Thursday, November 30, 2006, 12:30 pm, Pratt Conference Room
Improving the Cepheid Distance Scale:
A Progress Report on HST and Gemini Observations of Cepheids in NGC 4258
Dr. Lucas Macri, NOAO
| I will present results from an on-going HST program to establish NGC 4258 as a new "first rung" for the Extragalactic Distance Scale, taking advantage of its very precise and accurate maser-based distance. I will summarize our findings from a completed HST ACS/WFC survey of two fields within the galaxy (Macri et al. 2006, ApJ 652, 1133) and some preliminary results from follow-up NICMOS and Gemini observations. I will discuss the implications of our results for the value of the Hubble constant and the equation of state of dark energy. |
