0000000000362327
AUTHOR
B. Lopez-marti
Does the galaxy correlation length increase with the sample depth?
We have analyzed the behavior of the correlation length, $r_0$, as a function of the sample depth by extracting from the CfA2 redshift survey volume--limited samples out to increasing distances. For a fractal distribution, the value of $r_0$ would increase with the volume occupied by the sample. We find no linear increase for the CfA2 samples of the sort that would be expected if the Universe preserved its small scale fractal character out to the distances considered (60--100$\hmpc$). The results instead show a roughly constant value for $r_0$ as a function of the size of the sample, with small fluctuations due to local inhomogeneities and luminosity segregation. Thus the fractal picture ca…
Correlations at large scale
We show point processes generated in different ways and having different structure, presenting very similar power-law two--point correlation functions at small scales and quite different shapes at large scales.
Brown Dwarfs in ChaI Dark Cloud
We present the results of a multiband survey for brown dwarfs in the Chamaeleon I dark cloud with the Wide Field Imager (WFI) camera at the ESO/MPG 2.2-m telescope on La Silla (Chile) on 28-May to 03-Jun 1999. The survey has revealed a substantial population of brown dwarfs in this southern star-forming region. Candidates were selected from R, I and H{alpha} imaging observations. We also observed in two medium-band filters, M855 and M915, for spectral type determination. The former filter covers a wavelength range containing spectral features characteristic of M-dwarfs, while the latter lies in a relatively featureless wavelength region for these late-type objects. A correlation was found b…