Legacy surveys with SCUBA2 - to coldly go where no man has gone before…

Paul van derder Werf

Sterrewacht Leiden

Legacy surveys with SCUBA2 -Legacy surveys with SCUBA2 -to coldly go where no man has gone to coldly go where no man has gone

before…before…

ObergurglObergurgl

March 2007March 2007

SCUBA-2 Legacy SurveysSCUBA-2 Legacy Surveys 2

SCUBA surveysSCUBA surveys Many teams, many surveysMany teams, many surveys Blank field surveys Blank field surveys

(confusion-limited)(confusion-limited) Gravitationally lensed Gravitationally lensed

surveyssurveys Few 100 SMGs detectedFew 100 SMGs detected Small field Small field slow buildup slow buildup

of samplesof samples


A survey of SCUBA surveysA survey of SCUBA surveys

HDF SHADES

8 mJy


From SCUBA to SCUBA-2From SCUBA to SCUBA-2

Field of view 8’Field of view 8’8’: 108’: 10 SCUBA SCUBA SCUBA-2 brings rectangular array imaging to submm SCUBA-2 brings rectangular array imaging to submm

astronomyastronomy 8 arrays of 408 arrays of 4032 TES detectors – 4 arrays at 850 32 TES detectors – 4 arrays at 850 m, 4 m, 4

at 450 at 450 mm Fully sampled imaging at 850 Fully sampled imaging at 850 mm Per pixel NEP 50 (220) mJy/√Hz at 850 (450) Per pixel NEP 50 (220) mJy/√Hz at 850 (450) mm


SCUBA-2 type surveysSCUBA-2 type surveys

SCUBA-2 field-of-view

1 deg1 deg22 field, will be mapped to confusion field, will be mapped to confusion limit in 23 hours by SCUBA-2 at 850 limit in 23 hours by SCUBA-2 at 850 mm

(from Gastañaga et al.)


OutlineOutline

JCMT Legacy Survey processJCMT Legacy Survey process

SCUBA-2 Legacy SurveysSCUBA-2 Legacy Surveys

SCUBA-2 Cosmology Legacy SurveySCUBA-2 Cosmology Legacy Survey

850 850 m survey sciencem survey science

450 450 m survey sciencem survey science


Legacy survey processLegacy survey process

Concept of legacy surveys proposed to JCMT boardConcept of legacy surveys proposed to JCMT board Legacy surveys can use both SCUBA-2 and HARP Legacy surveys can use both SCUBA-2 and HARP (16-pixel 350 GHz receiver)(16-pixel 350 GHz receiver) Call for proposals by the board – resulted in Call for proposals by the board – resulted in

oversubscription of oversubscription of all all assumed assumed (usable) JCMT time in 2007-2009 time by factor 5.5(usable) JCMT time in 2007-2009 time by factor 5.5 International workshop in Leiden led to coordinated International workshop in Leiden led to coordinated proposalsproposals Each proposal evaluated by a number of referees from Each proposal evaluated by a number of referees from

outside the JCMT outside the JCMT communitycommunity Process overseen by the JCMT Survey Steering Group, Process overseen by the JCMT Survey Steering Group,

which made a which made a recommendation to the JCMT board, which was adoptedrecommendation to the JCMT board, which was adopted


Outcome of the processOutcome of the process Two sets of surveys: 2-year surveys and 5-year surveysTwo sets of surveys: 2-year surveys and 5-year surveys

Two-year plan approved; 5-year plan approved in principle, but newTwo-year plan approved; 5-year plan approved in principle, but new call for surveys after 2 yearscall for surveys after 2 years

During this period, 55% of the available time on JCMT will go to theDuring this period, 55% of the available time on JCMT will go to the Legacy SurveysLegacy Surveys

Surveys are overseen by the JCMT Survey Oversight Committee,Surveys are overseen by the JCMT Survey Oversight Committee, which advises the JCMT board;which advises the JCMT board; teams will report every six months andteams will report every six months and must demonstrate progress, keeping up with the data stream, ability tomust demonstrate progress, keeping up with the data stream, ability to produce a uniform dataset, etc.produce a uniform dataset, etc.

Data initially proprietary, but obligation to release reduced data Data initially proprietary, but obligation to release reduced data


JCMT Legacy SurveysJCMT Legacy Surveys

Cosmology Legacy SurveyCosmology Legacy Survey (most highly rated): (most highly rated): 490 hours band 1490 hours band 1 (this is 90% of the expected available band 1 time!) (this is 90% of the expected available band 1 time!) and and 630 hours band 2/3630 hours band 2/3 SCUBA-2 All-Sky Survey (SASSy): 500 hours band 4 to 150 mJy depthSCUBA-2 All-Sky Survey (SASSy): 500 hours band 4 to 150 mJy depth (all-sky in 5 years) – see Stephen Serjeant for details(all-sky in 5 years) – see Stephen Serjeant for details Debris disks – complete set of nearby starsDebris disks – complete set of nearby stars Nearby galaxies survey – SCUBA-2 and HARPNearby galaxies survey – SCUBA-2 and HARP

Gould’s Belt survey (2Gould’s Belt survey (2ndnd highly rated) – SCUBA-2 and HARP highly rated) – SCUBA-2 and HARP Galactic Plane survey – SCUBA-2 and HARPGalactic Plane survey – SCUBA-2 and HARP

Spectral line survey – HARP only Spectral line survey – HARP only


Debris disk surveyDebris disk survey

Few hundred nearby stars,Few hundred nearby stars, mapped to the confusion limitmapped to the confusion limit at 850 at 850 mm

Will likely Will likely produce very niceproduce very nice target set for adaptive opticstarget set for adaptive optics observations of SMGsobservations of SMGs

Fomalhaut at 450m

?

850m

Size of Pluto’s orbit

Beam size

Holland et al. (2001)


Star formationStar formation

Our lack of detailed understanding of star formation is a major Our lack of detailed understanding of star formation is a major stumbling block:stumbling block:

while we know a lot about low-mass star formation, very little is knownwhile we know a lot about low-mass star formation, very little is known about the formation of high-mass stars (rare and short-lived); yet theseabout the formation of high-mass stars (rare and short-lived); yet these power the SMGs.power the SMGs.

there is no good theory for the origin of the IMF and whether or notthere is no good theory for the origin of the IMF and whether or not there should be a “universal” IMF; yet this central to estimated of SFR,there should be a “universal” IMF; yet this central to estimated of SFR, stellar mass etc.stellar mass etc.


The IMF problem(s) in SMGsThe IMF problem(s) in SMGs

Integral under green curve Integral under green curve would exceed local would exceed local stellar mass estimates stellar mass estimates for normal IMF.for normal IMF.

SFR implied by SMG’s


SCUBA Galactic Centre Survey

≈15 shifts (or 120 hrs) of telescope time

M8

M16

SCUBA-2 Galactic PLANE Survey

SCUBA-2 Galactic plane surveySCUBA-2 Galactic plane survey

SCUBA-2 Legacy SurveysSCUBA-2 Legacy Surveys 14(Pierce-Price et al.)

SCUBA-2 FOV

SCUBA Galactic centre surveySCUBA Galactic centre survey

SCUBA FOV

450m

850m


IRAS 100 IRAS 100 m: m: Gould’s BeltGould’s Belt


Star formation surveysStar formation surveys

Galactic plane survey will reveal systematically reveal the progenitors ofGalactic plane survey will reveal systematically reveal the progenitors of massive star formation (IR dark clouds and similar very dense structures)massive star formation (IR dark clouds and similar very dense structures)

anatomy of the Milky Way at 850 anatomy of the Milky Way at 850 m – important reference point form – important reference point for extragalactic studiesextragalactic studies

Gould’s Belt survey – comprehensive survey of low-mass star formationGould’s Belt survey – comprehensive survey of low-mass star formation

These surveys could only be implemented as a result of the Legacy SurveyThese surveys could only be implemented as a result of the Legacy Surveyprocess. process.


SCUBA-2 Cosmology Legacy SurveySCUBA-2 Cosmology Legacy Survey 4 PIs: Jim Dunlop, Mark 4 PIs: Jim Dunlop, Mark Halpern, Halpern, Ian Smail, Paul van der Ian Smail, Paul van der Werf; Werf; + ≈ 100 co-I’s + ≈ 100 co-I’s

SCUBA-2 field-of-view

Time allocation for the 2-Time allocation for the 2-year year program: program: 41 nights band 1 41 nights band 1 weather,weather, 61 nights band 61 nights band 2/32/3

2-year program:2-year program: large survey (20 deglarge survey (20 deg22) at ) at 850 850 m, m, deep survey at 450 deep survey at 450 m m (0.5 deg(0.5 deg22)) 5-year program:5-year program: large survey (50 deglarge survey (50 deg22) at ) at 850 850 m, m, deep survey at 450 deep survey at 450 m m (1.3 deg(1.3 deg22))


Survey propertiesSurvey properties

Survey volumes are always Survey volumes are always very very longlong in the radial direction. in the radial direction. A A deeperdeeper submm survey submm survey

does not does not probe probe a larger volume, buta larger volume, but fainter galaxies at all fainter galaxies at all redshiftsredshifts..

JCMT/SCUBA-2 confusion JCMT/SCUBA-2 confusion

limit limit at 850 at 850 m is 0.8 mJy; to 3m is 0.8 mJy; to 3 we we resolve only resolve only ≈20%≈20% of of background.background. Bright sources are typically Bright sources are typically

20 mJy20 mJy limited dynamic range in limited dynamic range in fluxflux

Wide Wide 850 850 m survey of only m survey of only

1 layer1 layer

(from Andrew Blain)


Survey depths and widths (2-yr plan)Survey depths and widths (2-yr plan)

Wide 850Wide 850 m survey: 20 degm survey: 20 deg22 to 1 to 1 = 0.7 mJy = 0.7 mJy.. Comparable to a Schmidt plate to the depth of the Comparable to a Schmidt plate to the depth of the SCUBA-HDF-N map.SCUBA-HDF-N map. Expected to yield several 10Expected to yield several 1033 sources at >10 sources at >10, several , several 101044 at >3 at >3..

Deep 450Deep 450 m survey: 0.5 degm survey: 0.5 deg22 to 1 to 1 = 0.5 mJy = 0.5 mJy (expected (expected confusion limit).confusion limit). Intended area of SHADES, to average over sufficient Intended area of SHADES, to average over sufficient cosmic volume.cosmic volume. Expected to yield several 10Expected to yield several 1022 sources at >10 sources at >10, several , several 101033 at >3 at >3..

Deep 850Deep 850 m survey: 0.5 degm survey: 0.5 deg22 to 1 to 1 = 0.15 mJy = 0.15 mJy (ignoring (ignoring confusion).confusion). In parallel with 450 In parallel with 450 m map, which will be used for m map, which will be used for deconvolution.deconvolution.


Survey fieldsSurvey fields 850 850 m survey:m survey: 450 450 m survey:m survey:

fieldfield RARA areaarea

[deg[deg22]]

XMM-LSSXMM-LSS 22 55

ECDFSECDFS 33 33

CosmosCosmos 1010 22

LockmanLockman 1010 44

BootesBootes 1414 22

EGSEGS 1414 11

ELAIS-N1ELAIS-N1 1616 22

Akari-NEPAkari-NEP 1818 11

fieldfield RARA areaarea

[deg[deg22]]

UDSUDS 22 <0.25<0.25

ECDFSECDFS 33 <0.25<0.25

CosmosCosmos 1010 <0.25<0.25

GOODS-NGOODS-N 1212 0.050.05

Akari-NEPAkari-NEP 1818 0.020.02

SA22SA22 2222 0.020.02

Field selection (partly) driven by Field selection (partly) driven by complementary data complementary data of theof therequired depthrequired depth; e.g., ; e.g., KKABAB=25=25


Science case 850 Science case 850 m surveym survey

Clustering of SMGsClustering of SMGs

Relation with other populations through massive source stackingRelation with other populations through massive source stacking

Extreme objects (>30 mJy) – how many? what are they?Extreme objects (>30 mJy) – how many? what are they?

1010 detections: easier identification, better photo- detections: easier identification, better photo-zz

Properties of host galaxies – stellar masses, Properties of host galaxies – stellar masses, KK——zz diagram, growing AGN? diagram, growing AGN?

New tests for semi-analytical modelsNew tests for semi-analytical models

Rich source of follow-up by e.g., ALMARich source of follow-up by e.g., ALMA


Clustering and evolutionClustering and evolution

Clustering signal even Clustering signal even without without any redshift informationany redshift information

Photo-Photo-zz’s ’s clustering as clustering as function of function of zz

Assign halo masses to Assign halo masses to SMGsSMGs

Same at all redshifts?Same at all redshifts?


Relations between source populationsRelations between source populations Availability of very deep data from e.g., UDS and IRAC allows recoveryAvailability of very deep data from e.g., UDS and IRAC allows recovery of submm signal from a selected population. of submm signal from a selected population.

E.g.: Lyman Break Galaxies have no detectable submm emission even afterE.g.: Lyman Break Galaxies have no detectable submm emission even after massive source stacking, but Distant Red Galaxies (DRGs) do!massive source stacking, but Distant Red Galaxies (DRGs) do!

Defined by Defined by JJss——KKss > 2.3, which brings the Balmer break between > 2.3, which brings the Balmer break between JJss and and KKss

for for zz > 2 > 2

DRGs: massive galaxies with high SFRs; source density 3 arcminDRGs: massive galaxies with high SFRs; source density 3 arcmin–2–2

for for KK<22.5 is comparable to SMGs with >0.8 mJy at 850 <22.5 is comparable to SMGs with >0.8 mJy at 850 m (as estimatedm (as estimated from lensing from lensing surveys).surveys).

1 unlensed DRG detected directly with SCUBA (5 mJy). 1 unlensed DRG detected directly with SCUBA (5 mJy).


Stacking DRGsStacking DRGs

DRGs, EROsDRGs, EROs

random positionsrandom positions

DRGs:DRGs:SS850850 = 1.11 = 1.11 0.28 mJy 0.28 mJy

≈≈20% of background20% of background

(Knudsen (Knudsen et al.et al., 2005), 2005)


MicrowaveBackground IR/Optical

Background

X-RayBackground

Big BangBig Bang

Stars+BlackHolesStars+BlackHoles

AGNAGN

1mm 1m 1nm

(Puget et al. 1996, Hauser et al. 1998Fixsen et al. 1998)

Cosmic backgroundsCosmic backgrounds

IRBG peaks at ≈200m.At 850m, 30 lowerAt 450m, only 3 lower


Science case 450Science case 450m surveym survey Probe the IR/submm background close to its spectral peakProbe the IR/submm background close to its spectral peak

Resolve ≈ 75% of the 450Resolve ≈ 75% of the 450m background: new territory!m background: new territory!

Out to Out to zz=3: full census of ULIRGs in survey volume=3: full census of ULIRGs in survey volume Out to Out to zz=2: full census of >3=2: full census of >310101111 LL galaxies galaxies Out to Out to zz=1: full census of >2=1: full census of >210101111 LL galaxies galaxies

Connection to other populations without stackingConnection to other populations without stacking

Deconvolve confusion-limited 850Deconvolve confusion-limited 850m mapm map

Evolution of IR/submm luminosity function,Evolution of IR/submm luminosity function, obscured star formation historyobscured star formation history


Elbaz diagramElbaz diagram

SCUBA (450m)


Deep 850Deep 850m source counts m source counts

Currently from Currently from gravitationally gravitationally lensing cluster lensing cluster fieldsfields small survey small survey volumes, affected by cosmic volumes, affected by cosmic variancevariance

Deconvolved deep 850Deconvolved deep 850m m map largemap large enough to average out enough to average out cosmic cosmic variancevariance

Several 10Several 1033 sources sources expected at >10expected at >10 down to 1.5 mJy (resolves ≈ down to 1.5 mJy (resolves ≈ 40% of 40% of 850 850 m background)m background)

((Knudsen, Van der WerfKnudsen, Van der Werf & Kneib, & Kneib, 20072007))

1010


Practical challenges at 450Practical challenges at 450mm

Even in excellent weather observing at 450Even in excellent weather observing at 450m is challenging.m is challenging.

Special care needed in calibration – monitor conditions and takeSpecial care needed in calibration – monitor conditions and take beammaps several times per nightbeammaps several times per night

Need to establish a Need to establish a rigorous observing protocolrigorous observing protocol, since the data are going, since the data are going to be taken by many different persons (often not even member of theto be taken by many different persons (often not even member of the cosmology survey team).cosmology survey team).

Surface accuracy of JCMT dish <22Surface accuracy of JCMT dish <22m is needed; m is needed; this needs to be monitored and maintainedthis needs to be monitored and maintained..

Crucial requirement for 450Crucial requirement for 450m survey depth and uniformitym survey depth and uniformity


Conclusions and outlookConclusions and outlook

850 850 m survey will produce statistically accurate results, and robustm survey will produce statistically accurate results, and robust samples for easier follow-up.samples for easier follow-up.

Clustering is a key applicationClustering is a key application

The 450The 450m survey is unique in probing lower SFRsm survey is unique in probing lower SFRs

Deep complementary data is essentialDeep complementary data is essential

Follow-up is crucial: deep radio, near-IR deployable IFUs,Follow-up is crucial: deep radio, near-IR deployable IFUs, redshift machines using COredshift machines using CO

Numbers are still “low” Numbers are still “low” a next-generation instrument? a next-generation instrument?

Documents

Legacy surveys with SCUBA2 - to coldly go where no man has gone before…