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Do planetary nebulae indicate a lack of dark matter in elliptical galaxies?

Do planetary nebulae indicate a lack of dark matter in elliptical galaxies?. Are PNe in ellipticals young ?. with Avishai DEKEL ( HU, Jerusalem ), Felix STOEHR ( IAP, Paris ), TJ COX ( Harvard ), Greg NOVAK & Joel PRIMACK ( UC Santa Cruz ) Nature , accepted, astro-ph/0501622. and

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Do planetary nebulae indicate a lack of dark matter in elliptical galaxies?

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  1. Do planetary nebulae indicate a lack of dark matterin elliptical galaxies? Are PNe in ellipticals young? with Avishai DEKEL (HU,Jerusalem), Felix STOEHR (IAP,Paris), TJ COX (Harvard), Greg NOVAK & Joel PRIMACK (UC Santa Cruz) Nature, accepted, astro-ph/0501622 and Ewa ŁOKAS (CAMK, Warsaw) MNRAS, submitted, astro-ph/0405491

  2. Planetary Nebulae: Tracers at 1-3Reff [OIII] 5007 A N3379

  3. PN velocity dispersions are low Romanowsky et al. 03 DM no DM DM no DM DM no DM Mendez et al. 01 N4697 are Ellipticals naked?

  4. Predicted & observed M/L 3 M/L = 33? Romanowsky et al 03 Marinoni & Hudson 02 critical density Universe universal M/L=387 log (M/L)/(M/Lsun) log L/Lsun

  5. 1) Do ellipticals have normal contents of dark matter? ellipticals thought to be formed by mergers, mainly of spirals Toomre 77 Mamon 92, 00; Helsdon & Ponman 03 Springel et al. 01; Lanzoni et al. 05 Sofue & Rubin 02 spirals have dark matter halos

  6. Simulations of major mergers of spiral galaxies embedded in dark matter halos Cox 04, PhD thesis

  7. Velocity dispersions Dekel et al 05 DM with DM (R03) all stars young stars no DM (R03)

  8. 2) What causes this discrepancybetween kinematical & dynamical modelling? kinematical modelling  no dark matter dynamical modelling  normal dark matter

  9. Power-law solutions to Jeans equations Jeans eq. Dekel et al. 05, Nature in press

  10. Power-law solutions to Jeans equations (2) tracer density slope realistic outer slopes:+> 5 or los  = tracer density slope  = dark matter density slope velocity anisotropy

  11. Velocity dispersion vs anisotropy & dark halo model Mamon & Łokas 05b, MNRAS subm @ 2 Re isotropic Navarro+04 isotropic NFW anisotropic Navarro+04 @ 5 Re

  12. Effects on M/L at virial radius Mamon & Łokas 05b, MNRAS submitted

  13. 3D profiles from merger simulations

  14. Out of Jeans equilibrium? out of equilibrium! mass underestimated by ≈ 40% non-stationarity? non-sphericity

  15. Effects of triaxiality face-on edge-on edge-on face-on

  16. best concentration parameters Published M/L What M/Ls were found by Romanowsky et al. 03? Mamon & Łokas 05b, MNRAS submitted fbary > b/ m

  17. 3) Are observed PNe in ellipticalsyoung?

  18. Young stars have lower velocity dispersions Dekel et al 05 DM with DM (R03) all stars young stars no DM (R03)

  19. 4th order (h4) moments = all stars = young stars outer radii intermediate radii young stars have large |h4| as PNe in galaxies appear to

  20. PNe vs old globular clusters GCs have much higher outer velocity dispersions! Bergond, Zepf et al. 05 but GC < stars stars Côté et al. 01 GCs M87

  21. Marigo et al. 04 Mendez et al. 01 NGC 4697 PN luminosity function young ( 0.8 Gyr) PNe

  22. Alternative: • gas-rich dark dwarfs fall onto ellipticals, • tidal compression  smooth accretion star formation universal rate Possible solutions for young bright PNe in ellipticals } very low recent star formation in ellipticals universal PNLF (Es & SMC) Ciardullo et al. 89 young PNe? no recent major mergers One solution: blue stragglersCiardullo et al. 05 sufficient bright PN formation with low enough star formation?

  23. consistent with CDM scenario (weakly) favors young PNe accretion? Conclusions Merger simulations of spirals embedded in DM yield remnants that reproduce low PN vel. dispersions Low velocity dispersion produced by: radial anisotropy steep tracer density viewing oblate ellipticals face-on Spherical kinematical modelling is not fully adequate Kinematics of young stars in merger remnants

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