Angular Clustering of Galaxies to $z \sim 1$

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Session 114 -- Compact Groups, Galaxy and Quasar Clustering
Oral presentation, Thursday, 12, 1995, 10:00am - 11:30am

[114.06] Angular Clustering of Galaxies to $z \sim 1$

T. G. Brainerd (LANL), I. R. Smail (OCIW), J. R. Mould (MSSO)

We present results for the two-point angular correlation function of galaxies, $\omega(\theta)$, to a limiting magnitude of $r = 26$. The catalogue is constructed from deep imaging using the COSMIC imaging spectrograph on the Hale 5-m. The final sample is 97\% complete to $r=26.0$ yielding $\sim$5700 galaxies over a 90.1 sq.\ arcmin field. Our analysis shows $\omega(\theta)$ for faint galaxies can be parameterised by a power law of the form $A_\omega \theta^{-0.8}$, in agreement with the angular clustering statistics of shallower catalogues. The derived amplitude, $A_\omega$, for our catalogue is small, but non-zero. We combine this measurement with the latest statistical constraints on faint galaxy redshifts from gravitational lensing studies, which imply that the bulk of the $r\ls26$ field galaxies should be at redshifts $z\sim1$. Our derived $A_\omega$ is significantly lower than that predicted from the local bright, optically-selected galaxy correlation function using the lensing-determined galaxy redshift distribution and modest growth of clustering. However, this simplistic model does not include the variation in observed morphological mix as a function of redshift and apparent magnitude in our sample. At our faintest limits we reach sufficiently high redshifts that differential $K$-corrections will result in the observed galaxy mix being dominated by star bursting dwarf and low surface brightness irregulars, rather than the early-type systems used to define the local bright galaxy correlation function. Adopting the correlation function measured locally for these low surface brightness galaxies and assuming modest clustering evolution, we obtain reasonable agreement between our model and observations. This model, therefore, supports the scenario in which the high number density of faint galaxies is produced by normally clustered star forming dwarf galaxies at modest redshifts.

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