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

A 25meter FIR/submillimeter telescope that will operate at wavelengths as short as = 200  m, 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 What is CCAT: What is CCAT: Beam size  m]/100 arcsec e.g. 200  m FoV: 1 sq. deg. Half WF err: 9.5  m rms Continuum Sensitivity, 5 , 1 hr :  m First-light short camera: 50 kpix Several instruments in Nasmith focus, some simultaneously accessible in large FoV Project Cost: $120M

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

Where is CCAT?

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

Google Earth Cerro Chajnantor 5612 m (18500 ft) ALMA

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 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 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 T rec (SSB) < 50 K – contrast with ALMA with T rec (DSB) ~ 180 K – a factor of 3.3 for T sky ~ 150 K High receiver sensitivity: direct detection systems easily background limited with T rec (SSB) < 50 K – contrast with ALMA with T rec (DSB) ~ 180 K – a factor of 3.3 for T sky ~ 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 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! 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!

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

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. By the time the first galaxies form, the Universe is already dusty Goods (z=4.1) in optical (HST, left; Daddi et al. 2009) and submm (SMA, right)

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

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 ~10% of CFIRB resolved directly with Herschel ~50% inferred statistically, yielding estimated number count models to a depth of 2 mJy/beam ~50% inferred statistically, yielding estimated number count models to a depth of 2 mJy/beam CCAT will resolve (directly) sources to mJy, resolving the totality of the CFIRB CCAT will resolve (directly) sources to mJy, resolving the totality of the CFIRB 11 P(D) Detections See Patanchon et al. (2010), Glenn et al. (2011)

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

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

Dusty High z Galaxies Observed flux density of a dusty galaxy as a function of z and Observed flux density of a dusty galaxy as a function of z and 1mm 1cm 100µm 10µm1µm Flux Density (mJy) 10cm SMM J z = (lensed) SPIRE Ivison et al. (2010) Blain et al. (2002)

Wide area coverage (> 100 deg 2 ) 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 Desiderata for a high z SMG galaxy Survey

Atomic fine structure & molecular lines: ZEUS Bradford et al. (2009) Flux Density ( W/m 2 /bin) v (km/sec)  Stacey & Hailey- Dunsheath et al. (2010) [CII] 158  m, [OI] 63 & 146 µm, [NII] 122 & 205 µm, CO ladder… Speculative: 17  m and 28  m lines of H 2 at high z?... ~10 3 galaxies/deg 2 detectable spectroscopically by CCAT  Spectroscopic survey of 1 in photometric detections doable with MOS (source centroiding should be better than 1”)

Wide area coverage (> 100 deg 2 ) 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. Desiderata for a high z SMG galaxy Survey

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

Bolocam Galactic Plane Survey (Bally et al. 2010) BOLOCAM: Orange VLA 20 GHz: purple Spitzer 8  m: cyan

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

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

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

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

To make a definitive determination of the clump mass function, observations require surveys: Sensitive to clumps capable of forming a 0.01 Msun brown dwarf – an order of magnitude more sensitive than current surveys  CCAT will probe clumps with mass ~ Msun (25x smaller than Herschel) 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 Msun brown 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 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 Msun brown 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 deg 2 in many fields to sample different environments Multicolor submm observations to measure dust temperatures and masses. Desiderata for a Molecular Clump MW Survey

A facility of large synergy with ALMA 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) 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 Ideal Complementarity

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