posted on 2024-07-12, 17:17authored byBrad K. Gibson, Peter B. Stetson
Based on multiepoch Hubble Space Telescope observations, we present the discovery of 16 high-quality Cepheid candidates in NGC 4527. Corrected for metallicity effects in the Cepheid period-luminosity relation, we derive a distance, including both random (r) and systematic (s) uncertainties, of 13.0+/-0.5(r)+/-1.2(s) Mpc. Our result is then used to provide a calibration of the peak B-, V-, and I-band luminosities of the peculiar Type Ia supernova SN 1991T, a resident of NGC 4527. Despite its documented spectroscopic peculiarities, after correction for the decline rate-luminosity correlation, the corrected peak luminosity is indistinguishable from those of so-called ``normal'' Type Ia SNe. With nine local calibrators now at our disposal, we determine a robust value for the Hubble constant of H0=73+/-2(r)+/-7(s) km s-1 Mpc-1.