software modelling of ifu spectrometers

ADASS XVII - September, 20071

Software Modelling of IFU Spectrometers

Nuria P. F. Lorente

UK Astronomy Technology Centre

Royal Observatory, Edinburgh, UK

Alistair C. H. Glasse, Gillian S. Wright (UK ATC, JWST-MIRI), Suzanne Ramsay Howat (UK ATC, KMOS), Chris J. Evans (UK ATC, EELT)


Why do we need instrument simulators?



Increasing scale and complexity of telescopes and instruments with time




We need to know how design and construction changes may potentially affect the science we can do with the instrument





Development of data reduction and analysis software requires test data






An understanding of the data products will help in designing effective calibration strategies






An understanding of the data products will help in designing effective calibration strategies

Synthetic data products are an effective communication tool in a distributed scientific and engineering environment


JWST-MIRI MRS

• Launch in 2013

• Positioned at L2

• 4 instruments on board


JWST-MIRI MRS

• Launch in 2013

• Positioned at L2

• 4 instruments on board

• Collaborative project between

• Consortium of 21 institutes under ESA

• NASA

• Imager, coronograph, low-resolution spectrometer, IFU medium resolution spectrometer


JWST-MIRI MRS

• 4 spectral channels (5 – 28 microns)

• FoV 3.70x3.70arcsec – 7.74x7.93 arcsec

• Spectral resolution ~3000

• One IFU slicer per channel

• All channels are observed simmultaneously

• Dichroic filters divide each IFU channel into 3 sub-bands

• Data from pairs of channels are captured on two 1024x1024 pixel detectors

• Expected sensitivity 1.21e-20 Wm^-2, 6.4microns, 5.610e-20 W^m-2 at 22.5 microns


Specsim: Modelling the Field of ViewSpecsim GUI



Sky Background



Sky Background

Targets



Sky Background

Targets

Sky Model


Specsim: Modelling the IFU Spectrometer



Transmission Function Definitions




Cosmic RaysNoise

Exposure Length


JWST-MIRI MRS

Modelling Observations of a YSO

(Glasse et al., in prep. 2007)


JWST-MIRI MRS



Spitzer IRS spectrometer (Lahuis et al., 2006)


"IRS46 at 875 pc"N_TARGETS 1{"Dither_A"0 0.485 1.01N_CONT 20 0.015 700.00 0.002 160.0N_BROAD 20 -0.001 15.2 0.301 -0.014N_NARROW 36012.02300 -0.245 “NL1"12.03510 -0.023 “NL2"...}

JWST-MIRI MRS






JWST-MIRI MRS




Point source

Black-body continuum

CO2 Gaussian absorption feature, and silicate spectrum

360 narrow absorption lines (HCN etc.)



JWST-MIRI MRS




Specsim synthetic spectrum

Point source

Black-body continuum

CO2 Gaussian absorption feature, and silicate spectrum

360 narrow absorption lines (HCN etc.)


JWST-MIRI MRS



1B

2B

3B4B1B

2B

3B4B

Simulated detector image Simulated white-light images


VLT - KMOS

• NIR multi-object IFU spectrometer

• 3 identical channels

• 8 IFUs per channel

• 14 slices of 14 pixels per IFU

• 3 spectrographs

• 2048 x 2048 pixel detector images


VLT - KMOS“Emission line galaxy with 3 lines”

N_TARGETS 1

{

“Galaxy continuum”

1 0.0 0.0 2.0 0.6 50

N_CONT 1

0 0.000003 2500.0

N_BROAD 0

N_NARROW 0

}

“Emission line – different extent”

1 0.0 0.0 2.0 1.0 140.0

N_CONT 0

N_BROAD 0

N_NARROW 3

1.1 90.0 “Line1”

1.7 60.0 “Line2”

2.2 100.0 “Line3”

}


VLT - KMOS

• White-light image of the galaxy

• Image of the galaxy at the wavelength of the emission line

• Portion of the detector image

• Note the spectral line and the galaxy continuum


Simulated field of view

E-ELT Investigating the effect of adaptive optics on image quality



E-ELT

Seeing-limited PSF

Investigating the effect of adaptive optics on image quality


Simulated white-light image, with no AO correction

E-ELT

Seeing-limited PSF




Ground-layer correction PSF



Simulated white-light image with ground-layer correction

Ground-layer correction PSF




Laser Tomography PSF



Simulated white-light image with laser-tomography correction

E-ELT

Laser Tomography PSF



E-ELT

• Seeing-limited field

• Ground layer correction only

• Laser-tomography


software modelling of ifu spectrometers

Documents

instrument simulators

ifu channel

ifu spectrometer specsim

ifu slicer

complexity of telescopes

construction changes

lowresolution spectrometer

analysis software