Non-circular motions and the cusp-core discrepancy in dwarf galaxies

Eymeren, J. van; Trachternach, C.; Koribalski, B. S.; Dettmar, R.‐J.

doi:10.1051/0004-6361/200912119

Cited by 38 publications

(44 citation statements)

References 61 publications

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“…This is consistent with results previously found in other nearby dwarf and LSB galaxies (e.g., de Blok & Bosma 2002;Kuzio de Naray et al 2008;van Eymeren et al 2009;Oh et al 2011b). The slowly increasing DM rotation curves in the inner region of the sample galaxies reflect a halo whose gravitational potential is not deep enough to sustain the power-law DM density cusps that are as steep as ρ ∝ − R 1.0 .…”

Section: Core-like Halo Modelsupporting

confidence: 93%

High-Resolution Mass Models of Dwarf Galaxies From Little Things

et al. 2015

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We present high-resolution rotation curves and mass models of 26 dwarf galaxies from "Local Irregulars That Trace Luminosity Extremes, The H I Nearby Galaxy Survey" (LITTLE THINGS). LITTLE THINGS is a high-resolution (∼6″ angular; <2.6 km s −1 velocity resolution) Very Large Array H I survey for nearby dwarf galaxies in the local volume within 11 Mpc. The high-resolution H I observations enable us to derive reliable rotation curves of the sample galaxies in a homogeneous and consistent manner. The rotation curves are then combined with Spitzer archival 3.6 μm and ancillary optical U, B, and V images to construct mass models of the galaxies. This high quality multi-wavelength data set significantly reduces observational uncertainties and thus allows us to examine the mass distribution in the galaxies in detail. We decompose the rotation curves in terms of the dynamical contributions by baryons and dark matter (DM) halos, and compare the latter with those of dwarf galaxies from THINGS as well as ΛCDM Smoothed Particle Hydrodynamic (SPH) simulations in which the effect of baryonic feedback processes is included. Being generally consistent with THINGS and simulated dwarf galaxies, most of the LITTLE THINGS sample galaxies show a linear increase of the rotation curve in their inner regions, which gives shallower logarithmic inner slopes α of their DM density profiles. The mean value of the slopes of the 26 LITTLE THINGS dwarf galaxies is α = − ± 0.32 0.24 which is in accordance with the previous results found for low surface brightness galaxies (α = − ± 0.2 0.2) as well as the seven THINGS dwarf galaxies (α = − ± 0.29 0.07). However, this significantly deviates from the cusp-like DM distribution predicted by DM-only ΛCDM simulations. Instead our results are more in line with the shallower slopes found in the ΛCDM SPH simulations of dwarf galaxies in which the effect of baryonic feedback processes is included. In addition, we discuss the central DM distribution of DDO 210 whose stellar mass is relatively low in our sample to examine the scenario of inefficient supernova feedback in low mass dwarf galaxies predicted from recent ΛCDM SPH simulations of dwarf galaxies where central cusps still remain.

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Section: Core-like Halo Modelsupporting

confidence: 93%

High-Resolution Mass Models of Dwarf Galaxies From Little Things

et al. 2015

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“…The sample consists of 211 galaxies of different types. We used the following approaches to the DM parameter estimation described in Section 2: (i) -best fit modelling of the rotation curves (Shchelkanova et al 2013, Barnes et al 2004, Kasparova 2012, Chemin et al 2006, van Eymeren et al 2009, Weijmans et al 2008, Spano et al 2008 (iv) -approach based on the spectral energy distribution and longslit spectra modelling (Kasparova et al 2014); (v) -method relying on the marginal gravitational stability of the disc (Shchelkanova et al 2013, Saburova & Zasov 2012); (vi) -approach taking into account the presence of spiral structure (Athanassoula et al 1987); (vii) -method in which the stellar mass-to-light ratio is obtained from the colour index (the so-called "Bottema disc" of de Blok & McGaugh 1997); (viii) -method based on the X-ray properties of hot gas (Humphrey et al 2006); (ix) -Jeans analysis based on planetary nebulae or stellar kinematical data (Napolitano et al 2009, Napolitano et al 2011, Weijmans et al 2009, Frigerio Martins 2009; (x) -modelling reproducing the observed velocity dispersion profiles and number density profiles (Wu 2007). …”

Section: Resultsmentioning

confidence: 99%

On the surface density of dark matter haloes

Saburova

Popolo

2014

Monthly Notices of the Royal Astronomical Society

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In this article, we test the conclusion of Donato et al. (2009) concerning the universality of the DM halo surface density µ 0D = ρ 0 r 0 . According to our study, the dispersion of values of µ 0D is twice higher than that found by Donato et al. (2009). We conclude, in contrast with Donato et al. (2009), that the DM surface density and its Newtonian acceleration are not constant but correlate with the luminosity, morphological type, (B − V ) 0 colour index, and the content of neutral hydrogen. These DM parameters are higher for more luminous systems of early types with red colour and low gas content. We also found that the correlation of DM parameters with colour index appears to be the manifestation of a stronger relation between DM halo mass and the colour of a galaxy. This finding is in agreement with cosmological simulations (Guo et al, 2011). These results leave little room for the recently claimed universality of DM column density. We also found that isolated galaxies in our sample (contained in the Analysis of the interstellar Medium of Isolated GAlaxies (AMIGA) catalogue) do not differ significantly in their value of µ 0D from the entire sample. Thus, since the AMIGA catalogue gives a sample of galaxies that have not interacted with a significant mass neighbour in the past 3 Gyr, the difference between the systems with low and high values of µ 0D is not related to the merging events during this period of time.

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“…Astronomical observations show that the DM galaxy density profiles are cored till scales below the kpc [20][21][22][23][24][25]. On the other hand, N -body CDM simulations exhibit cusped density profiles with a typical 1/r behavior near the galaxy center r = 0.…”

Section: Introductionmentioning

confidence: 99%

Equation of state, universal profiles, scaling and macroscopic quantum effects in warm dark matter galaxies

Vega

Sánchez

2017

Eur. Phys. J. C

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The Thomas-Fermi approach to galaxy structure determines self-consistently and non-linearly the gravitational potential of the fermionic warm dark matter (WDM) particles given their quantum distribution function f (E). This semiclassical framework accounts for the quantum nature and high number of DM particles, properly describing gravitational bounded and quantum macroscopic systems as neutron stars, white dwarfs and WDM galaxies. We express the main galaxy magnitudes as the halo radius r h , mass M h , velocity dispersion and phase space density in terms of the surface density which is important to confront to observations. From these expressions we derive the general equation of state for galaxies, i.e., the relation between pressure and density, and provide its analytic expression. Two regimes clearly show up: (1) Large diluted galaxies for M h 2.3 × 10 6 M and effective temperatures T 0 > 0.017 K described by the classical self-gravitating WDM Boltzman gas with a space-dependent perfect gas equation of state, and (2) Compact dwarf galaxies for 1.6 × 10 6 M M h M h,min 3.10 × 10 4 (2 keV/m) 16 5 M , T 0 < 0.011 K described by the quantum fermionic WDM regime with a steeper equation of state close to the degenerate state. In particular, the T 0 = 0 degenerate or extreme quantum limit yields the most compact and smallest galaxy. In the diluted regime, the halo radius r h , the squared velocity v 2 (r h ) and the temperature T 0 turn to exhibit square-root of M h scaling laws. The normalized density profiles ρ(r )/ρ(0) and the normalized velocity profiles v 2 (r )/v 2 (0) are universal functions of r/r h reflecting the WDM perfect gas behavior in this regime. These theoretical results contrasted to robust and independent sets of galaxy data remarkably reproduce the observations. For the small galaxies, 10 6 M h ≥ M h,min , the equation of state is galaxy mass dependent and the density a e-mail: Norma.Sanchez@obspm.fr and velocity profiles are not anymore universal, accounting to the quantum physics of the self-gravitating WDM fermions in the compact regime (near, but not at, the degenerate state). It would be extremely interesting to dispose of dwarf galaxy observations which could check these quantum effects.

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Non-circular motions and the cusp-core discrepancy in dwarf galaxies

Cited by 38 publications

References 61 publications

High-Resolution Mass Models of Dwarf Galaxies From Little Things

High-Resolution Mass Models of Dwarf Galaxies From Little Things

On the surface density of dark matter haloes

Equation of state, universal profiles, scaling and macroscopic quantum effects in warm dark matter galaxies

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