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 Galaxies@NRAO

Galaxy Formation Efficiency M*/Mhalo maximizes at ~3% at 1012 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

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

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?

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.

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

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.

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

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

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: 3x1012M⊙ for 1.5L* LBGs, 5x1012M⊙ for 2.5L* LBGs Occupy high halo mass end.

Dark Mater Halo Mass of Faint LBGs LBGs at z~4 0.2-0.4 L* in GOODS field (Lee+06): Halo mass 4-8x1011M⊙ LBGs at z~5 0.4-1.0L* in GOODS field (Lee+06): Halo mass 2-4x1011M⊙ LBG at z~4 0.2-1L* 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⊙

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

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 (2x1011- 5x1012 M⊙) Bian+2013

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.