70 likes | 176 Views
Gravitational Lensing Distorts Counts of Very High Redshift Galaxies. Stuart Wyithe (Univ. Melbourne), Haojing Yan (Ohio State Univ.), Rogier Windhorst (Arizona State Unv.), Shude Mao (Univ. Manchester & NAOC, China) (Based on Publication in Nature, Jan 12, 2011)
E N D
Gravitational Lensing Distorts Counts of Very High Redshift Galaxies • Stuart Wyithe (Univ. Melbourne), Haojing Yan (Ohio State Univ.), Rogier Windhorst (Arizona State Unv.), Shude Mao (Univ. Manchester & NAOC, China) • (Based on Publication in Nature, Jan 12, 2011) • AAS 217th Meeting, Seattle, WA • January 12, 2011
Gravitational Lensing Is Well Known (1990) (1996) (2005) Lensing of background objects by foreground galaxy clusters Lensing of background objects by individual foreground galaxies
Implication for High-redshift Studies Yet to Be Fully Explored • Gravitational lensing by individual foreground galaxies amplifies background high-redshift galaxies • It happens more often than we used to think • The effect manifests itself by concentration of high-redshift galaxies around foreground galaxies Credit: NASA, ESA, Z. Levay and A. Feild (STScI)
High Lensing Rate at Very High Redshifts: Initial Evidence Hubble Ultra Deep Field Image, Optical + IR
About 20% of candidate galaxies at redshifts ~ 8 - 10 are found to be very close to foreground galaxies, consistent with our prediction
Y-band “dropouts”: candidate galaxies at redshifts ~ 8 J-band “dropouts”: candidate galaxies at redshifts ~ 10 Red Band Blue Band
Why This Is Important • Bright distribution of galaxies at very high redshifts is crucial to our understanding of how the universe was forming galaxies in its infancy • High incidence of lensing implies that there are many very faint galaxies at these very high redshifts