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Large Scale Structure of the Universe at high redshiftsPowerPoint Presentation

Large Scale Structure of the Universe at high redshifts

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LSS at small redshifts – luminous matter

Ly- forest-LSS in DM & barions

- Three characteristics
of absorber

Redshift – z

Width - b km/s

Depth - NHIcm-2

and

UV background

Properties of ~6000 absorbers 1015cm-2 >NHI > 1012cm-2

PUZZLES

- 1. Weak redshift dependence of the PDFs,
P(b/<b>), P(NHI/<NHI>), P(dsep/<dsep>)

- 2. <b>=const.(z), b < bbg
- 3. Slow regular redshift variations of
<NHI> ~(1+z)2 and <dsep>~(1+z)-2

DM simulation

- Lbox =150h-1Mpc, Np= 2563 , Lcell=0.6h-1Mpc
- Mass resolution: 2 107Mo,
- Force resolution: 20h-1kpc,
- Selected clusters: 10 < Np < 5000, =1.76

clusters

Np~<Np>/3

For hotter

clusters

Np~3<Np>

Relaxation:

frel~0.6-0.8

Simulated clustersCore-sampling approachLcore=0.5h-1Mpc

Probable causes of self similarity

- Deterministic character of simulations:
all structure properties are determined by

the initial power spectrum.

- Zeldovich’ approximation
- ri=(1+z)-1[qi-B(z) Si(q)]
- Power spectrum
- P(k)~k-3, k/k0> 1, k0~0.15Mpc-1

Possible interpretation

- <b>=const(z), W(xi)=const(z)
- <dsep/(1+z)>~(1+z)-3~1/<nabsSabs>
- Version 1 – relaxed clouds
- nabs~(1+z)3, Sabs~const.
- BUT <NHI>~(1+z)2
- Version 2 -- expanded clouds
- Sabs~(1+z)-p, nabs~(1+z)3+p
- BUT <b>=const., W(xi)=const(z)

Comparison with simulations.

Lbox=100 h-1Mpc, Np=(256)3 , Lcell=0.4Mpc

- Z=0, 1, 1.5, 2, 2.5, 3, 4, 5
- Two populations of clouds, and
- Strongly deterministic approach
- Previously – relaxed halos only
- (galaxies, clusters of galaxies)

PDFs for cloud velocities, W(U), mass function, W(M), and surface density, W(q)

PDFs for three principle sizes of clouds, L, w, h

PDFs for the velocity dispersionsalong three principle axes of clouds

Mean characteristics

High density clouds,

L~ (1+z)1/4, w~ (1+z)1/2, h~(1+z)1/2

Vh~ (1+z)-1/2.

Low density clouds,

L~w~h~ const(z)

Vh~ const(z).

Cores and envelopes

Problems and prospects

- 1. Ly-ά emitters and population
of earlier galaxies (~20 000 LBG)

- 2. DM compact objects
- 3. First luminous objects -
stars or galaxies

- 4. Spatial distribution of metal
systems – bubbles ~2Mpc

DM simulation

- Lbox =150h-1Mpc, Np= 2563
- Mass resolution 2 107Mo, Force resolution 20kpc/h
- Selected clusters: 10 < Np < 5000, > 1.7
- Mean comoving principal sizes:
- L~0.5h-1Mpc, W~0.2h-1Mpc, S~0.1h-1Mpc
- Velocity dispersions along principal directions:

Z~2 - 3

- Lgal ~1026 erg/s/Hz/Mpc3
Giavalisco et al. 2004, GOODS,

- LQSO~1023 – 1024 erg/s/Hz/Mpc3,

Next Steps

- Detailed analysis of evolution of the Universe.
- Properties of DM particles
(composition, masses, stability).

- Shape of the small scale initial power spectrum at L<100 kpc.
- Galaxy and quasar formation.
- Reheating and reionization of the
Universe.

- Etc….

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