Bianchi IX gravitational collapse of matter inhomogeneities

We investigate a model of gravitational collapse of matter inhomogeneities where the latter are modelled as Bianchi type IX (BIX) spacetimes. We found that this model contains, as limiting cases, both the standard spherical collapse model and the Zeldovich solution. We study how these models are affected by small anisotropies within the BIX potential. For the spherical collapse case, we found that the model is equivalent to a closed FLRW Universe filled with matter and two perfect fluids representing the anisotropic contributions. From the linear evolution up to the turnaround, the anisotropies effectively shift the value of the FLRW spatial curvature, because the fluids have effective Equation of State (EoS) parameters w ≈ -1/3. Then we estimate the impact of such anisotropies on the number density of haloes using the Press-Schechter formalism. If a fluid description of the anisotropies is still valid after virialization, the averaged over time EoS parameters are w ≈ 1/3. Using this and demanding hydrostatic equilibrium, we find a relation between the mass M, the average radius R and the pressure p of the virialized final structure. When we consider within the BIX ansatz small deviations from the Zeldovich solution, our qualitative analysis suggests that the so called pancakes exhibit oscillatory behavior, as would be expected in the case of a vacuum BIX spacetime.

Note:

v2, replaced to match the accepted version. Comments are welcome!

cosmic web
Cosmological perturbation theory in GR and beyond
galaxy clustering
semi-analytic modeling

References(49)

Figures(0)

General Relativity

Robert M. Wald
(
- Chicago U., EFI
)

DOI:
- 10.7208/chicago/9780226870373.001.0001

[2]

Gravitation and Cosmology: Principles and Applications of the General Theory of Relativity, John

S. Weinberg

[3]

Planck 2018 results. VI. Cosmological parameters

Planck

Collaboration

•

N. Aghanim
(
- Orsay, IAS
)

et al.

- Astron.Astrophys. 641 (2020) A6,
- Astron.Astrophys. 652 (2021) C4 (erratum)
•
e-Print:
- 1807.06209
•
DOI:
- 10.1051/0004-6361/201833910

DOI:
- 10.1086/149077

[5]

On the Infall of Matter into Clusters of Galaxies and Some Effects on Their Evolution

James E. Gunn
(
- Caltech and
- Carnegie Inst., Wash., D.C.
)
,
J. Richard Gott, III
(
- Princeton U. Observ.
)

- Astrophys.J. 176 (1972) 1-19
•
DOI:
- 10.1086/151605

[6]

On the Spherical collapse model in dark energy cosmologies

D.F. Mota
(
- Oxford U.
)
,
C. van de Bruck
(
- Oxford U.
)

- Astron.Astrophys. 421 (2004) 71-81
•
e-Print:
- astro-ph/0401504
•
DOI:
- 10.1051/0004-6361:20041090

[7]

The Hierarchical peak patch picture of cosmic catalogs. 1. Algorithms

J.R. Bond
(
- Canadian Inst. Theor. Astrophys.
)
,
S.T. Myers
(
- Caltech and
- Canadian Inst. Theor. Astrophys.
)

- Astrophys.J.Suppl. 103 (1996) 1
•
DOI:
- 10.1086/192267

[8]

Formation of galaxies and clusters of galaxies by selfsimilar gravitational condensation

William H. Press
(
- Caltech
)
,
Paul Schechter
(
- Caltech
)

- Astrophys.J. 187 (1974) 425-438
•
DOI:
- 10.1086/152650

[9]

Cosmology

S. Weinberg

[10]

Ellipsoidal collapse and an improved model for the number and spatial distribution of dark matter haloes

- Mon.Not.Roy.Astron.Soc. 323 (2001) 1
•
e-Print:
- astro-ph/9907024
•
DOI:
- 10.1046/j.1365-8711.2001.04006.x

[11]

Triaxial collapse and virialisation of dark-matter haloes

- Astron.Astrophys. 518 (2010) A38
•
e-Print:
- 1001.4984
•
DOI:
- 10.1051/0004-6361/201014147

[12]

The formation of CDM haloes – I. Collapse thresholds and the ellipsoidal collapse model

- Mon.Not.Roy.Astron.Soc. 445 (2014) 4110-4123
•
e-Print:
- 1107.5808
•
DOI:
- 10.1093/mnras/stu2021

[13]

Ellipsoidal collapse and primordial black hole formation

Florian Kühnel
(
- Stockholm U. and
- Stockholm U., OKC
)
,
Marit Sandstad
(
- Stockholm U. and
- Nordita
)

- Phys.Rev.D 94 (2016) 6, 063514
•
e-Print:
- 1602.04815
•
DOI:
- 10.1103/PhysRevD.94.063514

[14]

Evolution and Statistics of Non-Sphericity of Dark Matter Halos from Cosmological N-Body Simulation

- Publ.Astron.Soc.Jap. 68 (2016) 6, 97
•
e-Print:
- 1608.06494
•
DOI:
- 10.1093/pasj/psw088

[15]

Gravitational instability: An Approximate theory for large density perturbations

Ya.B. Zeldovich
(
- Moscow, IPM
)

- Astron.Astrophys. 5 (1970) 84-89

[16]

Formation of clusters of galaxies: Protocluster fragmentation and intergalactic gas heating

R.A. Sunyaev
(
- Moscow, IPM
)
,
Ya.B. Zeldovich
(
- Moscow, IPM
)

- Astron.Astrophys. 20 (1972) 189-200

[17]

Hierarchical pancaking: Why the Zel'dovich approximation describes coherent large scale structure in N body simulations of gravitational clustering

Jennifer L. Pauls
(
- Kansas U.
)
,
Adrian L. Melott
(
- Kansas U.
)

- Mon.Not.Roy.Astron.Soc. 274 (1995) 99-109
•
e-Print:
- astro-ph/9408019
•
DOI:
- 10.1093/mnras/274.1.99

[18]

Radio detections of neutral hydrogen at redshift Z=3.4

- Phys.Rev.Lett. 67 (1991) 3328-3331
•
DOI:
- 10.1103/PhysRevLett.67.3328

[19]

Asymptotic behavior of homogeneous cosmological models in the presence of a positive cosmological constant

Robert M. Wald
(
- Chicago U., EFI
)

- Phys.Rev.D 28 (1983) 2118-2120
•
DOI:
- 10.1103/PhysRevD.28.2118

[20]

Inhomogeneous Anisotropic Cosmology

Matthew Kleban
(
- New York U., CCPP and
- New York U.
)
,
Leonardo Senatore
(
- SLAC and
- KIPAC, Menlo Park and
- Stanford U., ITP and
- Stanford U., Phys. Dept.
)

- JCAP 10 (2016) 022
•
e-Print:
- 1602.03520
•
DOI:
- 10.1088/1475-7516/2016/10/022

[21]

Sugli spazi a tre dimensioni che ammettono un gruppo continuo dei movimenti, Memorie di Matematica e di Fisica della Societa Italiana delle Scienze serie terza, 11, 267 (1898)

L. Bianchi

[22]

Oscillatory approach to a singular point in the relativistic cosmology

- Adv.Phys. 19 (1970) 525-573
•
DOI:
- 10.1080/00018737000101171

[23]

A General Solution of the Einstein Equations with a Time Singularity

- Adv.Phys. 31 (1982) 639-667
•
DOI:
- 10.1080/00018738200101428

[24]

The Cosmological Singularity

Vladimir Belinski
,
Marc Henneaux

[25]

Null signal for the cosmic anisotropy in the Pantheon supernovae data

Hua-Kai Deng
(
- Beijing, Inst. Tech.
)
,
Hao Wei
(
- Beijing, Inst. Tech.
)

- Eur.Phys.J.C 78 (2018) 9, 755
•
e-Print:
- 1806.02773
•
DOI:
- 10.1140/epjc/s10052-018-6159-4

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