CONSTRAINING THE STAR FORMATION HISTORIES IN DARK MATTER HALOS. I. CENTRAL GALAXIES

Journal Article · Thu Jun 20 04:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/770/2/115· OSTI ID:22127075

Xiaohu, Yang ^[1]; Mo, H. J.; Zhankui, Lu ^[2]; Van den Bosch, Frank C.; Bonaca, Ana ^[3]; Shijie, Li; Yi, Lu ^[4]

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1. Center for Astronomy and Astrophysics, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)
2. Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305 (United States)
3. Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States)
4. Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Nandan Road 80, Shanghai 200030 (China)

Using the self-consistent modeling of the conditional stellar mass functions across cosmic time by Yang et al., we make model predictions for the star formation histories (SFHs) of central galaxies in halos of different masses. The model requires the following two key ingredients: (1) mass assembly histories of central and satellite galaxies and (2) local observational constraints of the star formation rates (SFRs) of central galaxies as a function of halo mass. We obtain a universal fitting formula that describes the (median) SFH of central galaxies as a function of halo mass, galaxy stellar mass, and redshift. We use this model to make predictions for various aspects of the SFRs of central galaxies across cosmic time. Our main findings are the following. (1) The specific star formation rate at high z increases rapidly with increasing redshift [{proportional_to}(1 + z){sup 2.5}] for halos of a given mass and only slowly with halo mass ({proportional_to}M{sub h}{sup 0.12}) at a given z, in almost perfect agreement with the specific mass accretion rate of dark matter halos. (2) The ratio between the SFR in the main branch progenitor and the final stellar mass of a galaxy peaks roughly at a constant value, {approx}10{sup -9.3} h {sup 2} yr{sup -1}, independent of the halo mass or the final stellar mass of the galaxy. However, the redshift at which the SFR peaks increases rapidly with halo mass. (3) More than half of the stars in the present-day universe were formed in halos with 10{sup 11.1} h {sup -1} M{sub Sun} < M{sub h} < 10{sup 12.3} h {sup -1} M{sub Sun} in the redshift range 0.4 < z < 1.9. (4) The star formation efficiencies (SFEs) of central galaxies reveal a ''downsizing'' behavior, in that the halo ''quenching'' mass, at which the SFE peaks, shifts from {approx}10{sup 12.5} h {sup -1} M{sub Sun} at z {approx}> 3.5 to {approx}10{sup 11.3} h {sup -1} M{sub Sun} at z = 0. (5) At redshift z {approx}> 2.5 more than 99% of the stars in the progenitors of massive galaxies are formed in situ, and this fraction decreases as a function of redshift, becoming {approx}60% at z = 0. For a Milky-Way-sized halo of M{sub h} {approx} 10{sup 12} h {sup -1} M{sub Sun} more than 80% of all the stars are formed in situ, as opposed to having been accreted from satellite galaxies.

• OSTI ID: 22127075
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 770; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
AUGMENTATION
FORECASTING
MASS
MILKY WAY
NONLUMINOUS MATTER
PEAKS
QUENCHING
RED SHIFT
SATELLITES
SIMULATION
STARS
UNIVERSE