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Kavli Institute for Cosmology, Cambridge



The James Webb Space Telescope, is the largest telescope in space. Regarded as the successor of the Hubble Space Telescope, it is dubbed "The First Light Telescope", detecting and characterizing the first generation of galaxies and accreting supermassive black hole seeds. KICC researchers are heavily involved in the primary spectrograph of JWST, NIRSpec, which will be the first multi-object spectrograph in space, orders of magnitude more sensitive than any previous facilities.

Primary Mirror Segment Cryogenic Testing


With its 6.5m diameter primary mirror and four science instruments, JWST operates at near- and mid-infrared wavelengths.  Its unprecedented sensitivity and resolution at these wavelengths allows it to address science questions both near and far: from characterising planets and stellar nurseries nearby to searching for the first galaxies to populate the Universe.
The four science instruments are:
  • NIRCam - a Near-Infared camera, with a wide range of photometric filters spanning 0.7-5um, and also GRISM spectroscopy at 2.4-5um 
  • NIRSpec - a Near-Infrared spectrograph covering 0.7-5um with three spectroscopy modes:
    • fixed slit
    • multi-object spectroscopy with the use of a micro-shutter array (MSA) - allowing hundreds of objects to be observed simultaneously over a ~3’x3’ field of view
    • Integral field spectroscopy covering a 3”x3” field of view
  • MIRI - a mid-infrared imager and spectrograph covering 5-28um
  • NIRISS - Near-InfraRed Imager and Slitless Spectrograph. Imaging over 0.8-5um and wide-field slitless spectroscopy over 0.8-2.2um
Members at the KAVLI are heavily involved in the NIRSpec guaranteed time observations (GTO) team.  In particular the extragalactic surveys which are described briefly here (see also here) and represent a time investment of >700 hours of NIRSpec GTO time:
  • JADES (JWST Advanced Deep Extragalactic Survey) is a joint NIRCam/NIRSpec GTO team survey.   The DEEP and MEDIUM portions of the NIRSpec extragalactic survey will be taken in collaboration with the NIRCam GTO team.  We will target GOODS-S and GOODS-N with NIRCam imaging and NIRSpec spectroscopy.  This collaborative approach will allow NIRSpec follow-up from NIRCam-selected targets.  We will also make use of coordinated parallel observations, meaning when NIRCam is taking imaging, NIRSpec will target existing HST-detected sources, and while NIRSpec is taking observations, NIRCam will be adding area to the imaging campaign. 
  • WIDE Shorter NIRSpec observations over a wider area with sources selected from existing HST imaging surveys. The bottom layer of the wedding cake structure of the NIRSpec extragalactic survey.
  • IFS - Integral field spectroscopic observations of ~47 high redshift objects 


Members of KICC involved in JWST include: