WFMOS Feasibility Study Value-added Science Bob Nichol, ICG Portsmouth

Science Productivity Big spectroscopic surveys produce big scientific results Many of the major results of WFMOS surveys are hard to predict today Datasets will have vast legacy benefits (e.g. more data going out of the HST archive than coming in)

Science Productivity – 2dFGRS Focused collaboration (~30) with specific science goals Since 2001, 2dFGRS has 17 th most cited paper in Astronomy. Also plays major role in most cited paper in this period (Spergel et al. 2003) Has 10 of the top 150 cited papers in this period

Science Productivity - SDSS Large collaboration (~200) with diverse science goals. 684 SDSS papers (so far) with citations 23 papers with >100 citations 1 st & 4 th most cited paper in 2004 “Breakthrough of the Year” Science 2003

WFMOS Legacy WFMOS is like both 2dFGRS and SDSS: Has focused science objectives, but will be significant archival science and new community observations Need to provide support to the community to maximise return: analysis tools, easy access to data and instrument, and useful measured quantities

Archival Science with DE Survey Constrain dark energy from cluster counts (Newman et al. 2002) and Alcock-Paczsynki test (Yamamoto et al. 2004) Spectroscopically identify thousands of SNe Ia Constrain the distance-duality relation [d A /d L = (1+z) 2 ] which tests the nature of gravity and photon conservation (axion-photon interactions) Accurately measure luminosity functions and star-formation rate densities with redshift and environment z~1) Constrain the shape of primordial power spectrum to 2% and thus measure mass of the neutrino (to 0.1eV)

Archival Science with SA Survey Elemental abundance patterns of Pop III enrichment. Signature in floor of chemical abundances, place limit on metallicity of gas accreted onto Milky Way Extract radial velocities of faint distant giants and determine total mass of Milky Way. We will have targets out as far as stars exist!

Community Science - examples of new observational programs Detailed studies of local low luminosity galaxies e.g. M r ~-11 (r~24) in the Coma Cluster (Bernstein et al. 1995) High redshift (z>4) studies of galaxies and QSOs from multi-color photometry Simultaneously observing QSOs and galaxies (in the same fields) to quantify the relation between the IGM and the large-scale structures as traced by galaxies.

Summary WFMOS is a unique survey instrument and therefore there will be substantial interest in archival data and new observations Tens of extra science projects outlined in Feasibility Study and KAOS Purple Book Follow in the footsteps of SDSS and 2dFGRS in terms of size and therefore, legacy value