Extragalactic surveys with CCAT: Extragalactic surveys with CCAT: distant galaxies and nearby distant galaxies and nearby

templatestemplates

Contribution from Blain et al.Contribution from Blain et al.

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Summary of CCAT’s galaxy scienceSummary of CCAT’s galaxy science

Telescope design optimized for fast wide-field imaging at an Telescope design optimized for fast wide-field imaging at an excellent site, CCAT can:excellent site, CCAT can:

Find huge numbers of distant galaxies (z~1-5) at rate >10Find huge numbers of distant galaxies (z~1-5) at rate >1033 hr hr-1-1

Use colors to sift the sample to find examples with extreme Use colors to sift the sample to find examples with extreme redshifts/luminosities to better understand the way the bulk of redshifts/luminosities to better understand the way the bulk of galaxy luminosity evolves and confront galaxy formation modelsgalaxy luminosity evolves and confront galaxy formation models

Resolve the emission from a large sample of low-redshift galaxies Resolve the emission from a large sample of low-redshift galaxies to reveal the final, authoritative bolometric galaxy luminosity to reveal the final, authoritative bolometric galaxy luminosity function to z~0.2, based on SDSS redshiftsfunction to z~0.2, based on SDSS redshifts

Covering the whole submm/mm band, it will provide the best Covering the whole submm/mm band, it will provide the best possible photo redshifts, based on redshifted far-IR SED peakspossible photo redshifts, based on redshifted far-IR SED peaksCCAT will enhance capability of new facilitiesCCAT will enhance capability of new facilities

Leverage small-field, ultradeep, high-resolution imaging with Leverage small-field, ultradeep, high-resolution imaging with ALMA by feeding targets to the big interferometerALMA by feeding targets to the big interferometer

Easily match the survey area coverage of Herschel Space Easily match the survey area coverage of Herschel Space Observatory to better locate and understand the targetsObservatory to better locate and understand the targets

Systematically identify all point sources from the Planck all-sky Systematically identify all point sources from the Planck all-sky surveysurvey

Remove point-source confusion from existing/future CMB mapsRemove point-source confusion from existing/future CMB maps

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Dust-enshrouded UniverseDust-enshrouded Universe

Orion through telephoto lens(~2 degree field)

Resolved in detail only in Milky WayResolved in detail only in Milky Way ~50% of all energy absorbed by dust~50% of all energy absorbed by dustMore in molecular star-forming regionsMore in molecular star-forming regionsDust cooling is crucial for star Dust cooling is crucial for star formationformationMost ISM metals in dustMost ISM metals in dustDust is vital ISM componentDust is vital ISM componentDust present at z>6Dust present at z>6Physics and chemistry of dust still Physics and chemistry of dust still complex and unfinishedcomplex and unfinished

Molecular gas provides diagnostic Molecular gas provides diagnostic information about the most intense information about the most intense regions of star formationregions of star formationALMA will map it in great detail, but ALMA will map it in great detail, but CCAT can provide maps of total power CCAT can provide maps of total power from nearby galaxiesfrom nearby galaxies

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Resolved `example’: the AntennaeResolved `example’: the Antennae

Excellent example of distinct Excellent example of distinct opt/UV and IR luminosityopt/UV and IR luminosity

BUT modest luminosityBUT modest luminosity

Interaction long known, but great Interaction long known, but great luminosity unexpected luminosity unexpected

~90% energy escapes at far-IR ~90% energy escapes at far-IR wavelengths wavelengths

Resolved images important Resolved images important here to reveal dust location here to reveal dust location

Different structure in hot Different structure in hot and cool dust and cool dust

Relevant scales ~1” at Relevant scales ~1” at high redshifthigh redshift

This is a task for ALMAThis is a task for ALMA Low redshift examples and Low redshift examples and

identification of high-redshift identification of high-redshift examples from CCATexamples from CCAT

HST WFPC2

ISOCAM

CSO/SHARC-2Dowell et al.

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Mm/submm gives direct view out to Mm/submm gives direct view out to highest redshiftshighest redshifts

The mm/submm waveband in The mm/submm waveband in the continuum allows direct the continuum allows direct access to high redshiftsaccess to high redshifts

CCAT can reach quickly (in CCAT can reach quickly (in minutes) down to sub-mJy flux minutes) down to sub-mJy flux densities where typical high-densities where typical high-redshift galaxies are foundredshift galaxies are found

Existing surveys reach ~1mJy Existing surveys reach ~1mJy at 1.2mm, ~5mJy at 0.85mmat 1.2mm, ~5mJy at 0.85mm

These see only the most These see only the most luminous galaxiesluminous galaxies

Multi-band imaging with Multi-band imaging with CCAT, expanded further with CCAT, expanded further with optical, radio and optical, radio and Spitzer/Herschel observations Spitzer/Herschel observations should identify most should identify most distant/interesting by colordistant/interesting by color

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Obscured galaxies: backgroundObscured galaxies: background

Many sources of dataMany sources of dataTotal far-IR and optical Total far-IR and optical background intensity background intensity comparablecomparable

Simple statement of importance Simple statement of importance of obscured emissionof obscured emission

Most of the submm (0.8mm) Most of the submm (0.8mm) background already detected by background already detected by SCUBA SCUBA

Order of magnitude deeper is Order of magnitude deeper is enough to catch most of far-IR enough to catch most of far-IR luminosityluminosity

ISO and more precise, but ISO and more precise, but similar Spitzer limits detect similar Spitzer limits detect ~20-30% in mid-IR~20-30% in mid-IRNote: backgrounds yield weaker Note: backgrounds yield weaker constraints on evolution than constraints on evolution than N(S) counts to see nextN(S) counts to see next

SCUB

A

ISO

Models: BJSLKI 99SC

UBA

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Populations of galaxies to findPopulations of galaxies to find

Current generations of surveys Current generations of surveys have identified have identified

~500 high-redshift galaxies at ~500 high-redshift galaxies at wavelengths of wavelengths of 1.2/1.1/0.85mm1.2/1.1/0.85mm

Handful at 0.35/0.45mmHandful at 0.35/0.45mm

Redshifts are typically 2-3Redshifts are typically 2-3 Likely to be a relatively rare Likely to be a relatively rare

high-redshift tailhigh-redshift tail Low-redshift galaxies can also Low-redshift galaxies can also

be detectedbe detected Signs of galaxies being Signs of galaxies being

clustered more strongly than clustered more strongly than average galaxiesaverage galaxies

Current samples too small to Current samples too small to define accurate luminosity define accurate luminosity functionfunction

Galaxies too luminous to tie Galaxies too luminous to tie them clearly to larger samples them clearly to larger samples at optical wavelengthsat optical wavelengths

Confusion noise and mapping Confusion noise and mapping speed both a problemspeed both a problem

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Global luminosity evolutionGlobal luminosity evolution

Points: optical/IR/UV dataPoints: optical/IR/UV data Blue: optical / UV Blue: optical / UV Red: IR and dust correctedRed: IR and dust corrected Black: SDSS fossil recordBlack: SDSS fossil record

Lines: results from combined Lines: results from combined submm/far-IR counts & submm/far-IR counts & backgroundbackground

Note high-z decline certainly Note high-z decline certainly realreal

Decline less rapid than for Decline less rapid than for QSOs?QSOs?

CaveatsCaveats AGN power (Alexander et al. AGN power (Alexander et al.

& Chandra implies low?)& Chandra implies low?) High-z / high-L IMF changeHigh-z / high-L IMF change

Submm-selected sample probes Submm-selected sample probes most intense epoch of galaxy most intense epoch of galaxy evolution directlyevolution directly

Neo-WMAP cosmology

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Redshift distribution N(z) for radio-Redshift distribution N(z) for radio-pinpointed SMGspinpointed SMGs

Red histogram: Chapman et alRed histogram: Chapman et alLines: expected submm & radio Lines: expected submm & radio N(z)’s from Chapman’s modelN(z)’s from Chapman’s model

Consistent with early submm-Consistent with early submm-derived Madau plots but result is derived Madau plots but result is now now MUCHMUCH more robust more robust

Magenta shade at z~1.5 is Magenta shade at z~1.5 is ‘spectroscopic desert’: rest-UV ‘spectroscopic desert’: rest-UV & rest-optical lines both hard to & rest-optical lines both hard to observe observe

Blue shading at highest z is Blue shading at highest z is incompleteness due to radio incompleteness due to radio non-detection. Likely modest, non-detection. Likely modest, but uncertainbut uncertain

Now 73 redshifts (ApJ 2005)Now 73 redshifts (ApJ 2005) Median z=2.4 and spread in Median z=2.4 and spread in

redshift redshift zz~0.65 is good ~0.65 is good descriptiondescriptionChapman et al. (2003; 2005)

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Luminosity functionLuminosity function

Based on known redshifts and fraction of Based on known redshifts and fraction of population with redshifts (~50%) can see population with redshifts (~50%) can see dramatic evolution from z=0 to 1 to 2.5dramatic evolution from z=0 to 1 to 2.5Plausible connection to the luminosity Plausible connection to the luminosity function of optically-selected high-z function of optically-selected high-z galaxiesgalaxies

Lower limits from stacked high-z Lower limits from stacked high-z galaxies as only a fraction of far-IR galaxies as only a fraction of far-IR luminous objects are detected in UV luminous objects are detected in UV surveyssurveys

Interesting to see Spitzer LF results at Interesting to see Spitzer LF results at z~1 for comparisonz~1 for comparison

Spectroscopy not trivial at z~1Spectroscopy not trivial at z~1

Most of luminosity from far-IR Most of luminosity from far-IR luminous galaxies emitted at ~10luminous galaxies emitted at ~101212 LLoo

CCAT can reveal this CCAT can reveal this Too faint for existing telescopesToo faint for existing telescopes

Chapman et al. (2005); astro-ph/0412573

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Future toolsFuture tools

LMT *-shownSOFIA*/BLASTCARMAAT25SCUBA-II Herschel*/Planck*ALMA* (and APEX)SPICASAFIR (JWST-based?)*SPECS/SPIRIT

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CCAT confusion limitsCCAT confusion limits

Current missions in blackCurrent missions in blackSpitzer is +Spitzer is +SOFIA/Herschel are SOFIA/Herschel are and and ALMAALMA bar is a 500-m baseline bar is a 500-m baselineCCAT CCAT bar is ground-based 25-mbar is ground-based 25-mSAFIR SAFIR is space-borne 10-m is space-borne 10-m

Confusion from galaxies not met Confusion from galaxies not met for many minutesfor many minutes

At shortest wavelengths very At shortest wavelengths very deep observations are possibledeep observations are possible

Factor of a few increase in Factor of a few increase in resolution over existing facilities resolution over existing facilities is very powerfulis very powerful

Reaching sub-mJy fluxes at Reaching sub-mJy fluxes at >500GHz allows connection >500GHz allows connection between optical and existing far-between optical and existing far-IR galaxiesIR galaxies

Confusion falls away quickly on Confusion falls away quickly on scales of 5 arcsec and 500-scales of 5 arcsec and 500-1000GHz1000GHz

▬▬▬

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CCAT: Confusion noiseCCAT: Confusion noise

Model based on galaxies in Model based on galaxies in SCUBA/ISO populationsSCUBA/ISO populations

Also consistent with Also consistent with Spitzer resultsSpitzer results

Galactic cirrus modest Galactic cirrus modest herehere

Flux for 1 source per beam Flux for 1 source per beam ~ RMS noise~ RMS noiseExtragalactic sources Extragalactic sources dominate for small aperturesdominate for small apertures

When < 500When < 500µm ~25-m µm ~25-m aperture or bigger is aperture or bigger is very importantvery important

At fluxes <0.1mJy sure At fluxes <0.1mJy sure to find submm to find submm counterparts to high-z counterparts to high-z optical galaxiesoptical galaxies

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Survey speed / timeSurvey speed / time

Large format cameras essential to rapid mappingLarge format cameras essential to rapid mapping Gain from ALMA is approximately product of bandwidth and Gain from ALMA is approximately product of bandwidth and

pixel numberpixel number This can be a huge numberThis can be a huge number Also huge compared with existing facilitiesAlso huge compared with existing facilities

And essential part of CCAT program is developing these And essential part of CCAT program is developing these instrumentsinstrumentsSky is large enough for a 25-year programSky is large enough for a 25-year programSubmm spectroscopy will always be of a subset of the Submm spectroscopy will always be of a subset of the detectionsdetections

Natural role for ALMANatural role for ALMA Wide-field optical design will enable future development of Wide-field optical design will enable future development of

multi-object spectroscopymulti-object spectroscopy

Imaging is prime goal. ALMA can provide resolved imaging Imaging is prime goal. ALMA can provide resolved imaging and spectroscopy of the detectionsand spectroscopy of the detections

CCAT provides enough color information to help to sift targets CCAT provides enough color information to help to sift targets for ALMAfor ALMA

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Mapping speed comparing other Mapping speed comparing other facilitiesfacilities

CCAT is an ultrafast mapperCCAT is an ultrafast mapperAssumptionsAssumptions

10000 pixel detector, Nyquist 10000 pixel detector, Nyquist sampled at all bands 0.2, 0.35, sampled at all bands 0.2, 0.35, 0.45, 0.67, 0.85,1.1mm (in 0.45, 0.67, 0.85,1.1mm (in order from violet-red)order from violet-red)

Observationally verified counts Observationally verified counts (good to factor 2)(good to factor 2)

Confusion and all sky limitsConfusion and all sky limits

1.2/0.85/0.35mm imaging 1.2/0.85/0.35mm imaging speeds are compatiblespeeds are compatible

To reach confusion at 0.35mm To reach confusion at 0.35mm go several times deeper at go several times deeper at 0.85mm0.85mm

Detection rates are Detection rates are 150150 SCUBA-2; SCUBA-2; 300300 ALMA ALMA About 100-6000 per hourAbout 100-6000 per hour Lifetime detection of order 10Lifetime detection of order 107-7-

8 8 galaxies: ~1% of ALL galaxies! galaxies: ~1% of ALL galaxies! `1/3 sky survey’: ~1000 deg`1/3 sky survey’: ~1000 deg-2-2

for 3 degfor 3 deg22hrhr-1-1 gives 5000 hr gives 5000 hr

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Detection rate in surveysDetection rate in surveys

Note the comparable detection rate in different Note the comparable detection rate in different atmospheric windowsatmospheric windowsMulti-band detection rate can be quantified, but most are Multi-band detection rate can be quantified, but most are detected in more than one banddetected in more than one band

Knowledge about SED comes from two bands in submm, not a Knowledge about SED comes from two bands in submm, not a great deal gained by getting more. Not true in optical or mid-IRgreat deal gained by getting more. Not true in optical or mid-IR

There is a limit to a deep survey, imposed by confusionThere is a limit to a deep survey, imposed by confusion ALMA will go deeperALMA will go deeper Limit is about local L*Limit is about local L*

Wide survey limited just by the elevation/latitudeWide survey limited just by the elevation/latitude Number of ‘extreme’ and lensed objects for detailed and easy Number of ‘extreme’ and lensed objects for detailed and easy

ALMA study will come from hereALMA study will come from here

Spitzer will reveal luminosity function in enough detail to Spitzer will reveal luminosity function in enough detail to plan the intermediate depth survey conesplan the intermediate depth survey conesDesign limits from aperture and field of view respectively Design limits from aperture and field of view respectively

These are being driven to best possibleThese are being driven to best possible

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SEDs: full & zoom of IRAC-24 regionSEDs: full & zoom of IRAC-24 region

SED peak wave-length ranges over factor SED peak wave-length ranges over factor 33No nice stellar SED peak in IRAC, no neat No nice stellar SED peak in IRAC, no neat spectral breaks/features...spectral breaks/features...All SMG far-IR photometric redshifts will All SMG far-IR photometric redshifts will need careneed careOther information from optical/near-IR Other information from optical/near-IR color will be valuable to obtain better color will be valuable to obtain better constraints. CCAT should be considered in constraints. CCAT should be considered in context.context.

Normalised to 60 & 100 quantity from the far-IR:radio relation

IRAC & MIPS-24 zoomed plotRadio-far-IR relation seems to hold OK

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‘‘Photometric redshifts’ from dust SEDsPhotometric redshifts’ from dust SEDs

Can combine different bands to Can combine different bands to estimate T & z togetherestimate T & z together

No strong far-IR spectral breaks or No strong far-IR spectral breaks or featuresfeatures

24mm band can see redshifted PAH 24mm band can see redshifted PAH emission lines and Si absorption emission lines and Si absorption features from dust grainsfeatures from dust grains

Plot shows flux ratio against Spitzer Plot shows flux ratio against Spitzer MIPS 70mmMIPS 70mm

Strongest lever from 200-600µmStrongest lever from 200-600µm

Based on better knowledge of galay Based on better knowledge of galay properties from Spitzer and weather properties from Spitzer and weather at CCAT site, can probably design at CCAT site, can probably design optimal band shapes to do photo-z’s optimal band shapes to do photo-z’s Once z known, get accurate Once z known, get accurate luminosityluminosityALMA can do this too (a few galaxies ALMA can do this too (a few galaxies at a time), combined with real at a time), combined with real redshift information from submm redshift information from submm spectral linesspectral lines

Color cf 70m from Spitzer

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Galaxies at lower redshiftsGalaxies at lower redshifts

Can resolve images of ~4000 galaxies larger than Can resolve images of ~4000 galaxies larger than 30 arcsec across in a single CCAT pointing30 arcsec across in a single CCAT pointing

10kpc is >30 arcsec at distances < 60Mpc, which 10kpc is >30 arcsec at distances < 60Mpc, which encloses ~4000 galaxies, and is most of the way to the encloses ~4000 galaxies, and is most of the way to the Coma clusterComa cluster

Resolve GMCs on 2-10 arcsec scales for ALMA single Resolve GMCs on 2-10 arcsec scales for ALMA single pointing followup of most enshrouded/active regionspointing followup of most enshrouded/active regions

Interacting galaxies on 30kpc scales can have Interacting galaxies on 30kpc scales can have extent of 0.35mm emission measured to >1Gpc / extent of 0.35mm emission measured to >1Gpc / z~0.25z~0.25

True local luminosity function, including cold dust True local luminosity function, including cold dust not easy to select using IRAS imagesnot easy to select using IRAS images

Interesting synergy with ASTRO-F/IRIS all-sky survey, Interesting synergy with ASTRO-F/IRIS all-sky survey, which is available in 2007+5years? which is available in 2007+5years?

Also WISE allsky 12 & 24Also WISE allsky 12 & 24m survey in 2009/2010m survey in 2009/2010