The COSMOS Southern LSB Galaxy Survey

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Session 3 -- Galaxy Surveys
Display presentation, Wednesday, January 12, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[3.06] The COSMOS Southern LSB Galaxy Survey

B. W. Miller (UWash), H. T. MacGillivray (ROE)

We present the first results from the COSMOS Southern LSB Galaxy survey. Selection effects in most previous photographic surveys resulted in mainly high surface brightness galaxies being catalogued. However, recent surveys have shown that low surface brightness (LSB) galaxies are common and that they may be unbiased mass tracers (Bothun et al. 1993, AJ, 106, 530). However, until now there has not been a large-scale, magnitude limited survey of LSB galaxies.

We have used the COSMOS high speed plate measuring machine at the Royal Observatory in Edinburgh to do a survey of LSB galaxies over the entire southern sky with $\vert b>20^{\circ} \vert$ using plate material from the ESO/SERC J southern sky survey. The COSMOS software detects objects above a threshold intensity above the sky and determines the size, shape, magnitude, and areal (roughly intensity) profile for each object. Multivariate data analysis is then used to classify the objects. Our algorithm selects objects with blue surface brightnesses greater than 23.25 mag/arcsec$^{2}$ and $b_J < 17.5$ mag. We estimate that there will be about 7000 galaxies in the final catalog.

In this paper we present a description of our method and results from a small area of sky centered on the Sculptor Group. Visual inspection of the results indicates that there may be an over-density of LSB galaxies around NGC~247.

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