The Araucaria Project. The Distance to the Sculptor Group Galaxy NGC 7793 from Near-Infrared Photometry of Cepheid Variables

Bartłomiej Zgirski, Wolfgang Gieren, Grzegorz Pietrzyński, Paulina Karczmarek, Marek Górski, Piotr Wielgórski, Weronika Narloch, Dariusz Graczyk, Rolf-Peter Kudritzki and Fabio Bresolin

We have performed deep near-infrared J- and K-band photometry of a subsample of Cepheids in the Sculptor Group spiral galaxy NGC 7793. It allowed to derive the distance to this galaxy with a higher accuracy than what was possible from optical photometry alone, by minimizing the effects of reddening and metallicity on the distance result. Combining our new near-infrared period-luminosity relations with the previous optical photometry, we obtain the true distance modulus to NGC 7793 of 27.66±0.04 mag (statistical) ±0.07 mag (systematic), i.e. the distance of 3.40±0.17 Mpc. We also determine the mean reddening affecting the Cepheids to be E(B-V)=0.08±0.02 mag.

Proceedings of the Polish Astronomical Society, vol. 6, 329-330 (2018)

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