The Hubble Space Telescope key project on the extragalactic distance scale. XII. the discovery of Cepheids and a new distance to NGC 2541

摘要

We report the detection of Cepheids and a new distance to the spiral galaxy NGC 2541, based on data obtained with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope (HST). 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 pack- ages, DoPHOT and DAOPHOT II/ALLFRAME, which give very good agreement in the measured magnitudes.