 000 km s-1 -: III.: A standardized catalogue of Fundamental Plane data
    (2001) Hudson, MJ; Lucey, JR; Smith, RJ; Schlegel, DJ; Davies, RL
    We report the construction of a new, standardized all-sky catalogue of Fundamental Plane (FP) data from early-type galaxies in clusters, for peculiar velocity applications. This catalogue is based on a compilation of spectroscopic and photometric data consisting of data reported in previous papers of this series, plus data from published sources. We compare velocity dispersion and Mg-2 line-strength data from 27 sources, and determine the corrections that bring, all data sets on to a standardized system. For the velocity dispersions, the corrections are typically at the level of similar to0.015 dex, corresponding to 5 per cent in the FP-estimated distance. The uncertainties in these corrections, however, are considerably smaller: the new data obtained by our group are closely matched on to the standard system, with systematic uncertainties at the level of similar to0.005 dex in velocity dispersion (<2 per cent in distance). In this respect our catalogue significantly improves upon previously published FP data sets. For the Mg2 line-strength index, corrections are typically at the level of 0.01 mag, but the uncertainties in these corrections are only 0.002 mag.