Dimitri Gadotti(Max Planck Institute for Astrophysics – Garching)

MAGPOP Network Meeting

What can we learn from imaging and spectroscopy of well-resolved galaxies?

1. The BUDDA code:

- from bulge/disk decomposition to multi-component decomposition

2. Dating secular evolution:

- the ages of bars

3. On bars and haloes:

- inferring halo properties from bar properties

The BUDDA Code(de Souza, Gadotti & dos Anjos 2004)

• BUlge/Disk Decomposition Analysis (http://www.mpa-garching.mpg.de/~dimitri/budda.html)

• 2D (Image Fitting)• reliable results (de Jong 1995) for galaxies with different components (constraints from PA and ellipticity)• discrepancies among 1D fits can be as large as 100% (Baggett, Baggett & Anderson 1998)

• Bulge (Sérsic 1968)

• Disk (Freeman 1970)

• Residual Images (sub-structures)

Dimitri Gadotti (MPA – Garching)

A Structural Analysis of 51 Early-Type Galaxies

• R-band images

• Structural parameters

• Inner disks in ~ 1/3 of Es• merger signature (see Burstein et al. 2001)?

direct image residual image

NGC 1052 (E4 – Sey2)

Dimitri Gadotti (MPA – Garching)

IC 1459

direct image

residual image

A Structural Analysis of 51 Early-Type Galaxies

• Classified as E3 (RC3) but has a disk! It’s an S0! Also a LINER…

• Wrong morphological classification in ~ 1/3 of Es and S0s

Dimitri Gadotti (MPA – Garching)

NGC 1291

Residual Images and Sub-StructuresN

GC

22

17NGC 4314 (B band – Steward Obs.)

(Gadotti & de Souza 2006)

NG

C 5850 (K

s – Kitt Peak)

(Gadotti &

de Souza 2005, 2006)

Dimitri Gadotti (MPA – Garching)

Residual Images and Sub-Structures

Dimitri Gadotti (MPA – Garching)

The New BUDDA:Generalized Ellipses

Pure Boxy

Disky

(e.g., Athanassoula et al. 1990)

• Boxy Es emit strongly in radio/X-ray, are more luminous & massive, and show slow rotation compared to disky Es (e.g., Bender et al. 1989)

• Different formation histories (Naab & Burkert 2003)?

Dimitri Gadotti (MPA – Garching)

The New BUDDA:Edge-on Disks

van der Kruit & Searle (1981)

Dimitri Gadotti (MPA – Garching)

The New BUDDA:Double Exponential Disks

• Truncation (Freeman 1970 type II - e.g., Pohlen 2002)

• Anti-truncation (Erwin, Beckman & Pohlen 2005)

Origin: bars, spirals, interactions…???

?3-5 h0 3-5 h0

Dimitri Gadotti (MPA – Garching)

The New BUDDA:Four Components

• Central Source• Moffat (1969) profile: fits better seeing effects (see Trujillo et al. 2001a,b)

• Bar• Sérsic profile• n=1: late-type bars• n=0.5-1: early-type bars

Dimitri Gadotti (MPA – Garching)

The New BUDDA:Four Components

AGN

DiskBar

Bulge

Dimitri Gadotti (MPA – Garching)

Dimitri Gadotti (MPA – Garching)

Bars and Secular Evolution

Bars are to a large extent shaping the physical properties of galaxies (see Kormendy & Kennicutt 2004):

- creating rings & spirals arms

- attenuating metallicity & color gradients

- fueling AGN & central star formation

- building bulges

Questions

- When did the first bars appear?

- How fast bars drive gas to the center?

- For how long a bar modifies the evolution of its host galaxy?

- What is the fraction of pseudo-bulge stars?

- Are bars really recurrent?

Dimitri Gadotti (MPA – Garching)

Estimating the Ages of Bars(see Gadotti & de Souza 2005)

y

xσz

- Thin bars ↔ recently-formed; thick bars ↔ evolved

- Measure the stellar vertical velocity dispersion

Dimitri Gadotti (MPA – Garching)

Spectroscopy

- 14 face-on barred galaxies: Kitt Peak (2.3m) & La Silla (1.5m)- Diversified sample: morphology, AGN and environment

Dimitri Gadotti (MPA – Garching)

Espectros

NGC 4608

NGC 5850

NGC 4394

NGC 4579

Gauss-Hermite series (van der Marel & Franx 93)

K0III stars

Determining the LOSVDs

Dimitri Gadotti (MPA – Garching)

Radial Profiles of σz

r

σz

r

σz

Young bar

Old bar

Central drop in σz (inner disk?)

Dimitri Gadotti (MPA – Garching)

Clear Cases

Dimitri Gadotti (MPA – Garching)

Let’s Quantify

- σZ,bar: at 50%-60% of bar semi-major length

σZ: difference to σZ in the disk at same distance

- Young bars: σZ,bar ~ 30 Km/s and σZ ~ 5 Km/s

- Old bars: σZ,bar ~ 100 Km/s and σZ ~ 40 Km/s

- Statistical tests indicate different populations at the 98% confidence level

Dimitri Gadotti (MPA – Garching)

Some Results

- AGN activity seems to be found preferentially in young bars (timescale for AGN fueling is short):- 2/8 (25%) of old bars have AGN, but 3/5 (60%) of young bars

show activity- Better bar x AGN correlation with young bars!

- Bar recurrence may be more frequent in late-type galaxies:- 7/8 (88%) of old bars are early-type, but only 2/5 (40%) of

young bars are early-type

Dimitri Gadotti (MPA – Garching)

On Bars and Haloes

• Previous studies concluded that haloes are against bars (Ostriker & Peebles 1973)

• Using live haloes the truth is the opposite (Athanassoula & Misiriotis 2002; see also Athanassoula 2003)!

• Angular momentum transfer between halo and disk makes stronger bars• Depends on halo properties like mass and velocity distribution

MH | MD

Dimitri Gadotti (MPA – Garching)

On Bars and Haloes

J and Ks near-infrared observations at the Cananea 2.1-m telescope

• Compare the properties of N-body models and real barred galaxies

N-body simulations

MH | MD

Dimitri Gadotti (MPA – Garching)

On Bars and Haloes

MH | MD

N-body simulations

Dimitri Gadotti (MPA – Garching)

On Bars and Haloes

MH | MD

Real galaxies

Dimitri Gadotti (MPA – Garching)

On Bars and Haloes

Real galaxies N-body simulations

Dimitri Gadotti (MPA – Garching)