JWST/NIRSpec P. Ferruit (ESA JWST project scientist)
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Slide #1 Acknowledgements
• Thanks for giving me the opportunity to present the JWST and in particular the NIRSpec instrument.
• All along this presentation you will see the results of work conducted by a large number of teams in Europe, USA and Canada. • Many elements of this presentation are based on existing presentations prepared by other members of the JWST project, the instrument teams and STScI.
FLARE meeting - 14 march 2016 Slide #2 Table of contents
• The JWST mission in a few slides. • NIRSpec – The origin, the team and the hardware. • NIRSpec – Spectral configurations and modes. • NIRSpec - Multi-object spectroscopy mode (MOS). • NIRSpec - Integral field spectroscopy mode (IFU). • NIRSpec - “Fixed” slit spectroscopy mode (SLIT). • NIRSpec & JWST – Scientific timeline. • Conclusion.
• Backup slides (JWST).
FLARE meeting - 14 march 2016 Slide #3 The James Webb Space Telescope (JWST) The mission in a nutshell
• JWST will be one of the “great observatories” of the next decade. • Often presented as the next step after the Hubble Space Telescope (HST) • Joint mission between NASA, ESA and CSA. • High-priority endeavor for the associated astrophysical communities. • Setup similar to the HST one. • Over the duration of the mission, > 15% of the total JWST observing time goes to ESA member states applicants. • To be launched at the end of 2018 for a minimum mission duration of 5 years (10-year goal).
FLARE meeting - 14 march 2016 Slide #4 The James Webb Space Telescope (JWST) The mission in a nutshell
FLARE meeting - 14 march 2016 Slide #5 The James Webb Space Telescope (JWST) The mission in a nutshell
• The end of the dark ages: first light and re-
ionization. Sketch - P. Geil
• The assembly of galaxies: the formation and evolution of galaxies.
Hubble Ultra-deep Field
• The birth of stars and proto-planetary systems.
Artist view – D. Hardy
• Planetary systems (including our solar system and exoplanets) and the origin of life.
Artist view – R. Hurt
See Gardner et al., 2006, Space Science Reviews, 123, 485
FLARE meeting - 14 march 2016 Slide #6 The James Webb Space Telescope (JWST) The mission in a nutshell
payload module segmented primary the telescope mirror the 4 instruments (4 optical elements, (18 hexagonal mirrors of and their 1.32m flat-to-flat; only 2 visible here) electronic boxes collecting surface > 25m2) secondary mirror (0.74m diameter)
the sunshield 5 membranes of Kapton foil allowing passive cooling of the telescope and the instruments down to ~40K the size of a tennis court
Note that a cryogenic cooler is used to cool JWST’s the spacecraft bus and solar panels mid-infrared instrument (MIRI) down to 6-7K.
FLARE meeting - 14 march 2016 Slide #7 The James Webb Space Telescope (JWST) The mission in a nutshell
The electronic boxes in their compartment.
The flight instruments in the payload module (ISIM).
To get a better idea of the scale!
The telescope with all the mirrors in place! (with protective covers)
FLARE meeting - 14 march 2016 Slide #8 The James Webb Space Telescope (JWST) The mission in a nutshell
MIRI = Mid-InfraRed Instrument 50/50 partnership between a nationally funded consortium of European institutes (MIRI EC) under the auspices of ESA and NASA/JPL. PIs: G. Wright and G. Rieke
NIRSpec = Near-infrared Spectrograph Provided by the European Space Agency. Built by an industrial consortium led by Airbus Defence and Space.
NIRISS = Near-infrared Imager and Slit-less Spectrograph FGS = Fine Guidance Sensor Provided by the Canadian Space Agency. PIs: R. Doyon & C. Willott
NIRCam = Near-InfraRed Camera Developed under the responsibility of the University of Arizona. PI: M. Rieke
JWST’s instruments FLARE meeting - 14 march 2016 Slide #9 JWST/NIRSpec – Overview From JWST’s science goals to an instrument…
• To achieve JWST science goals a near-infrared spectrograph was needed in the instrument suite. It should be capable of: • Deep multi-object spectroscopy at low, medium (around 1000) resolution over a “wide” field of view. • Spatially-resolved, single-object spectroscopy at “high” (a few thousands) spectral resolution over a “small” (a few arc seconds) field of view. • High-contrast slit spectroscopy at various spectral resolutions, including an aperture for extra-solar planet transit observations.
FLARE meeting - 14 march 2016 Slide #10 JWST/NIRSpec – Overview From JWST’s science goals to an instrument…
FLARE meeting - 14 march 2016 Slide #11 JWST/NIRSpec – The team
• Built for ESA by an industrial consortium led by Airbus Defence and Space (Astrium GMBH at the time). • NASA-provided the detectors and micro-shutter arrays.
FLARE meeting - 14 march 2016 Slide #12 JWST/NIRSpec – The hardware
Figure credit: B. Dorner, PhD, 2012
Spectrograph region, including detectors
Fore-optics region
MSA, IFU and slits Size: ~ 1.9 m x 1.3 m x 0.7 m Mass: < 220 kg
FLARE meeting - 14 march 2016 Slide #13 JWST/NIRSpec – The hardware
• NIRSpec flight model was delivered to NASA at the end of 2013.
See also: Birkmann et al., proceedings of the SPIE, Volume 9143 (2014)
FLARE meeting - 14 march 2016 Slide #14 JWST/NIRSpec – The hardware
• NIRSpec was integrated JWST’s payload module (ISIM) in 2014. • The ISIM and the instruments are now ready for their integration on the telescope.
NIRSpec
FLARE meeting - 14 march 2016 Slide #15 JWST/NIRSpec – Overview From JWST’s science goals to an instrument…
FLARE meeting - 14 march 2016 Slide #16 JWST/NIRSpec – Overview Main spectroscopic configurations
JWST/NIRSpec - spectral confgurations 1 μm 2 μm 3 μm 4 μm 5 μm
Low spectral resolution 0.6 μm 5.3 μm confguration Medium and 0.7 μm 1.2 μm high spectral 1.0 μm 1.8 μm resolution 1.7 μm 3.1 μm confgurations 2.9 μm 5.2 μm
Configurations that can be obtained thanks to a combination of filters and dispersers installed on two wheels (FWA and GWA)
FLARE meeting - 14 march 2016 Slide #17 JWST/NIRSpec – Overview Main spectroscopic configurations domain mid-infrared mid-infrared Classical lines moving into the moving Classical diagnostics instruments near-infrared near-infrared available in the available
FLARE meeting - 14 march 2016 Slide #18 JWST/NIRSpec – Overview Putting 3 instruments in one?
• A complex field-of view layout / Fighting for detector real estate • Using the magnet arm of the micro-shutter array to block/ unblock the entrance of the IFU and select between the MOS and IFU modes. • A specific area is dedicated to the SLIT mode.
FLARE meeting - 14 march 2016 Slide #19 JWST/NIRSpec Multi-object spectroscopy (MOS)
• The challenge of multi-object spectroscopy • Letting the light from selected objects go through while blocking the light from all the other objects. • A configurable mask was needed.
Using 4 arrays of 365x171 micro-shutters each, provided by NASA GSFC. This gives us a total of almost 250 000 small apertures that can be individually opened/ closed
MEMS device – 105x206 We typically need > 90 % micron shutters of the shutters operable.
FLARE meeting - 14 march 2016 Slide #20 JWST/NIRSpec Multi-object spectroscopy (MOS)
• An unusual MOS: a regular grid of apertures. à Finding the best combination of pointing parameters (RA, DEC, PA) AND the best list of targets. à There will be a dedicated tool for the preparation of the observations.
In yellow: non- operable shutters (cannot be opened) Conceptual example on a very Only basic data processing applied crowded field! Omega Centauri.
http://www.stsci.edu/jwst/science/sodrm/highlightSpecDenseStellarFields.pdf
FLARE meeting - 14 march 2016 Slide #21 Example of MOS test data
• Opening a collection of “dashed-slits”.
Only basic data processing applied
Data obtained before the replacement of the detectors FLARE meeting - 14 march 2016 by new ones with much improved cosmetics! Slide #22 JWST/NIRSpec Example of MOS data
• And getting spectra… G140M configuration. 1.3-1.7 micron source with absorption lines.
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FLARE meeting - 14 march 2016 Slide #23 JWST/NIRSpec Multi-object spectroscopy
• Limiting sensitivity • Conservative estimates including a recipe to account for data loss due to detector cosmetics.
• Low spectral resolution
100 nJy = 1e-30 erg s-1 cm-2 Hz-1 = 1e-33 W m-2 Hz-1 = 26.4 AB mag FLARE meeting - 14 march 2016 = 24.3 K-band mag Slide #24 JWST/NIRSpec Multi-object spectroscopy
• Medium spectral resolution
FLARE meeting - 14 march 2016 Slide #25 JWST/NIRSpec Multi-object spectroscopy
• High spectral resolution
high
FLARE meeting - 14 march 2016 Slide #26 JWST/NIRSpec Multi-object spectroscopy – Example
• Simulations of a spectroscopic deep field • Point-like galaxies, zodiacal light background • Instrument model / IPS software • PhD thesis of B. Dorner (2011) using the source catalog of Pacifici et al. 2012.
CLEAR/PRISM (low spectral resolution)
Single exposure of 970 s.
No cosmic ray.
Basic detector noise properties only (i.e. no 1/f noise).
FLARE meeting - 14 march 2016 Slide #27 JWST/NIRSpec Multi-object spectroscopy – Example
• Spectrum extraction pipeline applied to the simulated data • Software originally developed by B. Dorner (PhD thesis, 2012). Now maintained and further developed by ESA. • Used as a prototype for the support to the development of the actual pipeline by STScI.
CLEAR/PRISM (low spectral resolution)
High-intensities / noise at short and long wavelength are flat-fielding artifacts.
FLARE meeting - 14 march 2016 Slide #28 JWST/NIRSpec Multi-object spectroscopy – Example
• Another way to illustrate the sensitivity of NIRSpec • i’ drop-out galaxies from Eyles et al. 2006 (GOODS + Spitzer IRAC imaging). Best fit SED (few 1010 solar masses, current SFR of 9 solar masses per year; fairly evolved population) CLEAR/PRISM (low spectral resolution) Photometry data points (Eyles et al. 2006)
JWST/NIRSpec limiting sensitivity in 10,000 s at low spectral resolution. Impact of detector cosmetics not included.
FLARE meeting - 14 march 2016 Slide #29 JWST/NIRSpec Multi-object spectroscopy – Example
CLEAR/PRISM (low spectral resolution)
From Maiolino 2014, presentation at the HST conference IV in Rome
FLARE meeting - 14 march 2016 Slide #30 JWST/NIRSpec Multi-object spectroscopy – Example
CLEAR/PRISM (low spectral resolution)
From Bunker 2015, presentation at the JWST2015 conference at ESA/ESTEC
FLARE meeting - 14 march 2016 Slide #31 JWST/NIRSpec Integral field spectroscopy
FLARE meeting - 14 march 2016 Slide #32 JWST/NIRSpec Integral field spectroscopy
NIRSpec IFU properties
Concept Advanced image slicer module (Content 1997)
Manufacturer Surrey Satellite Technology LTD (SSTL) University of Durham – CfAI as a sub-contractor Size and weight Size of a shoebox for a weight of less than 1kg
Number of slices 30
Field of view 3 arcsec × 3 arcsec
Spaxel size 0.1 arcsec × 0.1 arcsec
Throughput > 50 % from 0.6 to 3.0 microns; > 80 % above 3 microns
Spectral Coverage of the 0.6-5.0 µm spectral domain in one shot at 25 ≤ R ≤ Configurations 300 (using a prism) (using NIRSpec Coverage of the 0.7-5.0 µm spectral domain in four configurations at spectrograph) R ≈ 1000 and R ≈ 2700 (using gratings)
FLARE meeting - 14 march 2016 Slide #33 JWST/NIRSpec Integral field spectroscopy
FLARE meeting - 14 march 2016 Slide #34 JWST/NIRSpec Integral field spectroscopy
FLARE meeting - 14 march 2016 Slide #35 JWST/NIRSpec Integral field spectroscopy
• Observations of a small sample of nearby LIRGs in the [NII]+Ha range with the VLT/VIMOS IFU.
From figure 4 – Bellocchi et al. 2012
FLARE meeting - 14 march 2016 Slide #36 JWST/NIRSpec Integral field spectroscopy
• Some velocity structure. From figure 4 – Bellocchi et al. 2012
FLARE meeting - 14 march 2016 Slide #37 JWST/NIRSpec Integral field spectroscopy
• “XL version” - The object was scaled to fit in the 3”x3” NIRSpec IFU field of view (arbitrary scaling). • Just for the sake of having a nice example of a spatially resolved object observed in IFU mode. • “compact version” – Object size of roughly 1”x1” • Arbitrary scaling once more. More similar to the z=3 case example present in the paper. • The [NII]+Ha spectra were “redshifted” to z=1, putting the Ha line around 1.3 microns. • Mimicking an observation in the 1.0-1.8 micron band of NIRSpec (with a medium resolution grating). • Only considering the [NII]+Ha line region (this is just an example…).
FLARE meeting - 14 march 2016 Slide #38 JWST/NIRSpec Integral field spectroscopy
XL version compact version
Reconstructed datacubes (i.e. at NIRSpec IFU spatial resolution).
FLARE meeting - 14 march 2016 Slide #39 JWST/NIRSpec Integral field spectroscopy
Normalized to a peak value of unity
Velocity structure is still clearly visible as we progress diagonally through the cube.
FLARE meeting - 14 march 2016 Slide #40 JWST/NIRSpec “high-contrast” slit spectroscopy
• A set of 5 “fixed” slits for high-contrast spectroscopy of individual objects • Specific detector real estate (can be used in parallel to the other modes). • 3 x 0.2” + 1 x 0.4” + aperture of 1.6”x1.6”
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FLARE meeting - 14 march 2016 Slide #41 NIRSpec & JWST – Scientific timeline
The presentations are available on the web. Follow the instructions in the conference web site.
Sessions covering a broad range of scientific topics.
From end 2015. http://www.cosmos.esa.int/web/jwst/ FLARE meeting - 14 march 2016 conferences/jwst2015 Slide #42 NIRSpec & JWST – Scientific timeline
This is less than 2 years from Early now! Release Science (ERS) program
Community- Extracted from a driven early presentation by observation N. Reid during the Winter AAS programs meeting (January (director’s 2016) discretionary time). See also presentation at the JWST2015 conference http:// www.cosmos.esa. int/web/jwst/ conferences/ jwst2015
FLARE meeting - 14 march 2016 Slide #43 NIRSpec & JWST – Scientific timeline
• There will be dedicated activities in Europe supported by ESA. • Will be harmonised with those of STScI and initiatives in individual countries. http://www.cosmos.esa.int/web/jwst/esac2016
FLARE meeting - 14 march 2016 Slide #44 Conclusion
• JWST/NIRSpec • A very versatile near-infrared spectrograph with an unprecedented combination of sensitivity and spatial resolution. • In the few years remaining before launch… • NIRSpec together with the other instruments will go through JWST’s remaining integration and test steps. • The ESA scientific operation team and the team at STScI will continue working on the suite of tools necessary to prepare the observations, execute them, process the data and archive them!
FLARE meeting - 14 march 2016 Slide #45 Backup slides
BACKUP SLIDES (JWST)
FLARE meeting - 14 march 2016 Slide #46 JWST imaging capabilities
Instrument Wavelength Pixel scale Field of view (in microns) (in mas/pixel) (arcmin x arcmin) NIRCam 0.6-2.3 32 2.2’ x 4.4’ NIRCam 2.4-5.0 65 2.2’ x 4.4’ NIRISS 0.9-5.0 65 2.2’ x 2.2’ MIRI 5.0-28 110 1.3’ x 1.7’
NIRCam: Simultaneous imaging of the same field of view in the ‘blue’ and ‘red’ channels.
• More than one order of magnitude sensitivity improvement in some bands. • Extremely powerful observatory, a lot of discovery space.
FLARE meeting - 14 march 2016 Slide #47 JWST imaging capabilities Mapping of the focal plane
FLARE meeting - 14 march 2016 Slide #48 JWST imaging capabilities
NIRISS (2.2’ x 2.2’) NIRCam (4.4’ x 2.2’) MIRI (1.7’ x 1.3’)
FLARE meeting - 14 march 2016 Not to scale. Slide #49 JWST/NIRCam – A wide choice of filters
FLARE meeting - 14 march 2016 Slide #50 JWST/NIRCam – A wide and wise choice of filters
FLARE meeting - 14 march 2016 Slide #51 JWST spectroscopic capabilities
• Take-home message: in JWST, spectroscopy comes in many different flavors… • Can address many different scientific needs. • Unique combination of sensitivity & spatial resolution. Instrument Type Wavelength Spectral Field of view (microns) resolution NIRISS slitless 1.0-2.5 ~150 2.2’ x 2.2’ NIRCam slitless 2.4-5.0 ~2000 2.2’ x 2.2’ NIRSpec MOS 0.6-5.3 100/1000/[2700] 9 square arcmin. NIRSpec IFU 0.6-5.3 100/1000/2700 3” x 3” MIRI IFU 5.0-28.8 2000-3500 >3” x >3.9” NIRSpec SLIT 0.6-5.0 100/1000/2700 Single object MIRI SLIT 5.0-10.0 60-140 Single object NIRSpec Aperture 0.6-5.3 100/1000/2700 Single object NIRISS Aperture 0.6-2.5 700 Single object
FLARE meeting - 14 march 2016 Slide #52 JWST spectroscopic capabilities Spectral resolution
~ 100 km/s
~ 300 km/s
FLARE meeting - 14 march 2016 Slide #53 JWST coronagraphic and aperture masking interferometry capabilities
• Like for spectroscopy a variety of modes are available, spread over the wavelength range covered by JWST.
Instrum Wavelength Pixel scale Field of Type ent (in microns) (in mas/pixel) view NIRCam 0.6-2.3 32 20” x 20” Lyot NIRCam 2.4-5.0 65 20” x 20” Lyot NIRISS 3.8-4.8 65 0.1-0.5” Aperture masking interferometry MIRI 10.65 110 24” x 24” 4QPM MIRI 11.4 110 24” x 24” 4QPM MIRI 15.5 110 24” x 24” 4QPM MIRI 23 110 30” x 30” Lyot
• QPM = four-quadrant phase masks
FLARE meeting - 14 march 2016 Slide #54 JWST - Orbit and field-of-regard
How mobile is the telescope given that it needs to remain constantly in the shade?
FLARE meeting - 14 march 2016 Slide #55 The James Webb Space Telescope (JWST) Orbit and field-of-regard
At any time during the year, JWST will be able to observe an “annulus” corresponding to 35-40% of the sky.
http://www.stsci.edu/jwst/overview/design/field-of-regard
FLARE meeting - 14 march 2016 Slide #56 The James Webb Space Telescope (JWST) Orbit and field-of-regard
Periods of visibility / orientation of the field of view
Small regions visible all year long (CVZ), around the ecliptic poles
Two visibility windows per year separated by 6 months
Single, longer visibility window
FLARE meeting - 14 march 2016 Slide #57 Visibilities and orientation during a 1-year cycle
CVZ = continuous viewing zone around the ecliptic poles
FLARE meeting - 14 march 2016 Slide #58 Visibilities and orientation during a 1-year cycle
Along the ecliptic: restricted range of orientations, 2 windows per year, long time with the same orientation (~50 days).
Artifact from the beginning and end of a 1- year cycle
CVZ: visible all year long, all orientations possible along the year, short time with the same orientation (~10 days). FLARE meeting - 14 march 2016 Slide #59