Total Neutral Gas Mass, WHI, at z>2

~~~~~

Céline Péroux (ESO, Germany)

~~~~~

Dessauges-Zavadsky (Geneva)
D'Odorico (ESO, Germany)
Kim, McMahon (IoA, Cambridge, UK)

PLAN

Defining sub-DLAs

A homogeneous sample of sub-DLAs

Impact on WHI and baryon census

PLAN

Defining sub-DLAs

A homogeneous sample of sub-DLAs

Impact on WHI and baryon census

Baryon Census

DLAs: selection regardless of luminosity, morphology, SF...

(adapted from Pettini, 2003, Canary Islands Winter School)

z~2.5

Neutral Gas Mass

DLAs: major component of neutral gas

Stars form from HI gas

(Storrie-Lombardi et al., 1996, MNRAS, 283, L79)

Cumulative Number

(Péroux et al. 2001, AJ, 121, 1799)

Newly Defined Absorbers

Sub-DLA with
N(HI)>1019 cm-2
(Péroux, McMahon, Storrie & Irwin. 2003a, MNRAS, 346, 1103)

PLAN

Defining sub-DLAs

A homogeneous sample of sub-DLAs

Impact on WHI and baryon census

Survey's Sensitivity

ESO archive sample:
22 UVES quasar spectra

new z>4 data:
17 UVES quasar spectra

(Péroux, Dessauges, D'Odorico, Kim & McMahon, 2003b, MNRAS, 345, 480)

log N(HI)=20.21

log N(HI)=19.80

Voigt Profiles Examples

Number Density

Solid lines: no evolution curves

d(n)/dz evolves
from z=5 to z~3

Absorber Sizes

Same parent population

Schechter luminosity function

Holmberg relation

Cumulative Number

Sub-DLAs/DLAs surveys are independent

(Péroux, Dessauges, D'Odorico, Kim & McMahon, 2005, MNRAS)

Differential N(HI) Distribution

low z

high z

PLAN

Defining sub-DLAs

A homogeneous sample of sub-DLAs

Impact on WHI and baryon census

Neutral Gas Mass

Sub-DLA contribute
at all redshifts from z=5 to z=2

(Rao & Turnshek, 2000; Zwaan et al., 2005; Péroux, Dessauges, D'Odorico, Kim & McMahon, 2005, MNRAS)

Neutral Gas Mass

Sloan: big & homogeneous sample
(Prochaska & Herbert-Fort, 2004, PASP, 116, 622)

Baryon Census

WHI(z=4)<W*(z=0)

WHI~cte at 0<z<5?

WHI(z>0)>WHI(z=0)

Conclusion

A homogeneous of 31 sub-DLAs

Departure for no evolution in n(z) between z=5-3 for all classes of absorbers

f(N,z) evolves with redshift

Sub-DLAs contribute to WHI at all redshifts (z>2)

The total neutral gas mass is: WHI ~ 10-3 at z>2

Gaz neutre et métallicité de l'Univers mesurés par les systèmes

2005-03-05T18:25:08