Journal Article

The clustering of <i>K</i>∼20 galaxies in 17 radio galaxy fields

Nathan Roche, Steve Eales and Hans Hippelein

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 295, issue 4, pages 946-958
Published in print April 1998 | ISSN: 0035-8711
Published online April 1998 | e-ISSN: 1365-2966 | DOI:
The clustering of K∼20 galaxies in 17 radio galaxy fields

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We investigate the angular correlation function, ω(θ), of the galaxies detected in the 2.1-μm K′ band in 17 fields (101.5 arcmin2 in total), each containing a z∼1.1 radio galaxy. There is a significant detection of galaxy clustering at a limit of K∼20, with a ω(θ) amplitude similar to that estimated by Carlberg et al. at K=21.5. The ω(θ) amplitudes of these K-limited samples are higher than expected from the faint galaxy clustering in the blue and red passbands, but consistent with a pure luminosity evolution model if clustering is stable (ϵ=0) and the correlation function of early-type galaxies is steeper than that of spirals.

We do not detect a significant cross-correlation between the radio galaxies and the other galaxies in these fields. The upper limits on the cross-correlation are consistent with a mean clustering environment of Abell class 0 for z∼1.1 radio galaxies, similar to that observed for radio galaxies at z∼0.5, but would argue against an Abell class 1 or richer environment. As Abell 0 clustering around the radio galaxies would not significantly increase the ω(θ) amplitude of galaxies in these fields, stable clustering with a steep ξ(r) for E/S0 galaxies appears to remain the most likely interpretation of the ω(θ) amplitude.

At K≤20, the number of galaxy-galaxy pairs of 2–3 arcsec separation exceeds the random expectation by a factor of 2.15±0.26. The excess of close pairs is comparable to that previously reported for R-band data, and consistent with a ∼(1+z)2 evolution of the galaxy merger rate.

Keywords: galaxies: clusters: general; infrared: galaxies

Journal Article.  0 words. 

Subjects: Astronomy and Astrophysics

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