Alex Fullerton NIRISS Team Lead RE207 / x1341 / fullerton@stsci.edu JWST FGS Almost All About JWST / NIRISS: Near Infrared Imager and Slitless Spectrograph Alex Fullerton NIRISS Team Lead RE207 / x1341 / fullerton@stsci.edu INS Training 2016 July 13

OTE + ISIM + OTIS

JWST: Four Science Instruments NIRCam Near Infrared Camera NIRSpec Near Infrared Spectrograph MIRI Mid-Infrared Instrument GR150R GR150C NIRISS

JWST Focal Plane GR150R GR150C

The Elevator Pitch: FGS & NIRISS Fine Guidance Sensor (FGS) The camera to acquire targets and guide on them during observations. Used for purely functional purposes. Supplied by CSA Prime Contractor: COM DEV International GR150R Optical Bench GR150C NIRISS A near-infrared science instrument for imaging and slitless (grism) spectroscopy. Supplied by CSA Prime Contractor: COM DEV International Principal Investigator: René Doyon, Université de Montréal

Optical Layout of NIRISS NIRISS has a very simple, all-reflective design

Detector Parameter Value Array Size 2048 × 2048 (2040 x 2040 active) Pixel size 18 μm × 18 μm Dark rate < 0.02 e−/s Noise 23 e− (correlated double sample) Gain 1.6 e− / ADU Field of View 2.2´ × 2.2´ Plate scale in x 0.0654 arcsec/pixel Plate scale in y 0.0658 arcsec/pixel Detector: HAWAII 2RG HgCdTe 5.2 μm cutoff

epoxy void features occulting spots detector defects cross-hatching Flight Detector F200W External Flat epoxy void features detector defects occulting spots cross-hatching POM spot

What Can NIRISS Do? Pupil Wheel Filter Wheel

NIRISS Has 4 Observing Modes Name Acronym What It’s Good For 1) Imaging Imaging Imaging with filters matched to NIRCam 2) Wide-Field Slitless Spectroscopy WFSS Getting spectra of everything in the field of view 3) Single Object Slitless Spectroscopy SOSS Getting very precise spectra of bright objects. Especially transiting exoplanets 4) Aperture Masking Interferometry AMI High-contrast imaging with very high spatial resolution

1) Imaging

Filter Transmission & Sensitivity nJy m(Vega) F090W 11.28 28.28 F115W 11.22 28.06 F140M 14.80 27.43 F150W 9.19 27.83 F158M 12.88 27.39 F200W 7.81 27.54 F277W 6.63 27.09 F356W 6.89 26.56 F380M 18.74 24.34 F430M 28.32 24.65 F444W 12.29 25.49 F480M 36.85 24.14 S/N = 10 in 10 ks

2) Wide-Field Slitless Spectroscopy

Seeking Rare Objects in the High-z Universe MACS J0647+7015 HST Image: Composite of ACS and WFC3 exposures. Credit: NASA, ESA, M. Postman, D. Coe (STScI), and the CLASH Team. Simulation of the CLASH field through the NIRISS F200W filter by Chris Willott (NRC) and Van Dixon (STScI).

WFSS Simulations: F200W + GR150R GR150R Disperses Along Rows

WFSS Simulations: F200W + GR150C GR150C Disperses Along Columnss

Orthogonal Dispersion of GR150R and GR150C 89.99 ± 0.04 degrees 0th order

Geometry of Orders: GR150R + blocking filters -1 +1 +2 +3 +4 +5 F090W F115W F150W F200W +1 +2

First-Order Sensitivity: Emission Lines

NIRISS Can Detect the Oesch et al. z=11.09 Source in ~20 hours

3) Single-Object Slitless Spectroscopy

Transiting Exoplanet Science Seager & Deming (2010, ARAA, 48, 631) Precision needed: 1 part in 1,000 This is a schematic illustration (not to scale!) of how transits and eclipses of planets around other stars provide information about the planet. In general, we see the combined light from the star + planet; but the planet’s contribution is extremely small. Periodically – if the orientation is correct – the planet passes in front of the star (“transits”) and blocks out a bit of starlight, so the combined signal drops. When the planet moves behind the star, it is eclipsed; but since its contribution to the total is small, the reduction in the total signal is also small. Looking for periodic reductions in light is how NASA’s Kepler satellite has successfully detected many planetary systems around other stars (more than 700 announced last week!). The duration of the eclipse provides information about the size of the planet. By disentangling spectra of (star + planet) and (star alone during secondary eclipse), we can obtain the spectrum of the planet alone – AMAZING! The spectrum tells us about the physical conditions in the atmosphere of the planet. The trick is that we need to be able to do this with extraordinary precision. During a transit we can also use spectroscopy to probe the light that’s transmitted by the planet’s atmosphere, but that requires even greater precision. Transit Learn about atmospheric circulation from thermal phase curves Measure size of planet. Precision needed: 1 part in 100 See starlight transmitted through planet atmosphere. Precision needed: 1 part in 10,000

cylindrical surface (lens) GR700XD Grism weak cylindrical surface (lens) Weird Stuff! Prism: ZnS (Zinc Sulfide) Grism: ZnSe (Zinc Selenide) Weak Lens + Prism Side Grism Side Unruled Perimeter

GR700XD Trace & Orientation 0.6 – 2.8 μm Rλ 500 – 1600

GR700XD Monochromatic PSF Spatial CV3 monochromatic PSF FWHM Dispersion Trace Width (Defocus) Point spread function of the monochromatic source at 1.309 μm seen through the GR700XD element. The intensity is displayed in a logarithmic scale. The width of the PSF is due to the GR700XD weak lens and the height of the PSF depends on the quality of the optics, since the width of the monochromatic the source spectrum is much smaller than 1 pixel.

SOSS Expected Performance 2nd order 1st order

SOSS Saturation Limits

NIRISS Can Access Most Targets That Will Be Detected by TESS

4) Aperture Masking Interferometry

Non-Redundant Mask (NRM) 7 undersized apertures: ~15% throughput Arranged so that the 21 distances between pairs of apertures (“baselines”) are unique (“non-redundant”) Science Coffee 2013 May 23

Signal is Not the Problem Throw away light but get the science! Rayleigh Criterion  = 1.22 /D Michelson Criterion  = 0.5 /D Huge blob Airy Price on redundancy of short baselines If you know you’re looking for a binary the tight core of fringe is great! Coro obscures out to several Airy rings, not just central core

V = V(u,v) exp{if(u,v} Works like Magic But It’s Really Science Subapertures in pupil Image on detector Each pixel points to different part of sky, acts like a different t in correlator Pixel records square of electric field Fourier transform image data V = Abs(V ) displayed here f array has same areas of data f is still a FRINGE PHASE V = V(u,v) exp{if(u,v} Science Coffee 2013 May 23

ONE VOLTAGE per antenna E1(t) E2(t) Correlator t One fringe per antenna pair Visibility (amplitude) & phase V12 = V12 exp{if12} visibility t

Interferogram Produced by the NIRISS NRM “The Snowflake”

AMI in [Simulated] Action

A Niche for AMI 70 mas 400 mas NIRCam soft occulting spot inner working angle (IWA; 50% transmission point)

Predicted Performance of AMI

The NIRISS@STScI Team (5/26/16) Key: NIRISS Expertise NIRISS Responsibility NIRISS Liaison Cross-SI WG Lead Alex Fullerton PhD Astronomy Toronto (1990) Van Dixon PhD Astronomy JHU (1995) Team Lead WFSS Pipeline WG Team Deputy Paul Goudfrooij PhD Astronomy Amsterdam (1994) Nikole Lewis PhD Planetary Sci Arizona (2012) André Martel PhD Astronomy UC Santa Cruz (1996) Swara Ravindranath PhD Astronomy IIA Bangalore (2000) SOSS Ops Cross-SI Ops SOSS TrExo WG I&T Commissioning WFSS ETC JDox Anand Sivaramarkrishnan PhD Astronomy UT Austin (1983) Deepashri Thatte MSc Physics South Carolina (2004) Kevin Volk PhD Astronomy Calgary (1986) Michael Wolfe MSc Applied Physics Washington (2007) AMI AMI Calibration Imaging Reference Files SOSS

Reinforcements are on their Way! Gabe Brammer Joe Filippazzo Katie Gossmeyer Julia Roman-Duval Johannes Sahlmann

FGS / NIRISS