ETC Teaching Session Instructor: Swara Ravindranath JWST Proposal - - PowerPoint PPT Presentation

The Canadian NIRISS Unbiased Cluster Survey (CANUCS)

ETC Teaching Session Instructor: Swara Ravindranath

JWST Proposal Planning Workshop STScI May 15 – 18, 2017

The Canadian NIRISS Unbiased Cluster Survey (CANUCS)

• Slitless spectroscopy and Imaging of 5 massive galaxy clusters

and 10 parallel fields using NIRISS WFSS, NIRCam imaging, and NIRSpec MOS modes

• Primary science goals:
• 1. DetecJon and CharacterizaJon of galaxies within the reionizaJon epoch
• 2. EvoluJon of low-mass galaxies across cosmic Jme
• 3. Resolved emission-line maps and line raJos for galaxies in the cosmic noon

The Canadian NIRISS Unbiased Cluster Survey (CANUCS)

• Cluster SelecDon:
• 1. High mass and large area with high magnificaJon
• 2. CriJcal curves fit within the 2.2’ x 2.2’ FOV of

NIRISS

• 3. More than 10 degrees away from zodiacal plane
• 4. Minimal area lost to bright stars
• 5. At z>0.35 to avoid contaminaJon from ICL and

cluster galaxies

• 6. High quality data available at other wavelengths

The Canadian NIRISS Unbiased Cluster Survey (CANUCS)

NIRISS Wide Field Slitless Spectroscopy

• IdenJcal grisms (GR150R and GR150C) with R=150
• Grisms disperse along Orthogonal direcJons
• Grisms mounted on Filter wheel
• Blocking filters in the Pupil wheel
• Can use 6 short wavelength filters for WFSS

• NIRISS Prime ObservaDons (137/199 hrs)

– NIRISS direct imaging in F115W, F150W, F200W

4 exposures of NIS Ng=13 (4x558s = 2232s)

– NIRISS GR150R grism in F115W, F150W, F200W

8 exposures of NIS Ng=33 (8x1417.3s = 11338s)

– NIRISS GR150C grism in F115W, F150W, F200W

8 exposures of NIS Ng=33 (8x1417.3s = 11338s)

• NIRISS WFSS Observing sequence

Direct image --- GR150C --- Direct image Direct image --- GR150R --- Direct image

The Canadian NIRISS Unbiased Cluster Survey (CANUCS)

CANUCS GTO also includes:

NIRCam Imaging NIRSpec MOS NIRCam Imaging parallels NIRISS WFSS parallels

JWST ETC - Topics being covered

• Re-useability of scenes in mulDple calculaDons

(point src sensiJviJes)

• Batch expansion

(deciding on integraJons, exposure Jmes)

• Adding Emission Lines to source spectra

(grism exposure sensiJviJes)

• Sky Background with posiDon

(effect of background on SNR)

JWST ETC -Topics being covered

• Complex scenes

(eg; lensed galaxies)

• Spectral overlap from close targets

(esJmate contaminaJon for the 2 grisms)

• Aperture Size

(choosing aperture radius for strategy)

• Upload Source Spectrum

(user-supplied spectra for special targets)

Direct image GR150R+200W GR150C+200W

JWST ETC - Downloads

• FITS files of 2D SNR, Detector image, SaturaJon Maps
• FITS file of 3D data cube
• Tables of the lineplots for SNR, extracted source flux,

background flux, and contaminaJon

Scene 1 has mulJple sources to examine the SNR in direct & grism exposures

Adding emission lines to source spectrum Examine the sources, overlap,

• rientaJon

Examine the source spectrum and flux levels

Complex scenes and sources can be created in 2D Galaxy spectra templates Reusability of sources Examine the sources, overlap,

• rientaJon

Examine the source spectrum and flux levels, adjust wavelength range in plots

GR150R: Overlap along dispersion direcJon GR150C: Overlap minimal along

• rthogonal dispersion direcJon

Over-subtracJng the background from within the scene

Line spread funcJon depends on morphology of source. In GR150C, lensed arc is along the dispersion direcJon and results in lower spectralresoluJon relaJve to GR150R.

GR150C GR150R

CalculaKons for z=8.79 starburst galaxy near bright cluster galaxy at z=0.45 Plot results for 3 filters for full λ coverage Ly-α CIII]