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Seeing the Distant Universe in. 3D. 3D. Integral Field Spectroscopyat high redshift. Andrew Bunker, AAO & Oxford. Redshift z. 1100. After era probed by WMAP the Universe enters the so-called “dark ages” prior to formation of first stars
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Seeing the Distant Universe in 3D 3D Integral Field Spectroscopyat high redshift Andrew Bunker, AAO & Oxford
Redshift z 1100 After era probed by WMAP the Universe enters the so-called “dark ages” prior to formation of first stars Hydrogen is then re-ionized by the newly-formed stars When did this happen? What did it? DARK AGES 10 5 2 0
z~1 HDF spiral Near Infrared Camera NICMOS H (1.6m) J (1.2m) V (0.6m) I (0.8m) HUBBLE SPACE TELESCOPE U (0.3m) B (0.45m)
H (1.6m) J (1.2m) I (0.8m) V (0.6m) B (0.45m) U (0.3m)
"3D" Spectroscopy Previously used a "long slit" in spectroscopy - cut down background light, become more sensitiveRelatively new technique - integral field spectroscopy - arrange elements to survey a 2D area (rather than a 1D line)The spectra gives a 3rd dimension (wavelength, or velocity)
Cambridge IR Panoramic Survey Spectrograph Integral Field Spectroscopy
What is CIRPASS? • Near-infrared integral field unit (spectra over a 2D area) • Built by the IoA with support of Sackler foundation & PPARC • Wavelengths 0.9-1.8mm (z, J, H): doubles range of Gemini IFU science • 490 spatial samples & variable image scales 0.05"-0.33" up to 5"x12" field • Large wavelength coverage (Dl=2200Å) at R~4000: great sensitivity between OH sky lines • Limiting line flux on an 8m ~2x10-18 ergs/sec/cm^2 (53 hours) • Successfully demonstrated in August 2002 on Gemini-South telescope, community access 2003A 500 fibres IFU Instrument cryostat On dome floor
Exquisitely sensitive to line emission redshifted between OH • Star formation at z>1 (H, [OIII]5007Å, H, [OII]3727Å) • Robust star formation rate measures down to 1M⊙/yr • Rotation curves, kinematics • Masses, extinction, metallicity • Nature of damped Lyman- systems at high-z • Lensed galaxies/dark matter sub-clumping • Ages of young star clusters IFU Science
Gemini Integral Field Spectroscopy • Institute of Astronomy, Cambridge: Andy Bunker(AAO/Oxf), Joanna Smith (PhD student), Rachel Johnson (Oxf), Gerry Gilmore & Ian Parry, Rob Sharp, Andrew Dean etc CIRPASS team • Gemini: Matt Mountain, Kathy Roth, Marianne Takamiya, Inger Jørgensen, Jean-Rene Roy, Phil Puxley, Bryan Miller, etc. (Director's discretionary time) • Durham: Richard Bower, Roger Davies (Oxf), Simon Morris, Mark Swinbank etc. & GMOS team • Program with Gemini Observatory to demonstrate the power of IFUs (5nights GMOS+8 nights CIRPASS) • Large interntational team (CIRPASS observations involve ~50 scientists) lead by Cambridge/Gemini/Durham • First demonstration of near-IR IFU science
GEMINI-NORTH GMOS-IFU optical: Gemini Multi-Object Spectrograph Hawaii June 02 Andrew Bunker, Gerry Gilmore (IoA, Cambridge) & Roger Davies (Durham/Oxford) Chile Aug '02,Mar/Jun 03 GEMINI-SOUTH
Q2237+03 - Einstein cross Search for dark matter substructure - Ben Metcalf, Lexi Moustakas, Bunker z=1.7 QSO, z=0.04 lens
Substructure at 104M⊙<M<108M⊙ is 4%-7% of surface mass density - high compared to some CDM predictions (but poss. variability/microlensing)
Ben Metcalf, Lexi Moustakas, Andy Bunker & Ian Parry (2004, accepted by ApJ, astro-ph/0309738) Q2237+03 - Einstein cross
A z=1.2 radio galaxy 3C324(Joanna Smith PhD) • Extended blue light over >5", aligned with radio • 3C radio galaxy z=1.2 deep HST im. • studied by Spinrad & Dickinson • evidence of a cluster • size well-suited to GMOS/CIRPASS • study emission lines [OII] & [OIII]/H (kinematics)
[OIII] map in 3D of a z=1.2 galaxy (Smith, Bunker et al.) Sky (xy) (xz) (yz) Semi-raw frame
CIRPASS [OIII]5007 GMOS-IFU [OII]3727 HST R-band HST B-band (rest-UV) 3C324 alignment effect, with Joanna Smith (PhD student)
GMOS IFU Spectroscopy Gemini-N • 3C324 z=1.21 radio galaxy - "reduced" 2D (still has sky & cosmics, but extracted fibres) 8300Å 8000Å [OII]3727Å @z=1.2
[OII]3727 structure has two velocity components at +/-400km/s 3C324 3-D data cube Wavelength/velocity
CIRPASS [OIII]5007 GMOS-IFU [OII]3727 HST R-band HST B-band (rest-UV) 3C324 - Smith, Bunker, et al. : alignment effect
Galaxy kinematics redshift 1! H map of a CFRS disk galaxy with CIRPASS (Smith, Bunker et al., submitted)
Wavelength/velocity z=1 arc 3D data cube [OII]3727Å doublet, ~300km/s velocity shift
z=1 arc de-lensedMark Swinbank, Joanna Smith, Richard Bower, Andrew Bunker et al sky (lensed) de-lensed HST/WFPC (B,R,I) F450W, F606W, F814W [OII]3727Å velocity map
Galaxy Kinematics at High Redshift:Why do we care? - For disk galaxies, velocity at flat part of rotation curve correlates with the stellar mass of the galaxy (I- or K-band) - the Tully Fisher relation-How does this scaling relation evolve with time?- In "classical" model, dark halo forms first, and disk forms later: M/L decreases with time.-So circular velocity at a fixed stellar mass less in the past- BUT in hierarchical assembly, make galaxies through mergers, so stellar mass vs. circular velocity follows same relation over a wide range of redshifts- Can test this through rotation curves of z~1 galaxies- Use rest-optical lines redshifted into near-infrared- IFUs ideal - no uncertainty of slit axis vs. galaxy axis
Emission lines ⇒ Star formation rates, metallicity, dust extinction, kinematics
Damped Ly- QSO Absorption Systems Bunker, Warren et al.
CIRPASS refereed Publications • "Spectroscopic Gravitational Lensing and Limits on the Dark Matter Substructure in Q2237+0305" R.B. Metcalf, L.A. Moustakas, A.J. Bunker & I.R. Parry ApJ (astro-ph/0309738) • "Extragalactic integral field spectroscopy on Gemini" A. Bunker, J. Smith, I. Parry, R. Sharp, A. Dean, G. Gilmore, R. Bower, A.M. Swinbank, R. Davies, R.B. Metcalf & R. de Grijs (astro-ph/0401002) • "CIRPASS near-IR integral field spectroscopy of massive star clusters in the starburst galaxy NGC1140" R. de Grijs, L.J. Smith, A. Bunker, R. Sharp, J. Gallagher, P. Anders, A. Lancon, R. O'Connell & I. Parry; MNRAS (astro-ph/0404422) • "The Tully-Fisher Relation at z~1 from CIRPASS near-IR IFU H-alpha spectroscopy" J. Smith, A. Bunker, N. Vogt et al. MNRAS 2004
Seeing fluorescence from neutral hydrogen 20" z=4.5 QSO illuminating its protogalaxy 200Å zem=4.487 5" Spatially Extended Ly- Emission
Extended Ly- , narrow (FWHM~1000km/s) Central QSO (solid line)broad Ly- Recombination line probably powered by reprocessed QSO UV flux rather than by local star formation. Extended narrow Ly- (dashed line),no continuum The HI cloud of the host galaxy is ~>35kpc/h70 (=0.3)
SPH simulations, distribution of neutral gas at z~3 (from Katz et al. and Rauch, Haehnelt & Steinmetz). Left box is 22Mpc comoving, 15arcmin; right zoomed x10
The catch: very faint low surface brightness Wavelength/Å The deepest spectrum in the Universe?
Rauch, Haehnelt, Bunker, Becker et al. (2007) Win with IFUs rather than long-slit: MUSE?
DAZLE - Dark Ages 'z' Lyman-alpha Explorer (IoA - Richard McMahon, Ian Parry; AAO - Joss Bland-Hawthorne
"Lyman break technique" - sharp drop in flux at below Ly-. Steidel et al. have >1000 z~3 objects, "drop" in U-band. Pushing to higher redshift- Finding Lyman break galaxies at z~6 : using i-drops.
The Star Formation History of the Univese Bunker, Stanway, z=5.8 Ellis, McMahon & McCarthy (2003) Keck/DEIMOS spectral follow-up & confirmation I-drops in the Chandra Deep Field South with HST/ACS Elizabeth Stanway, Andrew Bunker, Richard McMahon 2003 (MNRAS)
Galaxies at z~6 are small - barely resolved by HST. E-ELT diffraction limit ~0.01” (~50-100pc). See individual HII regions?
What is JWST? • 6.55 m deployable primary • Diffraction-limited at 2 µm • Wavelength range 0.6-28 µm • Passively cooled to <50 K • Zodiacal-limited below 10 µm • Sun-Earth L2 orbit • 4 instruments • 0.6-5 µm wide field camera (NIRCam) • 1-5 µm multiobject spectrometer (NIRSpec) • 5-28 µm camera/spectrometer (MIRI) • 0.8-5 µm guider camera (FGS/TF) • 5 year lifetime, 10 year goal • 2014 launch
NASA/ESA/CSA - JWST • NIRSpec • ESA near-IR MOS to 5um, 3’x3’ • NIRCAM - 3’x3’ imager <5um • FGS (Canada) - has tunable 1% narrow-band NIR filters in • MIRI - mid-infrared Europe/US (closely similar to HST model…)
Absorption lines at z>5 - a single v. bright Lyman break z=5.5 galaxy, Dow-Hygelund et al (2005), AB=23-24, VLT spectrum (22 hours), R~3000; S/N=3-10 at R=1000,2700 in 1000sec NIRSpec
For I-drops (z~6) would only get ~1 per NIRSpec field bright enough for S/N~3-10 in continuum in 1000sec for abs line studies
Does AO Help you? • If Ly-alpha is compact, AO will boost point-source sensitivity • - Unclear if this will be the case - extended Ly-alpha haloes known, and expected through resonant scattering (see the far edge of the ionized bubble) • -For morphological analysis, unclear that high-tech ELT AO is better than a poorer but better-quantified PSF (e.g. from space) • -If you can’t quantify where 10-20% of the light goes from a centrally-condensed core, that’s the difference between a disk and bulge morphology when fitting Sersic index • -Even worse when looking for QSO host galaxies…
Conclusions • - 3D IFU spectroscopy at high redshift is (finally) realising its potential, but still small sample sizes • -Important as a probe of galaxy kinematics, and spatially-resolved maps of stellar populations, metallicity • - Trace the evolution of the assembly of stellar mass • -Explore the nature of gravitational lenses (dark matter) • - Explore the nature of the galaxies responsible for QSO absorption lines • -In future might see fluorescence of the HI gas • -Compact galaxies at high-z: need AO on ELTs to get real IFU benefit