J/A+A/643/A161 Coadded rotation curves of disk galaxies (Dehghani+, 2020)
Navarro-Frenk-White dark matter profile and the dark halos around disk systems.
Dehghani R., Salucci P., Ghaffarnejad H.
<Astron. Astrophys. 643, A161 (2020)>
=2020A&A...643A.161D 2020A&A...643A.161D (SIMBAD/NED BibCode)
ADC_Keywords: Models ; Galaxies, rotation ; Rotational velocities
Keywords: galaxies: kinematics and dynamics - dark matter
Abstract:
The Lambda-cold dark matter (Lambda CDM) scenario is able to describe
the Universe at large scales, but clearly shows some serious
difficulties at small scales. The core/cusp issue is one of those: as
a fact, the inner dark matter (DM) density profiles of spiral galaxies
generally appear to be cored, without the r-1 profile as predicted
by N-body simulations in the above scenario.
It is well known that, in a more physical context, the baryons in the
galaxy, through supernovae explosions could back react and erase the
original cusp. Before investigating the efficiency and the presence of
such effect, it is important to know how wide and how frequent the
discrepancy between observed and N-body predicted profiles is and what
its features are.
We use more than 3200 good quality and high resolution, quite extended
rotation curves (RCs) of disk systems including normal and dwarf
spirals as well as low surface brightness galaxies covering their
whole ranges of magnitudes. All these RCs are condensed in 26 coadded
RCs, each of them built with individual RCs of galaxies of similar
luminosity and morphology. We mass model these 26 RCs using the NFW
profile for the contribution of the DM halo to the circular velocity
and the exponential Freeman disk for that of the stellar disk.
The fits are generally poor in all the 26 cases: in several cases we
find chi2red> 2. Moreover, the best fitting values of three
parameters of the model (c, MD, M{vir}) combined with those of
their 1-sigma uncertainty show clear conflict with well-known
expectations of Lambda-CDM scenario. We also test the scaling
relations which exist in spirals with the outcome of the current mass
modelling: the latter is found not to account for such scaling
relations.
The results of testing NFW profile in disk systems indicate that such
DM halo density law cannot account for the kinematics of the whole
family of disk galaxies. The need of transforming initial cusps in the
observed cores is therefore mandatory for the success of the
Lambda-CDM scenario, in any disk galaxy of any luminosity or maximum
rotational velocity.
Description:
Throughout this work, we obtained the mass modeling of 26 coadded RCs
which includes the disk and halo components and discuss their
implications, in particular the implications from the resulting
best-fitting values of the model-free parameters, MD; Mvir and c.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 14 26 Bins information
table2.dat 54 543 Coadded rotation curves and their relevant
quantities
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- j [1/26] Index of velocity bins (j)
4- 6 I3 km/s Vopt [40/330] Optical velocity (Vj,opt)
8- 11 F4.1 km/s Ropt [2.5/29.1] Optical radius (Rj,opt)
13- 14 I2 --- N [9/30] Number of data in each bin
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- j [1/26] Index of velocity bins (j)
4- 6 I3 km/s Vopt [40/330] Optical velocity (Vj,opt)
8- 11 F4.1 km/s Ropt [2.5/29.1] Optical radius (Rj,opt)
13- 14 I2 --- N [9/30] Number of data in each bin
16- 27 F12.9 kpc R [0.275/46.528] Physical radius
29- 41 F13.9 km/s V(R) [7.2822/335.346] Physical velocity
43- 54 F12.9 km/s e_V(R) [0.36/24.552] rms uncertainty on V(R) (dV)
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Acknowledgements:
Razieh Dehghani, dehghani.r66(at)gmail.com
(End) Patricia Vannier [CDS] 10-Aug-2020