GALEX-ASTRO-F Project

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GALEX-ASTRO-F Project Studies on Dust Extinction
and Star Formation in Galaxies
Tsutomu T. Takeuchi NAOJ/the University of
Tokyo 2001.7.19
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Introduction of GALEX and Laboratoir
dAstrophysique de Marseille
Thanks to Dr. B. Milliard
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Cross-comparison of the GALEX and ASTRO-F Galaxy
Sample
Thanks to Dr. V. Buat and Dr. Boselli
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GALEX-FIR comparison studies
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UV and FIR sample selection
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We will discuss this point later.
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Robust Measure of Attenuation Factor
Witt Gordon 2000, ApJ, 528, 799
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Geometry of dust and stars
Shell
Cloudy
Dusty
But spherical symmetry is assumed in Witt
Gordon model (DIRTY).
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Relations between various extinction
characteristics
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FIR-optical flux ratio and UV attenuation factor
Still not very robust.
Because B and V band photons are not efficient
for dust heating.
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UV-FIR flux ratio a robust measure
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Summary
UV-to-FIR flux ratio is a robust measure of UV
attenuation factor. This requires the measurement
of the entire spectral energy distribution of
galaxies! (But there still remains dependence on
the geometry because Witt Gordon assume
spherical symmetry. Further numerical studies are
also required.)