6dFGS Workshop, Epping

11 July 2003

Fred Watson (and the RAVErs)

6dFGS Workshop, Epping

11 July 2003

Fred Watson (and the RAVErs)

OverviewWhat is RAVE?

Science goals—why are we RAVEing?

Instrumentation

The RAVE’s progress

A few other issues...

What is RAVE? RAdial Velocity ExperimentInternational collaboration—22 scientists in 11 nationsAll-sky survey of stellar velocities & metallicities50 million stars, complete to I=15 (Biggest EVER)Enables true galactic archaeologySpawned from (now-defunct) space missionsUK Schmidt Telescope and a northern counterpartCompletely externally funded ($A, €, $US, ¥?)Public data-base; VO compliant

Science goals Comparison with simulations of structure-growthwithin a CDM Universe (Steinmetz & Navarro, 2002)Substructure in the halo (cold stellar streams)Chemical signatures ([/Fe], [Fe/H]) to identifycommon formation sites among widely-separated starsFormation of bulgesOrigin of the thick diskDynamical state of the thin disk and neighbouring spiral armswww.aip.de/RAVE/

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 Survey105 stars with I<13.5, B-V<0.8 Centred on Ca triplet: 8498Å, 8542Å, 8662Å in the far red region of the spectrumCurrently measuring 700 stars per nightPhase II: 2006–10, all UKST time once the Galaxy Survey is completeWill measure 22,000 stars per night

Instrumentation for RAVEing Instrumentation for RAVEing

Phase I instrumentation: 6dF robot

(with 100µm fibres)

Grating Reciprocal Instrumental CCD Spectraldispersion resolution resolution range (Å/mm) (Å) (Å/pixel) (Å)

425R 169 6.6 2.20 5300-7600

580V 126 4.9 1.64 3900-5600

1201B 60 2.1 0.78 3600-4400

1700I 30 1.0 ~0.4 8415-8800

(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

Moduleassembly

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 deg2 – Feeds spectrograph with 3750 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 ProgressThe RAVE’s Progress

Implementation plan

RAVE timeline

1.4.03 - 30.6.05 (2.25y): Phase 0/I

(External staff required: 2.0FTE by 31.12.03)

1.7.05 - 31.12.05 (0.5y): UKidna installation/comm.

1.1.06 - 31.12.10 (5.0y): Phase II

(External staff required: 6.0FTE by 1.7.05)

6dFGS RAVE N/S Total Exp2003 (flds) (flds) (flds) (flds) (hours)

Jan/Feb 25 10 35 95.9Feb/Mar 16 19 35 72.3Mar/Apr 24 3 14 41 96.3Apr/May 37 32 9 78 115.9May/Jun 33 12 8 53 84.9Jun/Jul* 37 21 2 60 80.5

Total 172 68 62 302 548.8

* 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?