Revision d606122dc24b56ecf537d55eda38f4bf5ac4de1f authored by Adrian Baddeley on 25 October 2010, 10:40:51 UTC, committed by cran-robot on 25 October 2010, 10:40:51 UTC
1 parent 66bc933
shapley.Rd
\name{shapley}
\alias{shapley}
\alias{shapley.extra}
\docType{data}
\title{Galaxies in the Shapley Supercluster}
\description{
A point pattern recording the sky positions of 4215 galaxies
in the Shapley Supercluster.
}
\format{
\code{shapley} is an object of class \code{"ppp"}
representing the point pattern of galaxy locations
(see \code{\link{ppp.object}}).
\code{shapley.extra} is a list containing additional data
described under Notes.
}
\usage{data(shapley)}
\examples{
data(shapley)
shapley.extra$plotit(main="Shapley Supercluster")
}
\source{M.J. Drinkwater, Department of Physics, University of
Queensland}
\section{Notes}{
This dataset comes from a survey by Drinkwater et al (2004)
of the Shapley Supercluster, one of the most massive concentrations
of galaxies in the local universe. The data give the sky positions
of 4215 galaxies observed using the FLAIR-II spectrograph
on the UK Schmidt Telescope (UKST). They were kindly provided by
Dr Michael Drinkwater through the Centre for Astrostatistics
at Penn State University.
Sky positions are given using the coordinates
Right Ascension (degrees from 0 to 360) and
Declination (degrees from -90 to 90).
The point pattern has three mark variables:
\describe{
\item{Mag}{
Galaxy magnitude (a negative logarithmic measure of
visible brightness).
}
\item{V}{
Recession velocity (km/sec) inferred from redshift,
with corrections applied.
}
\item{SigV}{
Estimated standard error for \code{V}.
}
}
The region covered by the survey was approximately the
UKST's standard quadrilateral survey fields 382 to 384 and 443 to 446.
However, a few of the galaxy positions lie outside these fields.
The point pattern dataset \code{shapley} consists of all 4215 galaxy
locations. The observation window for this pattern is a
dilated copy of the convex hull of the galaxy positions,
constructed so that all galaxies lie within the window.
The auxiliary dataset \code{shapley.extra} contains
the following components:
\describe{
\item{\code{UKSTfields}}{
a list of seven windows
(objects of class \code{"owin"}) giving the UKST standard survey
fields.
}
\item{\code{UKSTdomain}}{
the union of these seven fields,
an object of class \code{"owin"}.
}
\item{\code{plotit}}{
a function (called without arguments)
that will plot the data and the survey fields
in the conventional astronomical presentation,
in which Right Ascension is converted
to hours and minutes (1 hour equals 15 degrees) and
Right Ascension decreases as we move to the right of the plot.
}
}
}
\references{
Drinkwater, M.J., Parker, Q.A., Proust, D., Slezak, E.
and Quintana, H. (2004)
The large scale distribution of galaxies in the Shapley
Supercluster.
\emph{Publications of the Astronomical Society of Australia}
\bold{21}, 89-96. \code{DOI 10.1071/AS03057}
}
\keyword{datasets}
\keyword{spatial}
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...