1 / 14

Ultra- Deep galaxy surveys with DIORAMAS@EELT the early build -up of galaxies

Ultra- Deep galaxy surveys with DIORAMAS@EELT the early build -up of galaxies. Olivier Le Fèvre With the DIORAMAS team (F, IT, CH, SP). Galaxy populations at and after reionisation. What do we need ? Find the “first” galaxies: exciting ! Journal headlines !

fawn
Download Presentation

Ultra- Deep galaxy surveys with DIORAMAS@EELT the early build -up of galaxies

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Ultra-Deepgalaxysurveyswith DIORAMAS@EELTthe earlybuild-up of galaxies Olivier Le Fèvre With the DIORAMAS team (F, IT, CH, SP)

  2. Galaxy populations at and afterreionisation • What do we need ? • Find the “first” galaxies: exciting ! Journal headlines ! • Study the population of galaxies as it quickly evolves: astrophysics ! • Requires large surveys • Search for objects and then study them • Several time steps, types, environment: need thousands of objects • Surveys are more than ever the backbone of exploration • Statistical robustness

  3. Understandinggalaxy formation and evolutionrequiresmulti-stepsurveys A severalstepprocess • Search for objects: need to findobjectsbeforedoingphysics ! • Estimate the meanproperties: N(z), luminosity, gas/stellar masses, SFRD, morphology, clustering, …. assemble representativesamples • Isolatewelldefinedsub-populations for detailedstudies, e.g. kinematics • Infer a scenario & compare to models / simulations Deep multi-band imaging Large multiplex MOS IFU, AO-imaging, high-resspectra… Instrument flow Followed by all major surveys:CFRS, DEEP2, VVDS/MASSIV, IMAGES, LBG/SINS, zCOSMOS…

  4. GalaxyredshiftsurveysWhatis to beexpectedwhen EELT starts ? z<2 “all sky” coverage from EUCLID: 50 million spectroscopic redshifts • 2<z6 willstillbeunder-explored: • ~20 sq.deg • ~50000 zspec • Not enough for a comprehensivepicture • 6<z<10+: HST then JWST starting 2018 • ~1 sq.deg • 1000 zspec? • Not enough for robuststatistics • Not enough for welldefinedcase studies

  5. Finding first light objectsz>6.5 What are we looking for ? • Very faint objects AB>26.5 • Relatively sparse: 0.1 to 1 object per arcmin² per Δz=1 • The IGM will cut their observed flux below Ly • Main signatures: Ly-dropout and Ly emission • Need to sample from very rare bright objects to more numerous small building bricks (still rare on the plane of the sky) • At z>6.5 all the information is in the NIR Careful: • Take predictions on number density with caution (see historical perspective) Expect the unexpected… Keep a large parameter space for instruments

  6. MOS(s) on the VLT MOS: a fundamentalleapforward in instrumentation All major telescopes have one or more MOS VLT: 5-6 MOS flavors To cover a consistent parameter (discovery) spaceweneedat least 2 of these, ideallycombining modes, on the EELT

  7. 2 imaging-multi-slit MOS in the top 3 @VLT • Demonstrates « work-horse » versatile use • Galactic and Extra-Galactic Science • VLT science output isdominated by MOS ! FORS2 VIMOS

  8. Select the sample • Magnitudes, colors, NB... • Multi-slit Spectroscopy • Spectral features • Redshift • The best performances • High sky subtraction accuracy 0.1% Power of imaging-MOS • Multi-band imaging • Positions, magnitudes, shapes Main target, z=1.02 SerendipitousLyman z=4.3

  9. led to DIORAMASinstrument concept – phase A study • High multiplex MOS withslits • Imaging mode • Use EELT naturalseeing or GLAO-correctedbeam • Instrument concept accomodatesboth • Widefield: 6.8x6.8 arcmin² • 0.37-1.6 microns A versatile instrument

  10. DIORAMAS Opto-mechanicallayout

  11. DIORAMAS design parameters High throughput: 30% VIS, 45% NIR (with detector) Excellent image quality: 150 mas 80% encircledenergy Gain @1µm 10-25 compared to JWST-NIRSPEC: x5 multiplex, x2.5-5 FOV, at equivalent depth/unit time

  12. Wide field, multi-mode Multi-slitR~300 High multiplex 480 slits giJ Imaging VIS VIS NIR NIR >30,000 sources in 7’x7’ to rAB=29.8 JWST-NIRSPEC JWST-NIRCAM 12

  13. Wide field, multi-mode Multi-slitR~3000 High multiplex: 160 slits giJ Imaging VIS VIS NIR NIR >30,000 sources in 7’x7’ to rAB=29.8 JWST-NIRSPEC JWST-NIRCAM 13

  14. MOS spectroscopy at the EELT“extragalactic” science Need 2 MOS flavors A powerfulcombinationfor high-z: Imaging-MOS and multi-IFU+AO 3D IFU-MOS Imaging-MOS DIORAMAS

More Related