4MOST: 4-metre Multi-Object Spectroscopic Telescope
Roelof de Jong AIP
www.4most.eu Conceptual Design Study for ESO
• Now: Conceptual Design study, completed by Feb 2013 • Science: space mission follow-up: Gaia, eROSITA, Euclid • Selection: 4MOST/MOONS decided ~May 2013 • Goal: start all-sky public surveys 2019 • Telescope: VISTA, 4m-class telescope • Data: yearly public data releases with higher level data products
• Expected specs: – Very high multiplex: ~2400 fibers – Full optical wavelength coverage: 390-950 nm – Large field-of-view: =2.6° • 4MOST provides in a 5 year, all-hemisphere survey 6 – >20 ×10 spectra @ R~5000 to mV~20 mag at S/N=20 6 – > 1 × 10 spectra @ R~20,000 to mV~16 mag at S/N=50
Roelof de Jong | 4MOST
Consortium effort
4MOST – 4-metre Multi-Object Spectroscopic Telescope
Roelof S. de Jonga, Olga Bellido-Tiradoa, Cristina Chiappinia, Éric Depagnea, Roger Haynesa,n, Diane Johla, Olivier Schnurra, Axel Schwopea, Jakob Walchera, Frank Dioniesa, Dionne Haynesa,n, Andreas Kelza, Francisco S. Kitauraa, Georg Lamera, Ivan Mincheva, Volker Müllera, Sebastián E. Nuzaa, Jean-Christophe Olaya a,n, Tilmann Piffla, Emil Popowa, Matthias Steinmetza, Uğur Urala, Mary Williamsa, Roland Winklera, Lutz Wisotzkia, Wolfgang R. Ansorgeb, Manda Banerjic, Eduardo Gonzalez Solaresc, Mike Irwinc, Robert C. Kennicutt, Jr.c, David Kingc, Richard McMahonc, Sergey Koposovc, Ian R. Parryc, David Sunc, Nicholas A. Waltonc, Gert Fingerd, Olaf Iwertd, Mirko Krumped, Jean-Louis Lizond, Mainieri Vincenzod, Jean-Philippe Amanse, Piercarlo Bonifacioe, Mathieu Cohene, Patrick Francoise, Pascal Jagourele, Shan B. Mignote, Frédéric Royere, Paola Sartorettie, Ralf Benderf, Frank Gruppf, Hans-Joachim Hessf, Florian Lang-Bardlf, Bernard Muschielokf, Hans Böhringerg, Thomas Bollerg, Angela Bongiornog, Marcella Brusag, Tom Dwellyg, Andrea Merlonig, Kirpal Nandrag, Mara Salvatog, Johannes H. Pragth, Ramón Navarroh, Gerrit Gerlofsmah, Ronald Roelfsemah, Gavin B. Daltoni,o, Kevin F. Middletoni, Ian A. Toshi, Corrado Boechej, Elisabetta Caffauj, Norbert Christliebj, Eva K. Grebelj, Camilla Hansenj, Andreas Kochj, Hans-G. Ludwigj, Andreas Quirrenbachj, Luca Sbordonej, Walter Seifertj, Guido Thimmj, Trifon Trifonovj, Amina Helmik, Scott C. Tragerk, Sofia Feltzingl, Andreas Kornm, Wilfried Bolandn
aLeibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam, Germany, bRAMS-CON Management Consultants, Assling, Germany, c University of Cambridge, United Kingdom, d European Southern Observatory, Garching bei München, Germany, e GEPI, Observatoire de Paris-Meudon, CNRS, Univ. Paris Diderot, France, f Universität-Sternwarte München, Germany, g Max-Planck-Institut für extraterrestrische Physik, München, Germany, hNOVA-ASTRON, Dwingeloo, the Netherlands, i Rutherford Appleton Lab., United Kingdom, jZentrum für Astronomie der Universität Heidelberg, Germany, k Kapteyn Astronomical Institute, Groningen, the Netherlands, l University of Lund, Sweden, m University of Uppsala, Sweden, ninnoFSPEC, Potsdam, Germany, oUniversity of Oxford, United Kingdom, nNOVA, the Netherlands
ABSTRACT AIP, LSW, LMU, MPE (D), IoA, RAL The 4MOST consortium is currently halfwaySPIE through a Conceptual paper Design study for ESO with the aim to develop a wide-field (>3 square degree, goal >5 square degree), high-multiplex (>1500 fibres, goal 3000 fibres) spectroscopic (UK), NOVA, RuG (NL), GEPI (F), survey facility for anhttp://arxiv.org/abs/1206.6885 ESO 4m-class telescope (VISTA). 4MOST will run permanently on the telescope to perform a 5 LU, UU (S), ESO year public survey yielding more than 20 million spectra at resolution R∼5000 (λ=390–1000 nm) and more than 2 million spectra at R~20,000 (395–456.5 nm & 587–673 nm). The 4MOST design is especially intended to complement three key all-sky, space-based observatories of prime European interest: Gaia, eROSITA and Euclid. Initial design and performance estimates for the wide-field corrector concepts are presented. Two fibre positioner concepts are being considered for 4MOST. The first one is a Phi-Theta system similar to ones used on existing and planned facilities. The second one is a new R-Theta concept with large patrol area. Both positioner conceptsRoelof effectively deaddress Jong the issues | of 4MOST fibre focus and pupil pointing. The 4MOST spectrographs are fixed configuration two-arm spectrographs, with dedicated spectrographs for the high- and low-resolution fibres. A full facility simulator is being developed to guide trade-off decisions regarding the optimal field-of-view, number of fibres needed, and the relative fraction of high-to-low resolution fibres. The simulator takes mock catalogues with template spectra from Design Reference Surveys as starting point, calculates the output spectra based on a throughput simulator, assigns targets to fibres based on the capabilities of the fibre positioner designs, and calculates the required survey time by tiling the fields on the sky. The 4MOST Design philosophy: 4MOST is a survey facility
– 4MOST runs all the time: minimal instrument changes, no significant time sharing – Coordinated system: survey and target selection, strategy for operating surveys in parallel, instrument capabilities, and data product delivery are all part of facility and are tuned to work together – One design fits many (4most) science cases: minimize constraints on science cases, but the number of observing modes (e.g. spectrograph configurations) should be kept to a minimum – Open data policy: all surveys public: raw data published immediately, higher-level data products in yearly Data Releases
Roelof de Jong | 4MOST Instrument Specification
Specification Concept Design
Field-of-View (hexagon) 4.3 degree2 ( >2.6°)
Multiplex fiber positioner ~2400 Medium Resolution Spectrographs R~5000-8000 Fibres 1600 fibres Passband 390-930 nm High Resolution Spectrograph R~20,000 Fibres 800 fibres Passband 395-456.5 & 587-673 nm
# of fibers in =2’ circle >5
Area (5 year survey) >2h x 20,000 deg2
Objects (5 year survey) >15x106
Start operations Mid 2019
Roelof de Jong | 4MOST Wide-field corrector can be inserted into VISTA like IR camera
Roelof de Jong | 4MOST Wide-field corrector VISTA =2.6°
IoA Cambridge, King, Parry, Sun, et al. Roelof de Jong | 4MOST
"*&=!c*(,#(0!&()!?&+D7(!A:7',2#:!B,:#$$&2#7(,N!
^#*$)!@7++*:27+!&()!:&1*+&!XJK@&1Y[-\.!&()!(7;!#(!#2,!:711#,,#7(#(0!G3&,*N!O3*!!#,!27!:7(,2+&#(!J&+=!K(*+0D!C#&!
! !JK%!#,!&!PID*&+!1'$2#5&()!#1&0#(0!,'+C*D!7C*+!PFFF!)*0 .!',#(0!23*!?$&(:7!2*$*,:7G*!270*23*+!;#23!&!(*;!ZNZ !"#)*!
Z Z
! !;#$$b&&7N07CN&'
-
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!
2'5*.!23*!+*,'$2#(0!,2#:=I,$#G!8+#:2#7(!5*2;**(!:'G!&()!5&$$!&$$7;,!23*!,G#(*!27!5*!2#$2*)!27!&(D!)*,#+*)!G7,#2#7(N!
,2**$!5&$$.!;3#:3!#,!3*$)!1&0(*2#:&$$D!#(!23*!:'GN!"3*(!&!,'#2&5$*!,&;27723!;&C*87+1!#,!&GG$#*)!27!23*!G#*>7:*+&1#:!
7(!27G!;3#:3!&$,7!:7(2&#(,!&!,1&$$!+#(0!1&0(*2N!O3*!,G#(*!:7(,#,2,!78!&!2'5*!:7(2&#(#(0!23*!8#5*+.!;3#:3!G&,,*,!23+7'03!&!
G#*>7:*+&1#:!2'5*!;#23!87'+!*$*:2+7)*,!#(!Q'&)+&(2,!7(!23*!7'2,#)*.!:*1*(2*)!#(27!23*!17)'$*.!270*23*+!;#23!&!:'G!0$'*)!
#,2,!78!&!
L5&,*M!&()!&!L,G#(*M!X*N0N!^#0'+*!PYN!O3*!5&,*!:7(, Echidna style positioner I0JK32!DE!>L2!I#$;.: O3*!K:3#)(&!&:2'&27+,!:7(,#,2!78!2;7!:71G7,#2*!G&+2,!a!&! ![H\N!! ;3#:3!3&,!HFF!&:2'&27+,!7(!&!ENZ11!G#2:3!X^#0'+*!-Y • Large, overlapping patrol areas enables #1G$*1*(2*)!87+!23*!^9B%IK:3#)(&!#(,2+'1*(2!87+!%'5&+'.! (! :71G&:2!&()!,#1G$*N!O3#,!2*:3(7$70D!3&,!&$+*&)D!5** – sparse fibres for high resolution $D! AABM,!L2#$2#(0!,G#(*M!2*:3(7$70D.!;3#:3!#,!#(3*+*(2 spectrograph :'++*(2$D!G+*8*++*)!G7,#2#7(*+!:7(:*G2!#,!5&,*)!7(!23*! &$$.!23*! SNEP11!7+!$*,,N!?*:&',*!23*!+*Q'#+*)!G#2:3!#,!,7!,1 – clustered fibres (e.g. galaxy clusters) 23*!G#2:3!X23*!)#,2&(:*!5*2;**(!&:2'&27+!:*(2*+,Y!1',2!5*! 3!1*&(,! ,'+8&:*N!A2!$*&,2!HFFF!&:2'&27+,!&+*!+*Q'#+*).!;3#: • Pitch ~10 mm, Patrol R: ~1.2x pitch 7G2#:,.!&()!23*!+*Q'#+*1*(2!87+!2*$*:*(2+#:#2D!&2!23*!87:&$! !"^@! G&+&1*2*+,!&+*!8#W*)!5D!23*!2*$*,:7G*.!23*!*W#,2#(0 • Reconfiguration time <1 min ;#23!R]1!+&)#',!78!:'+C&2'+*.!#$$'1#(&2*)!&2!R^_ZN`N!O3*,*! 8&:*.! JK%G*:!;#$$!3&C*!&!RHPF11!)#&1*2*+!:'+C*)!87:&$!,'+ • Proven technology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chidna on Subaru Positioner: AAO, Metrology & Control: AIP JK%G*:!87:&$!G$&(*!#,!HPF11!&:+7,,!&()!:'+C*).!&()!23*!+*Q'#+*)!G#2:3!#,!RSNEP11N!O3*!,#>*.!('15*+!78!8#5*+,!&()! "*!G+*,*(2!&!:7(:*G2!87+!&!HFFFI8#5+*!G7,#2#7(*+!87+!JK%G*:.!5&,*)!7(!23*!K:3#)(&!L2#$2#(0!,G#(*M!2*:3(7$70DN!O3*! &=;>?&@>! A',2+&$#&(!A,2+7(71#:&$!B5,*+C&27+D.!%D)(*D!<%"!-E-F.!A',2+&$#&! <#:=!%2&,>&=.!4'+*=!?+>*,=#.!%2&(!9#>#&+,=#.!9&223*;!@7$$*,,! "#$$!%&'()*+, .!/+*0!%1#23.!4&1*,!/#$5*+2.!67$8!9'$$*+.!9#:3&*$!/77);#(.!! - ! !"#$%&'()!*!+!,---./0123!4560705823!/53!9:;42 • Spectrographs gravitation invariant and outside dome environment • Short fibre run (~10–15 m) • Location High and Medium Resolution Spectrographs may be swapped (TBD) • Fixed configuration spectrographs, high throughput with VPH gratings • Two arm spectrographs, two 3k x 8k CCDs per arm Fibres: AIP High-Res Spectrograph: GEPI Roelof de Jong | 4MOST NOVA/ASTRON & RAL/Oxford, LSW What shall 4MOST deliver? • 4MOST shall be able to obtain: – Radial velocities of ≤2 km/s accuracy and Stellar parameters of <0.15 dex accuracy of any Gaia star • R~5000 spectra of 19.5 r-mag stars with S/N=10 per Ångström – Abundances of up to 15 chemical elements • R~20000 spectra of 15.5 r-mag stars with S/N=140 per Ångström – Redshifts of AGN and galaxies (also in clusters) • R~500 spectra of 22 r-mag targets with S/N=5 with >3 targets in =2’ • In a 5 year survey 4MOST shall obtain: – 20 (goal 30) million targets at R~5000 – 2.0 (goal 3.0) million targets at R~20,000 – 16,000 (goal 23,000) degree2 area on the sky at least two times Roelof de Jong | 4MOST How are we going to run 4MOST? • 4MOST program defined by Public Surveys of 5 years • Surveys will be defined by Consortium and Community • All Surveys will run in parallel – Surveys share fibres per exposure for increased efficiency • Key Surveys will define observing strategy – Millions of targests all sky • Add-on Surveys for smaller surveys – Small fraction fibers all sky – Dedicated small area Roelof de Jong | 4MOST How are we going to run 4MOST? • Consortium Surveys will ensure whole hemisphere covered with at least ~120 minutes total exposure time • Each exposure 20 minutes, repeats possible • Total exposures times per target between 20 and 120 min (and more) possible • Areas with more targets visited more than 120 min Roelof de Jong | 4MOST Main science drivers Roelof de Jong | 4MOST Design Reference Surveys • Milky Way halo R>5000 (~2M objects – Chemo-dynamics streams • Milky Way halo R>20,000 (~ 0.2M objects) – Chemical evolution of accreted components • Milky Way disks/bulge R>5000 (~10M objects) – Chemo-dynamics of bulge/disks • Milky Way disks/bulge R>20,000 (~1.5M objects) – Chemical evolution in situ components • eROSITA galaxy clusters (~50,000 clusters, ~2.5M objects) – Dark Energy and galaxy evolution • eROSITA AGN (~1M objects) – Evolution of AGN and the connection to their host galaxies • Extra-galactic/BAO survey (~10M objects) – Luminous red and blue galaxies survey Roelof de Jong | 4MOST Gaia needs spectroscopic follow-up to achieve its full potential • Gaia astrometric mission due for launch end-2013 – paralaxes and proper motions for 4MOST extents the ~1 billion stars to mG<20 mag Gaia volume by 1000x – spectra for radial velocities and in the red and 1 million metallicities for 150 million stars in the blue! to mG<~15 mag Cover the bulge/halo interaction and the Magellanic Clouds Roelof de Jong | 4MOST Gaia astrometric detections • Accurate radial velocities of Gaia will cover only Solar vicinity Roelof de Jong | 4MOST Near-field cosmology with Milky Way chemo-dynamics • Determine the Milky Way 3D potential to ~100kpc • Mass spectrum of Dark Matter subhalos by the kinematic imprint on cold streams • Measure the effect of baryons: – has there been adiabatic contraction? Cooper+ (2010)! – is there a disk-like DM component? • Chemical abundance substructure Milky Way halo • Chemical abundances of very first stars • Requirements for |b|>25°: – ~2M objects at R~5000 to mV=20 – ~0.2M objects at R~20,000 to mV=16 Yoon+ (2011)! Roelof de Jong | 4MOST Dissect the Assembly history of the Milky Way bulge and disks • Detailed 6D chemo-dynamics of bar/spiral structure in disks • Chemo-dynamical formation history of the bulge – how much is a classical merger remnant versus disk migration • Formation mechanisms of the thickened disk (in situ formation, heating, accretion, migration, etc.) • Quantify the importance secular evolution, resonances, radial migration in the disks Galactic bulge • Early chemical evolution in bulge/disk Sun (rare stars!) • Requirements (all sky): – ~10M objects at R~5000 to mV=20 – ~2M objects at R~20,000 to mV=16 Roelof de Jong | 4MOST Milky way bar creates moving groups in velocity distribution • So far only done out to 200 pc with Hipparcos • Gaia combined with 4MOST can do this to ~5 kpc, i.e. in almost a quarter of the Milky Way Minchev et al. " (2010)! Study global structure and abundance gradients with faint Giants sample • Due to the complexity of asymmetries expected, such as multiple spiral patterns, we need to survey the entire disk • Strong variation in the migration efficiency expected with galactic radius • Mergers create thick disks flares and thus we need to know the thick disk scale-height as a function of Galactic radius Roelof de Jong | 4MOST eROSITA follow-up • German - Russian mission • 0.3-4.5 keV, beam ~25” • 8x all sky survey (4 year) + 3 years pointed observations • Sky divided in two, German and Russian half • Launch 2014 • Mission goals: – Dark Matter and Energy, growth of structure – X-ray detection of 100000 galaxy clusters – X-ray detection of 3 million point sources (AGN and Galactic) Merloni talk Thursday Roelof de Jong | 4MOST Figure 2.4.1: The eROSITA telescope structure during the integration phase at MPE, in spring 2012. The telescope is is telescope The 2012. spring in MPE, at phase integration the during structure telescope eROSITA The 2.4.1: Figure mounted on a ring support for ease of manipulation, and shows, without its front cover, the mirror modules. modules. mirror the cover, front its without shows, and manipulation, of ease for support ring a on mounted Figure 2.4.2: Schematic diagram of the eROSITA telescope structure. structure. telescope eROSITA the of diagram Schematic 2.4.2: Figure 12 eROSITA needs spectroscopic follow-up to reach its full potential • X-ray selected galaxy clusters: – Competitive cosmological constraints using both growth rate of most massive over-densities and topology of large scale structure – Calibrate the LX – M relation to z~0.8 using cluster velocity dispersions – Evolution of galaxies in dense environments – Requirements: • R~500, redshifts to z~1 @ r~22 mag • X-ray selected AGN: – Cosmology from large scale structure formation – Evolution of active galaxies up to z=5 – Galaxy–Black Hole co-evolution relations to z=3 – Properties of gas around AGN – Requirements: • R~3000, emission line redshifts to z=5 Roelof de Jong | 4MOST Figure 2.4.1: The eROSITA telescope structure during the integration phase at MPE, in spring 2012. The telescope is is telescope The 2012. spring in MPE, at phase integration the during structure telescope eROSITA The 2.4.1: Figure mounted on a ring support for ease of manipulation, and shows, without its front cover, the mirror modules. modules. mirror the cover, front its without shows, and manipulation, of ease for support ring a on mounted Figure 2.4.2: Schematic diagram of the eROSITA telescope structure. structure. telescope eROSITA the of diagram Schematic 2.4.2: Figure 12 Cosmological constraints by obtaining redshifts and velocity dispersions of galaxy clusters • Using both cluster abundance and clustering, but no additional constraints • Blue: no redshifts • Red: with redshifts • This is for 8000 clusters, goal for 4MOST is 50,000 clusters Roelof de Jong | 4MOST BAO with X-ray selected AGN Klodzig, Gilfanov et al. in prep. Roelof de Jong | 4MOST Strengths of 4MOST • Dedicated spectroscopic survey facility • Full, continues optical wavelength coverage • All-sky coverage • High multi-plex • Power of 4m-class telescope exposing several hours 4MOST enables high quality statistical surveys of 103 to 107 objects, both all-sky and deep Roelof de Jong | 4MOST Other Science feasible with thousand to million object surveys • Follow-up of LSST and Euclid transients • Support Euclid photometric redshift calibrations – (but not to 99.5% completeness at I=24.5) • Star formation history of the Milky Way from 100,000 White Dwarfs • Ages of astro-seismology objects from e.g. CoRoT, Kepler • Nature of peculiar variable stars discovered by Gaia, LSST, Euclid • High resolution spectroscopy survey of Open Clusters • Radial velocities time series of low mass binary systems • Galaxy evolution from redshift surveys to z~1.5 • Nature of radio galaxies from SKA • Insert your idea here Roelof de Jong | 4MOST Simulate throughput, fibre assignment, survey strategy and verify total survey quality • Trade-off configurations: – Field-of-View – Fibre count – Positioner concepts – High/low resolution – Exposure time/overhead MPE, Garching, Boller, Dwelly et al. GEPI, Paris, Sartoretti et al. – Survey strategy IoA, Cambridge, Gonzalez-Solares et al. Roelof de Jong | 4MOST Large Area Spectroscopic Surveys Science with 4MOST Workshop • Program: – 4MOST facility capabilities – Galactic, extra-galactic, cosmology science – Discussion of Consortium and Community science • 13-15 November 2012 at AIP, Potsdam • Registration at workshop.4most.eu by Nov 1 Roelof de Jong | 4MOST Conceptual Design Study for ESO • Now: Conceptual Design study, completed by Feb 2013 • Selection: 4MOST/MOONS decided ~May 2013 • Goal: start all-sky public (consortium & community) surveys 2019 • Telescope: VISTA, 4m-class telescope • Science: space mission follow-up: Gaia, eROSITA, Euclid • Data: yearly public data releases with higher level data products • Current specs: – Very high multiplex: ~2400 fibers – Full optical wavelength coverage: 390-950 nm – Large field-of-view: =2.6° • 4MOST provides in a 5 year, all-hemisphere survey 6 – >20 ×10 spectra @ R~5000 to mV~20 mag at S/N=20 6 – > 1 × 10 spectra @ R~20,000 to mV~16 mag at S/N=50 • Your input welcome at this stage! Roelof de Jong | 4MOST