We report the oxygen abundances of the HII regions of a sample of low surface brightness (LSB) galaxies. We provide analytic functions describing the McGaugh (1991) calibration of the R₂₃ method. We use this and the equivalent width (EW) method to determine oxygen abundances, and also make direct estimates in a few cases where the temperature sensitive [OIII] 4363 line is available. We find LSB galaxies to be metal poor, consistent with the L-Z relation of other galaxies. The large gas mass fractions of these objects provide an interesting test of chemical evolution models. We find no obvious deviation from the closed-box model of galactic chemical evolution. Based on our abundance and gas mass fraction measurements, we infer that LSB galaxies are not fundamentally different than other galaxy types but are perhaps at an early stage of evolution.

Below are high-resolution images of the LSB galaxies studied.

Fig 1: F563-1 (click for postscript)

R-band image of F563-1. North is up and East to the left. The observed HII regions are labeled along the slit.

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Fig 2: F571-5 (click for postscript)

V-band image of F571-5. The observed HII region is labeled.

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Fig 3: UGC 1230 (click for postscript)

Halpha image of UGC 1230. Observed HII regions are labeled along the slit.

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Fig 4: UGC 5005 (click for postscript)

R-band image of UGC 5005. The observed HII regions are labeled along the slit.

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Fig 5: UGC 9024 (click for postscript)

Halpha image of UGC 9024. Observed HII regions are labeled along the slit.

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Fig 6: UGC 12695 (click for postscript)

Halpha image of UGC 12695. Observed HII regions for both slit positions are labeled. Slit position (1) runs East-West; slit position (2) runs roughly North-South.

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