ST–ECF UC, Dec 01 1 NGST support at the ST-ECF Bob Fosbury

ST–ECF UC, Dec 01 2 Current activities Science oversight: ISWG (NASA), SST (ESA) Performance studies Simulations PR Future plans Support of European instrument procurement process Provision of ESA contribution to Science Operations

ST–ECF UC, Dec 01 3 ESA-NASA top level schedule /01 05/01 02/02 09/0303/04 09/04 06/09 12/06 Activity NASA Phase 1 (A/Early B) Phase 2 (Late B/C/D) Single Prime Select Instrument AO Release Instrument Selection PDR/NAR CDR Launch ESA Delta-Studies (NIR) Technology Developments MIR Studies Decision on ESA Contributions Definition Phase (NIR) Phase B (NIR) Phase C/D (NIR) MIR Instrument Development Instrument Delivery

ST–ECF UC, Dec 01 4 Current activities ST-ECF contribution in 2001: < 2 FTE including instrument science, s/w engineering and PR Fosbury, Cristiani & Freudling members of ESA Study Science Team Fosbury ex-officio member of ISWG

ST–ECF UC, Dec 01 5 Studies Parasitic light in NGST instruments… Cristiani, Arnouts & Fosbury, ISR , astro- ph/ Study of slit size optimisation and crowding effects Freudling with Arribas (STScI) “Spoilers” in MEMS-based spectrographs Cristiani, Pirzkal, Freudling et al. Coherence and interference effects in multi- mirror slits: NGST spectral calibration. Freudling et al.

ST–ECF UC, Dec 01 6 Future plans ESA intends to contribute to NGST Science Operations. NASA needs to minimise operational costs by using ‘community effort’. ESA, through the ST-DIV, will provide instrument science, data-flow and user support components for the European instrument contributions. It will also carry out PR and educational activities. STScI and ST-ECF are currently discussing how best to distribute this effort.

ST–ECF UC, Dec 01 7 Parasitic light effects ‘Uniform’ sky (Zodi or extended continuum source) background flooding the detector with the attenuation produced by the off-MEMS A set of ‘unwanted’ spectra (stars and galaxies) in the FOV, brighter than the target sources but attenuated by the off-MEMS — “SPOILERS” Light scattered from the MEMS structure which does not directly enter the collimator Imperfect filter blocking

ST–ECF UC, Dec 01 8 Toy model Direct and dispersed images with spoilers (bright)

ST–ECF UC, Dec 01 9 Source sizes Assumed source sizes and their dispersion for the overlap calculations Based on HDF NICMOS data

ST–ECF UC, Dec Spoiler probabilities Probability of overlap of target source by attenuated bright spoiler with different contrast factors (W Freudling assumptions)

ST–ECF UC, Dec Range from different authors Exploitable contrast limit set by direct leakage from PSF wings of bright sources

ST–ECF UC, Dec Simulations Catalogues based on HST observations of HDF-S Simulations performed using selectively attenuated slitless spectroscopy methodology developed for ACS (SLIM, Pirzkal et al.). Sensitivity and performance based on current NGST Mission Simulator

ST–ECF UC, Dec Simulation parameters R = h exposure time in 46x1000s integrations Target continuum sources are typical Ly-break at z ~ 3-4 with H AB ~ Emission line objects are Ly-break with added emission lines corresponding to low metallictiy HII regions scaled to give a Ly  EW of 2000 Å and a typical H AB ~ FOV is 3'x3' with pixels of 0.1" = 1800x1800 pixels The resulting spectra cover 750 pixels with 16 Å/pixel (constant) in the range 1.2 – 2.4 µm

ST–ECF UC, Dec Direct image based on NICMOS HDF-S targets targets and spoilers

ST–ECF UC, Dec Targets no noise Spoilers and targets no noise

ST–ECF UC, Dec Targets and spoilers with noise Targets with noise

ST–ECF UC, Dec Targets and spoilers with noise Targets with noise

ST–ECF UC, Dec Emission targets — 50% of sources have emission Emission targets & spoilers

ST–ECF UC, Dec Emission with noise Emission and spoilers with noise

ST–ECF UC, Dec Targets and spoilers with noise Emission targets with noise

ST–ECF UC, Dec R100 simulations spectra cover 440 pixels with 100Å/pixel in the range 0.6 – 5 µm Typical magnitudes of the candidates H AB ~ 27–28 1/2 of the candidates with very strong emission lines Exposure time is 19.6hr to get a H AB ~ 28

ST–ECF UC, Dec Targets no noise Spoilers and targets no noise

ST–ECF UC, Dec Targets and noise Spoilers and targets and noise

ST–ECF UC, Dec MEMS phase errors Study of the throughput (flux calibration) effects produced by phase differences introduced between adjacent MEMS mirrors in the NGST focal plane. Fourier optics methodology (Freudling)

OTA & mirror errors

Optical layout

ST–ECF UC, Dec Realisations — 1 Efficiency for randomly chosen mirror parameters The maximum tilt is 0.1°, the maximum offset 0.2µm

ST–ECF UC, Dec Realisations — 2 Maximum tilt is 0.5°

ST–ECF UC, Dec Realisations — 3 Randomly chosen position on MEMS ‘slit’ subarray

ST–ECF UC, Dec MEMS/detector = 2

ST–ECF UC, Dec MEMS/detector = 1.5

ST–ECF UC, Dec Array alignment 45° ~0°