Baryonic signature in the large-scale clustering of SDSS quasars

Kazuhiro Yahata 　 <yahata@utap.phys.s.u-tokyo.ac.jp>

Dept. of Phys., University of Tokyo.

Issha Kayo, Yasushi Suto, Matsubara Takahiko, Andy Connolly, Daniel Vanden Berk and others.

1

Comparison of survey volumes

Galaxy Quasar

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We can investigate ＞ 100Mpc/h structure.

EH

・ Eisenstein & Hu matter transfer function (1998)

Theoretical matter 2PCF

zero crossing

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B dependence

Predicted Ωb-dependence

Ωb↑・ slope↓・ zero-crossing scale↑

Λ dependence

Predicted ΩΛ-dependence

ΩΛ↑・ slope↓・ zero-crossing scale↑

We can derive constraints on Ωb and ΩΛ from these dependence.

Quasar sample selection

・ DR3 spectroscopic sample. 　・ point source

・ Northern sky (80 ≦ α ≦ 300)

・ 15.0 ≦ mi,rc ≦ 19.1

・ 0.16 ≦ z ≦ 2.24

Quasar sample selection

sample

The quasar sample

NQSO = 20303

2D distribution

Mi’r

cN

redshift

2PCF

2PCF of SDSS quasars (Ωm=0.3,ΩΛ=0.7,h=0.7)

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It seems that the baryon bump exists in quasar 2PCF.

・ binning

We derive constraints on Ωb fromSDSS QSO clustering.

Fitting Proc

Fitting procedure

・ h = 0.7, (0.6, 0.8)

・ spatially flat: Ωb + ΩΛ + Ωd =1

・ scale independent bias: bQSO(z)

→fitting parameters: 　 Ωb ， ΩΛ

・ compute 2PCF (theory and observation) for grids　 of Ωb and ΩΛ. at linear regime, s ≧ 10Mpc/h

・ compute χ2

z evolution

Redshift evolution

・ Light-cone effect (Hamana, et al. 1998)

・ The Kaiser effect

・ evolution of scale independent bias

All above effects are scale independent.Thus we can introduce effective quasar bias:

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Chi2 h70

Result Δχ2

Approximate fit: 2.6Ωb + ΩΛ = 0.9

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Contours: 68%, 95%, 99.7%

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2.6Ωb + ΩΛ = 0.9

h-dependence is weak.

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Δχ2 (h=0.70)

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2.6Ωb + ΩΛ = 0.9

h-dependence is weak.

Chi2 h8０

Δχ2 (h=0.80)

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2.6Ωb + ΩΛ = 0.9

h-dependence is weak.

Degeneracy

Due to the huge errors of large scale bins, the zero-crossing scale is not well constrained yet.

Future data are important in improving the constraints.

The 2PCFs preferred from the current analysis.

Summary

Summary

We derived constraints on Ωb and ΩΛ fromSDSS QSO 2PCF.

The result is approximately fitted to　 2.6Ωb ＋ ΩΛ=0.9±0.1

Future quasar data will constrain the zero crossing scale well. We willbreak the degeneracy between Ωb and ΩΛ.

END

End

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