Webb Update

Jason Kalirai, kalirai@stsci.edu

Webb’s Science Instruments Begin Integration and Testing

The summer of 2012 saw the Webb program achieve several major milestones. Among the highlights was the delivery of two of the four science instruments from international partners to NASA’s Goddard Space Flight Center (NASA/GSFC). The delivery of these instruments marks an important transition from the development phase to the integration and testing phase. In the next step, the instruments will be attached to the Integrated Science Instrument Module (ISIM) at NASA/GSFC.

On May 29, 2012, NASA took delivery of the Mid-Infrared Instrument (MIRI), which was developed by a consortium of European countries in partnership with the Jet Propulsion Laboratory (JPL). MIRI will provide astronomy’s first high-resolution view of the universe at mid-infrared wavelengths (5–28.3 microns). The instrument includes an imager with a 1.23 × 1.88 arcmin field of view at 0.11 arcsec pixel scale, coronagraphic capability at four wavelengths, a low-resolution spectrometer, and an integral-field spectrograph. Following the delivery, MIRI was checked out at NASA/GSFC and successfully passed both functional and metrology tests.

Table 1:Observing Modes for the MIRI Instrument on Webb

Mode Wavelength (microns)

Pixel Size / Spectral Resolution Field of View

Imaging 5.0–28 0.11 arcsec 1.23 × 1.88 arcminSingle Slit

Spectroscopy 5.0– ~14 = ~100 at 7.5 microns 0.6 × 5.5 arcsec slit

IFU Spectroscopy

5.0–7.7 = 3500 3.0 × 3.9 arcmin7.7–11.9 = 2800 3.5 × 4.4 arcmin11.9–18.3 = 2700 5.2 × 6.2 arcmin18.3–28.8 = 2200 6.2 × 7.7 arcmin

Coronagraphy

10.65 0.11 arcsec 24 × 24 arcsec11.4 0.11 arcsec 24 × 24 arcsec15.5 0.11 arcsec 24 × 24 arcsec23 0.11 arcsec 30 × 30 arcsec

The second science instrument to be delivered to NASA/GSFC is the NIRISS/FGS, and comes from the Canadian Space Agency. The Near-Infrared Imager and Slitless Spectrograph (NIRISS) supports four modes of observation at near-infrared wavelengths (1–5 microns). This includes high-resolution imaging in several wide-band filters, wide-

field slitless spectroscopy at resolving power R ~ 150, single-object slitless spectroscopy at R ~ 700, and aperture-mask interferometry. The Fine Guidance Sensor (FGS) shares the same bench as NIRISS, but is functionally independent. FGS will provide mission-critical support for Webb’s attitude control system by locking onto guide stars. The camera can image two adjacent, 2.4 arcmin fields and read out a small detector subarray ~16 times per second.

Table 2: Observing Modes for the NIRISS Instrument on Webb

Mode Wavelength (microns)

Pixel Size / Spectral Resolution Field of View

Imaging 0.9–5.0 0.065 arcsec 2.2 × 2.2 arcminSlitless

Spectroscopy1.0–2.5 = 150 2.2 × 2.2 arcmin0.6–2.5 = 700 single object

Aperture Mask Interferometry 3.8–4.8 0.065 arcsec ----

Congratulations to everyone involved in the development of these instruments, including the European consortium and JPL for MIRI, and the Canadian Space Agency and ComDev for NIRISS/FGS!

Scientific Interaction with the Webb Team—DPS and AAS Meetings

The Webb team is looking forward to community engagement at several upcoming, large meetings. First, Webb will be represented at the Division of Planetary Science Annual Meeting in Reno on October 14–19, 2012. In addition to our booth presence, we are organizing a special workshop titled “Planning your Solar System Observations with Webb.” This workshop will take place from 9 a.m. to noon on Sunday October 14th, and will cover topics such as moving target capabilities, bright observing modes, imaging and spectroscopic sensitivities for solar-system objects, and much more.

The Webb team will also have a strong presence at the winter AAS Long Beach meeting (January 6–10, 2013). Scientists will be on hand at the Institute booth, and will be available to answer questions about the observatory status and science potential. Additionally, this year’s meeting will feature a special Webb science session at 2 p.m. on Monday, January 7, 2013, called “Scientific Opportunities with the James Webb Space Telescope.” Six speakers will give 15-minute presentations, highlighting the unique science potential of Webb for a wide range of astrophysical problems:

• Mark Dickinson (NOAO): JWST and deep field studies of galaxy evolution at high redshift;

• Jessica Lu (IfA): The Galactic center seen through the precise, multiplexed eye of JWST;

• Daniela Calzetti (UMASS): Studies of nearby galaxies in the era of JWST;

• Tommaso Treu (UCSB): Strong lensing, dark matter, and dark energy with the James Webb Space Telescope;

• Margaret Meixner (STScI): The potential of JWST for studies of the Magellanic Clouds and beyond; and

• David Lafreniere (UMontreal): The science potential of JWST for exoplanet studies.

We will also organize a JWST Town Hall meeting at the AAS on Wednesday, January 9, 2013, at 12:45 p.m. The Town Hall will include three short presentations by (1) Dr. Eric Smith (NASA HQ) on the status of Webb; (2) Dr. Randy Kimble (NASA/GSFC) on the Webb integration and test plan; and (3) Dr. Mike Brown (Caltech) on the promise of Webb for solar-system exploration (Dr. Brown was recently awarded the Kavli Prize in Astrophysics).

Please come and visit us at the DPS and AAS!

Figure 1: MIRI being shipped. Credit: Nick Morrish/British Airways

Figure 2: MIRI at NASA/GSFC. Credit: NASA/Chris Gunn

Figure 3: NIRISS/FGS being shipped. Credit: NASA/Chris Gunn

Figure 4: NIRISS/FGS at NASA/GSFC. Credit: NASA Webb Telescope’s photostream