The Size of Absorption Line Systems

Cloud (inhomogeneities) – Object – Large scale correlation

Patrick PetitjeanInstitut d’Astrophysique de Paris

B. Aracil R. Srianand C. Ledoux F. Stoehr C. Pichon

J. Bergeron E. Rollinde M. Longhetti F. Coppolani E. Scannapieco

Damped Lyman-alpha Systems

1. System as a whole Broad-band imaging of the field : HST - z < 1 Le Brun et al. (1997, A&A, 321, 733), Chen et al., Rao et al. -> 10 kpc - z = 1.892 LBQS 1210+1731; Kulkarni et al. (2000, ApJ 536, 36) -> 2 kpc Lenses: - z = 0.93 ; HE0512-3329; 5 kpc ; Lopez et al. 2005, astro-ph/0503026 Lyman- emission : - z > 1.9; Moeller et al. (2004, A&A, 422, L33) => Small sizes -> a few kpc : 2 (high z) to 10 (low z) kpc Additional argument ? : Homogeneity of the gas for abundance ratios Prochaska (2003, ApJ, 583, 49); Rodriguez et al. (submitted)

SiII/SII or FeII/SII are fairly constant through the profile

2. Clouds Physical conditions in the gas: nH = 1 to 100 cm-3 (Srianand et al. 2005;

Ledoux et al. 2003, MNRAS, 346, 209) => 1 (H2) to 100 (diffuse) pc Lenses: < 25 pc (Churchill et al., 2003, ApJ, 593, 203)

MgII systems

1. Systems (z ~ 1) * Broad band imaging and spectroscopic follow-up -> 35 kpc Bergeron & Boissé (1991, A&A 243, 344); Steidel (1993) * Weak MgII systems ? Churchill et al. (2000) -> larger ?

2. Clouds * The case APM08279+5255

Inhomogeneities over 1kpc

Ellison et al. (2004, A&A, 414, 79)

-> photometric redshifts ?

MgII z = 0.73

100 kpc

CIV sytems

1. Clouds - Lenses : Rauch et al. (2001, ApJ, 554, 823)Featureless on scales < 300 pc

2. SystemsMuch larger cross-sectionEspecially for weak systems

=> Correlation functions

Longhetti & Petitjean in prep

CIV z = 1.339

150 kpc

MgII z = 0.58

200 kpc

Overall Picture

• The IGM

• Where are the metals ?

• Physical state ?

• Expelled from the center of Halos -> Winds

• Along filaments

• What about the Voids ?

•Correlations

Along the los -> Big Sample

Transverse -> Pairs or groups

CIV longitudinal correlation function

Large Programme ESO – 643 CIV systems

Column density distribution

SPH Simulation : -Bubbles (radius Rbubble) around haloes of mass Mhalo

- Ionized by the UV background - Los analized the same way as data

Fitting the CIV longitudinal correlation function

Fitting the column density distribution and the correlation function => Mhalo = 5x1011 Msun and Rbubble = 2.5 Mpc

Scannapieco et al., 2005, astro-ph/0503001

for Z/20

Correlation in the Lyman-alpha forest

Longitudinal : Large Programme ESO : 20 LOS UVES R=45000 S/N=40-100

Transverse : 32 pairs 1-3 arcmin observed with FORS

Simulated correlation functions

- Hydro simulations in a 100 Mpc simulation box- Effect of thermal broadening and peculiar velocities on longitudinal and transverse correlation functions

Longitudinal

Transverse

Longitudinal correlation function

UVES

FORS

z=2

z=3

Observed versus Simulated correlation functions

see poster Aghaee

Transverse correlation functionAlcock & Paczynski test

Sample should be increased to derive

Very good prospect for further investigation

Groups of QSOs

Conclusion

Small scales : One to one association

Impact parameters of metal line systems : bigger sample

Completeness ?

Star-formation vs physical state of the gas

Large Scales

Where are the metals ? How are they expelled from the site of

star-formation ?

Spatial distribution of the gas and galaxies; Topology and kinematics (see poster Caucci)