Top-level requirements
New frontiers of spectroscopic surveys
Learn about the capabilities of the WST, the requirements on each instrument, how it compares with other facilities and how it will adapt to new technologies and needs.
Top-level requirements
From science goals to system requirements
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TABLE HEADER 1
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TABLE HEADER 2
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TELESCOPE
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Telescope Aperture
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12 m
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Telescope FoV
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3.1 sq. deg
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Telescope Spec Range
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0.35-1.6 µm
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MOS & IFS parallel operations
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ToO implemented at telescope and fibre level
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INSTRUMENTS
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MOS LR Multiplex
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30,000
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MOS LR Resolving Power
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> 3,000
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MOS LR Spec Range
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370-930 nm (simultaneous)
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MOS HR Multiplex
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2.000
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MOS HR Resolving Power
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40,000
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MOS HR Spec Range
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370-930 nm (4 regions)
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IFS FoV
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3 x3 sq. arcmin
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IFS Resolving Power
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>3,000
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IFS Spec Range
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370-930 nm (simultaneous)
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IFS Patrol Field
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13 arcmin diameter
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|
TABLE HEADER 1
|
TABLE HEADER 2
|
|---|---|
|
TELESCOPE
|
|
|
Telescope Aperture
|
12 m
|
|
Telescope FoV
|
3.1 sq. deg
|
|
Telescope Spec Range
|
0.37-1.6 µm
|
|
MOS & IFS parallel operations
|
|
|
ToO implemented at telescope and fibre level
|
|
|
TABLE HEADER 1
|
TABLE HEADER 2
|
|---|---|
|
INSTRUMENTS
|
|
|
MOS LR Multiplex
|
30,000
|
|
MOS LR Resolving Power
|
> 3,000
|
|
MOS LR Spec Range
|
370-930 nm (simultaneous)
|
|
MOS HR Multiplex
|
2.000
|
|
MOS HR Resolving Power
|
40,000
|
|
MOS HR Spec Range
|
370-930 nm (4 regions)
|
|
IFS FoV
|
3 x3 sq. arcmin
|
|
IFS Resolving Power
|
> 3,000
|
|
IFS Spec Range
|
370-930 nm (simultaneous)
|
|
IFS Patrol Field
|
13 arcmin diameter
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Note: FoV = Field of View, ToO = Targets of Opportunity, MOS = multi-object spectrograph, IFS = integral field spectrograph
How does the WST compare to other facilities?
These ambitious requirements will place the WST MOS and IFS capabilities far ahead of the existing or planned competing facilities. Using the collecting area and the fibre multiplex gain as a measure of the survey speed, WST MOS will be [Bryson, I1] faster by x27 than PFS@Subaru, by x22 than MOONS@VLT, and by x6 than MUST. The WST IFS, with its large field of view, good spatial resolution, and large simultaneous example, using the etendue metric, it will be 19 and 16 times faster than the European MUSE@VLT and the US KCWI@Keck, respectively.
Comparison of WST MOS and IFS capabilities with existing and proposed ground-based spectroscopic facilities. Circle areas are proportional to the etendue (i.e., aperture times field of view area). For clarity, MOS or IFS with small multiplex or field of view are not shown in these figures. Multi-IFUs (e.g. KMOS, Hector or MaNGA) or sparse-field panoramic IFS (e.g. HETDEX) are not shown in this comparison, which only considers panoramic (monolithic) IFS with 100% fill-factor. However, multi-IFUs are considered as a possible WST upgrade to the MOS components.
However, not only will the WST perform significantly better than any existing or planned MOS or IFS instruments, but the parallel operation of its MOS and IFS capabilities as a single facility will represent a significant advance in the overall scientific capability available to astrophysicists and cosmologists. Its built-in time-domain capabilities will position WST as a cornerstone of multi-messenger science in the 2040s.
Looking ahead: an adaptive strategy for an evolving framework
As with previous ESO flagship telescopes such as the VLT and ELT, the WST is expected to have an operational lifetime exceeding 50 years. To ensure the facility remains at the forefront of scientific discovery over such a long timescale, a strategy for long-term evolution and upgradeability is being developed. This will allow WST to adapt to evolving scientific priorities and to take advantage of emerging technologies.
Several upgrade paths have already been identified, including:
- An infrared extension of the MOS-LR, and
- Deployment of mini-IFUs within the MOS
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The WST top-level requirements
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