Evolution of spiral galaxies in modified gravity

Tiret, O.; Combes, F.

doi:10.1051/0004-6361:20066446

Cited by 110 publications

(158 citation statements)

References 32 publications

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“…In Milgromian dynamics, galaxy evolution and interactions have been shown, with the first available simulations, to naturallly reproduce observational properties of galaxies (Combes & Tiret 2010;Tiret & Combes 2007), and TDGs form readily (Tiret & Combes 2008).…”

Section: No Dark Matter But Modified Gravitymentioning

confidence: 99%

The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology

Kroupa¹

2012

Publ. – Astron. Soc. Aust

243

275

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Abstract:The current standard model of cosmology (SMoC) requires The Dual Dwarf Galaxy Theorem to be true according to which two types of dwarf galaxies must exist: primordial dark-matter (DM) dominated (type A) dwarf galaxies, and tidal-dwarf and ram-pressure-dwarf (type B) galaxies void of DM. Type A dwarfs surround the host approximately spherically, while type B dwarfs are typically correlated in phasespace. Type B dwarfs must exist in any cosmological theory in which galaxies interact. Only one type of dwarf galaxy is observed to exist on the baryonic Tully-Fisher plot and in the radius-mass plane. The Milky Way satellite system forms a vast phase-space-correlated structure that includes globular clusters and stellar and gaseous streams. Other galaxies also have phase-space correlated satellite systems. Therefore, The Dual Dwarf Galaxy Theorem is falsified by observation and dynamically relevant cold or warm DM cannot exist. It is shown that the SMoC is incompatible with a large set of other extragalactic observations. Other theoretical solutions to cosmological observations exist. In particular, alone the empirical mass-discrepancyacceleration correlation constitutes convincing evidence that galactic-scale dynamics must be Milgromian. Major problems with inflationary big bang cosmologies remain unresolved.

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Section: No Dark Matter But Modified Gravitymentioning

confidence: 99%

The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology

Kroupa¹

2012

Publ. – Astron. Soc. Aust

243

275

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“…We developed a new full multigrid (FMG) solver in the same spirit as Brada & Milgrom (1995) and Tiret & Combes (2007). It solves Eq.…”

Section: Appendix A: Full Multi-grid Mond Potential Solvermentioning

confidence: 99%

Galactic kinematics with modified Newtonian dynamics

Bienaymé

Famaey

et al. 2009

A&A

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We look for observational signatures that could discriminate between Newtonian and modified Newtonian (MOND) dynamics in the Milky Way, in view of the advent of large astrometric and spectroscopic surveys. Indeed, a typical signature of MOND is an apparent disk of "phantom" dark matter, which is uniquely correlated with the visible disk-density distribution. Due to this phantom dark disk, Newtonian models with a spherical halo have different signatures from MOND models close to the Galactic plane. The models can thus be differentiated by measuring dynamically (within Newtonian dynamics) the disk surface density at the solar radius, the radial mass gradient within the disk, or the velocity ellipsoid tilt angle above the Galactic plane. Using the most realistic possible baryonic mass model for the Milky Way, we predict that, if MOND applies, the local surface density measured by a Newtonist will be approximately 78 M /pc 2 within 1.1 kpc of the Galactic plane, the dynamically measured disk scale-length will be enhanced by a factor of 1.25 with respect to the visible disk scale-length, and the local vertical tilt of the velocity ellipsoid at 1 kpc above the plane will be approximately 6 degrees. None of these tests can be conclusive for the present-day accuracy of Milky Way data, but they will be of prime interest with the advent of large surveys such as GAIA.

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“…It has been shown that on galactic scales MOND can explain many phenomena better than CDM (Begmann 1989;Begmann et al 1991;Sanders & McGaugh 2002;A&A 527, A33 (2011) Sanchez-Salcedo & Hernandez 2007; Haghi et al 2006;Malekjani et al 2009;Gentile et al 2007;Milgrom 1994;Brada & Milgrom 2000;Milgrom 1995;Wu et al 2008;Tiret & Combes 2007;Hasani et al 2010). MOND has been generalized to a general-relativistic version (Bekenstein 2004;Sanders 2005;Zlosnik et al 2007;Milgrom 2009), making it possible to test its predictions for gravitational lensing.…”

Section: Introductionmentioning

confidence: 99%

Distant star clusters of the Milky Way in MOND

Haghi

Baumgardt

Kroupa³

2011

A&A

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We determine the mean velocity dispersion of six Galactic outer halo globular clusters, AM 1, Eridanus, Pal 3, Pal 4, Pal 15, and Arp 2 in the weak acceleration regime to test classical vs. modified Newtonian dynamics (MOND). Owing to the nonlinearity of MOND's Poisson equation, beyond tidal effects, the internal dynamics of clusters is affected by the external field in which they are immersed. For the studied clusters, particle accelerations are much lower than the critical acceleration a 0 of MOND, but the motion of stars is neither dominated by internal accelerations (a i a e ) nor external accelerations (a e a i ). We use the N-body code N-MODY in our analysis, which is a particle-mesh-based code with a numerical MOND potential solver developed by Ciotti et al. (2006, ApJ, 640, 741) to derive the line-of-sight velocity dispersion by adding the external field effect. We show that Newtonian dynamics predicts a low-velocity dispersion for each cluster, while in modified Newtonian dynamics the velocity dispersion is much higher. We calculate the minimum number of measured stars necessary to distinguish between Newtonian gravity and MOND with the Kolmogorov-Smirnov test. We also show that for most clusters it is necessary to measure the velocities of between 30 to 80 stars to distinguish between both cases. Therefore the observational measurement of the line-of-sight velocity dispersion of these clusters will provide a test for MOND.

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Evolution of spiral galaxies in modified gravity

Cited by 110 publications

References 32 publications

The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology

The Dark Matter Crisis: Falsification of the Current Standard Model of Cosmology

Galactic kinematics with modified Newtonian dynamics

Distant star clusters of the Milky Way in MOND

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