Clarifying the Role of Thermodynamics in Self-gravitating Dark Matter Systems

Colin Egerer

Abstract


Astrophysicists currently favor the idea that the vast majority of mass in the uni- verse exists in a collisionless form that interacts only through gravity. This paradigm has been successful in allowing computer simulations of cosmological volumes to re- produce structures similar to those observed. Our work aims to better understand the physics at work in collisionless systems, in general. Specifically, we investigate how well thermodynamics-based approaches to understanding equilibrium structures agree with results of computer simulations. Using a suite of N -body simulations with differ- ing initial conditions, we examine the density and velocity profiles of self-gravitating collisionless systems. Statistical comparisons between simulated equilibrium struc- tures and two thermodynamics-based models indicate the relative appropriateness of the models. We find that no single model can describe systems resulting from the entire range of initial conditions investigated here. Our major result is that these thermodynamics-based models can successfully reproduce equilibria that arise in gen- tly evolving systems. However, the failure of thermodynamics-based models to de- scribe the equilibria of more violent evolutions suggests that they must retain some memory of their initial conditions.


Keywords


dark matter, thermodynamics

References


[ 1 ] Barnes, E. I., Williams, L. L. R., Babul, A., Dalcanton, J. J., 2007, The Astrophysical Journal, 655, 847

http://dx.doi.org/10.1086/509871

[ 2 ] Binney, J., Tremaine, S. 1987, Galactic Dynamics, Princeton University Press, Princeton, N.J.

[ 3 ] de Vaucouleurs, G. 1948, Ann. d'Astrophys., 11, 247.

[ 4 ] Governato, F., Brook, C., Mayer, L., Brooks, A., Rhee, G., Wadsley, J., Jonsson, P., Willman, B., Stinson, G., Quinn, T., Madau, P. 2010, Nature, 463, 203.

http://dx.doi.org/10.1038/nature08640

[ 5 ] Kronberger, T., Leubner, M. P., van Kampen, E. 2006, Astronomy & Astrophysics, 453, 21.

http://dx.doi.org/10.1051/0004-6361:20065151

[ 6 ] Lithwick, Y., Dalal, N. 2011, The Astrophysical Journal, 734, 100.

http://dx.doi.org/10.1088/0004-637X/734/2/100

[ 7 ] Lynden-Bell, D., 1967, Monthly Notices of the Royal Astronomical Society, 136, 101.

http://dx.doi.org/10.1093/mnras/136.1.101

[ 8 ] Moore, B., Quinn, T., Governato, F., Stadel, J., Lake, G., 1999, Monthly Notices of the Royal Astronomical Society, 310, 1147.

http://dx.doi.org/10.1046/j.1365-8711.1999.03039.x

[ 9 ] Navarro, J. F., Frenk, C. S., White, S. D. M. 1996, The Astrophysical Journal, 462, 563.

http://dx.doi.org/10.1086/177173

Navarro, J. F., Frenk, C. S., White, S. D. M. 1997, The Astrophysical Journal, 490, 493.

http://dx.doi.org/10.1086/304888

Navarro, J. F., Hayashi, E., Power, C., Jenkins, A. R., Frenk, C. S., White, S. D. M., Springel, V., Stadel, J., Quinn, T. R. 2004, Monthly Notices of the Royal Astronomical Society, 349, 1039.

http://dx.doi.org/10.1111/j.1365-2966.2004.07586.x

Plastino, A. R., Plastino, A. 1993, Physics Letters A, 174, 384.

http://dx.doi.org/10.1016/0375-9601(93)90195-6

Plummer, H. C. 1911, Monthly Notices of the Royal Astronomical Society, 72, 460.

http://dx.doi.org/10.1093/mnras/71.5.460

Springel, V. 2005, Monthly Notices of the Royal Astronomical Society, 364, 1105.

http://dx.doi.org/10.1111/j.1365-2966.2005.09655.x

Taylor, J. E., Navarro, J. F. 2001, The Astrophysical Journal, 563, 483.

http://dx.doi.org/10.1086/324031

Tsallis, C. 1988, Journal of Statistical Physics, 52, 479.

http://dx.doi.org/10.1007/BF01016429

van Albada, T. S. 1982, Monthly Notices of the Royal Astronomical Society, 201, 939.

http://dx.doi.org/10.1093/mnras/201.4.939




DOI: https://doi.org/10.17307/wsc.v1i1.113

Refbacks

  • There are currently no refbacks.


Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.