The Discovery of Cepheids and a Distance to NGC 5128

dc.creatorFerrarese, Laura
dc.creatorMould, Jeremy R.
dc.creatorStetson, Peter B.
dc.creatorTonry, John L.
dc.creatorBlakeslee, John P.
dc.creatorAjhar, Edward A.
dc.date2006-05-29
dc.date.accessioned2026-07-07T10:39:08Z
dc.date.available2026-07-07T10:39:08Z
dc.descriptionWe 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 Virginis class, associated with the bulge or halo of NGC 5128. Based on the period and V and I-band luminosities of a sub-sample of 42 classical (Pop I) Cepheids, and adopting a Large Magellanic Cloud distance modulus and extinction of 18.50 +/- 0.10 mag and E(B-V)=0.10 mag, respectively, the true reddening-corrected distance modulus to NGC 5128 is mu_0 = 27.67 +/- 0.12 (random)+/- 0.16 (systematic) mag, corresponding to a distance of 3.42 +/- 0.18 (random) +/- 0.25 (systematic) Mpc. The random uncertainty in the distance is dominated by the error on the assumed value for the ratio of total to selective absorption, R_V, in NGC 5128, and by the possible metallicity dependence of the Cepheid Period-Luminosity relation at V and I. This represent the first determination of a Cepheid distance to an early-type galaxy.
dc.descriptionAccepted by the Astrophysical Journal. 40 pages, 17 figures. A version of the paper including full resolution figures can be dowloaded from http://astrowww.phys.uvic.ca/~lff/publications.html
dc.identifierhttps://arxiv.org/abs/astro-ph/0605707
dc.identifierhttp://arxiv.org/abs/astro-ph/0605707
dc.identifierAstrophys.J.654:186-218,2006
dc.identifierdoi:10.1086/506612
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/180921
dc.subjectAstrophysics
dc.titleThe Discovery of Cepheids and a Distance to NGC 5128
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