TPF-I SWG Report - Exoplanet Exploration Program - NASA

G ENERAL A STROPHYSICS
Figure 3-8. Effective radii measured in the K-band as a function of redshift for a subsample
of FIRES/VLTsurvey with K AB > 25. TPF-I can resolve most of these galaxies, many more
than JWST.
shifts, Darwin/TPF-I will be needed to determine their galactic locations, to determine their relationships
to other galactic structures, and to characterize their global properties.
Current theory, modeling, and observations indicate that galaxies grow and evolve by merging. How do
these processes impact global and local star formation and the formation, growth, and evolution of black
holes Darwin/TPF-I will obtain milli-arcsecond resolution observations that can be directly compared to
models.
Scheduling flexibility will enable Darwin/TPF-I to respond to targets of opportunity and transient
phenomena such as ultra-high redshift, possibly population III, supernovae, flaring activity in the AGN,
or even currently unanticipated time-dependent phenomena. Darwin/TPF-I will provide milli-arsecond
characterization of these phenomena and their immediate environments.
Galactic evolution will remain a central theme of astrophysics for decades to come. The investigation of
large samples of distant galaxies will be crucial for such studies. The “Lyman break technique” has
defined samples of more than 1000 galaxies between 2.5 < z < 5 (e.g., Steidel et al. 1999). Lyα and Hα
emitting galaxies have also been found with deep imaging through narrow-band filters (e.g.. Venemans et
al. 2002; Kurk et al. 2003) or by selection of very red J−K colors (Franx et al. 2003). Spectroscopic
follow-up of Submillimetre Common-User Bolometer Array (SCUBA) galaxies, radio galaxies (e.g. de
Breuck et al. 2001), and X-ray emitters (e.g. Rosati et al. 2002) have yielded significant samples of z > 2
objects.
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