pne as mass tracers dark-to-luminous properties of early-type galaxies nicola r. napolitano kapteyn...

PNe as mass tracersDark-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

Collaborators N. Douglas Kapteyn InstitutePN.S Consortium K. Kuijken Un. Leiden

M. Arnaboldi INAF-OATM. Capaccioli INAF-OACA. Romanowsky Un. NottinghamM. Merrifield Un. NottinghamH. Merrett Un. NottinghamK. Freeman Mt. StromloO. Gerhard Un. Basel

PNe as mass tracersDark-to-luminous properties of early-type

galaxies

ESO workshop: PNe beyond the Milky Way. Garching 19-21 May 2004

Observed trends of the M/L in early type galaxies

Inner stellar kinematics(long-slit spectroscopy)

PNe kinematics

When we measure =M/L ratios in galaxies we basicly deal withdark-to-luminous mass distribution

B Mlum MDM

LB Mlum MDM

Mlum

assuming a radially constant stellar mass-to-light radius, * (from

stellar population synthesis models)

At every radius, R, (in B band for example):

BR

1 MDMRMlumRdark-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 CDM(=NFW+cvir)?

Can we predict the radial run of the M/L in galaxies?

BR

1 MDMRMlumR

NFW 97MDM=MDM(Mvir, cvir)

Hernquist (1990)Mlum=Mlum(Ml,tot,,Re)

MDM=MDM(Mvir) Mlum=Mlum(Ml,tot)

Stellar syntesis mod

Shen et al. (2003)Shen et al. (2003)

cvir20Mvir1011Msun

0.13Bullock et al. (2001)Bullock et al. (2001)

Predicted M/Ls in CDM framework

fb1

Mtot

Mb Mb MDM

Mb1

SFMvirMl,tot

fvir MvirMl,tot

1

SF1fb

1Ml,tot SFMb

Formation efficiencyFormation efficiency

Baryon fraction (CMB)Baryon fraction (CMB)Bennett et al. 2003Bennett et al. 2003

Re4.5Ml,tot1011Msun

0.56 kpc


BR

1 MDMRMlumR

Ml,tot = 1.1x1011Msol

sf=0.1 (Padmanabhan et al. 04)sf=0.2 (Fukugita et al. 98)sf=0.6 (Guzik&Seljak 02 Marinoni&Hudson 02)

M/Ls increase more quickly for decreasing efficiencies and ...

MA

SS


BR

1 MDMRMlumR



BR

1 MDMRMlumR

Ml,tot = 5x1011Msol

MA

SS

…and M/Ls increase more quickly for increasing masses Are these trends observed in early-type galaxies?


BR

1 MDMRMlumR

Ml,tot = 5x1011Msol

MA

SSNGC 1399

BR

out in

Rout Rin

M/L gradients


Log Ml,tot

sf=0.6

sf=0.2

sf=0.1

sf

M/L

gra

die

nts

sf=0.6

sf=0.2

sf=0.1


Log Ml,tot

Plateau

Spread distribution

Gerhard et al. 01 Magorrian&Ballantyne01

sf=0.6

sf=0.2

sf=0.1


Log Ml,tot

Napolitano et al. 2002

Equilibrium?

Log Ml,tot

Inconsistent withsf < 0.6 at 95% s.l.

Low concentrationsc=5±2

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 compact galaxies

Halo stripping?

ConclusionsWe have a “toy-model” to make predictions of the M/L trend in the CDM 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 CDM 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 CDM simulations, but qualitatively expected in adiabatic collapse picture);

b) low-luminosity/gradients galaxies are tendentially more consistent with very high formation efficiency (sf0.6) while high-luminosity/gradients galaxies are spread on all the range of allowed efficiencies (sf=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


BR

1 MDMRMlumR


Precisions of 20% at 5-6 Re in order to discriminate modelsSuch a precisions are expected to be reached with the PN.S

Dichotomy of ETs in DM properties as well as in luminous properties?

faint bright

boxy disky core power-law

Such a dichotomy is observed in X-ray properties(Pellegrini 1999)

Turn-off pointMB ~ -20.5L* galaxies

MA

SS


BR

1 MDMRMlumR

Ml,tot = 1.1x1011MsolNGC 3379

MA

SS


BR

1 MDMRMlumR


NGC 5128


BR

1 MDMRMlumR

Ml,tot = 5x1011Msol

MA

SSNGC 1399

…and M/Ls increase more quickly for increasing masses Are these trends observed in early-type galaxies?

sf=0.6

sf=0.2

sf=0.1


Log Ml,tot

Plateau

Spread distribution

gra

die

nts


M/L “gradients” for systems with PNe

kinematics

gra

die

nts


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 GALAXY n.PNe Rout/Re M/LM/L*

1986 M32 15 6 6 31993 N3379 29 3.5(6) 7 71994 N1399 37 5 21-45 91995 N5128 433 5 10 41995 N3384 68 7 9 -1996 N4406 19 3 13 -1998 N1316 43 2.5 8 42001 N4472 24 5 21 8Recently the improved observation techniques are allowing much larger samples

2001 N4697 535 3 11 92003 N821 100 ->150 5 15 82003 N4494 100 ->250 5 6 -2003 N3379 110 ->300 5 7 72004 N5128 780 15 14 4



PNe kinematics

B /

*



PNe kinematics


Sample of 21 ETGs

In order to improve statisticswe have added a sample of ETGs with extended long-slit

spectroscopy data

B /

*

B/

* B

/*

/ *


Sample of 21 ETGs

In order to improve statisticswe have added a sample of ETGs with extended long-slit

spectroscopy data

MA

SS


BR

1 MDMRMlumR


NGC 3379

MA

SS


BR

1 MDMRMlumR


NGC 5128


BR

1 MDMRMlumR

Ml,tot = 5x1011Msol

MA

SSNGC 3379

MA

SS


BR

1 MDMRMlumR



BR

1 MDMRMlumR

Ml,tot = 5x1011Msol

MA

SS


BR

1 MDMRMlumR

NGC 5128


* = 3.5


BR

1 MDMRMlumR

NGC 1399

Ml,tot = 5x1011Msol

* = 9


BR

1 MDMRMlumR

NGC 3379


* = 7

Stellar population versus dynamical M/L

Napolitano et al. 2002

Equilibrium?

Low concentrationc=5±2

2

sf=0.1sf=0.2sf=0.6

NFWrsrrs1 rrs2

Mvir

4 Acvir1r1 r2

Acvir ln1 cvir cvir1 cvir

lumrM

2

0.55 Re

rr 0.55 Re3 Re4.5 M0.56

cvir20Mvir1011Msun

0.13


Star mass following an Hernquist (1990) profile

NFW dark halos with concentrations by Bullock et al. (2001)

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).

NFWrsrrs1 rrs2

Mvir

4 Acvir1r1 r2

Acvir ln1 cvir cvir1 cvir

lumrM

2

0.55 Re

rr 0.55 Re3Re4.5 M

0.56

cvir20Mvir1011Msun

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).

R, B

R

1RMDM

Mlumout

MDMMlumin

Hernquist (1990)

NFW97 profileShen et al. (2003)

Bullock et al. (2001)

Total stellar mass virial mass

M SFMbar

fbar1

Mtot

Mbar Mbar MDM

Mbar1

SFMvirM

fvir MvirM

1

SF1fbar

1


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 halosand close to the cosmic value from CBM measurements (Bennett et al. 2003)

where

Star formation efficiency

R, B

R

1RMDM

Mlumout

MDMMlumin


BR

1 MDMRMlumR

NGC 5128


* = 3.5


BR

1 MDMRMlumR

NGC 1399

Ml,tot = 5x1011Msol

* = 9


BR

1 MDMRMlumR

NGC 3379


* = 7

pne as mass tracers dark-to-luminous properties of early-type galaxies nicola r. napolitano kapteyn...

Documents

lcdm frameworkml

lcdm frameworklog

lcdm expectations

1x1011msolmasspredicted

4x1011msolpredicted

gradientspredicted mls

5x1011msolmassand mls

magorrianballantyne01