VI photometry of new Cepheids in NGC 2541

A total of 25 exposures (divided into 13 epochs) were obtained using the F555W filter (transformed to Johnson V), and nine exposures were obtained (divided into five epochs) using the F814W filter (transformed to Cousins I). Photometric reduction of the data is performed using two independent packages, DoPHOT and DAOPHOT II/ALLFRAME, which give very good agreement in the measured magnitudes.

A total of 34 bona fide Cepheids, with periods ranging from 12 to over 60 days, are identified based on both sets of photometry. By fitting V and I period-luminosity relations, apparent distance moduli are derived assuming a Large Magellanic Cloud distance modulus and mean color excess of {mu}_LMC_=18.50+/-0.10mag and E(B-V)=0.10mag, respectively. Adopting A(V)/E(V-I)=2.45, we obtain a true distance modulus to NGC 2541 of {mu}_0_=30.47+/-0.11 (random) +/-0.12 (systematic) mag (D=12.4+/-0.6 [random] +/-0.7 [systematic] Mpc), and a total (Galactic plus internal) mean color excess E(B-V)=0.08+/-0.05 (internal error) mag.