This is a color composite image of the Hubble Ultra Deep Field. Green circles mark the locations of candidate galaxies at a redshift of z~8, while higher-redshift candidates are circled in red. The estimated distances to these candidates have not been confirmed spectroscopically.
About 20 to 30 percent of these high-z galaxy candidates are very close to foreground galaxies, which is consistent with the prediction that a significant fraction of galaxies at very high redshifts are gravitationally lensed by individual foreground galaxies. This will help as a guide for future observations planned for the James Webb Space Telescope when it is launched.
Credit: NASA, ESA, S. Wyithe (University of Melbourne), H. Yan (Ohio State University), R. Windhorst (Arizona State University), and S. Mao (Jodrell Bank Center for Astrophysics, and National Astronomical Observatories of China)
Acknowledgment: G. Illingworth and R. Bouwens (University of California, Santa Cruz), and the HUDF09 Team