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最近の z~7-8 LBG 探査

最近の z~7-8 LBG 探査. 2009 年 10 月 28 日 鍛治澤　賢. 最近の z~7-8 LBG 探査の論文紹介. Bouwens et al. 2009 arXiv:0909.1803 --- Y-dropout UVLF Oesch et al. 2009 arXiv:0909.1806 --- z-dropout UVLF Bunker et al. 2009 arXiv:0909.2255 --- z-dropout UVLF McLure et al. 2009 arXiv:0909.2437 --- photo-z SED fitting

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最近の z~7-8 LBG 探査

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  1. 最近の z~7-8 LBG探査 2009年10月28日 鍛治澤　賢

  2. 最近のz~7-8 LBG探査の論文紹介 Bouwens et al. 2009 arXiv:0909.1803 --- Y-dropout UVLF Oesch et al. 2009 arXiv:0909.1806 --- z-dropout UVLF Bunker et al. 2009 arXiv:0909.2255 --- z-dropout UVLF McLure et al. 2009 arXiv:0909.2437 --- photo-z SED fitting Labbe et al. 2009 arXiv:0910.0838 --- +IRAC stellar mass Oesch et al. 2009 arXiv:0909.5183 --- morphology Wilkins et al. 2009 arXiv:0910.1098 --- z-dropout Castellano et al. 2009 arXiv:0909.2853 --- z-dropout Hickey et al. 2009 arXiv:0909.4205 --- Y&z-dropout Ouchi et al. 2009 arXiv:0908.3191 --- z-dropout HUDF: HST/WFC3 GOODS-S: HST/WFC3 GOODS-S: VLT/HAWK-I SDF & GOODS-N: Subaru/Suprime-Cam COSMOS: UKIRT/WFCAM & CFHT/WIRCAM Capak et al. 2009 arXiv:0910.0444 --- z-dropout

  3. Lyman break feature Lyman break

  4. z=0.5 z=1.0 z=1.5 z=3.0

  5. Lyman Break Galaxies U-dropout z~3 G-dropout z~4

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

  7. 最近のz~7-8 LBG探査の論文紹介 Bouwens et al. 2009 arXiv:0909.1803 --- Y-dropout UVLF Oesch et al. 2009 arXiv:0909.1806 --- z-dropout UVLF Bunker et al. 2009 arXiv:0909.2255 --- z-dropout UVLF McLure et al. 2009 arXiv:0909.2437 --- photo-z SED fitting Labbe et al. 2009 arXiv:0910.0838 --- +IRAC stellar mass Oesch et al. 2009 arXiv:0909.5183 --- morphology Wilkins et al. 2009 arXiv:0910.1098 --- z-dropout Castellano et al. 2009 arXiv:0909.2853 --- z-dropout Hickey et al. 2009 arXiv:0909.4205 --- Y&z-dropout Ouchi et al. 2009 arXiv:0908.3191 --- z-dropout HUDF: HST/WFC3 GOODS-S: HST/WFC3 GOODS-S: VLT/HAWK-I SDF & GOODS-N: Subaru/Suprime-Cam COSMOS: UKIRT/WFCAM & CFHT/WIRCAM Capak et al. 2009 arXiv:0910.0444 --- z-dropout

  8. Bouwens et al. arXiv:09091803 Hubble Ultra Deep Field HST/ACS z-band image HST/WFC3 Y, J, H-bands Ultra deep HST/ACS optical images VLT/ISAAC Magellan/PANIC Ks-band HST/NICMOS J&H-bands McLure et al. HUDFHST/WFC3 による Y-dropout 探査

  9. HST/WFC3 WFC3 instrumental handbook

  10. HST/WFC3 WFC3 instrumental handbook

  11. Bouwens et al. arXiv:09091803 HUDF09 program first epoch data (August 26 ~ September 6, 2009) F105W （Y） --- 16 orbits F125W （J） --- 16 orbits F160W （H） --- 28 orbits (1 orbit ~ 40min) ~ 4.7 arcmin2 (two UDF05 fields will be also observed in 2010) PSF FWHM ~ 0.2” 5σ limit @ 0.4” diameter ~ 29ABmag • HST/ACS data B, V, i, z -bands ~29-29.5ABmag HST/WFC3 data

  12. Bouwens et al. arXiv:09091803 • Source detection • Color selection J + H combined image >5.5σ in J band • Y-J > 0.8 • J-H < 0.5 • J-H < 0.2 + 0.12×(Y-J) • no detection (<2σ) in B,V,i,z (those with 1.5~2σ detection in more than one optical band were rejected) Y-dropout selection

  13. Bouwens et al. arXiv:09091803 5 candidates blue J-H color (UV slope β<~-2.5) Possible contaminants >5σ in J & >4σ in H All WFC3 data were obrained in 12days brown dwarfs are more bluer and rare Simulation with 24.5~26mag objects  Not spurious objects  Not SNe  Not galactic stars the expected number of, contaminants by photometric scatter is very small (<~0.2) selected z~8 candnoidates

  14. Bouwens et al. arXiv:09091803 5 candidates blue J-H color (UV slope β<~-2.5) H~28.2-29.2 mag half light radius ~ 0.15” (~PSF) (~0.7h-1kpc @z~8) selected z~8 candidates

  15. Bouwens et al. arXiv:09091803 Expected number for no LF evolution • (1+z)-1 size evolution from z~4 • UV slope β=-2.5±0.4 • are assumed. z~6 i-dropout LF  24 Y-dropouts z~7 z-dropout LF  11 Y-dropouts (~70% statistical error ~35% field-to-field variance) Observed number is lower (~1σ level) Number counts

  16. Bouwens et al. arXiv:09091803 Extraoplation of UV LF at z<7 to z~8  M*UV~-19.45, φ*~0.0011Mpc-3, α~-1.74 good agreement with the observed results Fit M*UV with the observed data φ*~0.0011Mpc-3, α~-1.74 are assumed M*UV = -19.3±0.3 M*UV = -20.2±0.2 @z~6 M*UV = -21 @z~4  strong evolution of M* (?) Stepwise LF  weak evolution at -19~-18 mag Evolution of UV LF

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

  18. McLure et al. arXiv:0909.2437 • HST/WFC3 • HST/ACS • Spizter/IRAC HST/ACS z-band image Bouwens et al. と同じデータを独立に処理 PSF FWHM ~ 0.15”(Y), 0.16”(J), 0.18”(H) HST/WFC3 Y, J, H-bands 5σ limit @0.4” diameter ~29ABmag 5σ limit @0.6” diameter ~29mag (~28mag for z-band) VLT/ISAAC Magellan/PANIC Ks-band 5σ limit ~25.9(3.6μm) 25.5(4.5μm) 23.3(5.8μm) 22.9(8.0μm) HST/NICMOS J&H-bands McLure et al. z~6-9 galaxy search with HUDF HST/WFC3

  19. McLure et al. arXiv:0909.2437 • Source detection • Photometric redshift • >5σ@0.4” detection in at least one of YJH-bands • No detection (2σ) in i-band  300 objects BVizYJH-bands + 3.6 & 4.5μm upper limit Charlot & Bruzal 2007 templates + empirical U-dropout spectra 〇: z>7 candidates • χ2 distribution z>5.9 candidates Sample selection  49 candidates

  20. McLure et al. arXiv:0909.2437 example z Y J H • Photometric redshift Charlot & Bruzual 2007 templates + empirical U-dropout spectra τ=0.1~10Gyr Calzetti extinction Av=0~2mag 1 solar metallicity Salpeter IMF • χ2 distribution z>5.9 candidates  49 candidates Sample selection

  21. McLure et al. arXiv:0909.2437 SED magnitude χ2 distribution  visual check spurious artifact Transient object Contamination by T dwarfs • ~0.5 down to z=29ABmag • in 4.5arcmin2 WFC3 field The brightest candidate  SN or other transient soruce (not detected at all in NICMOS images) Sample selection

  22. McLure et al. arXiv:0909.2437 49 z>6 candidates No detection in i-band  incomplete at 5.9<z<6.25 including 15 out of 16 z-dropouts in Oesch et al. all 5 Y-dropouts in Bouwens et al. + additional 15 z>6.25 candidates The faintest z-dropout candidate in Oesch et al. Selected sample

  23. McLure et al. arXiv:0909.2437 15 z>7 candidates 8 z>7.5 candidates 3 z>8 candidates J~28-29mag Including 5 Y-dropouts in Bouwens et al. these 5 have acceptable secondary peak at z~1.6 4 z>7.8 candidates occur in two pairs 〇: z>7 candidates extremely high-z sample

  24. McLure et al. arXiv:0909.2437 15 z>7 candidates 8 z>7.5 candidates 3 z>8 candidates J~28-29mag Including 5 Y-dropouts in Bouwens et al. these 5 have acceptable secondary peak at z~1.6 4 z>7.8 candidates occur in two pairs extremely high-z sample

  25. McLure et al. arXiv:0909.2437 15 z>7 candidates 8 z>7.5 candidates 3 z>8 candidates J~28-29mag Including 5 Y-dropouts in Bouwens et al. these 5 have acceptable secondary peak at z~1.6 4 z>7.8 candidates occur in two pairs For the faintest candidates (J, H ~29), no detection in optical ACS images is not sufficient to pick up Lyman break exclusively. extremely high-z sample

  26. McLure et al. arXiv:0909.2437 redshift probability distribution + 1/Vmax method 6.5<z<7.5 z~7 UVLF z~8 UVLF • similar shape with z~6 UVLF • number density evolution of • a factor of ~2.5 from z~6 M*1500 ~ -20.11 Φ* ~ 0.0007Mpc-3 α ~-1.72 • cannot constrain the shape of UVLF • Number density at M1500~-19.5 is a factor of ~2 • smaller than at z~7 7.5<z<8.5 UV luminosity function

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

  28. Castellano et al. arXiv:0909.2583 HAWK-I 7.5’ x 7.5’ F.O.V 0.106”/pix Y-band 2 pointings Science Verification & ESO Large Program GOODS1 --- 16.25 hour 0.514” FWHM GOODS2 --- 16.93 hour 0.489” FWHM ~89.7arcmin2 ~100% complete at Y~26.2 ~30%compete at Y~26.8 spurious source negligible at Y<26.5 ~10% at Y~26.8 Multi-wavelength data 1σ limit VLT/VIMOS U, R-bands (29.1, 29.5) HST/ACS B, V, i, z-bands(29.0, 29.1,28.6,28.2) VLT/ISAAC J, H, K-bands (26.6,26.2,26.2) VLT/HAWK-I data

  29. Castellano et al. arXiv:0909.2583 Y-selected Y<26.7 Y-J>1.0 detect z>6.5 Lyαbreak HAWK-I Y-band ACS z-band sample selection

  30. Castellano et al. arXiv:0909.2583 Y-selected Y<26.7 Y-J>1.0 Y-J<1.5 & Y-K<2.0 detect z>6.5 Lyαbreak reject old/dusty galaxies at z~1-4 sample selection

  31. Castellano et al. arXiv:0909.2583 Y-selected Y<26.7 Y-J>1.0 Y-J<1.5 & Y-K<2.0 No detection in optical detect z>6.5 Lyαbreak reject old/dusty galaxies at z~1-4 <2σ in all UBVRI-bands <1σ in at least four of UBVRI-bands 139  9 candidates One of interlopers with z-Y>1 sample selection

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

  33. Castellano et al. arXiv:0909.2583 9 z~7 candidates 1 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<-1) is rejected  7 candidates Selected candidates

  34. Castellano et al. arXiv:0909.2583 B+V+i z Y J+H+K F110W F160W 3.6μm

  35. Castellano et al. arXiv:0909.2583 stacking of 7 candidates  zphot=6.80 Selected candidates

  36. Castellano et al. arXiv:0909.2583 Observed number counts of z~6.8 LBGs are smaller than predictions from z~6 LFs. (No evolution for UV LF between z~6 and z~6.8) • UV LF seems to evolve • between z~6 and z~6.8 Number Counts

  37. Castellano et al. arXiv:0909.2583 Assumed UV Luminosity function simulation (source detection, color selection) Expected z-dropout number counts Observed number counts Maximum likelihood Φ* = 0.35+0.16-0.11 ×10-3 Mpc-3 M*(1500Å) = -20.24±0.45 assuming α=-1.71 UV luminosity function

  38. Castellano et al. arXiv:0909.2583 Φ* = 0.35+0.16-0.11 ×10-3 Mpc-3 M*(1500Å) = -20.24±0.45 assuming α=-1.71 Evolution between z~6 and z~6.8 d(logΦ*)/dz = -0.59±0.25 dM*/dz = 0.13±0.51 rule out no evolution between z~6 and z~6.8 at 99% confidence level UV luminosity density ρUV = 1.5+2.0-0.9×1025 erg/s/Hz/Mpc3  a factor of ~3.5 lower than at z~6 Evolution of UV LF

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

  40. Ouchi et al. arXiv:0908.3191 y (zR)-band 2 fields --- 1568 arcmin2 Subaru Deep Field 26 hours 810 arcmin2 GOODS-North 33 hours 758 arcmin2 3σ limit @ 1.8” diameter SDF 26.4 ABmag GOODS-N 26.2 ABmag Other bands SDF BVR + z’ GOODS-N UBVR + z’ z-band 3σ limit SDF 27.7 mag GOODS-N 26.9 mag Suprime-Cam data

  41. Ouchi et al. arXiv:0908.3191 • y-selected samaple >4σ limit SDF y<26.1 GOODS-N y<25.9 • z’-y > 1.5 selection for z>6.5 galaxies possible contamination by cool dwarfs (no selection by Y-J color) • no detection in UBVR-bands (<2σ) <2σ limit SDF 29.4(B), 28.6(V), 28.8(R) GOODS-N 27.3(U), 28.0(B), 26.7(V), 27.0(R) Sample selection

  42. Ouchi et al. arXiv:0908.3191 15+7=22 candidates all candidates have y>25.4mag 1 (brightest) candidate  zspec=6.96 Selected candidates GOODS-N SDF

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

  44. Ouchi et al. arXiv:0908.3191 22 candidates Expected contamination ~1 spurious source ~0.1 transient object ~1 lower-z galaxies with photometric error ~8 L/T-type dwarfs redshift selection function UV luminosity function signifincantly decreases from z~6 at bright magnitude UV luminosity fobunction

  45. Ouchi et al. arXiv:0908.3191 Subaru/Scam + HST/NICMOS Φ* = 1.10+2.79-0.79×10-3 Mpc-3 M* = -19.9±0.7 α = -1.66±1.32 Evolution between z~6 and z~7 at >2σ level The decrease of L* is dominant factor ? UV luminosity function

  46. Ouchi et al. arXiv:0908.3191 integrating UV LF 2.7+6.9-1.9×1026 erg/s/Hz/Mpc3 SFR density 3.4+8.6-2.4×10-3 M◎/yr/Mpc3 evolution of a factor of >10 between z~2-3 and z~7 SFRD decreases even from z~6 to z~7. UV luminosity density

  47. Ouchi et al. arXiv:0908.3191 strong clustering of z~7 LBGs especially for UV bright LBGs Spatial distribution

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

  49. おまけ

  50. Oesch et al. arXiv:0909.5183 Size evolution Surface SFR density

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