Galaxy groups in the 2dF Galaxy Redshift Survey: luminosity and mass statistics
Article first published online: 11 DEC 2002
Monthly Notices of the Royal Astronomical Society
Volume 337, Issue 4, pages 1441–1449, December 2002
How to Cite
Martínez, H. J., Zandivarez, A., Merchán, M. E. and Domínguez, M. J. L. (2002), Galaxy groups in the 2dF Galaxy Redshift Survey: luminosity and mass statistics. Monthly Notices of the Royal Astronomical Society, 337: 1441–1449. doi: 10.1046/j.1365-8711.2002.06020.x
- Issue published online: 11 DEC 2002
- Article first published online: 11 DEC 2002
- Accepted 2002 August 29. Received 2002 August 26; in original form 2002 July 2
- galaxies: clusters: general;
- galaxies: luminosity function, mass function;
- galaxies: statistics
Several statistics are applied to groups and galaxies in groups in the 2° Field Galaxy Redshift Survey. First, we estimate the luminosity functions for different subsets of galaxies in groups. The results are well fitted by a Schechter function with parameters M*− 5 log (h) =−19.90 ± 0.03 and α=−1.13 ± 0.02 for all galaxies in groups, which is quite consistent with the results of Norberg et al. for field galaxies. When considering the four different spectral types defined by Madgwick et al. we find that the characteristic magnitude is typically brighter than in the field. We also observe a steeper value, α=−0.76 ± 0.03, of the faint end slope for low star-forming galaxies when compared with the corresponding field value. This steepening is more conspicuous, α=−1.10 ± 0.06, for those galaxies in more massive groups than that obtained in the lower-mass subset, .
Secondly, we compute group total luminosities using the prescriptions of Moore, Frenk & White. We define a flux-limited group sample using a new statistical tool developed by Rauzy. The resulting group sample is used to determine the group luminosity function and we find a good agreement with previous determinations and semi-analytical models.
Finally, the group mass function for the flux-limited sample is derived. An excellent agreement is obtained when comparing our determination with analytical predictions over two orders of magnitude in mass.