2. Overview of IFUs & science results

• Selected IFUs, science highlights & datacube visualization

• Brief overview of the major topics in astronomy

• Data formats in (optical & infrared) astronomy

IFUs

• Optical– SAURON, VIMOS, FLAMES, GMOS, PPAK

• Infrared– SINFONI, OSIRIS

• Many more exist– TIGER, OASIS, IMACS, NIFS, GNIRS, ...

• Near future– MUSE, KMOS, VIRUS

• Space based– NIRSpec, MIRI (both on JWST)

LensletsLenslets + FibresFibresSlicer

Astronomy 101

• Seeing: typically < ~1 arcsec for ground based telescope– telescope diffraction limit < 0.1 arcsec for D > 10 cm

• Redshift:

• IFU ⇒ complex data ⇒ complex data reduction and analysis ⇒ complex physics

Lenslet array: SAURON

SAURON • 1600 square lenslets• 0.94”/lenslet (33”x41” field) • 4810-5400 Angstrom range• R ~ 1500

Bacon et al.

Lenslet array: OSIRIS

OSIRIS • > 1000 square lenslets• AO corrected• 1- 2.5 micron range• R ~ 3800

Larkin et al.

Nearby galaxies

Bacon et al.

Examples from the SAURON survey

Distant galaxies: SSA22a

Paraview rendering

Bower et al. 2004

Spatially resolved observations of the diffuse Lyman alpha halo around a proto-galaxy

SSA22b (z = 3.09)

VolView rendering

Observational evidence for feedback process: crucial ingredient of galaxy formation scenarios.

Lenslet array + fibres: VIMOS

VIMOS • 6400 square lenslets• 0.67”/lenslet (54”x54” field) • 3500-9000 Angstrom range• R ~ 300 - 1500

VIMOS March ‘02

VLT 1st Gen. Instrument: FLAMES-IF

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Active galaxy: Seyfert 1.9

• Nearby AGN (z~0.1)

• Interacting/merging(?) with companion

• Triggered jet activity

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FLAMES - deployable IFUs

FLAMES (d-IFUs)• 15 d-IFU spectroscopy• 20 μ-lenses (2”x3” field)• 0.37-0.95 μm range• R ~ 1.1x 104

• λ/Δλ = 9.5; εF ~ 68%

VLT 1st Gen. Instrument: FLAMES-IF

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Multiplexed IFU observations of intermediate redshift galaxies

Flores et al. 2006

• Observed 35 galaxies

• Texp = 8 - 13 hours

• z: 0.4 to 0.7

• No TF evolution in in ‘regular’ galaxies

Tully-Fisher at z=0.6

GMOS-IFU

GMOS-IFU• 0.2”/lenslet (5”x7” field)• 0.4-1.0 μm range• R ~ 1.1x 104

• λ/Δλ = 9.5; εF ~ 68%

Allington-Smith et al.

VLT 1st Gen. Instrument: FLAMES-IF

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GMOS IFU observations of the prototypical Seyfert 2 NGC 1068

Complex emission-line profiles in the galaxy’s nucleus

GMOS IFU datacube of Hbeta in NGC 1068 + disk model

Slicers: Sinfoni

SINFONI• 250 – 100 - 25 mas slice width• 8”x8”- 3”x3”- 0.8”x0.8” field• 32 x 64 spaxels• 1.1-2.45 μm range• R : 1.5x103 (H+K) / 3x103 (H) /

4x103 (K)

SINFONI Jul. ‘04

Galactic centreYoung stars and infrared flares in the central light-month, Eisenhauer et al, 2005

High-z galaxiesRotation curves and dynamical evolution of galaxies at z=2, Förster Schreiber et al, 2006

As SAURON survey but for distant, hence young galaxies

Fibres: PPAK

PPAK • 331+36 non-contiguous fibres• 2.7”/fibre (74”x65” field)• 0.35-0.90 μm range• R ~ 5000

Roth et al.

PPAK

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

NGC 488

Long-slit data

Probe of secular evolution and appears to correlate with Hubble type

Summary of IFU applications

• Planets (searches for)

• Dense stellar clusters (eg. globular clusters)

• Galactic centre

• Planetary Nebulae

• Nearby galaxy: mass distribution, stellar population, central black holes

• Active galaxies (AGN): central engine, jet activity, feedback

• Distant galaxies: young galaxies, gravitational arcs, Ly-alpha galaxies

• Cosmology

Volumetric visualization:

Summary of IFU visualisation

IFU specific:

Euro3D: Sánchez, 2004

File format(s)

• FITS is the standard in astronomy– Header + data– Reference:

• A potential alternative for IFU data is Euro3D – Based on the FITS standard

The Euro3D Format

Major scientific objectives (of all new facilities, eg. ELT, JWST)

• The end of dark ages: first light and re-ionization• The assembly of galaxies• The birth of stars and the proto-planetary systems• The planetary systems and the birth of life

The end of the dark ages: first light and reionization

• What are the first galaxies?• When did reionization occur?

– Once or twice?• What sources caused reionization?

The assembly of galaxies• What are the physical processes that determine galaxy

properties?• How did the heavy elements form?• Can we test hierarchical formation and global scaling

relations?• What about ‘active’ galaxies (AGN)?

The birth of stars and protoplanetarysystems

• How do clouds collapse?• How does environment affect star-formation (and vice-versa) ?• What is the low-mass IMF (stars planets)?

Deeply embedded protostar

Agglomeration & planetesimals Mature planetary system

Circumstellar disk

David Hardy

The planetary systems and the origins of life

• How do planets form?• Are circumstellar disks like our Solar System?• How are habitable zones established?

Simulated JWST imageFomalhaut at 24 microns

Spitzer imageRobert Hurt

• Extra-solar giant planets– Coronagraphy

• Spectra of circumstellar disks, comets and KBOs• Spectra of icy bodies in outer Solar System

TitanMalfait et al 1998

The planetary systems and the origins of life

Exercises

• Datacube visualisation– FITS data format– Non-contiguous datacube

• Extract infomration from datacubes– Extract images over selected wavelength regions– Extract spectra of various sources

• Is an IFU the best choice for your science case?– www.eso.org/observing/etc