Submm Wide Field Surveys with CCAT

1. Submm Wide Field Surveys with CCAT Riccardo Giovanelli* (*with thanks for material to Gordon Stacey, Jason Glenn, John Carpenter et al.)

2. Project Cost: $120M What is CCAT: • A 25meter FIR/submillimeter telescope that will operate at wavelengths as short as l = 200 mm, an atmospheric limit • To be located in a high (5617m) desert environment • It will take advantage one of the fastest developing detector technology of any spectral regions, opening up the last, largely untapped frontier of ground-based astronomical research Beam size: l[mm]/100 arcsec e.g. 2” @ 200 mm FoV: 1 sq. deg. Half WF err: 9.5 mm rms Continuum Sensitivity, 5s, 1 hr : 1 mJy @ 350 mm First-light short l camera: 50 kpix Several instruments in Nasmith focus, some simultaneously accessible in large FoV

3. Who is CCAT ? A joint project of Cornell University, the California Institute of Technology and the Jet Propulsion Laboratory, the University of Colorado, a Canadian academic Consortium, the Universities of Bonn & Koeln, Associated Universities, Inc.

4. Where is CCAT?

5. At the driest, high altitude site you can drive a truck to…. Cerro Chajnantor (18,500 ft)

6. Cerro Chajnantor 5612 m (18500 ft) Google Earth ALMA

7. Maximizing Sensitivity • Wish to reach confusion limit determined by backgrounds and aperture as soon as possible  maximize system sensitivity • High site: Cerro Chajnantor 600 m above ALMA site  zenith transparency ~ 1.35 times better • High surface accuracy: goal of 9.5 m rms  Ruze ~ 90% at 350 m – contrast with APEX (18 m)  Ruze ~ 66%: 1.36  • High receiver sensitivity: direct detection systems easily background limited with Trec(SSB) < 50 K – contrast with ALMA with Trec(DSB) ~ 180 K – a factor of 3.3 for Tsky ~ 150 K • High receiver bandwidth: direct detection systems can easily take in the entire telluric windows (cameras) or several (spectrometers) – 80 GHz vs 8 GHz for ALMA • Best Point Source Sensitivity: Surprising conclusion: a camera on CCAT can have point source sensitivity equivalent to (25/12)^2  1.35  1.36  3.3 x sqrt(80/8) ~ 80 ALMA antennas!

8. Hierarchical mergers of galaxies Origins of cosmic structures: We’d like to learn… How did we get from this… Energy fluctuations in the very early Universe Formation of massive, dense clusters of galaxies …to this? Organization of matter into large filamentary structures Formation of stars and planetary systems

9. The First Stars, the First Galaxies Made of Hydrogen and Helium, probably formed a few hundred Myr after the Big Bang. They must have been very massive, evolved rapidly and produced the “first batch” of elements heavier than Helium, necessary for the formation of dust, complex molecules, planets and life. Goods 850-5 (z=4.1) in optical (HST, left; Daddi et al. 2009) and submm (SMA, right) By the time the first galaxies form, the Universe is already dusty

10. The Cosmic FIR Background • Dust reprocesses starlight into FIR • Cosmic expansion shifts light of early galaxies further into submm and mm bands CCAT STARLIGHT DUST COBE (1996) Lagache, Puget, & Dole 2005

11. Galaxy Counts and the Cosmic FIRB at Submm Wavelengths HerMES Lockman Hole North Oliver et al. (2010, 2011) ~10% of CFIRB resolved directly with Herschel ~50% inferred statistically, yieldingestimated number count models to a depth of 2 mJy/beam CCAT will resolve (directly) sources to 0.5-1 mJy, resolving the totality of the CFIRB See Patanchon et al. (2010), Glenn et al. (2011) Detections P(D)

12. Comparative Continuum Sensitivities, 5-sigma, 3600sec Confusion limits @ 30 (dark red), 10 (cyan) beams/src

13. Simulated maps of the same patch of sky based on Herschel number counts CCAT, Herschel, and ALMA ALMA primary beam (~7) Approximate FOV of first-light camera

14. 1000 Dusty High z Galaxies SMM J2135-0102 z = 2.326 (lensed) 100 SPIRE 10 Flux Density (mJy) 1 .1 Ivison et al. (2010) .01 1µm 10µm 1cm 1mm 100µm 10cm Blain et al. (2002) Observed flux density of a dusty galaxy as a function of z and 

15. Desiderata for a high z SMG galaxy Survey • Wide area coverage (> 100 deg2) to overcome sample variance • Arcsec–resolution to overcome confusion, resolve the vast majority of the CFIRB and identify source counterparts at other wavelengths • Comprehensive submm spectroscopic follow-up to measure z and characterize galaxies’ physical conditions and composition

16. [CII] 158 mm, [OI] 63 & 146 µm, [NII] 122 & 205 µm, CO ladder… Speculative: 17 mm and 28 mm lines of H2 at high z?... Atomic fine structure & molecular lines: ZEUS  Stacey & Hailey-Dunsheath et al. (2010) Flux Density (10-18 W/m2/bin) Bradford et al. (2009) • ~103 galaxies/deg2 detectable spectroscopically by CCAT • Spectroscopic survey of 1 in 10-100 photometric detections doable with MOS (source centroiding should be better than 1”) v(km/sec)

17. Desiderata for a high z SMG galaxy Survey • Wide area coverage (> 100 deg2) to overcome sample variance • Arcsec–resolution to overcome confusion, resolve the vast majority of the CFIRB and identify source counterparts at other wavelengths • Comprehensive submm spectroscopic follow-up to measure z and characterize galaxies’ physical conditions and composition • Submm and mm observations to identify the highest z candidates.

18. High-z galaxies will have low 350 µm to 850 µm flux density ratios (“350 µm dropouts”) flux density ratio Identifying Very High-z Galaxy Candidates 10 1 3 examples from Herschel (Dowell et al. 2010)

19. Bolocam Galactic Plane Survey 1.1mm @CSO (Bally et al. 2010) BOLOCAM: Orange VLA 20 GHz: purple Spitzer 8 mm: cyan

20. Structure of Molecular Clouds 2 degrees Molinari et al. 2010 Herschel 70μm, 160μm, and 350μm image at longitude = 59°

21. Filaments are pervasive ... Molinari et al. 2010 Filtered Herschel 250um image

22. ... and are where stars form Molinari et al. 2010

23. Filaments contains dense “clumps” Aquila molecular cloud • Clump Mass Function similar in shape to Stellar Mass Function •  Is Stellar IMF imprinted in the cloud structure? Andre et al. 2010

24. Desiderata for a Molecular Clump MW Survey • To make a definitive determination of the clump mass function, observations require surveys: • Sensitive to clumps capable of forming a 0.01 Msunbrown dwarf – an order of magnitude more sensitive than current surveys •  CCAT will probe clumps with mass ~ 0.001 Msun • (25x smaller than Herschel)

25. Desiderata for a Molecular Clump MW Survey • To make a definitive determination of the clump mass function, observations require surveys: • Sensitive to clumps capable of forming a 0.01 Msunbrown dwarf – an order of magnitude more sensitive than current surveys • With angular resolution < 5”to resolve 0.05 pc clumps to 1 kpc distance and to relieve the source confusion severely affecting Herschel, the BGPS, and SCUBA-2 surveys •  CCAT will probe scale of ~500 AU in nearest clouds

26. Desiderata for a Molecular Clump MW Survey • To make a definitive determination of the clump mass function, observations require surveys: • Sensitive to clumps capable of forming a 0.01 Msunbrown dwarf – an order of magnitude more sensitive than current surveys • With angular resolution < 5”to resolve 0.05 pc clumps to 1 kpc distance and to relieve the source confusion severely affecting Herschel, the BGPS, and SCUBA-2 surveys • Of both the dust continuum and high spectral resolution of molecular lines – to probe the dynamics of clumps • Covering tens of deg2 in many fields to sample different environments • Multicolor submm observations to measure dust temperatures and masses.

27. A facility of large synergy with ALMA ALMA will deliver very high spatial resolution, but only over a very small Field of View:  Will reveal fine detail, ONE SOURCE AT A TIME CCAT will not match ALMA in angular resolution (beam 2”-5” will not yield morphological info); it will however match it in sensitivity and will have a Field of View 30,000 times larger  FAST SURVEYOR (many objects at a time) Ideal Complementarity

28. October 2003: Partnership Workshop in Pasadena • Feb 2004: MOU signed by Caltech, JPL and Cornell • 2005: Project Office established • 2006: Feasibility Study Review • 2007-2010: Consortium consolidation, design development • Site selection completed • 2011-2013: Detailed Engineering Design • 2013-2017: Construction and First Light “Patience, n. A minor form of despair, disguised as a virtue.” Ambrose Bierce