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arXiv · astro-ph/9902276

Deep Intermediate-Band Surface Photometry of NGC 5907

BATC Collaboration·Z. Y. Zheng·Z. H. Shang·H. J. Su·D. Burstein·J. S. Chen
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Abstract

We obtained very deep exposures of NGC 5907 with a Schmidt telescope, large-format CCD, and intermediate-band filters centered at 6660A and 8020A. These two filters, part of a 15-filter set, are custom-designed to avoid the brightest (and most variable) night sky lines, with the result that our images go deeper, with lower sky noise, than those taken with broad-band filters. Our errors of observation reach 1 mag/arcsec^2 at 29.00 mag/arcsec-2 in the 6660A image (= 28.7 in R-band), and 27.4 mag/arcsec^ in the 8020A image (same zero point as I-band). Fainter than R = 27 mag arcsec^, the surface brightness around NGC 5907 is strongly asymmetric, being mostly brighter the NW side of the galaxy midplane. This asymmetry rules out a halo for the origin of the faint surface brightness we see. Rather, this asymmetry is likely an artifact due to a combination of light from a faint ring around this galaxy (as described in Shang et al. 1998, ApJL 504, 23) and residual surface brightness at faint levels from stars that our star-masking procedure cannot completely eliminate. Good agreement with the surface photometry of NGC 5907 by Morrison et al. and other workers lead us to conclude that their data are similarly affected at faint levels by ring light and residual effects from their star masking procedures. Inspection of the images published by Morrison et al. and Sackett et al. confirm this to be the case. Thus, we conclude that NGC 5907 does not have a faint, extended halo.

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BATC Collaboration, Z. Y. Zheng, Z. H. Shang, H. J. Su, D. Burstein, J. S. Chen. 1999-02-19. Deep Intermediate-Band Surface Photometry of NGC 5907. https://arxiv.org/abs/astro-ph/9902276

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