Kravtsov u chicago d ceverino nmsu
This presentation is the property of its rightful owner.
Sponsored Links
1 / 42

Kravtsov (U.Chicago) D. Ceverino (NMSU) PowerPoint PPT Presentation


  • 53 Views
  • Uploaded on
  • Presentation posted in: General

Galaxy Formation. Kravtsov (U.Chicago) D. Ceverino (NMSU). O. Valenzuela (U.Washington) G. Rhee (UNLV) F. Governato, T.Quinn, G.Stinson (U.Washington) J.Wadsley (McMaster, Canada). Hydrodynamic simulations of galaxies Rotation Curves and ISM of Dwarf Galaxies.

Download Presentation

Kravtsov (U.Chicago) D. Ceverino (NMSU)

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Kravtsov u chicago d ceverino nmsu

Galaxy Formation

  • Kravtsov (U.Chicago)

  • D. Ceverino (NMSU)

O. Valenzuela (U.Washington)

G. Rhee (UNLV)

F. Governato, T.Quinn, G.Stinson (U.Washington)

J.Wadsley (McMaster, Canada)


Kravtsov u chicago d ceverino nmsu

  • Hydrodynamic simulations of galaxies

  • Rotation Curves and ISM of Dwarf Galaxies


Kravtsov u chicago d ceverino nmsu

Numerical simulations: recent progress

  • Stellar Disk and Bulge:

  • is there a thin disk? Is bulge too massive?

  • Angular momentum

  • Tully-Fisher relation

  • Feedback

  • How gas gets to the disk?

  • Mbaryons/Mhalo ratio


Kravtsov u chicago d ceverino nmsu

stars

gas

Robertson et al. 2004

(50.000 DM particles)

Hydrodynamical simulations of galaxy formation in a cosmological context.

Abadi et al 2003

(40.000 DM particles)


A lcdm galaxy at z 0 governato et al 04

A LCDM galaxy at z=0Governato et al 04

N>100.000

Age > 10 Gyr

Age < 10 Gyr

Disk Bulge + Stellar Halo

Only Stars are shown (brighter colors for younger ages) boxes 40 kpc across


Kravtsov u chicago d ceverino nmsu

Increasing Resolution Conserves Angular Momentum in Disks

100.000 DM

10.000 DM

4000 DM

If DM+stellar component not collisionless:

Massive halo particles exchange E and J with disk particles

---> disks heat and lose angular momentum


Kravtsov u chicago d ceverino nmsu

Angular momentum of Stellar Disks

increases with resolution.

Galaxies still too concentrated

Abadi et al. 2003

Governato et al. 2004

(see also Robertson 05 Okamoto 05)

stars


Kravtsov u chicago d ceverino nmsu

Due to sufficient resolution 300pc disks

form with the right angular momentum

High Spin Halo

(0.05)

Vc =170Km/sec

Low Spin Halo

(0.01)

Vc =70Km/sec

Credits: Governato


Kravtsov u chicago d ceverino nmsu

Galaxies too concentrated. B/D 1:3 or higher.

Governato

3 10^12 solar masses

8 10^11 solar masses

Abadi et al 03

Governato et al. 04

Peak velocity higher than in the real Milky Way. No realistic feedback yet!


Kravtsov u chicago d ceverino nmsu

Total Mass 3e12 MsolSpin Parameter = 0.035

Vrot Max 270 Km/sec

Formation time z = 0.75

Last major merger z=3

Frame size ~ 200 Kpc

The Feedback and satellites:

Red: stars

Blue: gas

No Feedback.

UV+SN Feedback


F governato simulations with gasoline

F.Governato: simulations with GASOLINE


F governato simulations with gasoline1

F.Governato: simulations with GASOLINE


How gas gets to the disk

How gas gets to the disk

  • The old picture is wrong: do not even think about spherical accretion and shocking to virial temperature

  • Still not clear what fraction of gas comes with satellites and what comes with filaments


Kravtsov u chicago d ceverino nmsu

Credits: Kravtsov 100pc resolution Z=4

100 kpc scale

Gas density

1 Mpc scale

Tgas


Kravtsov u chicago d ceverino nmsu

350kpc

Z=2.5

40pc resolution. Mvir(z=0)=1.e12Msun. Ndm=400K


Kravtsov u chicago d ceverino nmsu

350kpc

Z=2.5


Kravtsov u chicago d ceverino nmsu

115kpc


Kravtsov u chicago d ceverino nmsu

7kpc


Kravtsov u chicago d ceverino nmsu

7kpc


Isolated galaxies

Isolated galaxies

  • Observations

  • Simulations


Kravtsov u chicago d ceverino nmsu

Simon etal 04: NGC 4605 Vmax =100km/s

-- Usual problems with NFW.

-- Disk is important: normal M/LR=1 M/LK= 0.5

1arcmin


Kravtsov u chicago d ceverino nmsu

Simon etal 04 NGC 4605

Changes in PA and inclination in central 1kpc are consistent with a weak bar

POSS II


Kravtsov u chicago d ceverino nmsu

DDO 47:

Vmax = 80km/s

Distance = 4Mpc

HI is very lumpy

Stellar light does not align with HI


Kravtsov u chicago d ceverino nmsu

Observations:

  • A large fraction of dwarf Galaxies in the central 1kpc has a maximal disk with expected stellar population (judging by colors).

  • Signs of a weak bar are frequent.

  • ISM is very clumpy.


Kravtsov u chicago d ceverino nmsu

Cosmological Simulations: feeback, 300pc resolution …

LMC HI distribution Venn+Stavely Smith 2003)

Multiphase ISM is nicely reproduced

Governato 2004


Kravtsov u chicago d ceverino nmsu

Valenzuela et al 05

Code: GASOLINE

Stars: phase-on

Isolated Galaxy:

NFW halo1-2M particles

Exponential disk 200K particles

Gas100K

Resolution50-100 pc

Star formation, feedback ….

Two simulations:

dwarf: 60km/s

M33-type: 120km/s


Kravtsov u chicago d ceverino nmsu

YoungStars

T<0.5Gyrs

Hot Gas

T=1e5 K

Cold Gas

T<1.5e4

Stars


Kravtsov u chicago d ceverino nmsu

YoungStars

T<0.5Gyrs

Hot Gas

T=1e5 K

Cold Gas

T<1.5e4

Stars


Kravtsov u chicago d ceverino nmsu

  • Cold gas hardly shows any traces of the bar.

  • Filaments and lumps of cold gas

  • Large bubbles filled by 105K gas

  • Stellar feedback feeds the multiphase ISM


Kravtsov u chicago d ceverino nmsu

Rotation Curves:

Cold and Hot gas

Little difference


Kravtsov u chicago d ceverino nmsu

Circular Velocity

Gas Rotation

Asymmetric drift (aka random motions) cannot help to explain why gas rotates too slow

Rms Velocities < 20km/s


Kravtsov u chicago d ceverino nmsu

Recovering total density


Kravtsov u chicago d ceverino nmsu

Another simulation: dwarf 5

Resolution: 60pc

Cold gas

stars

Valenzuela, Rhee, Klypin, Governato et al. 2005

Models of NGC3109 and NGC6822

dm

baryons

Gas rms velocity


Kravtsov u chicago d ceverino nmsu

Cold Gas density in the central 2kpc region:

Clear signs of multiphase medium


Kravtsov u chicago d ceverino nmsu

Stars

Cold/Hot Gas: density

Cold Gas:velocity


Kravtsov u chicago d ceverino nmsu

Observations

Vcirc(total)

NGC 6822

Magellanic-type dwarf irregular

0.5Mpc from Milky Way


Kravtsov u chicago d ceverino nmsu

CONCLUSIONS

  • -In dwarf galaxies gas does not rotates fast enough: Vgas < Vcirc

  • -Non-circular velocities are not large enough to account for the difference

  • -Pressure support from 1e5K gas is one of key ingredients

    Core is ‘observed’ where there is a real cusp.


Kravtsov u chicago d ceverino nmsu

Structure of the ISM at z= 0.5

(several 10^6 particles per halo, gas clouds resolved down to 10^5 solar masses)

Hot Halo (Blue)

Ram Pressure Stripping

Gas Rich Satellites

High Velocity Clouds

Cold Gas in Disks


Kravtsov u chicago d ceverino nmsu

Bars in galaxies:

Simulations with ART and Gadget.

50-100pc resolution

200K disk particles

2M dm particles.

Dt =1e4 yrs


  • Login