z~7-8 LBG

20091028

z~7-8 LBGHUDF: HST/WFC3

GOODS-S: HST/WFC3GOODS-S: VLT/HAWK-I

SDF & GOODS-N: Subaru/Suprime-CamCOSMOS: UKIRT/WFCAM & CFHT/WIRCAMBouwens et al. 2009 arXiv:0909.1803 --- Y-dropout UVLFOesch et al. 2009 arXiv:0909.1806 --- z-dropout UVLFBunker et al. 2009 arXiv:0909.2255 --- z-dropout UVLFMcLure et al. 2009 arXiv:0909.2437 --- photo-z SED fittingLabbe et al. 2009 arXiv:0910.0838 --- +IRAC stellar massOesch et al. 2009 arXiv:0909.5183 --- morphologyWilkins et al. 2009 arXiv:0910.1098 --- z-dropoutCastellano et al. 2009 arXiv:0909.2853 --- z-dropoutHickey et al. 2009 arXiv:0909.4205 --- Y&z-dropoutOuchi et al. 2009 arXiv:0908.3191 --- z-dropout Capak et al. 2009 arXiv:0910.0444 --- z-dropout

Lyman break featureLymanbreak

z=0.5z=1.0z=1.5z=3.0

Lyman Break GalaxiesU-dropout z~3G-dropout z~4

Previous studies of z~7 LBGs Bouwens et al. 2008HST/NICMOS J&H-bands data limiting mag. ~26.5-28ABmag

z~7-8 LBGHUDF: HST/WFC3

GOODS-S: HST/WFC3GOODS-S: VLT/HAWK-I

SDF & GOODS-N: Subaru/Suprime-CamCOSMOS: UKIRT/WFCAM & CFHT/WIRCAMBouwens et al. 2009 arXiv:0909.1803 --- Y-dropout UVLFOesch et al. 2009 arXiv:0909.1806 --- z-dropout UVLFBunker et al. 2009 arXiv:0909.2255 --- z-dropout UVLFMcLure et al. 2009 arXiv:0909.2437 --- photo-z SED fittingLabbe et al. 2009 arXiv:0910.0838 --- +IRAC stellar massOesch et al. 2009 arXiv:0909.5183 --- morphologyWilkins et al. 2009 arXiv:0910.1098 --- z-dropoutCastellano et al. 2009 arXiv:0909.2853 --- z-dropoutHickey et al. 2009 arXiv:0909.4205 --- Y&z-dropoutOuchi et al. 2009 arXiv:0908.3191 --- z-dropout Capak et al. 2009 arXiv:0910.0444 --- z-dropout

Bouwens et al. arXiv:09091803HUDF HST/WFC3 Y-dropout Hubble Ultra Deep FieldHST/ACS z-band imageHST/NICMOS J&H-bandsHST/WFC3 Y, J, H-bandsVLT/ISAAC Magellan/PANICKs-band

Ultra deep HST/ACS optical imagesMcLure et al.

HST/WFC3 WFC3 instrumental handbook

HST/WFC3 WFC3 instrumental handbook

Bouwens et al. arXiv:09091803HST/WFC3 data F105W Y --- 16 orbitsF125W J --- 16 orbitsF160W H --- 28 orbitsHUDF09 program first epoch data(two UDF05 fields will be also observed in 2010)PSF FWHM ~ 0.25 limit @ 0.4 diameter ~ 29ABmag(1 orbit ~ 40min) HST/ACS dataB, V, i, z -bands ~29-29.5ABmag(August 26 ~ September 6, 2009) ~ 4.7 arcmin2

Bouwens et al. arXiv:09091803Y-dropout selection Source detection

Color selectionJ + H combined image>5.5 in J band Y-J > 0.8 J-H < 0.5 J-H < 0.2 + 0.12(Y-J) no detection (

Bouwens et al. arXiv:09091803selected z~8 candnoidates 5 candidates blue J-H color(UV slope 5 in J & >4 in H

All WFC3 data were obrained in 12days

brown dwarfs are more bluer and rare

Simulation with 24.5~26mag objectsPossible contaminants Not spurious objects Not SNe Not galactic stars the expected number of, contaminants by photometric scatter is very small (

Bouwens et al. arXiv:09091803selected z~8 candidates 5 candidates blue J-H color(UV slope

Bouwens et al. arXiv:09091803Number counts Expected number for no LF evolution (1+z)-1 size evolution from z~4 UV slope =-2.50.4are assumed. z~6 i-dropout LF 24 Y-dropoutsz~7 z-dropout LF 11 Y-dropouts(~70% statistical error ~35% field-to-field variance)Observed number is lower (~1 level)

Bouwens et al. arXiv:09091803Evolution of UV LF Extraoplation of UV LF at z

Bouwens et al. arXiv:09091803SFR density at z~8 Integrate the stepwise UV LF UV luminosity densityunobscured SFR density(and dust correction with those estimated at z~5-6 )

z~6-9 galaxy search with HUDF HST/WFC3 McLure et al. arXiv:0909.2437HST/WFC3

HST/ACS

Spizter/IRACHST/ACS z-band imageHST/NICMOS J&H-bandsHST/WFC3 Y, J, H-bandsVLT/ISAAC Magellan/PANICKs-band

McLure et al.Bouwens et al. PSF FWHM ~ 0.15(Y), 0.16(J), 0.18(H)5 limit @0.4 diameter ~29ABmag5 limit @0.6 diameter ~29mag (~28mag for z-band)5 limit ~25.9(3.6m) 25.5(4.5m) 23.3(5.8m) 22.9(8.0m)

Sample selectionMcLure et al. arXiv:0909.2437Source detection

Photometric redshift >5@0.4 detection in at least one of YJH-bands No detection (2) in i-band 300 objectsBVizYJH-bands + 3.6 & 4.5m upper limit2 distribution z>5.9 candidates Charlot & Bruzal 2007 templates+ empirical U-dropout spectra 49 candidates: z>7 candidates

Sample selectionMcLure et al. arXiv:0909.2437Photometric redshiftCharlot & Bruzual 2007 templates

+ empirical U-dropout spectra=0.1~10GyrCalzetti extinctionAv=0~2mag1 solar metallicitySalpeter IMF example2 distribution z>5.9 candidates 49 candidateszYJH

Sample selectionMcLure et al. arXiv:0909.2437SEDmagnitude2 distribution visual checkspurious artifactTransient objectThe brightest candidate SN or other transient soruce Contamination by T dwarfs ~0.5 down to z=29ABmag in 4.5arcmin2 WFC3 field(not detected at all in NICMOS images)

Selected sample McLure et al. arXiv:0909.243749 z>6 candidatesNo detection in i-band incomplete at 5.9

extremely high-z sample McLure et al. arXiv:0909.243715 z>7 candidates

8 z>7.5 candidates

3 z>8 candidates: z>7 candidatesIncluding 5 Y-dropouts in Bouwens et al. these 5 have acceptable secondary peak at z~1.64 z>7.8 candidates occur in two pairsJ~28-29mag

extremely high-z sample McLure et al. arXiv:0909.243715 z>7 candidates

8 z>7.5 candidates

3 z>8 candidatesIncluding 5 Y-dropouts in Bouwens et al. these 5 have acceptable secondary peak at z~1.64 z>7.8 candidates occur in two pairsJ~28-29mag

extremely high-z sample McLure et al. arXiv:0909.243715 z>7 candidates

8 z>7.5 candidates

3 z>8 candidatesIncluding 5 Y-dropouts in Bouwens et al. these 5 have acceptable secondary peak at z~1.64 z>7.8 candidates occur in two pairsFor the faintest candidates (J, H ~29), no detection in optical ACS images is not sufficient to pick up Lyman break exclusively. J~28-29mag

UV luminosity function McLure et al. arXiv:0909.2437redshift probability distribution + 1/Vmax method6.5

Castellano et al. arXiv:0909.2583z-dropout search in GOODS-S with HAWK-IGreat Observatories Origins Deep Survey - South deep HST/ACS optical images deep Spizter/IRAC MIR images deep VLT/ISAAC NIR images

Chandra Spitzer/MIPS

Castellano et al. arXiv:0909.2583VLT/HAWK-I dataHAWK-I 7.5 x 7.5 F.O.V 0.106/pixY-band 2 pointingsScience Verification & ESO Large ProgramGOODS1 --- 16.25 hour 0.514 FWHMGOODS2 --- 16.93 hour 0.489 FWHM~89.7arcmin2 ~100% complete at Y~26.2 ~30%compete at Y~26.8spurious source negligible at Y

Castellano et al. arXiv:0909.2583sample selectionY-selected Y1.0

ACS z-bandHAWK-I Y-banddetect z>6.5 Ly break

Castellano et al. arXiv:0909.2583sample selectionY-selected Y1.0

Y-J

Castellano et al. arXiv:0909.2583sample selectionY-selected Y1.0

Y-J1

Castellano et al. arXiv:0909.2583Simulation for sample selectionadd artificial objects with Y=24-27.5 at z=5.5-8(assuming size and LF of z~5.5-6 LBGs)

Castellano et al. arXiv:0909.2583Selected candidates9 z~7 candidates1 known cool dwarf is rejected(relatively red Y-J color)expected contamination ~3.4 cool dwarfs for 2 HAWK-I F.O.V.another one which is not detected in the deep NICMOS H-band (Y-H

Castellano et al. arXiv:0909.2583B+V+izYJ+H+KF110WF160W3.6m

Castellano et al. arXiv:0909.2583Selected candidatesstacking of 7 candidates zphot=6.80

Castellano et al. arXiv:0909.2583Number CountsObserved number counts of z~6.8 LBGsare smaller than predictions from z~6 LFs.(No evolution for UV LFbetween z~6 and z~6.8) UV LF seems to evolve between z~6 and z~6.8

Castellano et al. arXiv:0909.2583UV luminosity functionAssumed UV Luminosity function

simulation (source detection, color selection)

Expected z-dropout number counts

Observed number countsMaximum likelihood* = 0.35+0.16-0.11 10-3 Mpc-3M*(1500) = -20.240.45assuming =-1.71

Castellano et al. arXiv:0909.2583Evolution of UV LFd(log*)/dz = -0.590.25dM*/dz = 0.130.51Evolution between z~6 and z~6.8* = 0.35+0.16-0.11 10-3 Mpc-3M*(1500) = -20.240.45assuming =-1.71 UV = 1.5+2.0-0.91025 erg/s/Hz/Mpc3UV luminosity density a factor of ~3.5 lower than at z~6rule out no evolution between z~6 and z~6.8 at 99% confidence level

Ouchi et al. arXiv:0908.3191z-dropout search in SDF & GOODS-N with Subaru/S-CamGOODS-NorthSubaru Deep Field

Ouchi et al. arXiv:0908.3191Suprime-Cam datay (zR)-band 2 fields --- 1568 arcmin2Subaru Deep Field 26 hours 810 arcmin2GOODS-North 33 hours 758 arcmin23 limit @ 1.8 diameter SDF 26.4 ABmag GOODS-N 26.2 ABmagOther bands SDF BVR + zGOODS-N UBVR + zz-band 3 limit SDF 27.7 mag GOODS-N 26.9 mag

Ouchi et al. arXiv:0908.3191Sample selection y-selected samaple>4 limit SDF y

Ouchi et al. arXiv:0908.3191Selected candidatesGOODS-NSDF15+7=22 candidatesall candidates have y>25.4mag1 (brightest) candidate zspec=6.96

Ouchi et al. arXiv:0908.3191Selected candidatesdetection completeness ~70%@y=25.5 >50%@y~25.8

Ouchi et al. arXiv:0908.3191UV luminosity fobunction22 candidatesExpected contamination ~1 spurious source ~0.1 transient object ~1 lower-z galaxies with photometric error ~8 L/T-type dwarfsredshift selection functionUV luminosity functionsignifincantly decreases from z~6 at bright magnitude

Ouchi et al. arXiv:0908.3191UV luminosity functionSubaru/Scam + HST/NICMOS* = 1.10+2.79-0.7910-3 Mpc-3M* = -19.90.7 = -1.661.32Evolution between z~6 and z~7 at >2 levelThe decrease of L* is dominant factor ?

Ouchi et al. arXiv:0908.3191UV luminosity densityintegrating UV LF2.7+6.9-1.91026 erg/s/Hz/Mpc33.4+8.6-2.410-3 M/yr/Mpc3SFR densityevolution of a factor of >10 between z~2-3 and z~7SFRD decreases even from z~6 to z~7.

Ouchi et al. arXiv:0908.3191Spatial distributionstrong clustering of z~7 LBGsespecially for UV bright LBGs

SummaryUV luminosity density(LBG number density) z~6(i-dropout) z~7(z-dropout) z~8(Y-dropout)factor of 2~3.5 decrease factor of 2~3 decrease

Redshift FieldTelescope/InstrumentArea(arcmin2)Limit mag(AB)Number of candidatesY-dropout (z~8)HUDFHST/WFC3~4.7H

Oesch et al. arXiv:0909.5183Size evolutionSurface SFR density

Labbe et al. arXiv:0910.0838Stacking analysis with IRAC dataStellar mass of z&Y-dropoutsEvolution of stellar mass density

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