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Paper: Period-Luminosity Relations of LPVs in Nearby Dwarf Galaxies
Volume: 445, Why Galaxies Care about AGB Stars II: Shining Examples and Common Inhabitants
Page: 491
Authors: Lorenz, D.; Nowotny, W.; Lebzelter, T.; Telting, J.; Kerschbaum, F.; Olofsson, H.; Schwarz, H. E.
Abstract: Using photometric time series in the i–band of the two dwarf galaxies NGC 147 and NGC 185 covering ∼ 2.5 years, we have measured the light variations of a large number of long period variables (LPVs). Roughly 35 data points per system could be used for the period analysis. In addition, single-epoch Ks–band photometry was obtained. A total of 323 LPVs in NGC 185 and 147 in NGC 147 were available for further analysis. Narrow-band photometry was used to separate a large fraction of the detected LPVs into carbon-rich and oxygen-rich cases. The resulting Ks–logP relations (PLRs) were compared with those from the Large Magellanic Cloud, found in the literature and shifted according to the distance to each galaxy. The PLRs of NGC 147 are in good agreement with the LMC relations, but for NGC 185 we suggest a revision of the distance. In the Ks–logP diagrams the sequence of fundamental mode pulsators (sequence C) is well populated for both galaxies. In NGC 185 a number of LPVs are lined up along the sequence for first overtone pulsators (C′), whereas in NGC 147 almost no LPVs populate that sequence. We speculate that this lack of stars might originate from a difference in the star formation history of the two galaxies.
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