On deriving distances from Cepheids using the Hubble Space Telescope

Citation
A. Saha et al., On deriving distances from Cepheids using the Hubble Space Telescope, PUB AST S P, 112(768), 2000, pp. 163-176
Citations number
13
Categorie Soggetti
Space Sciences
Journal title
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC
ISSN journal
00046280 → ACNP
Volume
112
Issue
768
Year of publication
2000
Pages
163 - 176
Database
ISI
SICI code
0004-6280(200002)112:768<163:ODDFCU>2.0.ZU;2-A
Abstract
In this paper we examine the methodology of obtaining Cepheid-based distanc es to galaxies from image data obtained with the Wide Field Planetary Camer a (WFPC2) on the Hubble Space Telescope. We identify the sources of error a nd how these propagate to the derived distances for the particular method u tilizing the modified DoPHOT program for photometry. Typical uncertainties from each of the identified sources are used to estimate the net uncertaint ies. In particular, the effect of skewed error distributions from object co nfusion and surface brightness fluctuation are studied, and tests to estima te the extent of such skewness in real data are shown. The effect of charge -transfer efficiency problems with the WFPC2 CCDs on photometric zero point s is calibrated empirically. The corrections applicable to published data a re given, which suggest that dereddened distance moduli using the DoPHOT me thodology published to date have been underestimated by up to 0.1 mag.