galaxies {MASS} | R Documentation

## Velocities for 82 Galaxies

### Description

A numeric vector of velocities in km/sec of 82 galaxies from 6 well-separated conic sections of an `unfilled` survey of the Corona Borealis region. Multimodality in such surveys is evidence for voids and superclusters in the far universe.

### Usage

    data(galaxies)

### Note

There is an 83rd measurement of 5607 km/sec in the Postman et al. paper which is omitted in Roeder (1990) and from the dataset here.

### Source

Roeder, K. (1990) Density estimation with confidence sets exemplified by superclusters and voids in galaxies. Journal of the American Statistical Association 85, 617–624.

Postman, M., Huchra, J. P. and Geller, M. J. (1986) Probes of large-scale structures in the Corona Borealis region. Astrophysical Journal 92, 1238–1247.

### References

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.

### Examples

    data(galaxies)
    gal <- galaxies/1000
    c(width.SJ(gal, method = "dpi"), width.SJ(gal))
    plot(x = c(0, 40), y = c(0, 0.3), type = "n", bty = "l",
         xlab = "velocity of galaxy (1000km/s)", ylab = "density")
    rug(gal)
    lines(density(gal, width = 3.25, n = 200), lty = 1)
    lines(density(gal, width = 2.56, n = 200), lty = 3)

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