Bulk flows from clusters of galaxies, KSZ and prospects with PLANCK

Transcription

Bulk Flows from Clusters of Galaxies.
Fernando Atrio-Barandela.
Fı́sica Teória. Facultad de Ciencias.
Universidad de Salamanca.
eml: [email protected]
A. Kashlinsky, Goddard SFC, Maryland.
D. Kocevski, UC at Davis.
H. Ebeling, University of Hawaii.
A. Edge, University of Durham.
Bulk flow think tank, Institute d’Astrophysique de Paris
Lundi 23 Novembre, 2009.
1
Summary.
1.2.3.4.5.6.-
References:
Introduction.
How to measure the Cluster Bulkflow?
Results with WMAP 5rd year-data.
Error Bars.
Cosmological Implications.
Conclusions.
-
Atrio-Barandela
Kashlinsky et al
Kashlinsky et al
Kashlinsky et al
et al (2008) ApJ 675, L57
(2008) ApJ 686, L49
(2009) ApJ 691, 1479
(2009) arXiv:0910.4958
2
1.- Introduction.
3
Bulk Flows.
♠ For a given matter power spectrum, the variance of the velocity field is:
Z
1
hV 2(R)i = 2 P (k)W 2(kR)dk
2π
For all scales larger than Matter-Radiation equality [∼ 100M pc/h], bulk flows
probe the primordial matter power spectrum generated during inflation.
P (k) ∝ k
⇒
Vrms ≃
r
100M pc/h
−1
100km/s
⇒
Test of the Inflation Paradigm!!!
4
The Sunyaev-Zeldovich Effect.
•Thermal:
∆T
(n̂) = G(ν)σT h
T
Z
neTX
~l ≃ G(ν)τ neTX
n̂
·
d
mec2
mec2
•Kinematic:
∆T
n̂ · ~vcl
(n̂) = −
σT h
T
c
Z
dlne = −τ
n̂ · ~vcl
c
5
Measuring Velocities of Individual Clusters.
♠ In the line of sight of a cluster:
TX
~v · n̂
T (~n) − T0 = ∆TCM B (n̂) + T0τ G(ν) 2 +
+ N (n̂)
mc
c
Orders of magnitude:
TX = 7KeV, τ = 4 × 10−3 , v = 300km/s ⇒
∆TtSZ = −300µK (RJ)
∆TkSZ = 10µK.
♠ If ∆TCM B = 100µK, N oise = 40µK the error is ∼ 2000km/s.
6
Moments of the Velocity Field at Cluster Locations.
Adding the velocities of cluster sample gives their CM motion ⇒ BULK
FLOW.
a1m = 1µK
Ncl
v
± 3µK
300km/s
1000
signal
1/2
± 0.6µK
Intrinsic CMB
Npixels
10000
Noise
1/2
± 0.2µK
Ncl
1000
1/2
tSZ Dipole
The dominant source of error is the cosmological CMB signal.
How can we measure the kSZ dipole?
7
2.- How to Measure the Cluster Bulflow?
8
Step I: Get a Good Cluster Sample!
♠ The Cluster Sample was derived from Rossat All Sky Survey.
properties were recomputed in a consistent manner for all clusters.
All
• Angular positions: l, b.
• Spectroscopic redshifts.
• X-ray fluxes at ROSSAT broad band [0.1-2.4]KeV and bolometric
luminosities.
• β model parameters: electron densities, core radii, β = 2/3.
S(r) = S0[1 + (r/rc)2]−3β+1/2
• X-ray extent of the cluster.
• The catalog comprises 1485 clusters and groups, 1283 outside the kp0
mask. Is the largest homogeneous X-ray cluster sample ever compiled.
9
Cluster Sample (2007).
Total number of clusters: 660. Mean Redshift: 0.1.
10
Cluster Sample (2009).
Total number of
clusters with LX ≤ 0.5×1044: 838
LX (1044 erg s-1, 0.1-2.4 keV)
10
zmean/zmedian
0.094/0.090
0.133/0.133
0.169/0.176
1
0.0
0.1
0.2
LX bin
1044 erg/s
0.5-1
1-2
>2
Ncl
11
240
276
322
0.3
z
Step II: Get an All-Sky CMB Data!
WMAP 3rd yr data.
Linear scale from -200 to 200µK.
Q: 41GHz
V: 61GHz
W: 94GHz
12
Step III: Check WMAP Data is Seeing the Clusters.
Left: tSZ contributions to WMAP 3rd yr data in subsamples with redshifts
z ≤ zbin and different X-ray extents. Middle: Measured signal (solid circles)
and β model prediction (open circles); solid line is a NFW profile. Right:
Temperature decrement for 2 NFW profiles.
13
Step IV: Filter out the CMB Contaminant.
Upper Left:
Unfiltered,
Right: Filtered Q1 Map.
Upper
Right: Number of observations.
14
Filters in Real and l-space:
|dl|2 − Clth ∗ Bl2
Fl =
|dl|2
15
Power spectrum of the
original WMAP V1 DA, best
theoretical model and power
spectrum of the filtered data.
♠ There are 2 different contributions: residual CMB dominates at l ≤ 200
and noise at l ≥ 200.
16
3.- Results.
17
The Cluster DARK FLOW [WMAP 3thyr Data].
dipole
(l,b)
CMB
Clusters
(276o ± 3o; 30o ± 3o)
(283o; 11o) ± 13o
WMAP-3yr data: ILC map.
In pink: direction of the matter flow.
18
2000
v/kms-1
1500
1000
500
100
150
200
R/Mpc
250
z median
Ncl
Npix
0.03
0.053
0.067
0.076
0.082
0.089
86
292
444
541
603
674
4,872
16,064
24,189
29,127
32,146
35,409
300
Amplitude of the Dark Flow for different subsamples.
19
The Cluster DARK FLOW [WMAP 5thyr Data].
Amplitude and Direction of the cluster bulkflow for different subsamples.
20
Amplitude of the flow for different subsamples.
Distance/h−1
70 M pc
250-370
370-540
380-650
385-755
LG-CMB
SUN-CMB
Ncl
516
547
694
838
Amplitude/[km/s]
934 ± 352
1230 ± 331
1042 ± 295
1005 ± 292
627 ± 22
369.5 ± 22
Direction
(282 ± 34, 22 ± 20)o
(292 ± 21, 27 ± 15)o
(284 ± 24, 30 ± 15)o
(296 ± 28, 39 ± 14)o
(276o ± 3o; 30o ± 3o)
(264o.4 ± 0o.3; 48o.4 ± 0o.5)
21
KSZ Signal with Respect to the Apex [WMAP 3rdyr].
∆T versus X = cos θ, where θ is the angle between the cluster position and
the direction of motion.
22
LX -Dipole Correlation.
v ∼ ∆T /τ
τ = σT h
Z
dlne.
The signal MUST correlate
with X-ray Luminosity (TSZ
amplitude). More luminous
clusters MUST have larger
kSZ signal.
23
3.3 Evidence & Significance.
Our Evidence:
-The signal is present at cluster locations.
-The signal is persistent for subsamples from ∼ 150 up to ∼ 900 clusters.
-Clusters are not isothermal but follow a NFW profile =⇒ the KSZ
component can be measured when the TSZ goes to zero.
-New: The TSZ signal correlates with the cluster dipole.
Statistical Significance:
- W M AP 3rdyr results: 94%
- W M AP 5rdyr results: 99.9%
24
Scale and Coherence of the Flow.
−→
Dipole amplitude measured in µK. The conversion factor to km/s and the
scale of the flow are our major uncertainties.
25
Comparison with Other Observations.
”Consistently Large Cosmic Flows on
Scales o 100/h Mpc: a Challenge for
the Standard ΛCDM Cosmology”.
Watkins, Feldman & Hudson (2009)
MNRAS, 392, 743
Robust Bulk Flow in the Galactic Y
direction (upper right panel).
26
”Cosmic flow from 2MASS
redshift survey: The origin of
CMB dipole and implications for
LCDM cosmology”
Lavaux, Tully, Brent & Colombi
ArXiv0810.3658.
Direction and amplitude of the bulk flow motion of a sphere of 30Mpc/h
centered on the local group. Out to 120Mpc/h the dipole has not reached
convergence.
27
4.- Error Bars.
28
Estimating Error Bars.
Method 1:
Clusters are placed at random on
filtered data.
Method 2:
The dipole is estimated over
simulated maps with fixed cluster
template.
29
Error bars: a1x (solid), a1y (dotted) and a1z (dashed) for Q1, V1, W1
channels. Upper panels: Method 1; Lower panels: Method 2 (10-15%
larger).
30
The Expected Uncertainty.
♠ There are 2 contributions:
residual CMB at l ≤ 200 and
noise at l ≥ 200:
2
2
σ
σ
noise
σ 2 = resCM B +
3Ncl
3NDANpix
In WMAP 5thyr, the residual CMB contribution dominates.
31
The Anisotropy of the Cluster Catalog.
Due to the Mask, multipoles can not be measured with the same accuracy.
32
Due to the anisotropies in the
cluster template, the X,Y and
Z components are measured
with different accuracy:
σ[0,x,y,z] =
[15, 25, 26, 30]
√
Ncl
33
5.- Cosmological Implications.
34
Origin of the Flow.
• Subhorizon
– 1Gpc void [Garcia-Bellido & Haugboelle ArXiv0810.4939]
– Dark Energy and Dark Matter reference frames move with respect to
each other [Beltran-Jimenez & Maroto ArXiv0812.2206]
• Superhorizon
– Tilted Universe [Turner 1991].
– Quantum coherence of vacua in the string landscape [MersiniHoughton & Holman ArXiv0810.5388].
– Breaking translational invariance during inflation [Carroll, Tseng &
Wise ArXiv0811.1086].
35
Lemaı̂tre-Tolman-Bondi Void Solution.
Voids can be produced during
inflation [Starobinski et al
(1996) δN -formalism].
♠ Cold Spot on the CMB:
∆T ∼ −100µK on θR ∼ 5o.
Compensated Void at z = 1.0:
R ∼ 0.7Gpc, δ ∼ −0.3.
Inoue & Silk ApJ (2008): Low multipole alignments, Cold Spot.
Enqvist GRG (2008), Clifton et al PRL (2008): LTB and SNIa
Garcia-Bellido & Haugbœlle (2008): LTB and shear
36
At a distance R from the center of the void:
R
1 0.6
vp = Ω HoRδ = 600km/s
6
1Gpc
δ
0.1
An observer off-center on a LTB void could explain the motion ⇒ the flow
has an intrinsic (measurable) shear.
37
A Tilted Universe?
Can a flow across the horizon exist? [Turner (1991)]
♠ A Superhorizon Isocurvature perturbations of wavelength L and amplitude
δ can produced anisotropies:
v
∼
c
cHo−1
L
δL ∼ 2 × 10−3
Q∼
v cH −1 o
c
L
δL ∼ 4 × 10−6
A pre-inflationary remnant of δL ∼ 1 requires L ∼ 500cHo−1.
38
New Scientist,
Jan 2009.
If the CMBR anisotropy is intrinsic, then viewed from the rest frame of the
CMBR the Universe appears to be tilted (!), with galaxies moving from one side
of our Hubble volume to the other with speeds of the order of 600 km s−1 .
-M. Turner, 1st Prize on General Relativity Essays, 1993.
39
6.- Conclusions.
40
Conclusions.
• We have developped a new method to measure peculiar velocities.
• KSZ has very different systematics than peculiar velocity surveys
• We have determined a coherent bulk flow on the direction of the CMB
dipole on a scale of ∼ 750Mpc.
• The amplitude of the flow is ∼ 1000km/s.
• This large scale flow could be generated by density perturbations on
superhorizon scales.
41
PLANCK.
ν /GHz
FWHM/arcmin
δT [µK/sqr-deg]
TSZ amplitude
30
33
3.0
-1.95
LFI
44
24
3.0
-1.90
70
14
3.0
-1.75
100
9.5
1.1
-1.51
143
7.1
1.4
-1.04
HFI
217
5.0
2.2
0.0
353
5.0
6.8
2.23
545
5.0
857
5.0
5.9
11
PLANCK vs. WMAP: Higher resolution and frequency coverage. Lower noise levels.
42
Peculiar Velocities of Individual Clusters.
PLANCK will permit the velocity
individual clusters to be determined.
of
Effect of A2163 on the intensity of the CMB.
[From Carlstrom et al ARAA 2002].
43

Bulk flows from clusters of galaxies, KSZ and prospects with PLANCK

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