Volume 643, November 2020
|Number of page(s)||21|
|Section||Cosmology (including clusters of galaxies)|
|Published online||19 November 2020|
Navarro-Frenk-White dark matter profile and the dark halos around disk systems⋆
SISSA, Via Bonomea 265, 34136 Trieste, Italy
2 Faculty of Physics, Semnan University, Semnan 35131-19111, Iran
e-mail: Razieh-Dehghani@semnan.ac.ir, firstname.lastname@example.org
Accepted: 25 July 2020
Context. The Λ cold dark matter (ΛCDM) scenario is able to describe the Universe at large scales, but clearly shows some serious difficulties at small scales. The core-cusp question is one of these difficulties: the inner dark matter (DM) density profiles of spiral galaxies generally appear to be cored, without the r−1 profile that is predicted by N-body simulations in the above scenario.
Aims. It is well known that in a more physical context, the baryons in the galaxy might backreact and erase the original cusp through supernova explosions. Before the efficiency and the presence of this effect is investigated, it is important to determine how wide and frequent the discrepancy between observed and N-body-predicted profiles is and what its features are.
Methods. We used more than 3200 quite extended rotation curves (RCs) of good quality and high resolution of disk systems that included normal and dwarf spirals as well as low surface brightness galaxies. The curves cover all magnitude ranges. All these RCs were condensed into 26 coadded RCs, each of them built with individual RCs of galaxies of similar luminosity and morphology. We performed mass models of these 26 RCs using the Navarro-Frenk-White (NFW) profile for the contribution of the DM halo to the circular velocity and the exponential Freeman disk for the contribution of the stellar disk.
Results. The fits are generally poor in all the 26 cases: in several cases, we find χred2 > 2. Moreover, the best-fitting values of three parameters of the model (c, MD, and Mvir) combined with those of their 1σ uncertainty clearly contradict well-known expectations of the ΛCDM scenario. We also tested the scaling relations that exist in spirals with the outcome of the current mass modeling: the modeling does not account for these scaling relations.
Conclusions. The results of testing the NFW profile in disk systems indicate that this DM halo density law cannot account for the kinematics of the whole family of disk galaxies. It is therefore mandatory for the success of the ΛCDM scenario in any disk galaxy of any luminosity or maximum rotational velocity to transform initial cusps into the observed cores.
Key words: galaxies: kinematics and dynamics / dark matter
The 26 stacked rotation curves are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/643/A161
© ESO 2020
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.