Instrumentation for CCAT - Tools for CCAT Science: First Light - Long-Term and Imager Strategy

Q: What capabilities are targeted for CCAT at first light?

The notes call for multicolor broadband wide-field imaging with large detector counts, plus multi-object moderate-resolution spectrometers to obtain CO and [CII] sensitivity over broad redshift ranges for follow-up target selection.

Q: How does the long-term plan expand on the first-light goals?

It emphasizes large-area visible-sky imaging, discovery of rare objects, serious submm/mm transient studies, and high spectral resolution heterodyne imaging spectroscopy with wide-field line mapping and high detector multiplexing.

Q: How is the weather and wavelength allocation intended to work?

A wavelength-band allocation is proposed using a reference PWV threshold for each band, with time availability at or better than the reference PWV and accounting for confusion-limited field counts per year.

Oct 3, 2026

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Instrumentation design notes for the CCAT facility outline how broadband wide-field imaging and multicolor selection enable rapid high-redshift science. The material proposes first-light capabilities, including large detector counts, sufficient colors for SED and T/(1+z) target selection, and multi-object moderate-resolution spectroscopy for CO and [CII] across broad redshift ranges. It then extends to long-term goals: imaging spectroscopy with high detector multiplexing and spectral resolution, a weather-wavelength allocation framework, and a strategy for imager channel splitting by wavelength to avoid survey-mode weather splits while preserving overlap considerations.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages22

Reading Time55 min

AccessFree to download

Tools for CCAT Science: First Light

Tools for CCAT Science: Long-Term

Weather-Wavelength Allocation, Mappable Area

Band time and confusion-limit allocation

Why to Focus on Multi-Object Spectroscopy

Imager Strategy

Instrumentation for CCAT Sunil Golwala/Caltech May 13, 2011 on behalf of the CCAT Consortium and with many thanks to the CCAT science and instrument working groups Tools for CCAT Science: First Light • There is general consensus on what is needed for CCAT to do the most exciting science quickly: • Multicolor, broadband wide-ﬁeld imaging with N ~ 10,000-50,000 and R ~ 3-10 • Enough colors to measure SEDs of galaxies and doT/(1+z) selection of high-z sources • FoV large enough (= enough detectors) to yield high-statistics studies in multiple z bins • FoV wide enough to study clustering of ~confusion-limit sources on interesting scales ‣ Criterion relaxes if one only wants to study clustering of high-S/N sources • Not the ultimate photometric survey at ﬁrst light ‣ Except perhaps at long λ where ﬁlling FoV is not challenging • Multi-object (N ~ 10) moderate resolution (R~1000) spectrometers • Focus is on sensitivity to CO and [CII] in very broad redshift ranges at R appropriate to velocity dispersions in high-z galaxies • Use SED andT/(1+z) selection to deﬁne target list for such followup CCAT Instrumentation 2 Sunil Golwala Tools for CCAT Science: Long-Term • One person’s view of what is needed for CCAT to do deﬁnitive science (given D = 25 m) during its lifetime: • Imaging large fractions of visible sky with FoV-ﬁlling cameras • Finding unique and rare objects • First serious study of transients in submm/mm • Not discussed here except to note that focal planes with 5x106 detectors are expected during CCAT lifetime • High spectral resolution heterodyne imaging spectroscopy in the galaxy and nearby galaxies • Wide-ﬁeld mapping in many lines, with spectral resolution sufﬁcient to separate dominant species, obtain infall information. • Imaging spectroscopy with N = 1000-10000, R ~ 100-1000, NxR ~ 5x106 • N = 50,000 @ R = 100 for ﬁner spectral bins for continuum SED studies in wide ﬁelds • N = 10,000 @ R = 1000 for deﬁnitive extragalactic imaging spectroscopy in smaller but cosmologically representative ﬁelds CCAT Instrumentation 3 Sunil Golwala Pardo et a l 2002 ATM mode l, p lot courtesy S. Radford CCAT Instrumentation 4 Sunil Golwala Weather-Wavelength Allocation, Mappable Area | • best 30-50% devoted to “short submm”(λ ≤ 620 µm)
• substantial fraction for “trans-mm”(λ ≥ 740 µm)
• focal plane technologies can obviate choosing between“long submm” and mm | | | | | | | ﬁrst-light access to cosmological volumes:
access to largest structures, beat down cosmic variance | | | --- | --- | --- | --- | --- | --- | --- | --- | --- | | Band Time Ref. CCAT (5612 m)
λ ν to CLa PWV b Time Availablec CL ﬁelds d
(µm) (GHz) (hr) (mm) (hr yr −1) (%) (yr −1) | | | | | | | 1st light
∅FoV
(’) | area to CL (deg2 yr-1) | | 200
350
620
740
865
1400 | 1500
857
484
405
347
214 | 1248
0.86
1.14
0.43
0.28
0.30 | 0.26
0.47
0.64
0.75
0.86
1.00 | 281
1936
716
639
1223
1517 | 3
22
8 7
14
17 | 2244
629
1488
4413
5093 | 7 26 13 23
20 319 20 436 | | | Total time for PWV < 1.1 mm: 6312 72 | | | | | | | (assumes~50 kpix/band) | | | a Time to reach the confusion limit (CL)– see Table 2. | | | | | | | | | CCAT facility submission to Astro2010 b The reference precipitable water vapor (PWV) is the adopted maximum value for observations in a given wavelength band. Several bands have equivalent thresholds (e.g. 350/450 µm) and for simplicity only one band is listed. c Time available at Ref. PWV or better, not already used at lower λ . c.f.: CSO typically does 350 µm observations d Number of confusion-limited ﬁelds per [year.](year. in)[ in](year. in) 20-25%Cof tCATi me witmuchhbPWetteVr! ≲ 1 mm; CCAT Instrumentation 5 Sunil Golwala !"\#$%&$'( ))*+ -./0 !"'$; &$&& '$7 8 9\#$ µ:!"'$\# What Can We Imagine? Zmuidzinas CCAT Instrumentatio

FAQs

What capabilities are targeted for CCAT at first light?

The notes call for multicolor broadband wide-field imaging with large detector counts, plus multi-object moderate-resolution spectrometers to obtain CO and [CII] sensitivity over broad redshift ranges for follow-up target selection.

How does the long-term plan expand on the first-light goals?

It emphasizes large-area visible-sky imaging, discovery of rare objects, serious submm/mm transient studies, and high spectral resolution heterodyne imaging spectroscopy with wide-field line mapping and high detector multiplexing.

How is the weather and wavelength allocation intended to work?

A wavelength-band allocation is proposed using a reference PWV threshold for each band, with time availability at or better than the reference PWV and accounting for confusion-limited field counts per year.

Oct 3, 2026

Upload by Riley