Density profiles of dark matter haloes on galactic and cluster scales

Abstract

Aims. In the present paper, we improve the "extended secondary infall model" (ESIM) of Williams and collaborators to obtain further insights into the cusp/core problem. Methods. A secondary infall model close to the collapse reality is obtained by simultaneously taking into account effects that till now have been studied separately, namely ordered and random angular momentum, dynamical friction, and baryon adiabatic contraction. The model is applied to structures on galactic scales (normal and dwarf spiral galaxies) and on galaxy cluster scales. Results. Our results imply that angular momentum and dynamical friction are able, on galactic scales, of overcoming the competing effect of adiabatic contraction and eliminating the Cusp. The NFW profile is not the standard outcome of the model, and it can be recovered in our model only if the system consists entirely of dark matter and the magnitude of angular momentum and dynamical friction are lower than the values predicted by the model itself. Comparison of the rotation curves of LSB galaxies with the results of our model are in good agreement. On scales smaller than 10 11 h −1 M , the slope is α 0, and on cluster scales we observe a similar evolution in the dark matter density profile but in this case the density profile slope flattens to α 0.7 for a cluster of 10 14 h −1 M . The total mass profile differs from that of dark matter showing a central cusp that is reproduced by a NFW model.

Constraining Satellite Galaxy Stellar Mass Loss and Predicting Intrahalo Light. I. Framework and Results at Low Redshift

“…It is important to note that the Z05 prescription for mass loss does not include the effects that baryons can have on dark matter. Adiabatic Contraction (AC; Blumenthal et al 1986;Ryden & Gunn 1987;Gnedin et al 2004) may increase the central density as the gas condenses and sinks to the center of the dark matter potential well (Diemand et al 2004;Fukushige et al 2004;Reed et al 2005;Del Popolo & Kroupa 2009). Conversely, processes during halo formation, such as gravitational heating from merger events, can counteract AC (e.g., Zappacosta et al 2006) and, in fact, the central density may decrease through baryonic feedback (Governato et al 2012).…”

On the Mass Dependence of the Inner Slopes of Dark Matter Density Profiles

“…A noteworthy discrepancy is that between the cuspy density profiles of dark matter (DM) halos obtained in simulations (e.g., Navarro, Frenk & White 1996;Navarro 2010), and the flat density profiles of dwarf galaxies and LSBs (Low Surface Brightness galaxies) (Burkert 1995;de Blok et al 2003;Del Popolo 2009 (DP09); Del Popolo & Kroupa (2009);Del Popolo 2012a,b (DP12a, DP12b); Del Popolo, Cardone & Belvedere 2013;Cardone & Del Popolo 2012;Del Popolo & Hiotelis 2014;Oh et al 2010Oh et al , 2011Kuzio de Naray & Kaufmann 2011). This discrepancy is known as Cusp/Core problem (see de Blok 2010).…”

Improvements in the Spherical Collapse Model and Dark Energy Cosmologies

“…A popular analytical approach to study the non-linear evolution of perturbations of dark matter (in the presence of a non-clustered dark energy (DE)) is the standard spherical collapse model (SSCM) proposed in the seminal paper of Gunn & Gott (1972) and extended in subsequent papers (Ryden & Gunn 1987;Gurevich & Zybin 1988a,b;White & Zaritsky 1992;Sikivie et al 1997;Le Delliou & Henriksen 2003;Williams et al 2004;Basilakos et al 2010;Del Popolo & Kroupa 2009;Cardone et al 2011a,b;Del Popolo 2012a,b. ).…”