the prime focus imaging spectrograph for the southern african large telescope: operational modes
DESCRIPTION
Chip Kobulnicky – Instrument Scientist, University of Wisconsin PFIS Team Kenneth Nordsieck PI – University of Wisconsin Eric Burgh Instrument Scientist – University of Wisconsin Darragh O’Donoghue Detector PI - South African Astrophysical Observatory - PowerPoint PPT PresentationTRANSCRIPT
The Prime Focus Imaging Spectrograph for the The Prime Focus Imaging Spectrograph for the Southern African Large Telescope: Southern African Large Telescope:
Operational ModesOperational Modes
Chip Kobulnicky – Instrument Scientist, University of Wisconsin
PFIS Team
Kenneth Nordsieck PI – University of WisconsinEric Burgh Instrument Scientist – University of WisconsinDarragh O’Donoghue Detector PI - South African Astrophysical ObservatoryMichael Smith Instrument Engineer – University of WisconsinJeffrey Percival Project Manager – University of WisconsinTed Williams Fabry-Perot PI – Rutgers University
PFIS OverviewPFIS Overview
First-generation, all-purpose First-generation, all-purpose spectrograph on the Southern African spectrograph on the Southern African Large Telescope (SALT). Large Telescope (SALT). Commissioning in fall 2004. Commissioning in fall 2004.
Optical imaging spectrograph Optical imaging spectrograph
3200Å - 9000Å3200Å - 9000Å 8’ Field of view8’ Field of view All-refractive collimator & cameraAll-refractive collimator & camera
(see 4841-164, Burgh et al., for (see 4841-164, Burgh et al., for
optical design of PFIS)optical design of PFIS)
PFIS SchematicSubsystems: 1. Focal Plane
openlongslit custom slitmask
2. Polarization Opticsopen (quartz block)½ wave plate¼ wave plate½ & ¼ wave plates
+ polarizing beamsplitter 3. Dispersive Elements
none (unarticulated)5 VPH gratingsFabry-Perot etalon(s)
4. CCD Detectornormal readoutframe transfercharge shuffle
Planned Future Upgrade
PFIS Operational ModesPFIS Operational Modes
ImagingImaging Grating SpectroscopyGrating Spectroscopy
CCD Readout CCD Readout ModeMode
Observing ModeObserving ModeFocalFocalPlane Plane UnitUnit
Field
Field
Waveplat
Waveplat
Observing ModeObserving ModeFocalFocalPlane Plane UnitUnit
Field
Field
Waveplat
Waveplat
Normal Normal ReadoutReadout
(<0.25 Hz)(<0.25 Hz)
Filter ImagingFilter Imaging nonenone 8’8’ NN Longslit SpectroscopyLongslit Spectroscopy slits 1-6slits 1-6 8’8’ NN
Fabry-Perot ImagingFabry-Perot Imaging nonenone 8’8’ NN Multi-slit SpectroscopyMulti-slit Spectroscopy maskmask 8’8’ NN
Imaging PolarimetryImaging Polarimetry Mask 2Mask 2 4’4’ YY Longslit SpectropolarimetryLongslit Spectropolarimetry slit 7slit 7 4’4’ YY
Fabry-Perot PolarimetryFabry-Perot Polarimetry Mask 2Mask 2 4’4’ YY Multi-slit SpectropolarimetryMulti-slit Spectropolarimetry maskmask 4’4’ YY
Frame TransferFrame Transfer(fast; ~1 Hz)(fast; ~1 Hz)
Fast Filter ImagingFast Filter Imaging Mask 1Mask 1 4’4’ NN Fast longslit SpectroscopyFast longslit Spectroscopy slit 8slit 8 4’4’ NN
Fast Fabry-Perot ImagingFast Fabry-Perot Imaging Mask 1Mask 1 4’4’ NN Fast multi-slit SpectroscopyFast multi-slit Spectroscopy maskmask 4’4’ NN
Fast Imaging PolarimetryFast Imaging Polarimetry -- -- -- Fast Longslit Polarimetry Fast Longslit Polarimetry -- -- --
Fast Fabry-Perot PolarimetryFast Fabry-Perot Polarimetry -- -- -- Fast Longslit SpectropolarimetryFast Longslit Spectropolarimetry -- -- --
Charge ShuffleCharge Shuffle(very fast;(very fast;
up to 20 Hz)up to 20 Hz)
V. Fast Filter ImagingV. Fast Filter Imaging maskmask ”” NN V. Fast Longslit Spectroscopy V. Fast Longslit Spectroscopy slits 1-8slits 1-8 ”” NN
V. Fast Fabry-Perot ImagingV. Fast Fabry-Perot Imaging maskmask ”” NN V. Fast Multi-slit SpectroscopyV. Fast Multi-slit Spectroscopy maskmask ”” NN
V. Fast Imaging PolarimetryV. Fast Imaging Polarimetry maskmask ”” YY V. Fast Longslit Spectropolar.V. Fast Longslit Spectropolar. slit 7slit 7 ”” YY
V. Fast Fabry-Perot PolarimetryV. Fast Fabry-Perot Polarimetry maskmask ”” YY V. Fast Multi-slit Spectropolar.V. Fast Multi-slit Spectropolar. maskmask ””
Y Y
Forbidden modes
λλ Coverage & Spectral Resolution Coverage & Spectral Resolution
Contours at 90%, 70%, 50% efficiency. Assumes 1.25” slit, αmax=45 deg
4500
1500
3000R
Redshift surveysNebular abundances
Planetary nebulakinematics & abundances
Ca H&K, [O II] kinematicsz = 1.6 Ly αz = 1-2 restframe UVBowen florescence
Ca II stellar kinematics
1.2” seeing
0.7” seeing
Spectral Resolution vs. ThroughputSpectral Resolution vs. Throughput
780 l/mm VPH grating: efficiency and 780 l/mm VPH grating: efficiency and wavelength coveragewavelength coverage
Field center
-2’ field angle
+2’ field angle
Readout Modes and TimesReadout Modes and Times
Normal readouts: 4096 x 6044 pixels – 3.6 s with 5e- read noise
Frame Transfer: 2048 x 6044 pixels – 1.8 s with 5 e- readnoise
Image Height(arcmin)
Image Height(pixels)
Readout Time(s)
4.0 2048 1.595
2.0 1024 0.797
0.5 256 0.199
0.125 64 0.050
2048 2048 2048
Image field4’
Charge transfer buffer
See 4841-052, O’Donoghue et al. for detector details
High Time Resolution
Fabry-Perot SpectroscopyFabry-Perot Spectroscopy
3 F-P Etalons3 F-P Etalons R=500 tunable filterR=500 tunable filter R=2500 (dual etalon)R=2500 (dual etalon) R=12000 (dual etalon)R=12000 (dual etalon)
4300 4300 ÅÅ – 8600 – 8600 ÅÅ
Star cluster kinematics Star cluster kinematics Galaxy cluster kinematics (z>0.4)Galaxy cluster kinematics (z>0.4)Flows in SF regions & galaxiesFlows in SF regions & galaxiesF-P imaging polarimetry of reflection nebulaeF-P imaging polarimetry of reflection nebulae
(PI - Ted Williams, Rutgers)
PolarimetryPolarimetry(See 4843-24 - Nordsieck et al.)
Linear polarimetry – ½ wave plate, 8 positions Imaging polarimetry, 4’ FOV – polarimetric surveysLongslit spectropolarimetry – novae, magnetic stars, AGN Time-resolved polarimetry or spectropolarimetry –
accreting binaries, AGN, GRB
Circular polarimetry – ½ wave plate (8 positions), ¼ wave plates (2 positions)
2048 2048 2048
40964’
mask
mask
Focal Plane Detector
PFIS Science & SummaryPFIS Science & Summary
Mu
lti-ob
ject
Rap
id R
ead
ou
t
Pola
rimetry
Fab
ry-Pero
t
Multi-slit spectral surveys (e.g., redshift surveys, stellar surveys) X
Wide-field polarimetric imaging (e.g., Magellanic Cloud surveys) X
Extreme blue λ galaxy kinematics & populations (z=1-2) X
High time resolution spectroscopy (CVs, GRB, AGN) X
High time resolution spectropolarimetry (CVs, GRB, AGN) X X
Imaging spectropolarimetry (novae, PNe, active galaxies) X X
?????
Signal-to-noise vs. Signal-to-noise vs. MagnitudeMagnitude
EfficiencyEfficiency
Spectral Resolution vs. ThroughputSpectral Resolution vs. Throughput