July 25th, 2000WFC3 Critical Science Review1 Performance Summary in Key Science Areas Verify that WFC3 as designed is capable of carrying out the WFC3 science as described in the WFC3 Science White Paper and in the Design Reference Mission

July 25th, 2000WFC3 Critical Science Review2 Performance Summary in Key Science Areas – cont’d The figure illustrates the exposure time such that background noise equals the detector noise. For longer exposure times the observations are background limited. Note that full orbit WFC3 exposures with broad band filters in the visible and in the near-IR are generally background limited.

July 25th, 2000WFC3 Critical Science Review3 High-z Universe WFC3 is capable of detecting star forming galaxies with star formation rate of 50 M O yr -1 up to z=5 and those with SFR of 160 M O yr -1 up to z=10.

July 25th, 2000WFC3 Critical Science Review4 Point source limiting magnitudes WFC3 science requires reaching faint magnitude limits for point-like or compact sources. The figure shows the limit for a detection in 10,000 s with S/N=5. The point source photometry components of the nearby galaxies, resolved stellar populations, stars and ISM science themes are enabled by the present CEIS.

July 25th, 2000WFC3 Critical Science Review5 Resolved Stellar Populations Goal: resolve individual stars in Virgo Cluster galaxies Assumptions: DM = 31.5 absolute magnitude of giant stars M V =-2.5 (B2 or red giant) no more than 1 bright star per 9 pixels The brightest stars in Virgo cluster galaxies can be individually resolved down to surface brightness = 23.5 mag arcsec -2

July 25th, 2000WFC3 Critical Science Review6 Resolved Stellar Populations Goal: resolve individual stars in reddened regions in the LMC Assumptions: DM = 18.6 A V = 3.0 All main sequence stars down to M6 are bright enough to be observed.

July 25th, 2000WFC3 Critical Science Review7 Extended source limiting magnitudes WFC3 is a sensitive instrument for extended sources photometry. The figure shows the magnitude limits for S/N=1 in a 10,000 s exposure. On chip binning in the UVIS increases only marginally the S/N for the broad band filters but has important effects for narrow band observations (up to 70 per cent more S/N.)

July 25th, 2000WFC3 Critical Science Review8 Limiting flux of emission lines WFC3 allows detection of faint emission line sources. The table illustrates the limiting flux for obtaining a S/N=5 in a square arcsec in a 10,000 s exposure. FilterOrion II spectrum ( erg s -1 cm -2 arcsec -2 ) PN spectrum ( erg s -1 cm -2 arcsec -2 ) F373N F487N20.0 F502N20.0 F631N1.25 F656N12.5 F953N

July 25th, 2000WFC3 Critical Science Review9 Conclusions WFC3 is capable of carrying out the WFC3 science as described in the WFC3 Science White Paper and in the Design Reference Mission.