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CCAT-Prime: An Ultra-widefield Submillimeter Observatory at Cerro Chajnantor Gordon Stacey Cornell University Representing the CCAT consortium Cornell,

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Presentation on theme: "CCAT-Prime: An Ultra-widefield Submillimeter Observatory at Cerro Chajnantor Gordon Stacey Cornell University Representing the CCAT consortium Cornell,"— Presentation transcript:

1 CCAT-Prime: An Ultra-widefield Submillimeter Observatory at Cerro Chajnantor
Gordon Stacey Cornell University Representing the CCAT consortium Cornell, Cologne, Bonn, Colorado, Association of Canadian Universities, AUI 04 August 2016 RMS Science Futures II

2 CCAT-Prime Precursor for CCAT – a 25 m submm telescope on Cerro Chajnantor Explore and develop site, reducing risk Open up exciting new science 04 August 2016 RMS Science Futures II

3 The CCAT-p Concept Principles: Enable forefront science
Exploit CCAT partnership framework Build on experience gained from CCAT project 04 August 2016 RMS Science Futures II

4 The CCAT-p Concept Principles: Enable forefront science
Exploit CCAT partnership framework Established international collaboration Established legal entity Access to same/other funding sources for smaller project Possibility to incorporate additional partners Build on experience gained from CCAT project 04 August 2016 RMS Science Futures II

5 The CCAT-p Concept Principles: Enable forefront science
Exploit CCAT partnership framework Build on experience gained from CCAT project Understanding and analysis of infrastructure requirements, solutions, costs and risks Body of CCAT documents: established capability Confidence from review outcomes: demonstrated capability Carry-over of “shovel ready” aspects For example, archeological/geological surveys completed; no one else is ready to take off. 04 August 2016 RMS Science Futures II

6 The CCAT-p Concept 6-meter off-axis submm telescope located at CCAT site at 5600 meters on Cerro Chajnantor Surface accuracy of <10 m (7 m goal) High site gives routine access to 350 m, 10% best weather to 200 m, advantage at longer s Novel off-axis crossed-Dragone design (Niemack 2016) yielding high throughput, wide field-of-view, flat focal plane immediately plus potential as Stage IV CMB observatory Targeted science programs taking advantage of aperture size, throughput, mapping speed, superb site in “campaign-mode” 04 August 2016 RMS Science Futures II

7 Cerro Chajnantor at 5600 m 04 August 2016 CCAT-Prime

8 5000 meter is good, but 5600 meters is better
Radford & Peterson, arXiv: Submillimeter sensitivity is all about telluric transmission Simon Radford has been running tipping radiometers at primary sites for more than a decade – Simultaneous period for CCAT vs. ALMA site: median is 0.6 vs. 1 mm H2O  factor of 1.7 in sensitivity Fraction of time Fraction of time 04 August 2016 RMS Science Futures II

9 Median Zenith Transmission
Median CCAT transmission even better than South Pole due to warmer, less dense atmosphere Tropics: Ω = 3 π sr, Amed = 1.1 (z < 60°) Pole: Ω = 1 π sr, Amed = 1.4 (z < 60°) 04 August 2016 RMS Science Futures II

10 Chajnantor Site 10% Opens up the THz Windows
04 August 2016 RMS Science Futures II

11 CCAT-Prime Science Investigating the the physical processes associated with star formation in the Milky Way, the Magellanic clouds and other nearby galaxies through submm spectroscopy and photometry Probing of the nature of dark energy, gravity on large scales and neutrino mass sum through kinetic SZ effect Probing the process of reionization in the early Universe through intensity mapping of the [CII] 158 m line emission associated with star formation in the epoch of reionization at redshifts from 6 to 8. The CCAT design also well suited to a “Stage IV” CMBR observatory with ~ 10 times the mapping speed of current facilities enabling probes of inflationary gravity waves and the sum of the neutrino masses. 04 August 2016 RMS Science Futures II

12 Implementation: The Crossed Dragone Telescope Design
astro-ph/ Applied Optics 15, 1688 04 August 2016 RMS Science Futures II

13 Optical Design Niemack, 2016 astro-ph/1511.04506
Applied Optics 15, 1688 Twin large convex mirrors deliver an f/3 beam with a flat focal plane Field of view is very large ~ 7 at 150 GHz for 6 m aperture Flat focal plane Two 6-m aperture telescope designed with f=3 (top and bottom) tilted to 45 elevation. Both have flat tertiary mirrors; optical clearances can be adjusted by changing telescope parameters and fold angles. 04 August 2016 RMS Science Futures II

14 Fails the “spill-over on sky” test And will need a ground shield
Clear Problems: Fails the “spill-over on sky” test And will need a ground shield 04 August 2016 RMS Science Futures II

15 The CCAT Pathfinder Concept CCAT-prime: CCAT-p
04 August 2016 RMS Science Futures II

16 In the range of 105 to 106 pixels to fill focal plane
300 GHz 230 GHz 150 GHz 300 GHz Plate scale is 32 cm/degree  Break it into subcameras with ~ 28 cm dewar windows Lenses are thinner – less lossy Structural support is much easier Camera “tubes” enable incremental build up to final arrays 50 optical tubes in inner regions providing diffraction limited performance at 150 GHz; additional 22 in 100 GHz diffraction limited zone In the range of 105 to 106 pixels to fill focal plane 04 August 2016 RMS Science Futures II

17 Tubes and Lyot Stops 04 August 2016 RMS Science Futures II

18 Science Cases 04 August 2016 RMS Science Futures II

19 Surveys of the Milky Way
15” imaging over degree scales of the Milky Way, LMC, etc in: [CI] tracing gas temperature and mass CO tracing gas excitation, shocks, density and mass [NII] tracing embedded SF regions and numbers of ionizing photons Tracing accumulation and flows of gas into cores and young stars Requires high site for submm transmission 04 August 2016 RMS Science Futures II

20 Fundamental Physics with kinetic Sunyaev-Zel’dovic Effect
04 August 2016 RMS Science Futures II

21 SZE: Sunyaev-Zel’dovich Effect
Spectral distortions of CMB spectrum: tSZ: due to random thermal motions of scattering electrons rSZ: due to populations of relativistic electrons kSZ: due to bulk velocity of the cluster relative to the CMB rest frame 04 August 2016 RMS Science Futures II

22 The CCAT-p Concept kSZ: Kinetic Sunyaev-Zel’dovich Effect
submm galaxies tSZ: dashed red rSZ: dashed orange kSZ: dashed blue Challenging to separate various signals on CMB: tSZ, rSZ, submm galaxies and radio sources leaving kSZ Observations over a wide wavelength range: 3.3 mm to 350 m needed Need better sensitivity and resolution than Planck radio sources kSZ Simultaneous bands 350 m – 3 mm Mike Zemcov 04 August 2016 RMS Science Futures II

23 Constraints on Peculiar Velocities with kSZ effect
A survey of 3000 hours, over ~1000 sqd with CCAT-p will substantially improve on upcoming CMB surveys. “no gal noise”: sub-mm emission from faint galaxies perfectly subtracted On going analysis by M. Niemack and F. deBernardis Optical depth of intracluster medium and peculiar velocity 04 August 2016 RMS Science Futures II

24 Constrains on Dark Energy and Modified Gravity with kSZ
Forecast dark energy and modified gravity constraints based on measuring 1000 clusters with 100 km/s accuracy (red); SPT-3G projections shown in blue. Such uncertainties will also enable a measurement of the sum of neutrino masses with a 1 uncertainty of ~ 0.03 eV. Blue: SPT3D expectations 4000 clusters: red what you could do with 1000 clusters with better 04 August 2016 RMS Science Futures II

25 Intensity Mapping of [CII] in the Epoch of Reionization
Detect aggregate clustering signal of faint galaxies in the EOR via redshifted [CII] 158 m line Spectral line IM gives 3-D spatial information - Process of structure formation - Fluctuations trace DM density fluctuations SKA 21 cm HI line (HERA) Requires SKA collecting area Foreground contamination/RFI 04 August 2016 RMS Science Futures II

26 A Familiar Example of Intensity Mapping
Spectral line intensity mapping: Not just fluctuation spectrum but how it changes over EOR redshift interval 04 August 2016 RMS Science Futures II

27 Intensity Mapping of [CII] from the EOR
Detect aggregate clustering signal of faint galaxies in the EOR via redshifted [CII] 158 m line [CII] directly traces sources of reionization (SF galaxies) Recent ALMA detection of [CII] in “normal” galaxies at z = 5-6 (e.g. Riechers+ 2014) Enhanced [CII] to dust continuum compared to lower redshifts  strong signal 04 August 2016 RMS Science Futures II

28 Full power in combination with HI 21cm experiments
HI 21cm: traces neutral gas not yet re-ionized [CII] 158m: traces ionization sources (star forming galaxies) [CII] advantage: No radio frequency interference Can be done before full SKA built 04 August 2016 RMS Science Futures II

29 Intensity Mapping of [CII] from the EOR
Measure large scale spatial fluctuations of collective aggregate of faint galaxies via redshifted [CII] 158 m line (+possibly other lines at other z’s) Resolution into individual galaxies not required Clustering scale 0.5 to 1 Mpc or ~1-2’ at z = 5-9, - good match for 6-m aperture 1mm) 162 surveys: spectral/spatial mapping speed critical FoV ~ > 1 matches 40 Mpc void size-scale: systematics Need moderate spectral resolution R ~ Bandwidth of z ~ 5-9 signal is mm ( GHz) Identify interloper lower z CO by line multiplicity – complete at z > 0.8 Sensitivity is at a premium: high site is helpful 04 August 2016 RMS Science Futures II

30 Redshift of Interlooper
CO Interloopers CO Transition Redshift of Interlooper [CII] Redshift (Distance Ratio)2 CO/[CII] Flux Ratio (2-1) 41,000-11,000 65-18 (3-2) 41, 20-2 (4-3) 940-98 5-0.5 (5-4) 240-41 1-0.2 0.80 Naive first order calculation of effects of low redshift interloopers Used standard line ratios, and assumed same luminosity sources at low and high redshifts Lowest redshifts are known sources Redshifts ~0.1 to 0.8 may be problematic – depends on details Redshifts beyond ~ 0.8 no problem since 2 CO lines will appear 04 August 2016 RMS Science Futures II

31 Future Stage IV CMB Observatory
Next generation CMB mapping Probe inflationary gravity waves at tensor-to-scalar ratios as low as 0.001 High-significance measurement of neutrino mass sum High-throughput, wide-field, flat focal plane design at high site even on 6 m telescope would enable mapping CMB 10X faster than ACTPol or SPT-3G CCAT-p would offer existing platform for deployment of cameras with > 105 detectors, likely developed with DOE funding on 5+ year timescale. Synergistic with Simons Observatory Adds the high frequency component that may be critical for removing submm galaxy foregrounds 04 August 2016 RMS Science Futures II

32 Instrumentation Science requires at least three instruments
Star formation in local galaxies requires large format heterodyne spectrometer arrays kSZ requires 350 m – 3.3 mm multichroic camera with degree-size field of view This camera might be precursor to larger FoV CMBR camera EOR studies requires large BW  FoV ~ 20,000 pixel direct detection spectrometer 04 August 2016 RMS Science Futures II

33 U Cologne: CHAI Heterodyne, dual frequency array
500 GHz (600 μm) and 850 GHz (350 μm): CO(4-3), CO(7-6) [CI]  2 64 (baseline), 128 (goal) pixels in each band 04 August 2016 RMS Science Futures II

34 Example First Light Camera
Seven subcamera “tubes” populated with ~1.5 f pixels with multichroic TES bolometers FoV ~ 1 degree each  60,000 pixels at 350 m; 6000 at 1.1 mm Cameras are modular (size, optics, filtration), easily exchanged Start with very modest numbers of pixels and growth to fill out camera, then entire CCAT-Prime FoV if so desired Note pupil for cold stop, 04 August 2016 RMS Science Futures II

35 Large BW  FoV Spectrometer
Trans-mm wave from ~ 0.95 to 1.6 mm ( GHz) Direct detection for optical sensitivity Resolving power requirement is modest, ~ 500 or 600 km/sec Need a spectral  spatial product > 20,000 to complete a 162 survey in 4000 hours. CO foregrounds: BW = 127 GHz. At z = 0 10% of the time get two lines. At z > 0.8 get two lines always. 04 August 2016 RMS Science Futures II

36 Spectrometer on a Chip Essentially filter bank tapping off of a superconducting transmission line Each channel is a half-wave resonator that dumps power to the detector Can cover very large instantaneous bandwidths, so that source redshifts (and science) are obtained 312 spectral  64 spatial pixels Early in development, but promising Several techniques for generating a broad bandwidth direct detection spectrometer. Several groups working in this field including Delft: DESHIMA GHz, 6-9 pixels, R ~ 1000 (A. Endo) GSFC: MicroSpect: S.H. Moseley JPL: SuperSpec GHz, R ~ 400 to 700 (C.M. Bradford) 04 August 2016 RMS Science Futures II

37 Or… Might well be an “evolution” from first light spectrometer to more sophisticated technologies “Traditional” grating spectrometer with full BW and “long slit” Imaging FPI spectrometer that spatially multiplexes with large FoV cameras 04 August 2016 RMS Science Futures II

38 Status New concept developed in early spring of this year
Approved for further study Need additional partner(s) at the level of $5 M Hoped for start is within a year 04 August 2016 RMS Science Futures II

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