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ON THE RELATION BETWEEN CIRCULAR VELOCITY AND CENTRAL VELOCITY DISPERSION IN HSB AND LSB GALAXIES

ON THE RELATION BETWEEN CIRCULAR VELOCITY AND CENTRAL VELOCITY DISPERSION IN HSB AND LSB GALAXIES. E . M . Corsini , A. Pizzella, E. Dalla Bont à, F.Bertola Dipartimento di Astronomia, Università di Padova , Italy L. Coccato Kapteyn Astronomical Institute, Groningen, The Netherlands

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ON THE RELATION BETWEEN CIRCULAR VELOCITY AND CENTRAL VELOCITY DISPERSION IN HSB AND LSB GALAXIES

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  1. ON THE RELATION BETWEEN CIRCULAR VELOCITY AND CENTRAL VELOCITY DISPERSION IN HSB AND LSB GALAXIES E.M. Corsini, A. Pizzella, E. Dalla Bontà, F.Bertola Dipartimento di Astronomia, Università di Padova, Italy L. Coccato Kapteyn Astronomical Institute, Groningen, The Netherlands M. Sarzi Physics Department, University of Oxford, UK

  2. Introduction  A possible relation between bulge c and disk Vc was found by Whitmore et al. (1979) studying a sample of spiral galaxies. They inferred from Vc / c  1.7 that halo and bulge are dynamically separate components.

  3. Whitmore et al. 1979

  4. Introduction  A possible relation between bulge c and disk Vc was found by Whitmore et al. (1979) studying a sample of spiral galaxies. They inferred from Vc / c  1.7 that halo and bulge are dynamically separate components.  Gerhard et al. (2001) derived the Vc- c relation for a sample of giant, nearly round and almost non-rotating ellipticals. It was explained as an indication of near dynamical homology of these galaxies,

  5. Gerhard et al. 2001

  6. Introduction  A possible relation between bulge c and disk Vc was found by Whitmore et al. (1979) studying a sample of spiral galaxies. They inferred from Vc / c  1.7 that halo and bulge are dynamically separate components.  Gerhard et al. (2001) derived the Vc- c relation for a sample of giant, nearly round and almost non-rotating ellipticals. It was explained as an indication of near dynamical homology of these galaxies.  Ferrarese (2002) and Baes et al. (2003) found that ellipticals and spirals define a common Vc- c relation. It was interpreted as a relation between the mass of the DM halo and SMBH.

  7. ellipticals spirals Ferrarese 2002

  8. Sample selection We enlarged the sample so far studied, namely 38 Sa-Scd = Ferrarese 2002; optical/HI RC’s from literature12 Sb-Sc = Baes et al. 2003; optical RC’s20 E0-E2 = Kronawitter et al. 2000; stellar dynamicsby including17 S0/a-Sab = Corsini et al. 1999, 2003; optical RC’s33 Sb-Sbc = Vega et al. 2001; Pizzella et al. 2004; optical RC’s11 LSB Sa-Sc = Pizzella et al. 2005; optical RC’s5 E’s = Bertola et al. 1993; HI RC’s from literature

  9. NGC6925 HSB Sbc Pizzella et al. 2004

  10. ESO206-G14 LSB Sc Pizzella et al. 2005

  11. Measuring Vc • E’s: from either the flat part of HI RC or dynamical modeling to test against model-depend biases HSB/LSB’s: from the flat part of gas RC V(R) = A R + B with |A|  2 km s-1 kpc-1 for R  0.35 R25 instead of Vc = V(Rlast) with Rlast R25

  12. warped rising asymmetric not extended Corsini et al. 2003

  13. Pizzella et al. 2005

  14. Measuring c • E’s: from aperture measurements of the stellar velocity dispersion corrected to re/8  HSB/LSB’s: from stellar velocity dispersion profile with no aperture correction

  15. Pizzella et al. 2004

  16. The Vc-c relation for HSB’s and E’s The sample consists of  40 HSB spirals(Rlast 0.8 R25 )  24 ellipticals 19 = Vc from stellar dynamics (Rlast 0.5 R25 ) 5 = Vc from HI kinematics (Rlast 3 R25 )We fitted a straight line to the data of HSB’s and E’s taking into account the errors on Vc and c

  17. ellipticals HI ellipticals HSB spirals

  18. The MBH - MDMrelation  c is related to MBH according to the MBH - c relation (Ferrarese & Ford 2004)Vc is related to MDM since Vc correlates with Vvir (e.g., Vc / Vvir = 1.8, Seljak 2002) and Vvir determines MDM (e.g., Bullock et al. 2001)

  19. the Vc- c relation translates into aMBH - MDMrelationwith some caveatsMBH- c for spirals  MBH- c extrapolation to c  50 km/s uncertainties in the MDM - Vc conversion

  20. The Vc-c relation for LSB’s The sample consists of 8 LSB spirals (Rlast 1.2 R25 ) According to KS test the distribution of normalized scatter of LSB’s is different from that of HSB’s and E’s. We fitted a straight line to the data of LSB’s taking into account the errors on Vc and c

  21. ellipticals HI ellipticals HSB spirals

  22. ellipticals HI ellipticals HSB spirals LSB spirals

  23. Conclusions Vc -c relation for 40 HSB’s, 24 E’s, and 8 LSB’s with flat RC’s. Vc -c relation for HSB’s is linear out to c  50 km/s.E’s with Vc based on dynamical models or directly derived from from HI RC’s follow the same relation as HSB’s. LSB’s follow a different Vc- c relation. This suggests that DM halos of LSB’s host smaller SMBH’s and were less affected by baryon collapse with respect to their HSB counterparts.

  24. Pizzella et al. 2005

  25. HI optical Ferrarese 2002

  26. ellipticals HI ellipticals HSB spirals

  27. ellipticals HI ellipticals HSB spirals LSB spirals

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