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PNe as mass tracers Dark-to-luminous properties of early-type galaxies Nicola R. Napolitano Kapteyn Institute Groningen (NL) ESO workshop: PNe beyond the Milky Way. Garching 19-21 May 2004 PNe as mass tracers Dark-to-luminous properties of early-type galaxies Collaborators PN.S Consortium N. Douglas K. Kuijken M. Arnaboldi M. Capaccioli A. Romanowsky M. Merrifield H. Merrett K. Freeman O. Gerhard Kapteyn Institute Un. Leiden INAF-OAT INAF-OAC Un. Nottingham Un. Nottingham Un. Nottingham Mt. Stromlo Un. Basel ESO workshop: PNe beyond the Milky Way. Garching 19-21 May 2004 Observed trends of the M/L in early type galaxies PNe kinematics Inner stellar kinematics (long-slit spectroscopy) When we measure =M/L ratios in galaxies we basicly deal with dark-to-luminous mass distribution At every radius, R, (in B band for example): Mlum MDM LB B Mlum MDM Mlum assuming a radially constant stellar mass-to-light radius, stellar population synthesis models) B R 1 MDM R Mlum R * (from dark-to-luminous mass fraction In presence of a significant(?) dark halo, this quantity must grow with the distance from the center: OK! HOW MUCH in order to be consistent with LCDM(=NFW+cvir)? Can we predict the radial run of the M/L in galaxies? Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Stellar syntesis mod NFW 97 MDM=MDM(Mvir, cvir) cvir 20 Mvir 1011 Msun Hernquist (1990) Mlum=Mlum(Ml,tot,,Re) 0.13 Re 4.5 Bullock et al. (2001) MDM=MDM(Mvir) SF fvir 0.56 kpc Shen et al. (2003) Formation efficiency Ml,tot Ml,tot 1011 Msun Mlum=Mlum(Ml,tot) Mb Mvir Ml,tot 1 SF 1 fb 1 Baryon fraction (CMB) Bennett et al. 2003 Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R esf=0.1 (Padmanabhan et al. 04) esf=0.2 (Fukugita et al. 98) esf=0.6 (Guzik&Seljak 02 Marinoni&Hudson 02) Ml,tot = 1.1x1011Msol M/Ls increase more quickly for decreasing efficiencies and ... Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 1.1x1011Msol Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 1.4x1011Msol Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 5x1011Msol …and M/Ls increase more quickly for increasing masses Are these trends observed in early-type galaxies? Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 5x1011Msol NGC 1399 M/L gradients Predicted M/Ls in LCDM framework esf esf=0.1 esf=0.2 esf=0.6 Log Ml,tot Predicted M/Ls in LCDM framework Gerhard et al. 01 Magorrian&Ballantyne01 Spread distribution esf=0.1 esf=0.2 Plateau esf=0.6 Log Ml,tot Predicted M/Ls in LCDM framework esf=0.1 esf=0.2 esf=0.6 Log Ml,tot Napolitano et al. 2002 Equilibrium? Log Ml,tot Baryon physics in galaxy luminous regions not accounted in simulation [adiabatic collapse (de Jong et al. 2003, Dutton et al. 2003)?]; hydrodynamical simulations (Meza et al. 2003, Wright et al. 2004) found DM not to be dominant up to 5Re in low-luminosity compactwith Inconsistent galaxies esf < 0.6 at 95% s.l. Low concentrations c=5±2 Halo stripping? Log Ml,tot Conclusions We have a “toy-model” to make predictions of the M/L trend in the LCDM framework, to be compared with future PNe observations AND other dynamical tracers (GCs, Xrays, lensing). Thanks to the PN.S statistical samples of PN radial velocities are reaching the precision which will allow to discriminate the efficiency of the baryon cooling in galaxies. We have shown on a sample of 21 galaxies that the M/L gradients by PN and stellar kinematics are generally in agreement with the LCDM expectations with some “critical points”: a) nearly L* galaxies are in conflict with “reasonable” formation efficiency unless we do not assume low-concentration halos (at odd with collisionless LCDM simulations, but qualitatively expected in adiabatic collapse picture); b) low-luminosity/gradients galaxies are tendentially more consistent with very high formation efficiency (esf0.6) while high-luminosity/gradients galaxies are spread on all the range of allowed efficiencies (esf=0.1-0.6). The turn-off point is around Ml,tot =1.2x1011 Msun, i.e. around L* luminosities (MB ~ -20.2). More (accurate) M/L estimates are needed in order to confirm these results…. FUTURE... …The PN Spectrograph Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Precisions of 20% at 5-6 Re in order to discriminate models Such a precisions are expected to be reached with the PN.S Ml,tot = 1.4x1011Msol Dichotomy of ETs in DM properties as well as in luminous properties? Turn-off point MB ~ -20.5 L* galaxies Such a dichotomy is observed in X-ray properties (Pellegrini 1999) faint boxy disky bright core power-law Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R NGC 3379 Ml,tot = 1.1x1011Msol Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 1.4x1011Msol NGC 5128 Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 5x1011Msol NGC 1399 …and M/Ls increase more quickly for increasing masses Are these trends observed in early-type galaxies? Predicted M/Ls in LCDM framework esf=0.1 Spread distribution esf=0.2 Plateau esf=0.6 Log Ml,tot Observed trends of the M/L in early type galaxies M/L “gradients” for systems with PNe kinematics Observed trends of the M/L in early type galaxies M/L “gradients” from PNe kinematics+ systems with extended long-slit spectroscopy (out to 2 Re) PNe have been extensively used in the recent past to constrain the mass distribution in early-type galaxies up to unprecedented distances from the galaxy center Early works were based on poor statistical sample (the reliability of which has been discussed in Napolitano et al. 2001) year 1986 1993 1994 1995 1995 1996 1998 2001 GALAXY M32 N3379 N1399 N5128 N3384 N4406 N1316 N4472 n.PNe 15 29 37 433 68 19 43 24 Rout/Re 6 3.5(6) 5 5 7 3 2.5 5 M/L 6 7 21-45 10 9 13 8 21 M/L* 3 7 9 4 4 8 Recently the improved observation techniques are allowing much larger samples 2001 2003 2003 2003 2004 N4697 N821 N4494 N3379 N5128 535 100 ->150 100 ->250 110 ->300 780 3 5 5 5 15 11 15 6 7 14 9 8 7 4 Observed trends of the M/L in early type galaxies PNe kinematics Inner stellar kinematics (long-slit spectroscopy) Observed trends of the M/L in early type galaxies B /* PNe kinematics Inner stellar kinematics (long-slit spectroscopy) Observed trends of the M/L in early type galaxies B /* In order to improve statistics we have added a sample of ETGs with extended long-slit spectroscopy data Sample of 21 ETGs Observed trends of the M/L in early type galaxies / B/ B*/ ** In order to improve statistics we have added a sample of ETGs with extended long-slit spectroscopy data Sample of 21 ETGs Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 1.1x1011Msol NGC 3379 Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 1.4x1011Msol NGC 5128 Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 5x1011Msol NGC 3379 Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 1.1x1011Msol Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 1.4x1011Msol Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 5x1011Msol Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 1.4x1011Msol * = 3.5 NGC 5128 Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 5x1011Msol * = 9 NGC 1399 Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 1.5x1011Msol * = 7 NGC 3379 Stellar population versus dynamical M/L Predicted M/Ls in LCDM framework Predicted M/Ls in LCDM framework 2 Napolitano et al. 2002 Equilibrium? esf=0.6 esf=0.2 Low concentration c=5±2 esf=0.1 Predicted M/Ls in LCDM framework Star mass following an Hernquist (1990) profile NFW dark halos with concentrations by Bullock et al. (2001) cvir 20 Mvir 1011 Msun 0.13 Luminous mass and dark mass are 1-parameter family models MDM/Mlum is a 2-parameter quantity: total stellar mass, M* , and virial mass, Mvir (or concentration cvir). Predicted M/Ls in LCDM framework B R, R Hernquist (1990) Total stellar mass 1 R MDM Mlum out MDM Mlum virial mass NFW97 profile Shen et al. (2003) cvir 20 Bullock et al. (2001) Mvir 1011 Msun 0.13 Luminous mass and dark mass are 1-parameter family models MDM/Mlum is a 2-parameter quantity: total stellar mass, M* , and virial mass, Mvir (or concentration cvir). in Predicted M/Ls in LCDM framework 1 R B R, R MDM Mlum out MDM Mlum in M* and Mvir are related to the efficiency which the baryons cool in stars with, assuming that the original baryon fraction is the same for all the dark halos and close to the cosmic value from CBM measurements (Bennett et al. 2003) where Star formation efficiency fvir Mvir M 1 SF 1 f bar 1 Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 1.4x1011Msol * = 3.5 NGC 5128 Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 5x1011Msol * = 9 NGC 1399 Predicted M/Ls in LCDM framework B R 1 MDM R Mlum R Ml,tot = 1.5x1011Msol * = 7 NGC 3379