Letter to the Editor

The z  ≤ 0.1 surface brightness distribution

NAIC/Arecibo Observatory, HC3 Box 53995, Arecibo, PR 00612, USA INAF-Osservatorio Astronomico di Brera, via Brera 28, 20121 Milano, Italy Canada-France-Hawaii Telescope Corporation, PO Box 1597, Kamuela, HI 96743

Corresponding author: K. O'Neil, koneil@naic.edu

Received: 22 May 2002
Accepted: 15 January 2003

Abstract

The surface brightness distribution (SBD) function describes the number density of galaxies as measured against their central surface brightness. Because detecting galaxies with low central surface brightnesses is both time-consuming and complicated, determining the shape of this distribution function can be difficult. In a recent paper Cross et al. suggested a bell-shaped SBD disk-galaxy function which peaks near the canonical Freeman value of 21.7 and then falls off significantly by 23.5 B mag arcsec^-2. This is in contradiction to previous studies which have typically found flat (slope = 0) SBD functions out to 24–25 B mag arcsec^-2 (the survey limits). Here we take advantage of a recent surface-brightness limited survey by Andreon & Cuillandre which reaches considerably fainter magnitudes than the Cross et al. sample (M_B reaches fainter than -12 for Andreon & Cuillandre while the Cross et al. sample is limited to 16) to re-evaluate both the SBD function as found by their data and the SBD for a wide variety of galaxy surveys, including the Cross et al. data. The result is a SBD function with a flat slope out through the survey limits of 24.5 B mag arcsec^-2, with high confidence limits.