Deep Intermediate-Band Surface Photometry of NGC 5907

Abstract

Intrigued by the initial report of an extended luminosity distribution perpendicular to the disk of the edge-on Sc galaxy NGC 5907, we have obtained very deep exposures of this galaxy with a Schmidt telescope, large-format CCD, and intermediate-band filters centered at 6660 Å and 8020 Å. These two filters, part of a 15-filter set, are custom designed to avoid the brightest (and most variable) night skylines. As a result, our images are able to go deeper with lower sky noise than those taken with broadband filters at similar effective wavelengths: e.g., 0.6 e- arcsec-2 s-1 for our observations versus 7.4 e- arcsec-2 s-1 for the R-band measures of Morrison et al. In our assessment of both random and systematic errors, we show that the flux level where the errors of observation reach 1 mag arcsec-2 are 29.00 mag arcsec-2 in the 6660 Å image (corresponding to 28.7 in the R band) and 27.4 mag arcsec-2 in the 8020 Å image (essentially on the I-band system).