Surface brightness fluctuations in NGC 5128 from wide-field photographic plates

• Published in: The Astronomical journal 1993-10, Vol.106 (4), p.1344-1353
• Main Authors: SHOPBELL, P. L, BLAND-HAWTHORN, J, MALIN, D. F
• Format: Article
• Language: English
• Subjects: Astronomy; Characteristics and properties of external galaxies and extragalactic objects; Distances, redshifts, radial velocities. Spatial distribution of galaxies; Earth, ocean, space; Exact sciences and technology; Fundamental astronomy and astrophysics. Instrumentation, techniques, and astronomical observations; Observation and data reduction techniques. Computer modeling and simulation; Photography and photometry (including microlensing techniques); Stellar systems. Galactic and extragalactic objects and systems. The universe
• ISSN: 0004-6256; 1538-3881
• DOI: 10.1086/116731

Deep R- and B-band photographic plates of NGC 5128, obtained under photometric conditions at the f/3.3 prime focus of the AAT 3.9 m telescope, clearly show surface brightness fluctuations from the luminous, stellar population. We exploit the distinct statistical properties of photographic plates when compared with CCDs to provide an independent analysis of the luminosity fluctuations. The threshold and saturation levels of a detector skew the statistics at both extremes. Our model successfully accounts for the first three statistical moments of the photographic grain response measured from the density wedges on the photographic plates. After removing the grain noise component, the derived form of the power spectrum for the seeing-convolved luminosity fluctuations is in good agreement with those of Tonry and Schechter (1990) in the V and I bands. In the R band, we determine a value of 3.84 +/- 1.1 Mpc for the distance to NGC 5128. Although less accurate, our approach constitutes a statistically independent test and therefore provides strong support for Tonry's luminosity fluctuation distance method.