THE DISTANCE MEASUREMENT OF NGC 1313 WITH CEPHEIDS

The Discovery of Cepheids and a Distance to Ngc

We discuss a new distance to NGC 5128 (Centaurus A) based on Cepheid variables observed with the Hubble Space Telescope. Twelve F555W (V ) and six F814W (I) epochs of cosmic-ray-split Wide Field Planetary Camera 2 observations were obtained. A total of 56 bona-fide Cepheids were discovered, with periods ranging from 5 to ∼ 50 days; five of these are likely Population II Cepheids of the W Virgin...

The Discovery of Cepheids and a Distance to Ngc 5128

We discuss a new distance to NGC 5128 (Centaurus A) based on Cepheid variables observed with the Hubble Space Telescope. Twelve F555W (V ) and six F814W (I) epochs of cosmic-ray-split Wide Field Planetary Camera 2 observations were obtained. A total of 56 bona-fide Cepheids were discovered, with periods ranging from 5 to ∼ 50 days; five of these are likely Population II Cepheids of the W Virgin...

Calibration of the Distance Scale from Cepheids

The ultraluminous X-ray source NGC 1313 X-2

NGC 1313 X-2 is one of the brightest ultraluminous X-ray sources in the sky, at both X-ray and optical wavelengths; therefore, quite a few studies of available ESO VLT and HST data have appeared in the literature. Here, we present our analysis of VLT/FORS1 and HST/ACS photometric data, confirming the identification of the B ∼ 23 mag blue optical counterpart. We show that the system is part of a...

The Extragalactic Distance Scale without Cepheids

Distances of galaxies in the Hubble Space Telescope Key Project are based on the Cepheid period-luminosity relation. An alternative basis is the tip of the red giant branch. Using archival HST data, we calibrate the infrared TullyFisher relation using 14 galaxies with tip of the red giant branch measurements. Compared with the Key Project, a higher value of the Hubble Constant by 10% ± 7% is in...