Surveys of high-z galaxies and Surveys of high-z galaxies and galaxy clusters with AzTECgalaxy clusters with AzTEC

Sungeun KimSungeun Kim

Astronomy & Space Science DepartmentAstronomy & Space Science Department

Sejong UniversitySejong University

AzTEC (Astronomical Thermal Emission AzTEC (Astronomical Thermal Emission Camera)Camera) InstrumentInstrument

AzTEC is a AzTEC is a bolometer camerabolometer camera(designed for imaging)(designed for imaging)

AC voltage output AC voltage output directly proportional to directly proportional to optical power. optical power.

Detectors read outDetectors read outcontinuously at 64Hz.continuously at 64Hz.

System designed toSystem designed tohave good low freq.have good low freq.stability (AC biased)stability (AC biased)

All commands andAll commands andsignals pass via signals pass via fiber optics (low flux demands low systematics)fiber optics (low flux demands low systematics)

144 element spiderweb bolo array – S. Golwala

AzTEC CollaboratorsAzTEC Collaborators

G. Wilson (PI), J. Austermann, K. Scott, T. Perera, G. Wilson (PI), J. Austermann, K. Scott, T. Perera, M. Yun (UMass, USA)M. Yun (UMass, USA) J. Bock, N. Scoville (Caltech, USA)J. Bock, N. Scoville (Caltech, USA) P. Mauskopf (Cardiff, UK)P. Mauskopf (Cardiff, UK) I. Aretxaga, D. Hughes (INAOE, Mexico)I. Aretxaga, D. Hughes (INAOE, Mexico) J. Lowenthal (Smith College, USA)J. Lowenthal (Smith College, USA) E. Chapin, M. Halpern, A. Pope, D. Scott (UBC, Canada)E. Chapin, M. Halpern, A. Pope, D. Scott (UBC, Canada) K. Coppin (University of Durham, UK)K. Coppin (University of Durham, UK) Y. Kang, S. Youn, Y. Kim, K. Kim (Sejong Univ., Korea)Y. Kang, S. Youn, Y. Kim, K. Kim (Sejong Univ., Korea)

AzTECAzTEC

• New ‘Science’ detector array• 110/144 working detectors

(others possibly repairable)• Pass band: 1.1 mm, 2.1 mm• Raw detector sensitivity: 15mJy • Beamsize: 18 arcsec. FWHM• Field of View: 4.8 arcmin • Jiggle Mapping Speed: 4hrs/FOV/mJy2

• Scan Mapping Speed: 20 arcmin2/hr/mJy2

Continuous JCMT Observing, Nov 10 – Jan 2> 400 hrs observing time on SMG

projects

sec

Pre-shipment checkout Optics alignment at JCMT

AzTEC on the JCMTAzTEC on the JCMT

AzTECAzTEC

• New ‘Science’ detector array• 110/144 working detectors

(others possibly repairable)• Pass band: 1.1 mm, 2.1 mm• Raw detector sensitivity: 15mJy • Beamsize: 18 arcsec. FWHM• Field of View: 4.8 arcmin • Jiggle Mapping Speed: 4hrs/FOV/mJy2

• Scan Mapping Speed: 20 arcmin2/hr/mJy2

Continuous JCMT Observing, Nov 10 – Jan 2> 400 hrs observing time on SMG

projects

sec

Oversized optics minimizemicrophonic pickup

24bit digitization of signals atcryostat eliminates pickup fromlong cable runs

The opacity at 225 GHz was recorded every 10minutes by the CSO tauMonitor.

The array orientation is fixed in Azimuth andElevation, the scan-angle in the RA-DEC planefor a raster scan map continuously changes due to sky rotation.

AzTEC/JCMT SMG StudiesAzTEC/JCMT SMG Studies

FieldField SizeSize[arcmin[arcmin22]]

Obs TimeObs Time[hrs][hrs]

target target σσ [mJ][mJ]

PIPI

SHADESSHADES 18001800 198.5 198.5 (225)(225)

0.70.7 DunlopDunlop

COSMOSCOSMOS 900900 4545 (45) (45) 1.01.0 D.SandersD.Sanders

GOODS-NGOODS-N 160160 4343 (90)(90) 0.30.3 E.ChapinE.Chapin

MS0451MS0451 225225 3030 (30) (30) 0.50.5 I.SmailI.Smail

4C41.174C41.17 200200 4848 (48) (48) 0.30.3 D.HughesD.Hughes

0316-2570316-257 5050 3030 (30) (30) 0.30.3 H.RottgeringH.Rottgering

BR0952BR0952 2121 14.65 (24)14.65 (24) 0.80.8 K.KnudsenK.Knudsen

~1deg2

Dust emission: far-IR & sub-Dust emission: far-IR & sub-mmmm

Dusty star-forming galaxies emit much of theirlight at IR to mm wavelengths

Figure from van Kampen(2005)

• AzTEC is aimed for making a series of confusion-limited surveys of the Submillimeter Galaxies (SMGs), environments of clusters at 1.1 mm wavelength in order to study the dusty starburst populations both in and behind clusters, and blank field.

Submillimeter Submillimeter GalaxiesGalaxies

Population of extremely Population of extremely luminous high-redshift dust-luminous high-redshift dust-obscured galaxies detected by obscured galaxies detected by their sub-mm and mm their sub-mm and mm wavelength emission.wavelength emission.

Massive galaxies, with SFR of Massive galaxies, with SFR of ~500-1000 M~500-1000 Msunsun/yr. Sub-mm /yr. Sub-mm SCUBA surveys in late 90s (Smail SCUBA surveys in late 90s (Smail et al 2000, Ivison et al. 98). et al 2000, Ivison et al. 98).

SMGs: FSMGs: F850850 > 1 mJy. > 1 mJy. Spectroscopic redshifts for Spectroscopic redshifts for higher redshift population (z~2), higher redshift population (z~2), median Fmedian F850850 ~ few mJy for z~2 ~ few mJy for z~2 population. population.

Before Spitzer and SHARC-2 Before Spitzer and SHARC-2 observations (Kovacs et al. observations (Kovacs et al. 2006), mostly 850 micron, some 2006), mostly 850 micron, some 450 micron, radio observations, 450 micron, radio observations, CO, and some mm imaging. CO, and some mm imaging.

SMM J02399-0136 (Genzel et al. 03)

ㅋ =2.5

AzTEC bandpass

z=1

Submm Galaxies as tracers of structure Submm Galaxies as tracers of structure formationformation

(model SMG spectrum by Efstathiou, Rowan-Robinson and Siebenmorgen, 2000)• One of the most exciting developments of the past decade has been the resolution of the cosmic far-infrared background into discrete sources, providing a first glimpse of the rapid build-up of massive galaxies in the early universe long predicted by theory.

AzTEC bandpass

z=1

z=2

Submm Galaxies as tracers of structure Submm Galaxies as tracers of structure formationformation

(model SMG spectrum by Efstathiou, Rowan-Robinson and Siebenmorgen, 2000)• Deep, wide blank-field surveys at mm & sub-mm wavelengths have shown that ultraluminous infrared galaxies (ULIRGs) at z>1, contribute significantly to the Observed far-IR background.

AzTEC bandpass

z=1

z=2

z=5

Submm Galaxies as tracers of structure Submm Galaxies as tracers of structure formationformation

(model SMG spectrum by Efstathiou, Rowan-Robinson and Siebenmorgen, 2000)• Multi-wavelegnth follow-up studies of these so-called sub-mm galaxies (SMGs) suggest that they are massive, young galaxies seen during the period of rapid stellar mass build-up with very high specific star formation rates at z>1. Here are four key questions we would like to address from AzTEC SMG surveys.

Scientific Goals of SMG StudiesScientific Goals of SMG Studies How is the SMG population How is the SMG population

distributed in redshift?distributed in redshift? Are SMG redshift associations Are SMG redshift associations

linked to overdensities of otherlinked to overdensities of other

more numerous galaxy classesmore numerous galaxy classes

at the same redshift? at the same redshift? Do they reside in such

massiveHalos? How are SMGs distributed in

relation to large scale structure?Overzier et al. (2003)

Answering these questions and more will require large confusion limited surveys with multi-spectral follow-up.

Galaxy Density Map of Galaxy Density Map of COSMOSCOSMOS

from Scoville et al. (2007), with the boundaries of the AzTEC, Bolocam, and from Scoville et al. (2007), with the boundaries of the AzTEC, Bolocam, and MAMBO mm surveys (including a massive galaxy cluster at z=0.73)MAMBO mm surveys (including a massive galaxy cluster at z=0.73)

Both MAMBO and BOLOCAM surveyscover a low galaxy density region ofthe COSMOS field, whilst our new AzTEC observations are designed to examine the impact of massive large-Scale foreground structures on SMG Surveys in order to provide a measureof the importance of cosmic variancein the observed source density at millimeter wavelengths.

AzTEC/COSMOS AzTEC/COSMOS

34 raster-scanObservations,Each centered at (RA,DEC)=(10h00m00s,02deg36’00’’)0.3deg2 regionScan speed of90”/s-150”/s

Mapping speed:34 arcmin2mJy-2hr-1

(strong function ofSky opacity at 225 GHz)

Disadvantages to Chopping• sensitive to differential pickup from dish (secondary support, temperature gradients, etc.)

• resolve out large scale structure

Advantages to Rastering• beam response stationary on telescope• uniform coverage achievable despite incomplete array• unlimited sky coverage possible

Typical AzTEC Chopped Signal

Mean traces out time evolution of atmosphere + variable offsets

2Jy

Atmosphere Subtraction with PCAAtmosphere Subtraction with PCA

AzTEC/BOLOCAM ComparisonAzTEC/BOLOCAM Comparison

Map shows >20% maximum coverage region, with 50% and 75% contours overlaid. Black circles are >3.5 Map shows >20% maximum coverage region, with 50% and 75% contours overlaid. Black circles are >3.5 sigma sources, and those in the source catalogue (75% region) are labeled by their number. Purple circles sigma sources, and those in the source catalogue (75% region) are labeled by their number. Purple circles indicate Bolocam sources. Solid purple line marks the Bolocam 1.9 mJy rms contour, dashed line is Bolocam 2.8 indicate Bolocam sources. Solid purple line marks the Bolocam 1.9 mJy rms contour, dashed line is Bolocam 2.8 mJy rms contour. 2 coincident sources: Bolocam #1 is 3.5 arcsec from AzTEC #1 and Bolocam #13 is 3.6 arcsec mJy rms contour. 2 coincident sources: Bolocam #1 is 3.5 arcsec from AzTEC #1 and Bolocam #13 is 3.6 arcsec from AzTEC #6.from AzTEC #6.

Scott et al.(2008)

COSMOS Clustering COSMOS Clustering measurementmeasurement

2-pt angular correlation function made using >2.0 sigma sources. Used a binsize of 36 arcsec, limited to angular 2-pt angular correlation function made using >2.0 sigma sources. Used a binsize of 36 arcsec, limited to angular separations between 60 and 500 arcsec. No strong clustering signal detected on any scale here. Angular correlation separations between 60 and 500 arcsec. No strong clustering signal detected on any scale here. Angular correlation function w(function w(θθ) is projection of the spatial function on the sky and is defined in terms of the joint probability delta P= ) is projection of the spatial function on the sky and is defined in terms of the joint probability delta P= NN22[1+w([1+w(θθ)]dὨ1Ὠ2 (N; mean surface density of objects); w=0, distribution is homogeneous.)]dὨ1Ὠ2 (N; mean surface density of objects); w=0, distribution is homogeneous.

Galaxy Density Map of COSMOSGalaxy Density Map of COSMOS

from Scoville et al. (2007), with the boundaries of the from Scoville et al. (2007), with the boundaries of the AzTEC, Bolocam, and MAMBO mm surveys (including a AzTEC, Bolocam, and MAMBO mm surveys (including a massive galaxy cluster at z=0.73)massive galaxy cluster at z=0.73)

Cross-Correlation function is computed Cross-Correlation function is computed between the galaxy overdensity map and the between the galaxy overdensity map and the

AzTEC mapAzTEC map

No obvious peak at the Center.No obvious peak at the Center.

Image Credit:Scott et al. (2006)

AzTEC/COSMOS: ConclusionAzTEC/COSMOS: Conclusion 0.3 deg0.3 deg22 region imaged within the COSMOS with 1.3 mJy/beam at region imaged within the COSMOS with 1.3 mJy/beam at

1.1mm1.1mm 50 sources found S/N>3.5; 16 detected with S/N>4.5, where the 50 sources found S/N>3.5; 16 detected with S/N>4.5, where the

number of false-detections is zero; 7 of >5number of false-detections is zero; 7 of >5σσ sources confirmed with sources confirmed with SMA.SMA.

AzTEC sources are spread throughout the field and only 3 are located AzTEC sources are spread throughout the field and only 3 are located in z=0.73 cluster environment.in z=0.73 cluster environment.

Our catalogue is 50% complete at an intrinsic flux density of 4 mJy, Our catalogue is 50% complete at an intrinsic flux density of 4 mJy, and 100% is complete at 7 mJy.and 100% is complete at 7 mJy.

Fraction of AzTEC sources with potential radio counterparts is 36% and Fraction of AzTEC sources with potential radio counterparts is 36% and is consistent with that found in SCUBA/SHADES survey (Ivison et al. is consistent with that found in SCUBA/SHADES survey (Ivison et al. 2007) at similar fluxes.2007) at similar fluxes.

A detailed comparison of the IRAC color-color plots and SEDs shows A detailed comparison of the IRAC color-color plots and SEDs shows that AGNs and SMGs are distinct from each other due to intrinsic that AGNs and SMGs are distinct from each other due to intrinsic differences in their energy source and dust distribution. SMGs as a differences in their energy source and dust distribution. SMGs as a group have a flatter SED in comparison with AGNs. Only 20% of the group have a flatter SED in comparison with AGNs. Only 20% of the objects overlap in the color-color plots and this suggests that SMGs objects overlap in the color-color plots and this suggests that SMGs powered by an AGN are not common. In the context of ULIRG-QSO powered by an AGN are not common. In the context of ULIRG-QSO evolutionary senario (Sanders et al. 1988; Norman & Scoville 1988), evolutionary senario (Sanders et al. 1988; Norman & Scoville 1988), the little overlap between the AGNs and the SMG population indicates the little overlap between the AGNs and the SMG population indicates that transition period is much shorter than the duration of the SMG or that transition period is much shorter than the duration of the SMG or the IR AGN phase.the IR AGN phase.

Estimates of resolved fraction of millimeter CIB due to radio & mid-IR Estimates of resolved fraction of millimeter CIB due to radio & mid-IR galaxy populations is 7±1% & 21±3% respectively.galaxy populations is 7±1% & 21±3% respectively.

(a) Empty squares are SMGs securely identified by radio and CO (a) Empty squares are SMGs securely identified by radio and CO interferometric imaging. Filled squares and pentagons are interferometric imaging. Filled squares and pentagons are SMGs identified as “starburst” and “starburst+AGN” by Spitzer SMGs identified as “starburst” and “starburst+AGN” by Spitzer IRS spectra, respectively (Menendez-Delmestre et al. 2007; IRS spectra, respectively (Menendez-Delmestre et al. 2007; Valiante et al. 2007; Rigby et al. 2008; Pope et al. 2008). IR Valiante et al. 2007; Rigby et al. 2008; Pope et al. 2008). IR QSOs with power-law spectrum identified in the FLS field by QSOs with power-law spectrum identified in the FLS field by Lacy et al. and Martinez-Sansigre et al. (2008) are shown as Lacy et al. and Martinez-Sansigre et al. (2008) are shown as stars. Small dots represent 4000 random field galaxies in the stars. Small dots represent 4000 random field galaxies in the COSMOS field (Sandetrs et al. 2007), and the large circle COSMOS field (Sandetrs et al. 2007), and the large circle centered near (-0.4,-0.4) represents the centroid of the IRAC centered near (-0.4,-0.4) represents the centroid of the IRAC sources in the FLS (Lacy et al. 2004). The long-dashed line sources in the FLS (Lacy et al. 2004). The long-dashed line outlines the region for AGNs proposed by Lacy et al. The solid outlines the region for AGNs proposed by Lacy et al. The solid line shows the extended region we propose for the line shows the extended region we propose for the identification of SMG counterparts. (b) Filled circles are 9 SMGs identification of SMG counterparts. (b) Filled circles are 9 SMGs identified by direct SMA measurements and empty circles identified by direct SMA measurements and empty circles represent the foreground/interloper IRAC sources. (c) Redshift represent the foreground/interloper IRAC sources. (c) Redshift evolution colour-colour tracks for 3 different starburst ages evolution colour-colour tracks for 3 different starburst ages based on theoretical starburst SED models and filled and empty based on theoretical starburst SED models and filled and empty squares along the redshift evolution colour tracks mark the squares along the redshift evolution colour tracks mark the redshifts of z=0.5,1,2,3,4,and 5. redshifts of z=0.5,1,2,3,4,and 5. The thick solid line represents The thick solid line represents power-law spectrum sources with s=0.3-1.0power-law spectrum sources with s=0.3-1.0. (d) Effects of . (d) Effects of extinction are demonstrated by the 72 Myr old starburst colour-extinction are demonstrated by the 72 Myr old starburst colour-colour model tracks with total extinction of Acolour model tracks with total extinction of AVV=50 and 200 (and 200 (Yun Yun et al. 2008et al. 2008).).

• Majority of SMGs appear scattered about the model SED colour tracks, consistent with their Spitzer IRS spectra being characteristic of starburst-dominated systems. For a given model SED, the IRAC color becomes monotonically redder with increasing redshift at z>1, and most SMGs have colors consistent with model SEDs redshifted to z=1-5; the weak dependence on extinction AV can be understood since optical depth is greatly reduced at these long wavelengths.• As redshift increases, the IRAC bands begin to probe the near-IR to optical bands, and an increasing dependence on extinction is expected. IRAC colors of the two model SEDs diverge at z>2, with the higher extinction AV=200 model predicting redder IRAC colors as expected.

• Among 50 SMG candidates in COSMOS, 7 AzTEC sources are confirmed with SMA interferometric imaging (Younger et al. 2007).• IRAC color-color plots of SMGs are systematically bluer than AGN identification and consistent with 30-70 Myr old starbursts observed at redshifts between z~1 and z~5 (Yun et al. 2008).

Figure Credit: Yun et al. (2008)

IRAC color-color plotIRAC color-color plot

Lacy et al. (2004) from Spitzer FLS. Dashed lines mark Lacy et al. (2004) from Spitzer FLS. Dashed lines mark “AGN-demarcated region”“AGN-demarcated region”

Hot dust

clustering

Spectral Energy Distribution Spectral Energy Distribution for the Starburst Modelfor the Starburst Model

τ Td

SFR

• Contribution functions & SEDsfrom Efstathiou (2000).• Cartoon by Y. Kim

Overall, starbursts age and redshift as the dominant physical parameters affect the observed IRAC colors. SMGs with reddest IRAC colors requires young (<30Myr old) starbursts at high redshifts (z>3) or a power-law AGN dominating the rest frame near-IR SED.

Young, dusty starbursts exhibit red IRAC colors, and red IRAC color is not unique to power-law AGNs. The popular AGN identification methods using red IRAC colors, such as by Lacy et al. (2004) and Stern et al. (2005) should be cautious.

AzTEC/COSMOS: ConclusionAzTEC/COSMOS: Conclusion

0.3 deg0.3 deg22 region imaged within the COSMOS with 1.3 mJy/beam at 1.1mm region imaged within the COSMOS with 1.3 mJy/beam at 1.1mm 50 sources found S/N>3.5; 16 detected with S/N>4.5, where the number 50 sources found S/N>3.5; 16 detected with S/N>4.5, where the number

of false-detections is zero; of false-detections is zero; 7 of >57 of >5σσ sources confirmed with SMA; IRAC sources confirmed with SMA; IRAC color-color plots indicate that SMGs are systematically bluer, consistent color-color plots indicate that SMGs are systematically bluer, consistent with 30 to 70 Myr old starbursts observed at redshifts between z~1 and with 30 to 70 Myr old starbursts observed at redshifts between z~1 and z~5.z~5.

AzTEC sources are spread throughout the field and only 3 are located in AzTEC sources are spread throughout the field and only 3 are located in z=0.73 cluster environment.z=0.73 cluster environment.

Our catalogue is 50% complete at an intrinsic flux density of 4 mJy, and Our catalogue is 50% complete at an intrinsic flux density of 4 mJy, and 100% is complete at 7 mJy.100% is complete at 7 mJy.

Fraction of AzTEC sources with potential radio counterparts is 36% and is Fraction of AzTEC sources with potential radio counterparts is 36% and is consistent with that found in SCUBA/SHADES survey (Ivison et al. 2007) at consistent with that found in SCUBA/SHADES survey (Ivison et al. 2007) at similar fluxes.similar fluxes.

A detailed comparison of the IRAC color-color plots and SEDs shows that A detailed comparison of the IRAC color-color plots and SEDs shows that AGNs and SMGs are distinct from each other due to intrinsic differences in AGNs and SMGs are distinct from each other due to intrinsic differences in their energy source and dust distribution. SMGs as a group have a flatter their energy source and dust distribution. SMGs as a group have a flatter SED in comparison with AGNs.SED in comparison with AGNs. Only 20% of the objects overlap in the Only 20% of the objects overlap in the color-color plots and this suggests that SMGs powered by an AGN are not color-color plots and this suggests that SMGs powered by an AGN are not common. In the context of ULIRG-QSO evolutionary senario (Sanders et al. common. In the context of ULIRG-QSO evolutionary senario (Sanders et al. 1988; Norman & Scoville 1988), the little overlap between the AGNs and 1988; Norman & Scoville 1988), the little overlap between the AGNs and the SMG population indicates that transition period is much shorter than the SMG population indicates that transition period is much shorter than the duration of the SMG or the IR AGN phase.the duration of the SMG or the IR AGN phase.

Estimates of resolved fraction of millimeter CIB due to radio & mid-IR Estimates of resolved fraction of millimeter CIB due to radio & mid-IR galaxy populations is 7±1% & 21±3% respectively.galaxy populations is 7±1% & 21±3% respectively.

AzTEC/COSMOS: ConclusionAzTEC/COSMOS: Conclusion 0.15 deg0.15 deg22 region imaged within the COSMOS with 1.3 mJy/beam at region imaged within the COSMOS with 1.3 mJy/beam at

1.1mm1.1mm 50 sources found S/N>3.5; 16 detected with S/N>4.5, where the 50 sources found S/N>3.5; 16 detected with S/N>4.5, where the

number of false-detections is zero; 7 of >5number of false-detections is zero; 7 of >5σσ sources confirmed with sources confirmed with SMA.SMA.

AzTEC sources are spread throughout the field and only 3 are located AzTEC sources are spread throughout the field and only 3 are located in z=0.73 cluster environment.in z=0.73 cluster environment.

Our catalogue is 50% complete at an intrinsic flux density of 4 mJy, Our catalogue is 50% complete at an intrinsic flux density of 4 mJy, and 100% is complete at 7 mJy.and 100% is complete at 7 mJy.

Fraction of AzTEC sources with potential radio counterparts is 36% and Fraction of AzTEC sources with potential radio counterparts is 36% and is consistent with that found in SCUBA/SHADES survey (Ivison et al. is consistent with that found in SCUBA/SHADES survey (Ivison et al. 2007) at similar fluxes.2007) at similar fluxes.

A detailed comparison of the IRAC color-color plots and SEDs shows A detailed comparison of the IRAC color-color plots and SEDs shows that AGNs and SMGs are distinct from each other due to intrinsic that AGNs and SMGs are distinct from each other due to intrinsic differences in their energy source and dust distribution. SMGs as a differences in their energy source and dust distribution. SMGs as a group have a flatter SED in comparison with AGNs.group have a flatter SED in comparison with AGNs. Only 20% of the Only 20% of the SMGs overlap in the color-color plots with AGNs and this suggests that SMGs overlap in the color-color plots with AGNs and this suggests that SMGs powered by an AGN are not common. SMGs powered by an AGN are not common. In the context of ULIRG-In the context of ULIRG-QSO evolutionary senario (Sanders et al. 1988; Norman & Scoville QSO evolutionary senario (Sanders et al. 1988; Norman & Scoville 1988), the little overlap between the AGNs and the SMG population 1988), the little overlap between the AGNs and the SMG population indicates that transition period is much shorter than the duration of indicates that transition period is much shorter than the duration of the SMG or the IR AGN phase (Yun et al. 2008).the SMG or the IR AGN phase (Yun et al. 2008).

Estimates of resolved fraction of millimeter CIB due to radio & mid-IR Estimates of resolved fraction of millimeter CIB due to radio & mid-IR galaxy populations is 7±1% & 21±3% respectively.galaxy populations is 7±1% & 21±3% respectively.

Summary Remarks

We are starting the transition from SMG discovery to SMG study.

AzTEC/JCMT is the first step towards developinga census of the SMG population.

AzTEC on the Large Millimeter Telescope cansystematically sample the faint end of the

flux spectrum.

LMT/GTM• 50m dia.

•70um surface•15000 ft alt

•Sierra Negra, MX

Summary Remarks

We are starting the transition from SMG discovery to SMG study.

AzTEC/JCMT is the first step towards developinga census of the SMG population.

Large Millimeter Telescope cansystematically sample the faint end of the

flux spectrum.

Thank you: 감사합니다 .

Number Counts and EvolutionNumber Counts and Evolution

Borys et al. 2003

no evolution

Observationally Speaking:• SCUBA/JCMT, MAMBO/IRAM 30-m, BOLOCAM/CSO• Fewer than100 sources with S/N > 4• Dynamic range: 1-10 mJy at 850 um• Severely confusion limited• Secure redshifts for only about 20-30 galaxies (controversial!!!)

Ivison et al. 2000 Laurent et al. 2005

1.4mJy rms3σ peaks circled

AzTEC Internal Optics LayoutAzTEC Internal Optics Layout

Folded optical design minimizes optical Folded optical design minimizes optical microphonic pickup and thermal gradientsmicrophonic pickup and thermal gradients

42 Jy2 pW

1010 photons/s

~1Jy

Beam Mapping Products:• relative bolometer positions• calibration• beam shapes

2MASS

Z~1500

Z~0.1

THE BIG QUESTIONHow does structure form and evolve in the Universe? WMAP

Z~1500

Z~0.1

THE BIG QUESTIONHow does non-linear structure form and evolve in the Universe?

SDSS, HST, Chandra …

2MASS

Z < few

WMAP

Epoch of structureformation

Atmosphere20-30K foreground13.7 pW8×1010 photons/s

Telescope~30K foreground13.7 pW8×1010 photons/s

Hughes et al. 19982 arcmin dia.5 sources > 1mJy(0.05 fW)(300,000 photons/s)

CMB2.7K backlight0.6 pW3.6×109 photons/s

Chopping vs RasteringChopping vs Rastering

Three aspects of mm-wavelength bolometry drive the Three aspects of mm-wavelength bolometry drive the observational modes:observational modes:

– High Background – Signal/Background ~ 10High Background – Signal/Background ~ 10-5-5

=> Raster preferred to Jiggle chop=> Raster preferred to Jiggle chop

– AtmosphereAtmosphere

=> Need algorithm to clean (jiggle preferred to => Need algorithm to clean (jiggle preferred to raster?)raster?)

– Detector Time ConstantDetector Time Constant

=> Limits speed of any continuous motions=> Limits speed of any continuous motions

Advantages to Chopping• focus integration time on FOV-sized region

• low frequency stability not required

Advantages to Chopping• focus integration time on FOV-sized region

• low frequency stability not required

Disadvantages to Chopping• sensitive to differential pickup from dish (secondary support, temperature gradients, etc.)

• resolve out large scale structure

PCA Atmosphere CleaningPCA Atmosphere CleaningD

etec

tor

Pow

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ensi

ty [n

V/r

t(H

z)]

10

100

Frequency [Hz]

0.1 1 10

Raw Signal

PCA cleaned (3,2)

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AzTEC/GOODS-N AzTEC/GOODS-N

AzTEC/JCMT05B ‘Local’ StudiesAzTEC/JCMT05B ‘Local’ Studies

FieldField SizeSize[arcmin[arcmin22]]

Obs TimeObs Time[hrs][hrs]

target target σσ

[mJ][mJ]

PIPI

MBM-12MBM-12 17,66217,662 2020 (20) (20) 1010 WilliamsWilliams

IC348/Taurus IC348/Taurus (B.D.)(B.D.)

20 (xN)20 (xN) 32.2 32.2 (32.2)(32.2)

0.80.8 MohantyMohanty

UCHII fieldsUCHII fields 20 (x52)20 (x52) 9.99.9 (26)(26) 55 KertonKerton

Class 0’s in GMCsClass 0’s in GMCs 20 (x80)20 (x80) 1212 (12) (12) 99 HatchelHatchel

G216, IC443, W3G216, IC443, W3 12.5 deg12.5 deg22 4.1 (30)4.1 (30) 1010 MooreMoore

M83, M51M83, M51 400400 11 (24)11 (24) 11 WallWall

M31M31 12381238 13 (24)13 (24) 33 LoinardLoinard

NGC4414NGC4414 2020 3131 (30) (30) 0.50.5 BraineBraine

Raster Observations … OMC1Raster Observations … OMC1

Johnstone & Bally 1999

SCUBA AzTEC

… … and Jiggle Mappingand Jiggle Mapping

Extended emission around ultra-compact HII regions

PI: Kerton

PRELIMINARY PRELIMINARY PRELIMINARY

AzTEC image of 4C41.17

HzRG850.2

HzRG850.3

HzRG850.1

4C41.17

AzTEC/SHADES - LH AzTEC/SHADES - LH

0.5 deg2 blank field - Lockman Hole

BOLO

CAM

AzTEC/COSMOS SourcesAzTEC/COSMOS Sources

Scott et al. (2008)Scott et al. (2008)

>3.5 sigma sources identified by circles with diameters equal to twice the AzTEC FWHM on the JCMT; map has been trimmed to “75% coverage region”; average RMS noise level of 1.3 mJy/beam

Coverage MapCoverage Map

VLA ComparisonVLA Comparison

Plot of the AzTEC 75% coverage region with >3.5 sigma sources circled in black. Purple circles Plot of the AzTEC 75% coverage region with >3.5 sigma sources circled in black. Purple circles indicate locations of the VLA 1.4 GHz radio sources. 40% (15) of the AzTEC sources have at least indicate locations of the VLA 1.4 GHz radio sources. 40% (15) of the AzTEC sources have at least one VLA source located within 9 arcsec, and 2 AzTEC sources have 2 VLA counterparts.one VLA source located within 9 arcsec, and 2 AzTEC sources have 2 VLA counterparts.

Stacking AnalysisStacking Analysis

Plot of the stacked AzTEC flux at the VLA source locations for radio sources within the 75% uniform coverage region (452 radio sources; Plot of the stacked AzTEC flux at the VLA source locations for radio sources within the 75% uniform coverage region (452 radio sources; Schinnerer et al. 2007). The signal to noise at the peak is 11. Since 17 radio sources lie close to bright AzTEC sources, so without Schinnerer et al. 2007). The signal to noise at the peak is 11. Since 17 radio sources lie close to bright AzTEC sources, so without including 17 radio source positions, and the signal to noise is 8, most of the stacked AzTEC flux is coming from pixels that fall below including 17 radio source positions, and the signal to noise is 8, most of the stacked AzTEC flux is coming from pixels that fall below the source detection threshold (Scott et al. 2008).the source detection threshold (Scott et al. 2008).

Correlation AmplitudeCorrelation Amplitude

A clustering strength between AzTEC and VLA sources is computed using the catalogs. An A clustering strength between AzTEC and VLA sources is computed using the catalogs. An estimator based on Landy & Szalay (1993) is used. Bias and variance of estimators for estimator based on Landy & Szalay (1993) is used. Bias and variance of estimators for

W(W(θθ); this means radio and AzTEC sources are clustered at 15’’ and smaller scales, ); this means radio and AzTEC sources are clustered at 15’’ and smaller scales, beyond being counterparts to each other.beyond being counterparts to each other.

Postage stamp Postage stamp imagesimages of the 22 of the 22 AzTEC-COSMOS -COSMOS sources are shown sources are shown below. The six below. The six greyscale images greyscale images represent a 20"x20" represent a 20"x20" box centered on the box centered on the Subaru i-band, IRAC Subaru i-band, IRAC 3.6 micron, 4.5 3.6 micron, 4.5 micron, 5.8 micron, micron, 5.8 micron, and 8.0 micron, and and 8.0 micron, and MIPS 24 micron MIPS 24 micron images. The images. The AzTEC contours are shown contours are shown in blue lines over in blue lines over the 8.0 micron the 8.0 micron image (levels are 4, image (levels are 4, 5, 6, 7, and 8 mJy). 5, 6, 7, and 8 mJy).

The VLA 1.4 GHz The VLA 1.4 GHz continuum contours continuum contours are shown in red are shown in red superposed over the superposed over the Subaru i-band Subaru i-band image (levels are image (levels are 30, 40, 60, & 100 30, 40, 60, & 100 micronJy).micronJy).

Continued Study on SMGsContinued Study on SMGs

Derive most accurate number counts to date.Derive most accurate number counts to date. Quantify cosmic variance.Quantify cosmic variance. Verify/characterize overdensity of SMGs around Verify/characterize overdensity of SMGs around

biased regions.biased regions. Determine host halo masses via angular Determine host halo masses via angular

correlation analysis for both biased regions and in correlation analysis for both biased regions and in the field.the field.

Constrain starburst time scales.Constrain starburst time scales. Constrain stellar initial mass function.Constrain stellar initial mass function.

Mo & White (2002)

Simulation by Neal Katz

Future Study Future Study

There is still lots to do to characterize AzTEC data:There is still lots to do to characterize AzTEC data:– Known issues in the current analysis pipelineKnown issues in the current analysis pipeline– A few mysteries still to be solvedA few mysteries still to be solved– Better noise estimationsBetter noise estimations– Calculations of false detection rates, biases, and completenessCalculations of false detection rates, biases, and completeness– Fluctuation analysis Fluctuation analysis

And a lot to do in terms of source follow-up:And a lot to do in terms of source follow-up:– Spitzer proposals are inSpitzer proposals are in– VLA observations of FLS field start soonVLA observations of FLS field start soon– SMA proposals are inSMA proposals are in– Gemini proposals are inGemini proposals are in– HST … next cycleHST … next cycle