6dFGS Workshop, Epping 11 July 2003 Fred Watson (and the RAVErs) 6dFGS Workshop, Epping 11 July 2003 Fred Watson (and the RAVErs)

Overview What is RAVE? Science goals—why are we RAVEing? Instrumentation The RAVE’s progress A few other issues...

What is RAVE? RAdial Velocity Experiment International collaboration—22 scientists in 11 nations All-sky survey of stellar velocities & metallicities 50 million stars, complete to I=15 (Biggest EVER) Enables true galactic archaeology Spawned from (now-defunct) space missions UK Schmidt Telescope and a northern counterpart Completely externally funded ($A, €, $US, ¥?) Public data-base; VO compliant

Science goals Comparison with simulations of structure-growth within a CDM Universe (Steinmetz & Navarro, 2002) Substructure in the halo (cold stellar streams) Chemical signatures ([  /Fe], [Fe/H]) to identify common formation sites among widely-separated stars Formation of bulges Origin of the thick disk Dynamical state of the thin disk and neighbouring spiral arms

RAVE—the first new-millennium survey…

Simulation of a galactic halo built up by accretion of 100 satellite galaxies Same simulation plotted in phase space, revealing the different orbits. The disrupted remnants can clearly be seen.

More RAVEing Phase I: April 2003–June 2005, using unallocated UKST bright time during the 6dF Galaxy Survey 10 5 stars with I<13.5, B-V<0.8 Centred on Ca triplet: 8498Å, 8542Å, 8662Å in the far red region of the spectrum Currently measuring 700 stars per night Phase II: 2006–10, all UKST time once the Galaxy Survey is complete Will measure 22,000 stars per night

Instrumentation for RAVEing

Phase I instrumentation: 6dF robot

(with 100µm fibres) GratingReciprocalInstrumentalCCDSpectral dispersionresolutionresolutionrange (Å/mm)(Å)(Å/pixel)(Å) 425R V B I301.0~ (All in 1st order) 6dF VPH Grating Parameters

6dF is too slow for 22,000 stars per night... Therefore adapt the 400-fibre positioner currently being developed by AAO for Subaru Echidna Ball-Spine Array Phase II instrumentation

Module assembly Top bridge Fibre cover Middle bridge Fibre spines and piezo actuators Module PCB Module base

Echidna complete design Single module

–2250 spines (each with 15 arcmin patrol area) –Covers full field area of 6  6 deg 2 –Feeds spectrograph with 3  750 banks of spectra –Who builds the spectrograph? –AAO has go-ahead for a UKidna design-study –But UKidna will cost ~$A2M –How might it be funded? Echidna for RAVE

The MOMFOS story…

The RAVE’s Progress

Implementation plan RAVE timeline (2.25y): Phase 0/I (External staff required: 2.0FTE by ) (0.5y): UKidna installation/comm (5.0y): Phase II (External staff required: 6.0FTE by )

6dFGSRAVE N/STotalExp 2003(flds)(flds)(flds)(flds)(hours) Jan/Feb Feb/Mar Mar/Apr Apr/May May/Jun Jun/Jul* Total * to 2003 July 8/9 6dF observations 03A

Data-format: easy to make VO compliant (though AAO may adopt CADC format rather than VOtable) Metadata: robot-generated data, etc. already written to data headers, but observer data is not Log6dF will allow additional metadata to be aatached (observing conditions, weather data, field alignment quality, observer’s name, observer comments, etc. etc.) VO-compliance

$ A vs. € $ A vs. £ $ A vs. $ US $ A vs. ¥ RAVE spectrum?