The cored distribution of dark matter in spiral galaxies

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Gentile, G. ; Salucci, P. ; Klein, U. ; Vergani, D. ; Kalberla, P. (2004)

We present the HI data for 5 spiral galaxies that, along with their Halpha rotation curves, are used to derive the distribution of dark matter within these objects. A new method for extracting rotation curves from HI data cubes is presented; this takes into account the existence of a warp and minimises projection effects. The rotation curves obtained are tested by taking them as input to construct model data cubes that are compared to the observed ones: the agreement is excellent. On the contrary, the model data cubes built using rotation curves obtained with standard methods, such as the first-moment analysis, fail the test. The HI rotation curves agree well with the Halpha data, where they coexist. Moreover, the combined Halpha + HI rotation curves are smooth, symmetric and extended to large radii. The rotation curves are decomposed into stellar, gaseous and dark matter contributions and the inferred density distribution is compared to various mass distributions: dark haloes with a central density core, $\Lambda$ Cold Dark Matter ($\Lambda$CDM) haloes (NFW, Moore profiles), HI scaling and MOND. The observations point to haloes with constant density cores of size $r_{core} \sim r_{opt}$ and central densities scaling approximately as $\rho_0 \propto r_{core}^{-2/3}$. $\Lambda$CDM models (which predict a central cusp in the density profile) are in clear conflict with the data. HI scaling and MOND cannot account for the observed kinematics: we find some counter-examples.
  • References (35)
    35 references, page 1 of 4

    Begeman, K. G., 1989, A&A, 223, 47 Begeman, K. G., Broeils, A. H., Sanders, R. H., 1991, MNRAS, 249, 523

    Bell, E. F., de Jong, R. S., 2001, ApJ, 550, 212 Borriello, A., Salucci, P., 2001, MNRAS, 323, 285 Bosma, A., 1981, AJ, 86, 1825

    Braun, R., 1997, ApJ, 484, 637

    Briggs, D., 1995, Ph.D. thesis, New Mexico Inst. Mining and Technology

    Bullock, J.S., Kolatt, T.S., Rachel, Y.S., Somerville, S., Kravtsov, A.V., Klypin, A.A., Primack, J.R., Dekel, A., 2001, MNRAS, 321, 559

    Burkert, A., 1995, ApJ, 447, L25

    Burkert, A., Silk, J., 1997, ApJ, 488, L55 Chengalur, J. N., Salpeter, E. E., Terzian, Y., 1993, ApJ, 419, 30

    Corbelli, E., Salucci, P., 2000, MNRAS, 311, 441 de Blok, W. J. G., McGaugh, S. S., Rubin, V. C., 2001, AJ, 122, 2396

    de Blok, W. J. G., Bosma, A., 2002, A&A, 385, 816 de Blok, W. J. G., Bosma, A., McGaugh, S., 2003, MNRAS, 340, 657

    Flores, R., Primack, J.R., 1994, ApJ, 427, L1 Fraternali, F., Oosterloo, T., Sancisi, R., van Moorsel, G., 2002, ApJ, 562, L47

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