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Science Case Fiber/Slit Wavelength Cov ResolutionWav.Cal. Stability
Typical Mag
Throughput FOV AO Multiplex
metals in the IGM fiber/slit 0.32-1.5 >100.000 15-21
few arcsec in the IR?
tomography fibers 0.35-0.70 10.000 19-21 (24) >10% 5 arcmin no ~10x
molecules fiber/slit 0.32-0.7 >100.000 15-20 >10%few arcsec no
galaxiesfiber/slit/IFU 0.35-2.4 10.000 K=24 >20% 30" not really ~10x
primordial Gals red-2.4
>4000-10000 J=26 >20% 3 arcmin not really ~10x
GRBs fiber/slit 0.32-2.4 >5000 15-24 >20%few arcsec in the IR
constants fibers 0.32-0.70 >150.000comb < 1m/s 15-18few arcsec no
expansion fiber 0.35-0.70 >100.000comb2 cm/s (20yr) 15-17 >20%
few arcsec no
HIGH REDSHIFT GALAXIES and COSMOLOGY SUMMARY
RESOLUTION
>100.000-150.000 (IGM metals, molecules, constants)(300.000 would be fine too – turbulence? See Evoli 2011)
~10.000 (galaxies, GRBs)
- “Linearly goeth Spectral Range, with the volume scaleth Resolution”
- “Only above R ~ 150.000 Astronomy becomes Astrophysics”
log NHI = 14.7 δ=7
log NHI = 13.5 δ=0
log NCIV = 12
20h
z=3
SPECTRAL RANGE
310-320 nm (constants, IGM metals, molecules, expans.?)350-370 nm (galaxies, tomography, expansion?)~red (primordial Gals)
~700 nm, optical (molecules, expansion, tomography)IR-H (metals in the IGM)IR-K (galaxies, primordial galaxies, GRBs)
X-shooter spectrum: J0818+1722 (zem= 6.00, Jvega = 18.5)
Si II 1260z=5.79
C II 1334O I 1302
Si II 1260z=5.87
O I 1302C II 1334
Si II 1526z=5.06
VIS
NIR
R=8800
R=5600
V.D’Odorico + 2010
Metal pollution in the Universe
13.8< log N(CIV) <15
Adelberger 05
D’Odorico, Cupani, Cristiani + 2012
An archaeological record of past star formation
Reionization: sources of systematics
Smaller transmission region due to the presence of associated strong overdensities !
WRONG estimate of the transmission region !!
SED of ionizing spectrum vs. ion.potentials
0.64
0.86
ADAPTIVE OPTICS ?
Most cases do not require adaptive optics(good, HIRES can be used during “bad” weather!)
The optical/higher res (constants, expansion, tomography, molecules …) [sky surface brightness]
Galaxies [intrinsic dimensions ~0.2”] not extreme AO
Would be useful for point-like sources in the IR, when we go faint (GRBs, metals in the IGM at high-z)GLAO?
FOV/Multiplex
• Most cases do not require multiplex/wide field of view (constants, expansion, GRBs, molecules, IGM metals)
• FOV: 30” galaxies, 3’ primordial galaxies, 5’ tomography
• limited multiplex (~10x)• MULTIPLEX ANTICORRELATES WITH
RESOLUTION (slicer!)
Fibers are OK or required for most of the cases (provided that the sky subtraction in the IR is correct)IFU for galaxies? (see also HARMONI)
The whole range UV-optical-IR in one shot is highly desired (e.g. transient phenomena – GRBs, see also economy of ELT time)
Throughput MUST be large (faint objects), [cf. HARMONI ~>35%]
CALIBRATIONS
• Justify stability at a level of few cm/s for ALL high S/N (~>200) cases
• Need for High-Fidelity spectroscopy (see Dravins 2010)
• Not only wavelength calibration (Laser Comb) but also (e.g.) flat fielding, relative flux resp., psf (fibers may be an advantage)
• Telluric lines?
Visible and near-infrared (0.47 to 2.45 µm) integral field spectrograph, over a range of resolving powers from R (≡λ/Δλ) ~ 4000 to R~20000. The instrument provides simultaneous spectra of ~32000 (8000) spaxels in the near-IR (visible) arranged in a 2:1 aspect ratio contiguous field.
HARMONI
Arribas, 2011
HARMONI Wavelength Ranges & Resolving Powers
Band min[µm] max[µm] [Å/pixel] R
H+K 1.450 2.450 2.500 3900
I+z+J 0.800 1.360 1.400 3857
V+R 0.470 0.810 0.850 3765
K 1.950 2.450 1.250 8800
H 1.460 1.830 0.925 8892
J 1.080 1.360 0.700 8714
I+z 0.820 1.030 0.525 8809
R 0.630 0.790 0.400 8875
V 0.500 0.630 0.325 8692
K high 2.090 2.320 0.575 19174
H high 1.545 1.715 0.425 19176
J high 1.170 1.290 0.300 20500
z 0.820 0.910 0.225 19222
R high 0.610 0.680 0.175 18428
V high 0.530 0.590 0.150 18666
HARMONI Sensitivity
20 mas spaxels provide best sensitivity for point sources 40 mas spaxels best for extended sources
JWST is not a competitor (complementary resolution) ☺nor we can expect a synergy [MIRI and FGS/NIRISS @ Goddard
NIRCAM and NIRSPEC in 2013]
HIRESHIGH REDSHIFT GALAXIES and COSMOLOGY SUMMARY
Fiber spectrograph2 res. Modes (15.000 – 150.000) 3 arms covering (0.32) 0.35-1.7 (2.4) micronHigh-throughput (>20%)3-5’ FOV10x multiplex for the low-res mode High-fidelity (few cm/s, S/N~200 in one exposure)
HIGH REDSHIFT GALAXIES and COSMOLOGY SUMMARY
Fiber spectrograph2 res. Modes (15.000 – 150.000) 3 arms covering (0.32) 0.35-1.7 (2.4) micronHigh-throughput (>20%)10x multiplex for the low-res modeHigh-fidelity (1 cm/s, S/N~200 in one exposure)
HIR
ESESO
HIRESHIGH REDSHIFT GALAXIES and COSMOLOGY SUMMARY
Fiber spectrograph2 res. Modes (15.000 – 150.000) 3 arms covering (0.32) 0.35-1.7 (2.4) micronHigh-throughput (>20%)3-5’ FOV10x multiplex for the low-res mode High-fidelity (1 cm/s, S/N~200 in one exposure)