Probing Stellar Populations in the Virgo an Fornax Clusters with Infrared Surface Brightness Fluctuations
Description
Surface brightness fluctuaHons (SBF) are a useful tool for measuring extragalacHc distances. At infrared wavelengths, SBF break the age-‐metallicity degeneracy and are useful for probing the properHes of the most luminous stars in a galaxy, even when individual stars are not resolved. We present a detailed comparison of F110W and F160W SBF measurements made using the Hubble Space Telescope WFC3/IR camera to a variety of stellar populaHon models, including those with solar-‐scaled and alpha-‐enhanced composiHons and models incorporaHng convecHve core overshoot for younger populaHons. We use these model comparisons to assess the star formaHon histories of 6 galaxies spanning a wide range in color and luminosity in the Virgo and Fornax clusters, measured as a funcHon of distance from the galaxy center in ellipHcal apertures. We discuss the implicaHons of populaHon variaHons on the fluctuaHon magnitudes and distance measurements.
Probing Stellar Populations in the Virgo an Fornax Clusters with Infrared Surface Brightness Fluctuations
The Leonardo Event Center
Surface brightness fluctuaHons (SBF) are a useful tool for measuring extragalacHc distances. At infrared wavelengths, SBF break the age-‐metallicity degeneracy and are useful for probing the properHes of the most luminous stars in a galaxy, even when individual stars are not resolved. We present a detailed comparison of F110W and F160W SBF measurements made using the Hubble Space Telescope WFC3/IR camera to a variety of stellar populaHon models, including those with solar-‐scaled and alpha-‐enhanced composiHons and models incorporaHng convecHve core overshoot for younger populaHons. We use these model comparisons to assess the star formaHon histories of 6 galaxies spanning a wide range in color and luminosity in the Virgo and Fornax clusters, measured as a funcHon of distance from the galaxy center in ellipHcal apertures. We discuss the implicaHons of populaHon variaHons on the fluctuaHon magnitudes and distance measurements.