Surface Brightness Fluctuation

The method of the Surface Brightness Fluctuation ( German translation: Surface brightness fluctuation ) is a secondary method of distance measurement for galaxies and globular clusters. The method is based on the decreasing amplitude of brightness fluctuations in stellar systems with increasing distance, since the random distribution of stars decreases according to their number and luminosity per point resolution with distance. The Surface Brightness Fluctuation method achieves an accuracy of up to two percent for early galaxy types.

The Surface Brightness Fluctuation is measured as the variance of a picture of a galaxy caused by the stochastic distribution of the luminosity and number of stars that fall into a resolved image element. After the withdrawal of the front and background sources, the average brightness profile of the galaxy is subtracted and the result calculated by the Power Spectrum. The mean amplitude of the brightness fluctuations depends on the population composition of the galaxy, where star formation in elliptical systems without the highest accuracy is achieved. Depending on the wavelength of various classes of stars bear the largest share of the emitted radiation and its distribution affects the achievable accuracy of the Surface Brightness Fluctuation method:

  • In the UV the stars on the horizontal branch and the post-AGB star
  • In the optical predominantly the red giant
  • In the near infrared, the AGB stars

The method of the Surface Brightness Fluctuation is calibrated using primary distance measurement methods, such as the period-luminosity relation of Cepheids, the Tip of the Red Giant Branch, Type Ia supernova, the luminosity function is planning nebula ( Planetary Nebula Luminosity Function) or on the basis of synthetic population calculations. The accuracy could weltraumgestütze observations by eg be considerably increased by the Hubble Space Telescope, as the atmospheric seeing is suppressed. The method can be used for distances between 10 and 150 Megaparsec today. Beyond these distances, the brightness fluctuations are too small at the currently achievable resolution.

Cite

  • Alexander Fritz: Distance Measurements and Stellar Population Properties via Surface Brightness Fluctuations. In: Astrophysics. Solar and Stellar Astrophysics. 2012, arXiv: 1205.1498v1.
  • John Blakeslee: Surface Brightness Fluctuations as Primary and Secondary Distance Indicators. In: Astrophysics. Solar and Stellar Astrophysics. 2012, arXiv: 1202.0581v1.
  • John P. Blakeslee, Michele Cantiello, Simona Mei, Patrick Cote, Regina Barber DeGraaff, Laura Ferrarese, Andres Jordan, Eric W. Peng, John L. Tonry, Guy Worthey: Surface Brightness Fluctuations in the Hubble Space Telescope ACS / WFC F814W bandpass and on update on Galaxy Distances. 2010, arXiv: 1009.3270v2.
  • Observation method of Astronomy
Elliptical galaxy Asymptotic giant branch
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