The Araucaria Project: Near‐Infrared Photometry of Cepheid Variables in the Sculptor Galaxy NGC 300

We have obtained deep near-infrared images in J and K filters of three fieldsin the Sculptor galaxy NGC 300 with the ESO VLT and ISAAC camera. For 16Cepheid variables in these fields, we have determined J and K magnitudes at twodifferent epochs, and have derived their mean magnitudes in these bands. Theslopes of the resulting period-luminosity relations are in very good agreementwith the slopes of these relations measured in the LMC by Persson et al.Fitting the LMC slopes to our data, we have derived distance moduli in J and K.Using these values together with the values derived in the optical V and Ibands in our previous work, we have determined an improved total reddening forNGC 300 of E(B-V)=0.096 +/- 0.006 mag, which yields extremely consistent valuesfor the absorption-corrected distance modulus of the galaxy from VIJK bands.Our distance result for NGC 300 from this combined optical/near infraredCepheid study is (m-M)_0 = 26.37 +/- 0.04 (random) +/- 0.03 (systematic) magand is tied to an adopted true LMC distance modulus of 18.50 mag. Both randomand systematic uncertainties are dominated by photometric errors, while errorsdue to reddening, metallicity effects and crowding are less important. Ourdistance determination is consistent with the earlier result from near-infrared(H-band) photometry of two Cepheids in NGC 300 by Madore et al., but far moreaccurate. Our distance value also agrees with the HST Key Project result ofFreedman et al., and with the recent distance estimate for NGC 300 from Butleret al. from the TRGB I-band magnitude when our improved reddening is used tocalculate the absorption corrections. Our distance results from the differentoptical and near-infrared bands indicate that the reddening law in NGC 300 mustbe very similar to the Galactic one.Comment: 24 pages, 5 figures, 4 tables, submitted to Ap