Abstract

view Abstract Citations (578) References (50) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Hubble Space Telescope Extragalactic Distance Scale Key Project. I. The Discovery of Cepheids and a New Distance to M81 Freedman, Wendy L. ; Hughes, Shaun M. ; Madore, Barry F. ; Mould, Jeremy R. ; Lee, Myung Gyoon ; Stetson, Peter ; Kennicutt, Robert C. ; Turner, Anne ; Ferrarese, Laura ; Ford, Holland ; Graham, John A. ; Hill, Robert ; Hoessel, John G. ; Huchra, John ; Illingworth, Garth D. Abstract We report on the discovery of 30 new Cepheids in the nearby galaxy M81 based on observations using the Hubble Space Telescope (HST). The periods of these Cepheids lie in the range of 10-55 days, based on 18 independent epochs using the HST wide-band F555W filter. The HST F555W and F785LP data have been transformed to the Cousins standard V and I magnitude system using a ground-based calibration. Apparent period-luminosity relations at V and I were constructed, from which apparent distance moduli were measured with respect to assumed values of μ_0_ = 18.50 mag and E(B- V) = 0.10 mag for the Large Magellanic Cloud. The difference in the apparent V and I moduli yields a measure of the difference in the total mean extinction between the M81 and the LMC Cepheid samples. A low total mean extinction to the M81 sample of E(B - V) = 0.03+/-0.05 mag is obtained. The true distance modulus to M81 is determined to be 27.80 +/- 0.20 mag, corresponding to a distance of 3.63 +/- 0.34 Mpc. These data illustrate that with an optimal (power-law) sampling strategy, the HST provides a powerful tool for the discovery of extragalactic Cepheids and their application to the distance scale. M81 is the first calibrating galaxy in the target sample of the HST Key Project on the Extragalactic Distance Scale, the ultimate aim of which is to provide a value of the Hubble constant to 10% accuracy. Publication: The Astrophysical Journal Pub Date: June 1994 DOI: 10.1086/174172 Bibcode: 1994ApJ...427..628F Keywords: Astrometry; Astronomical Photometry; Calibrating; Cepheid Variables; Distance; Scale (Ratio); Spiral Galaxies; Data Reduction; Data Sampling; Hubble Constant; Hubble Space Telescope; Interstellar Extinction; Red Shift; Stellar Luminosity; Stellar Magnitude; Astrophysics; COSMOLOGY: DISTANCE SCALE; GALAXIES: DISTANCES AND REDSHIFTS; GALAXIES: INDIVIDUAL MESSIER NUMBER: M81; STARS: VARIABLES: CEPHEIDS full text sources ADS | data products SIMBAD (5) NED (1) MAST (1) ESA (1) Related Materials (29) Part 2: 1994ApJ...428..143H Part 3: 1996ApJ...463...26K Part 4: 1997ApJ...478..430K Part 5: 1996ApJ...464..568F Part 6: 1997ApJ...475..853F Part 7: 1998ApJ...496..648H Part 8: 1996ApJ...470....1S Part 9: 1997ApJ...477..535G Part 10: 1997ApJ...490..517R Part 11: 1998ApJ...500..763P Part 12: 1998ApJ...501...32H Part 13: 1998ApJ...505..207T Part 14: 1998ApJ...507..655F Part 15: 1998ApJ...498..181K Part 16: 1999ApJ...515....1S Part 17: 1999ApJ...515...29M Part 18: 1999ApJ...512...48G Part 19: 1999ApJ...521..155M Part 20: 1999ApJ...514..614K Part 21: 1999ApJ...516..626G Part 22: 2000ApJ...528..655M Part 23: 1999ApJ...525...80P Part 24: 1999ApJ...523..540S Part 25: 2000ApJ...529..698S Part 26: 2000ApJ...529..723G Part 27: 2000ApJ...529..745F Part 28: 2000ApJ...529..768K Part 29: 2000ApJ...529..786M Part 30: 2000ApJ...545..547M