Chania, Crete, August 2004 “The environment of galaxies”

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Chania, Crete, August 2004 “The environment of galaxies” Pierre-Alain Duc Recycling in the galaxy environme F. Bournaud J. Braine U. Lisenfeld P. Amram P. Weilbacher

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Pierre-Alain Duc Recycling in the galaxy environment. F. Bournaud J. Braine U. Lisenfeld P. Amram P. Weilbacher. Chania, Crete, August 2004 “The environment of galaxies”. Looking between galaxies…. @ Gregg & West. Stars in the intracluster medium. Diffuse light - PowerPoint PPT Presentation

Transcript of Chania, Crete, August 2004 “The environment of galaxies”

Page 1: Chania, Crete, August 2004 “The environment of galaxies”

Chania, Crete, August 2004“The environment of galaxies”

Pierre-Alain DucRecycling in the galaxy environment

F. BournaudJ. BraineU. LisenfeldP. AmramP. Weilbacher

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

@ Gregg & West

Looking between galaxies…Looking between galaxies…

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

Gregg & West, 1998

•Diffuse lightStreams, filaments revealed by deep imaging

•Resolved stellar populationsGiant red stars (HST detections) Planetary nebulae (Narrow-band optical images;Spectroscopic confirmation) ULXs, Supernovae

Stars in the intracluster mediumStars in the intracluster medium

Arnaboldi et al., 2002

Between 10 and 50% (20%) of the stellar mass in the ICM

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

English, Koribalski & Freeman (2004)

Intergalactic HI cloudsIntergalactic HI clouds

Merger NGC 3256

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

Stephan’s quintet

HST/Gallagher et al., 2001;HI: Williams et al., 2002; CO:Lisenfeld et al., 2002

• More than 2.2 x 109 Moof H2 outside galactic disks

CO(1-0)

Intergalactic molecular hydrogenIntergalactic molecular hydrogenIRAM 30m CO(1-0)

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

Lisenfeld et al., 2002

IRAM Pdb

Lisenfeld et al., 2004

Intergalactic molecular hydrogenIntergalactic molecular hydrogen

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

Intergalactic ionized hydrogenIntergalactic ionized hydrogen

MOSCA/Calar Alto

Duc et al., 2004

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

Intergalactic ionized hydrogenIntergalactic ionized hydrogen

O Abundance (12=log(O/H) )

Rather high metallicity -> not primordial; pre-enriched

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

NGC 5291

• Emission line regions detected in H images:- Diffuse- Extended- “EL dots”• A range of star-formation rates:0.001 to 0.1 Mo / yr

Intergalactic star forming regionsIntergalactic star forming regions

Bournaud et al., 2004

Gavazzi et al., 2001

Ryan-Weber et al., 2004

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

Intergalactic recyclingIntergalactic recycling HI -> H2 -> stars -> HII

•HI•Old stars•Young stars

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

Duc & Mirabel, 1995

Hibbard & Barnes., 2004

Observations

Simulations

Weilbacher et al., 2002

Elmegreen et al., 1993

Super Star Clusters, Globular Clusters in tidal debrisSuper Star Clusters, Globular Clusters in tidal debris

106 - 108 Mo bound objects

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

““Tidal Dwarf Galaxies”Tidal Dwarf Galaxies”

109 Mo end-of-tail bound, gaseous accumulations

HI

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

• Kinematical signature Kinematical signature of “end-of-tail” projection effectsof “end-of-tail” projection effects

Simulations

Bournaud et al., 2004

Streaming motions: a change in the velocity gradient before the end of the tail may reveal projection effects

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

• Kinematical signature Kinematical signature of “end-of-tail” projection effectsof “end-of-tail” projection effects

Bournaud et al., 2004

Observations

Projection effects cannot account for all massive “end-of-tail” accumulations: some of them are real

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

Stars: 15kpc (50,000) Gas : 35 kpc (100,000)Dark matter halo: 45 kpc (100,000)

Bournaud, Duc & Masset, 2003

Truncated DM halo Reproducing the structure of tidal tailsReproducing the structure of tidal tails

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

Bournaud, Duc & Masset, 2003

Stars: 15kpc (50,000) Gas : 35 kpc (100,000)Dark matter halo: 150 kpc (100,000)

Extended DM halo Reproducing the structure of tidal tailsReproducing the structure of tidal tails

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

• Stars: 106 particles Gas : 106 particlesDark matter halo: 150 kpc (2 x 106)

• Full N-body(dissipation, self-gravity,Star formation, feedback)

• Vectorial computer NEC-SX6 CCRT CEA

Duc, Bournaud & Masset, 2004

Reproducing the structure of tidal Reproducing the structure of tidal tails tails with high-resolution simulationswith high-resolution simulations

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

N-body simulations Observations

Gas

Stars

M =109 Mo

M = 2 x109 Mo

Reproducing the formation of Tidal Dwarf GalaxiesReproducing the formation of Tidal Dwarf Galaxies

Duc, Bournaud & Masset, 2004

NGC 7252

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

Observations

Simulations

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

• without self-gravity • without gas dissipation

The proto-TDGs are still formed!

Their origin is fundamentally kinematical; only later self-gravity takes over, and the clouds collapse

Simulations

The formation of Tidal Dwarf GalaxiesThe formation of Tidal Dwarf Galaxies

Duc, Bournaud & Masset, 2004

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

According to the shape of the tidal field, matter from the external disk is either diluted or transported keeping its original surface brightness. This creates a density enhancement at the origin of the proto-TDGs

Extended halo Halo tronquéPotential of an isothermal sphere Keplerian potential

The role of the extended dark matter halo The role of the extended dark matter halo

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

Radial excursions of tidal material with an extended/truncated haloRadial excursions of tidal material with an extended/truncated halo

Dilution

Constant density

Duc, Bournaud & Masset, 2004

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

Internal kinematics of tidal tails and TDGs -> dynamical mass, compared to the luminous mass

NGC 5291 (optique + HI)

Bournaud et al., 2004

The role of a dark matter baryonic component The role of a dark matter baryonic component

If existing in the disk, it should also be present in tidal tails, and in particular in TDGs

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Chania, August 2004

Intergalactic recycling: the formation of Tidal Dwarf Galaxies

ConclusionsConclusions

All material available to fuel intergalactic star-formation:Stripped, pre-enriched HI, transformed into H2 and stars

“Recycled” gravitationally bound objects formed out of tidal debris around interacting systems and mergers

Observations and simulations: two types of tidal objects, with different physical origins:

• 106 - 108 Mo, distributed all along the tails, progenitors of Super Star Clusters and/or Globular Clusters, formed from growing local gravitational instabilities

• 109 Mo, at or near the tip of tidal tails, progenitors of Tidal Dwarf Galaxies, with a kinematical origin, formed within extended Dark Matter haloes, according to a top-down scenario