文档介绍：z～7 Galaxies in the HUDF: First Epoch WFC3/IR . Oesch, . Bouwens, . Illingworth, . Carollo, M. Franx, I. Labbé, D. Magee, M. Stiavelli, M. Trenti, and . van DokkumApJ, January 20, 2010Presented by Sean MarshallAST 494Terminologyz: redshiftHUDF: Hubble Ultra Deep Field: Wide Field Camera 3/wfc3/design/at_a_glance/TerminologyIntroduction?Detailed studies of galaxies up to z ~ 6?Use Lyman break galaxies (LBG)–Appear very faint (if at all) in UV filter–Lyman limit being redshifted past that filter–Indicate z > /~jfynbo/?Less study of galaxies of z ~ 7–About 13 billion years ago?Luminosity function – number per luminosity interval?Not well known for those galaxies?Would provide information on epoch of reionization and /~wright/?Light bluer than Lyman limit is absorbed–For the most part?Lyman limit redshifted into near infrared (NIR) for z ~ 7?NIR hard to observe well?But now we have WFC3!Figure 3Observations?WFC3/IR observations in three filters–H160 (F160W), J125 (F125W), and Y105(F105W)/wfc3/design/at_a_glance/Observations?62 orbits during August and September of 2009?See to magnitudes of - (AB)? arcmin2?This data set “allows us to generate the deepest NIR images ever seen”Source Selection?Lyman Break technique – based on colors (differences between magnitudes)Figure 1Source Selection?(z850? Y105) > ?(z850? Y105) > + (Y105? J125)?(z850? Y105) > ? + 4(Y105? J125)?S/N(J125) > 5 ∧ S/N(Y105) > 5?S/N(V606) < 2 ∧ S/N(i775) < 2Figure 1