Galaxies lacking dark matter in the Illustris simulation

M. Haslbauer; J. Dabringhausen; P. Kroupa; B. Javanmardi; I. Banik

doi:10.1051/0004-6361/201833771

Galaxies lacking dark matter in the Illustris simulation

M. Haslbauer^*, J. Dabringhausen, P. Kroupa, B. Javanmardi, I. Banik

^*Corresponding author for this work

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

Abstract

Context. Any viable cosmological model in which galaxies interact predicts the existence of primordial and tidal dwarf galaxies (TDGs). In particular, in the standard model of cosmology (ΛCDM), according to the dual dwarf galaxy theorem, there must exist both primordial dark matter-dominated and dark matter-free TDGs with different radii.

Aims. We study the frequency, evolution, and properties of TDGs in a ΛCDM cosmology.

Methods. We use the hydrodynamical cosmological Illustris-1 simulation to identify TDG candidates (TDGCs) and study their present-day physical properties. The positions of galaxies in the radius-mass plane, depending on their nonbaryonic content, are compared with observational data and other simulations. We also present movies on the formation of a few galaxies lacking dark matter, confirming their tidal dwarf nature. Tidal dwarf galaxy candidates can however also be formed via other mechanisms, such as from ram-pressure-stripped material or, speculatively, from cold-accreted gas.

Results. We find 97 TDGCs with M_stellar > 5 × 10⁷M⊙ at redshift z = 0, corresponding to a co-moving number density of 2.3 × 10^-4 h³ cMpc^-3. The most massive TDGC has M_total = 3.1 × 10⁹ M⊙, comparable to that of the Large Magellanic Cloud. Tidal dwarf galaxy candidates are phase-space-correlated, reach high metallicities, and are typically younger than dark matter-rich dwarf galaxies.

Conclusions. We report for the first time the verification of the dual dwarf theorem in a self-consistent ΛCDM cosmological simulation. Simulated TDGCs and dark matter-dominated galaxies populate different regions in the radius-mass diagram in disagreement with observations of early-type galaxies. The dark matter-poor galaxies formed in Illustris-1 have comparable radii to observed dwarf galaxies and to TDGs formed in other galaxy-encounter simulations. In Illustris-1, only 0.17 percent of all selected galaxies with M_stellar = 5 × 10⁷-10⁹ M⊙ are TDGCs or dark matter-poor dwarf galaxies. The occurrence of NGC 1052-DF2-type objects is discussed.

Original language	English
Article number	A47
Number of pages	28
Journal	Astronomy and Astrophysics
Volume	626
Early online date	12 Jun 2019
DOIs	https://doi.org/10.1051/0004-6361/201833771
Publication status	Published - Jun 2019

Keywords

Dark matter
Galaxies: dwarf
Galaxy: abundances
Galaxy: evolution
Galaxy: formation

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10.1051/0004-6361/201833771

Haslbauer_2019_AA_Galaxies-lacking_VoR
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https://arxiv.org/abs/1905.03258

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@article{9b8ff99fda814edb9d027452fd5c106e,

title = "Galaxies lacking dark matter in the Illustris simulation",

abstract = "Context. Any viable cosmological model in which galaxies interact predicts the existence of primordial and tidal dwarf galaxies (TDGs). In particular, in the standard model of cosmology (ΛCDM), according to the dual dwarf galaxy theorem, there must exist both primordial dark matter-dominated and dark matter-free TDGs with different radii. Aims. We study the frequency, evolution, and properties of TDGs in a ΛCDM cosmology. Methods. We use the hydrodynamical cosmological Illustris-1 simulation to identify TDG candidates (TDGCs) and study their present-day physical properties. The positions of galaxies in the radius-mass plane, depending on their nonbaryonic content, are compared with observational data and other simulations. We also present movies on the formation of a few galaxies lacking dark matter, confirming their tidal dwarf nature. Tidal dwarf galaxy candidates can however also be formed via other mechanisms, such as from ram-pressure-stripped material or, speculatively, from cold-accreted gas. Results. We find 97 TDGCs with Mstellar > 5 × 107M⊙ at redshift z = 0, corresponding to a co-moving number density of 2.3 × 10-4 h3 cMpc-3. The most massive TDGC has Mtotal = 3.1 × 109 M⊙, comparable to that of the Large Magellanic Cloud. Tidal dwarf galaxy candidates are phase-space-correlated, reach high metallicities, and are typically younger than dark matter-rich dwarf galaxies. Conclusions. We report for the first time the verification of the dual dwarf theorem in a self-consistent ΛCDM cosmological simulation. Simulated TDGCs and dark matter-dominated galaxies populate different regions in the radius-mass diagram in disagreement with observations of early-type galaxies. The dark matter-poor galaxies formed in Illustris-1 have comparable radii to observed dwarf galaxies and to TDGs formed in other galaxy-encounter simulations. In Illustris-1, only 0.17 percent of all selected galaxies with Mstellar = 5 × 107-109 M⊙ are TDGCs or dark matter-poor dwarf galaxies. The occurrence of NGC 1052-DF2-type objects is discussed. ",

keywords = "Dark matter, Galaxies: dwarf, Galaxy: abundances, Galaxy: evolution, Galaxy: formation",

author = "M. Haslbauer and J. Dabringhausen and P. Kroupa and B. Javanmardi and I. Banik",

note = "IB is supported by an Alexander von Humboldt research fellowship. We thank the DAAD-Ostpartnerschaftsprogramm f{\"u}r 2018 at the University of Bonn for funding exchange visits between Charles University in Prague and Bonn University. ",

year = "2019",

month = jun,

doi = "10.1051/0004-6361/201833771",

language = "English",

volume = "626",

journal = "Astronomy and Astrophysics",

issn = "0004-6361",

publisher = "EDP SCIENCES S A",

}

TY - JOUR

T1 - Galaxies lacking dark matter in the Illustris simulation

AU - Haslbauer, M.

AU - Dabringhausen, J.

AU - Kroupa, P.

AU - Javanmardi, B.

AU - Banik, I.

N1 - IB is supported by an Alexander von Humboldt research fellowship. We thank the DAAD-Ostpartnerschaftsprogramm für 2018 at the University of Bonn for funding exchange visits between Charles University in Prague and Bonn University.

PY - 2019/6

Y1 - 2019/6

N2 - Context. Any viable cosmological model in which galaxies interact predicts the existence of primordial and tidal dwarf galaxies (TDGs). In particular, in the standard model of cosmology (ΛCDM), according to the dual dwarf galaxy theorem, there must exist both primordial dark matter-dominated and dark matter-free TDGs with different radii. Aims. We study the frequency, evolution, and properties of TDGs in a ΛCDM cosmology. Methods. We use the hydrodynamical cosmological Illustris-1 simulation to identify TDG candidates (TDGCs) and study their present-day physical properties. The positions of galaxies in the radius-mass plane, depending on their nonbaryonic content, are compared with observational data and other simulations. We also present movies on the formation of a few galaxies lacking dark matter, confirming their tidal dwarf nature. Tidal dwarf galaxy candidates can however also be formed via other mechanisms, such as from ram-pressure-stripped material or, speculatively, from cold-accreted gas. Results. We find 97 TDGCs with Mstellar > 5 × 107M⊙ at redshift z = 0, corresponding to a co-moving number density of 2.3 × 10-4 h3 cMpc-3. The most massive TDGC has Mtotal = 3.1 × 109 M⊙, comparable to that of the Large Magellanic Cloud. Tidal dwarf galaxy candidates are phase-space-correlated, reach high metallicities, and are typically younger than dark matter-rich dwarf galaxies. Conclusions. We report for the first time the verification of the dual dwarf theorem in a self-consistent ΛCDM cosmological simulation. Simulated TDGCs and dark matter-dominated galaxies populate different regions in the radius-mass diagram in disagreement with observations of early-type galaxies. The dark matter-poor galaxies formed in Illustris-1 have comparable radii to observed dwarf galaxies and to TDGs formed in other galaxy-encounter simulations. In Illustris-1, only 0.17 percent of all selected galaxies with Mstellar = 5 × 107-109 M⊙ are TDGCs or dark matter-poor dwarf galaxies. The occurrence of NGC 1052-DF2-type objects is discussed.

AB - Context. Any viable cosmological model in which galaxies interact predicts the existence of primordial and tidal dwarf galaxies (TDGs). In particular, in the standard model of cosmology (ΛCDM), according to the dual dwarf galaxy theorem, there must exist both primordial dark matter-dominated and dark matter-free TDGs with different radii. Aims. We study the frequency, evolution, and properties of TDGs in a ΛCDM cosmology. Methods. We use the hydrodynamical cosmological Illustris-1 simulation to identify TDG candidates (TDGCs) and study their present-day physical properties. The positions of galaxies in the radius-mass plane, depending on their nonbaryonic content, are compared with observational data and other simulations. We also present movies on the formation of a few galaxies lacking dark matter, confirming their tidal dwarf nature. Tidal dwarf galaxy candidates can however also be formed via other mechanisms, such as from ram-pressure-stripped material or, speculatively, from cold-accreted gas. Results. We find 97 TDGCs with Mstellar > 5 × 107M⊙ at redshift z = 0, corresponding to a co-moving number density of 2.3 × 10-4 h3 cMpc-3. The most massive TDGC has Mtotal = 3.1 × 109 M⊙, comparable to that of the Large Magellanic Cloud. Tidal dwarf galaxy candidates are phase-space-correlated, reach high metallicities, and are typically younger than dark matter-rich dwarf galaxies. Conclusions. We report for the first time the verification of the dual dwarf theorem in a self-consistent ΛCDM cosmological simulation. Simulated TDGCs and dark matter-dominated galaxies populate different regions in the radius-mass diagram in disagreement with observations of early-type galaxies. The dark matter-poor galaxies formed in Illustris-1 have comparable radii to observed dwarf galaxies and to TDGs formed in other galaxy-encounter simulations. In Illustris-1, only 0.17 percent of all selected galaxies with Mstellar = 5 × 107-109 M⊙ are TDGCs or dark matter-poor dwarf galaxies. The occurrence of NGC 1052-DF2-type objects is discussed.

KW - Dark matter

KW - Galaxies: dwarf

KW - Galaxy: abundances

KW - Galaxy: evolution

KW - Galaxy: formation

U2 - 10.1051/0004-6361/201833771

DO - 10.1051/0004-6361/201833771

M3 - Article

AN - SCOPUS:85074930853

SN - 0004-6361

VL - 626

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

M1 - A47

ER -

Galaxies lacking dark matter in the Illustris simulation

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Keywords

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