Dark matter distribution in superthin galaxies

ABSTRACT This paper presents a new method of calculating dark matter density profiles for superthin axial symmetric galaxies without a bulge. This method is based on a simple physical model, which includes an infinitely thin galactic disc immersed in a spherically symmetric halo of dark matter. To obtain the desired distribution density, it suffices to know a distribution of visible matter surface density in a galaxy and a dependence of angular velocity on the radius. As a byproduct, the well-known expression, which reproduces surface density of a superthin galaxy expressed through a rotation law, was obtained.

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Cores vs. Cusps: Dark Matter Density Profiles in Spirals

Symposium - International Astronomical Union ◽

10.1017/s0074180900183469 ◽

2004 ◽

Vol 220 ◽

pp. 311-312

Author(s):

Gianfranco Gentile ◽

Uli Klein ◽

Paolo Salucci ◽

Daniela Vergani

Keyword(s):

Dark Matter ◽

Rotation Curve ◽

Spiral Galaxies ◽

Matter Density ◽

Matter Distribution ◽

Rotation Curves ◽

Density Profiles ◽

The Core ◽

Dark Matter Distribution ◽

A New Technique

We use photometric, Hα and Hi data to investigate the distribution of dark matter in spiral galaxies. A new technique for deriving the Hi rotation curve is presented. the final combined Hα+Hi rotation curves are symmetric, well resolved and extend to large radii. We perform the rotation curve decomposition into the luminous and dark matter contributions. the observations are confronted with different models of the dark matter distribution, including core-dominated and cusp-dominated halos as well as less conventional possibilities. the best agreement with the observations is found for the core-dominated halos.

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Imprint of Pressure on Characteristic Dark Matter Profiles: The Case of ESO0140040

Galaxies ◽

10.3390/galaxies8040074 ◽

2020 ◽

Vol 8 (4) ◽

pp. 74

Author(s):

Kuantay Boshkayev ◽

Talgar Konysbayev ◽

Ergali Kurmanov ◽

Orlando Luongo ◽

Marco Muccino

Keyword(s):

Dark Matter ◽

Complex Structure ◽

Matter Content ◽

Model Parameters ◽

Matter Distribution ◽

Density Profiles ◽

The Galaxy ◽

Dark Matter Distribution ◽

Observational Signature

We investigate the dark matter distribution in the spiral galaxy ESO0140040, employing the most widely used density profiles: the pseudo-isothermal, exponential sphere, Burkert, Navarro-Frenk-White, Moore and Einasto profiles. We infer the model parameters and estimate the total dark matter content from the rotation curve data. For simplicity, we assume that dark matter distribution is spherically symmetric without accounting for the complex structure of the galaxy. Our predictions are compared with previous results and the fitted parameters are statistically confronted for each profile. We thus show that although one does not include the galaxy structure it is possible to account for the same dynamics assuming that dark matter provides a non-zero pressure in the Newtonian approximation. In this respect, we solve the hydrostatic equilibrium equation and construct the dark matter pressure as a function for each profile. Consequently, we discuss the dark matter equation of state and calculate the speed of sound in dark matter. Furthermore, we interpret our results in view of our approach and we discuss the role of the refractive index as an observational signature to discriminate between our approach and the standard one.

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Stellar splashback: the edge of the intracluster light

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3590 ◽

2020 ◽

Vol 500 (3) ◽

pp. 4181-4192

Author(s):

Alis J Deason ◽

Kyle A Oman ◽

Azadeh Fattahi ◽

Matthieu Schaller ◽

Mathilde Jauzac ◽

...

Keyword(s):

Dark Matter ◽

Accretion Rate ◽

Matter Distribution ◽

Density Profiles ◽

Mass Accretion Rate ◽

Dark Matter Distribution ◽

Intracluster Light ◽

Physical Boundary ◽

Fraction Bound ◽

Good Agreement

ABSTRACT We examine the outskirts of galaxy clusters in the C-EAGLE simulations to quantify the ‘edges’ of the stellar and dark matter distribution. The radius of the steepest slope in the dark matter, commonly used as a proxy for the splashback radius, is located at $\sim \, r_{200 \rm m}$; the strength and location of this feature depends on the recent mass accretion rate, in good agreement with previous work. Interestingly, the stellar distribution (or intracluster light, ICL) also has a well-defined edge, which is directly related to the splashback radius of the halo. Thus, detecting the edge of the ICL can provide an independent measure of the physical boundary of the halo, and the recent mass accretion rate. We show that these caustics can also be seen in the projected density profiles, but care must be taken to account for the influence of substructures and other non-diffuse material, which can bias and/or weaken the signal of the steepest slope. This is particularly important for the stellar material, which has a higher fraction bound in subhaloes than the dark matter. Finally, we show that the ‘stellar splashback’ feature is located beyond current observational constraints on the ICL, but these large projected distances (≫1 Mpc) and low surface brightnesses (μ ≫ 32 mag arcsec−2) can be reached with upcoming observational facilities such as the Vera C. Rubin Observatory, the Nancy Grace Roman Space Telescope, and Euclid.

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NIHAO – XXIII. Dark matter density shaped by black hole feedback

Monthly Notices of the Royal Astronomical Society Letters ◽

10.1093/mnrasl/slaa058 ◽

2020 ◽

Vol 495 (1) ◽

pp. L46-L50 ◽

Cited By ~ 7

Author(s):

Andrea V Macciò ◽

Samuele Crespi ◽

Marvin Blank ◽

Xi Kang

Keyword(s):

Black Hole ◽

Dark Matter ◽

Stellar Mass ◽

Matter Density ◽

Matter Distribution ◽

Density Profiles ◽

Systematic Analysis ◽

Dark Matter Density ◽

Dark Matter Distribution ◽

Halo Masses

ABSTRACT We present a systematic analysis of the reaction of dark matter distribution to galaxy formation across more than eight orders of magnitude in stellar mass. We extend the previous work presented in the NIHAO-IV paper by adding 46 new high-resolution simulations of massive galaxies performed with the inclusion of black hole feedback. We show that outflows generated by the active galactic nucleus (AGN) are able to partially counteract the dark matter contraction due to the large central stellar component in massive haloes. The net effect is to relax the central dark matter distribution that moves to a less cuspy density profiles at halo mass larger than ≈3 × 1012 M⊙. The scatter around the mean value of the density profile slope (α) is fairly constant (Δα ≈ 0.3), with the exception of galaxies with halo masses around 1012 M⊙, at the transition from stellar to AGN feedback dominated systems, where the scatter increases by almost a factor of 3. We provide useful fitting formulae for the slope of the dark matter density profiles at few per cent of the virial radius for the whole stellar mass range: 105–1012 M⊙ (2 × 109 to 5 × 1013 M⊙ in halo mass).

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DARK MATTER DYNAMICS AND INDIRECT DETECTION

Modern Physics Letters A ◽

10.1142/s0217732305017391 ◽

2005 ◽

Vol 20 (14) ◽

pp. 1021-1036 ◽

Cited By ~ 82

Author(s):

GIANFRANCO BERTONE ◽

DAVID MERRITT

Keyword(s):

Dark Matter ◽

Total Mass ◽

Galactic Center ◽

Direct Detection ◽

Indirect Detection ◽

Matter Distribution ◽

Dark Matter Distribution ◽

Particle Dark Matter ◽

The Universe ◽

Rule Out

Non-baryonic, or "dark", matter is believed to be a major component of the total mass budget of the Universe. We review the candidates for particle dark matter and discuss the prospects for direct detection (via interaction of dark matter particles with laboratory detectors) and indirect detection (via observations of the products of dark matter self-annihilations), focusing in particular on the Galactic center, which is among the most promising targets for indirect detection studies. The gravitational potential at the Galactic center is dominated by stars and by the supermassive black hole, and the dark matter distribution is expected to evolve on sub-parsec scales due to interaction with these components. We discuss the dominant interaction mechanisms and show how they can be used to rule out certain extreme models for the dark matter distribution, thus increasing the information that can be gleaned from indirect detection searches.

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