quadrupole spectrum, baryonic signature in the 2df qso sample
TRANSCRIPT
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Quadrupole spectrum, baryonic signaturein the 2dF QSO sample
Kazuhiro Yamamoto
(Hiroshima Univ.)
K.Y. ApJ 595 577 (03)K.Y. ApJ 605 620 (04)K.Y., Bassett, Nishioka PRL 94 051301 (05)K.Y., Nakamichi, Kamino, Bassett, Nishioka astro-ph/0505
Collaborator B.A. Bassett, Nishioka, Nakamichi, Kamino
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Miller, Nichol & Batsuski ApJ (2001)
Detection of baryon acoustic oscillation ?
Baryon features in matter power spectrum
Eisenstein, Hu (1998)Meiksin, White, Peacock (1999) c.f. Sugiyama (1995)
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Time evolution effect on the statistical quantities
n(z) mean number density b(z) clustering bias D1(z) growth factor
Theoretical template of P(k)
(KY, Nishioka Suto 1999)
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Fitting of the power spectrum of the 2dF QSO sample (K.Y. ApJ, 2002,2004)
The 2QZ sample is publicly available at http://www.2dfquasar.org/
High-z sample, Time evolution effect, Geometric distortion effect
Power spectrum analysis by 2QZ group Hoyle et al. (02), Outram et al. (03)
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δ(r
ad)
α(rad)p2p
2p
2p−
75°
5°
Angular map of the 2dF quasars (~20000)
The 2QZ survey covers the two area of 5×75 deg2
19156 QSOs
In my analysis, incorporating the masked region, I used
0.2 < z < 2.2
x (1/H0)
Y (1
/H0)
2.2=z0=z
Map of QSOs in the NGC
The Final catalogue: http://www.2dfquasar.org/
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Power Spectrum of the 2dF QSOs
Outram et al.
Our work
ΛCDM model,045.0,28.0 =Ω=Ω Bm
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contours of the likelihood function
9.0,7.0,1 8 === σhn
045.0=ΩB
2
22
)(
])()([
kP
kPkP thobs
k D−= Âχ
2/2χ−∝ e
,06.0
,27.0
=Ω=Ω
B
m
Peak values
Consistent with other cosmological observations
Constraint on the density parameters
mΩ
m
BΩ
Ω
Finite baryon fraction model better matches the data!
ΛCDM model
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1.0
28.0
=Ω=Ω
B
m as w becomes larger
Theoretical curve depends on w (the equation of state parameter of the dark energy)
the equation of state can be measured if thepower spectrum was determined precisely
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Constraint on w from QSO power spectrum
mΩ
Contour of the likelihood function
w
9.0,1,7.0
05.0
8 ====Ω
σnhB fixed
The constraint on w isnot very tight.
The shot-noise contribution, the mean number density n=10-6/[h-1Mpc]3
The usefulness of the method when the power spectrum is measured precisely
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Redshift-space distortion Independent information Linear Distortion linear velocity field, Bias Finger of God effect random velocity, non-lin. Geometric distortion cosmological expansion (Alcock-Paczynski effect)
Quadrupole spectrum P2(k)
The KAOS/WFMOS promises the precise measurement of P(k)
Concern about Nonlinear effects on the power spectrum Clustering bias can be uncertain factor
‡‡‡=
=,2,0
)(cos)()cos,(l
ll LkPkP θθ
Obs. line of sightθ
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)(0 kP )(2 kP
)(4 kP
monopole spectrum quadrupole spectrum
Linear theory
Non-linear model
On small scales, the non-linear effects is important for l ≧2Higher multipoles l≧4 will not be measured even by KAOS
Theoretical prediction for P0 and P2, assuming KAOS like sample around Z~1
(0.5<Z<1.5, n=10-4 h3Mpc-3 , 103deg2)
(KY、Bassett, Nishioka 2005)
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Clustering Bias parameterization
ν,,, 110 pbb
Cosmology
marginalize
˜˜¯
ˆÁÁË
Ê˙˚
˘ÍÎ
È+˜
ˆÁÁË
Ê −+= −
ν
11
11
0
1.0
)(1
)(
11),(
1
hMpc
kzDb
zD
bkzb
p
mw Ω,
Feasibility to determine w, focusing on The scale dependence of the bias The nonlinear effects
Fisher matrix analysis wD
Theoretical modeling of P0(k) and P2(k)
(1-sigma error)
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1 sigma error of w as function of the baryon density
Linear Nonlinear
Constraint on w is significantly improved by combining P0 and P2 in the case of no baryon density
P0
P2
P0+P2 P0+P2
P0
P2
ΩBΩB
Δw Δw
P2 is useful in breaking degeneracy between bias and dark energy
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Measurement of the quandrupole spectrum in the 2dF QSO sample
K.Y., Nakamichi, Kamino,Bassett, Nishioka (2005)
)(
)(
0
2
kP
kP)(0 kP
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Chi2 for P0 and P2 as a function of bias
P0
P2
P0 and P2 give constraints on the bias b0 independently
2
22
)(
])()([
kP
kPkP thobs
k D−= Âχ
Bias parameter
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Conclusions
1. The 2dF QSO power spectrum P0(k) better matches the finite baryon fraction model, and the baryon oscillation might be detected.
2. We measured P2(k) in the 2dF QSO sample
3. P2(k) will be measured in the KAOS with high precision
4. P2(k) is sensitive to the nonlinear effects
5. P2(k) becomes useful in the small baryon fraction model This means the importance of the Alcock-Paczynski effect in the region where the baryon oscillation is not distinct