1. Gas Inflow and Cosmic Star Formation Efficiency in Galaxies at z>3
Fuyan Bian
Stromlo Fellow
Research School of Astronomy and Astrophysics,
Australian National University
Collaborators: Xiaohui Fan, Linhua Jiang, Ian McGreer, Dan Stark, Arjun Dey, Richard Green, Roberto Maiolino, Fabian Walter, Romeel Dave, Kyoung-Soo Lee , Yen-Ting Lin
2015 Gas Accretion on

2. Galaxy Formation Efficiency
M*/Mhalo maximizes at ~3% at M⊙ halo mass.
Much less than the global baryon fraction ~ 17%.
Conversion of baryons to stars has maximum efficiency ~10-30% and is much smaller at higher and lower halo mass.
Stellar Mass/Halo Mass
Halo Mass
Behroozi+2012
See also Kravstov talk

3. Star-Forming Band in Dark Matter Halo
Halo and stellar growths are associated with each other in the star-forming band
Mcrit, Mthresh, and galaxy formation efficiency(halos mass, galaxy property) are critical parameters for the galaxy formation models
AGN feedback and mass quenching
UV background and SN feedback
from Joel Primack

4. Questions to Explore
How does the stellar mass grows with dark mater halo? Or how do the gas accretion process and feedback regulates and the star formation in high-redshift galaxies?
What is the galaxy formation efficiency (the efficiency converting baryon into stars) in high-redshift galaxies and how does it change with the redshift, galaxy luminosity, and halo mass?

5. Galaxy Formation Efficiency at High-z
Galaxy formation efficiency = SFR/Gas accretion rate
SFR: from SFR indicators (dust-corrected UV luminosities)
Gas accretion rate = Ωb/Ωd × dark matter accretion rate
Dark matter accretion rate: a function of redshift (z) and halo mass (Mhalo) (e.g. EPS theory, Neistein 2008).
Request a sample of high-z galaxies with known SFRs, redshifts, and halo masses.

6. Luminous Z~3 Lyman Break Galaxies in the Deep and Wide Field Surveys
Fuyan Bian
Research School of Astronomy and Astrophysics,
Australian National University
Collaborators: Xiaohui Fan (Arizona), Linhua Jiang (KIAA), Ian McGreer (Arizona), Dan Stark (Arizona), Arjun Dey (NOAO), Richard Green (LBTO), Lisa Kewley (ANU) Roberto Maiolino (Cambridge), Fabian Walter (MPIA), Romeel Dave (Steward), Kyoung-Soo Lee (Purdue), Yen-Ting Lin (ASIAA)
Select high-z star-forming galaxies effectively.
Well-understood redshift distribution based-on broad-band photometry.
2015 Tsinghua Seminar

7. NOAO Deep and Wide Field Survey
NOAO Deep Wide-Field Survey (Jannuzi & Dey 1999) is a deep multicolor survey which covers two 9 deg2 areas: Bootes Field and Centus field.
The Bootes field is also covered by the new U- and Y- band data with the LBT/LBC (Bian+2013).
Multi-wavelength coverage in the Bootes field from X-ray to radio.

8. Lyman Break Galaxies (LBGs) in Bootes FieldU Bw R
With the large survey volume, 15,000 bright LBGs at z~3 are selected in the Bootes field.

9. Clustering of z~3 Luminous LBGs
Redshift Distribution
Angular Correlation Function
ω(θ)
θ (arcsec)
2D angular correlation function + Redshift distribution
=>Clustering (3D distribution) of two subsample of LBGs (L*- 1.5L* and 1.5L*-2.5L*) with r0=5.14h-1Mpc and r0=5.77h-1Mpc

10. Dark Matter Halo Mass of Luminous LBGs
ω(θ)
θ (arcsec)
Galaxy distributions trace underlying dark matter distributions
Dark matter halo power spectrum halo occupation distribution function to fit the galaxy clustering.
The average hosting dark matter halo masses are: x1012M⊙ for 1.5L* LBGs, 5x1012M⊙ for 2.5L* LBGs
Occupy high halo mass end.

11. Dark Mater Halo Mass of Faint LBGs
LBGs at z~ L* in GOODS field (Lee+06): Halo mass 4-8x1011M⊙
LBGs at z~ L* in GOODS field (Lee+06): Halo mass 2-4x1011M⊙
LBG at z~ L* in Subaru/XMM-Newton field (Ouchi+05): Halo mass 4x1011-2x1012M⊙
The existing LBG samples allow us to probe the halo mass from 2x1011 to 5x1012M⊙

12. Baryonic Gas Accretion on Galaxies
The baryonic gas accretion rate depends on redshift and halo mass (Dekel+2009) .
Lilly+2013

13. Galaxy formation efficiency in LBGs
A tight relation between redshift- scaled SFR and halo mass in LBGs.
The SF process in high-z LBG is feed by the gas accretion process.
The galaxy formation efficiency is 5%-20%.
This efficiency does not change significantly with redshift, galaxy luminosity, halo mass (2x x1012 M⊙)
Bian+2013

14. Conclusion
A tight relation between the redshift-scaled SFR and hosting halo mass in LBGs at z>3, which follows the slope predicted by the baryonic flow accretion.
This relation suggests that the star formation process is regulated by the gas accretion process in high-z galaxies
The galaxy formation efficiency is 5%-20%, and does not change with redshift, galaxy luminosity and halo mass.