The stellar mass function and efficiency of galaxy formation with a varying initial mass function

Abstract

Several recent observational studies have concluded that the initial mass function (IMF) of stars varies systematically with galaxy properties such as velocity dispersion. In this paper, we investigate the effect of linking the circular velocity of galaxies, as determined from the Fundamental Plane and Tully-Fisher relations, to the slope of the IMF with parameterizations guided by several of these studies. For each empirical relation, we generate stellar masses of ~600,000 SDSS galaxies at z ~ 0.1, by fitting the optical photometry to large suites of synthetic stellar populations that sample the full range of galaxy parameters. We generate stellar mass functions and examine the stellar-to-halo mass relations using sub-halo abundance matching. At the massive end, the stellar mass functions become a power law, instead of the familiar exponential decline. As a result, it is a generic feature of these models that the central galaxy stellar-to-halo mass relation is significantly flatter at high masses (slope ~ -0.3 to -0.4) than in the case of a universal IMF (slope ~ -0.6). We find that regardless of whether the IMF varies systematically in all galaxies or just early types, there is still a well-defined peak in the central stellar-to-halo mass ratio at halo masses of ~ 10E12 solar masses. In general, the IMF variations explored here lead to significantly higher integrated stellar densities if the assumed dependence on circular velocity applies to all galaxies, including late-types; in fact the more extreme cases can be ruled out, as they imply an unphysical situation in which the stellar fraction exceeds the universal baryon fraction.

18 pages, 10 figures. MNRAS, in press

References in corpus (19)

• The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
• UV Star Formation Rates in the Local Universe
• Some Aspects of Measurement Error in Linear Regression of Astronomical Data
• A systematic variation of the stellar initial mass function in early-type galaxies
• Analytical theory for the initial mass function: CO clumps and prestellar cores
• PRIMUS: Constraints on Star Formation Quenching and Galaxy Merging, and the Evolution of the Stellar Mass Function From z=0-1
• Evolution of asymptotic giant branch stars I. Updated synthetic TP-AGB models and their basic calibration
• Galaxy Cluster Baryon Fractions Revisited
• Baryons at the Edge of the X-ray Brightest Galaxy Cluster
• The Importance of Radiative Feedback for the Stellar Initial Mass Function
• An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field South: High resolution 870um source counts
• The Evolution of Stellar Mass and the Implied Star Formation History
• The Tully-Fisher Relation and Its Residuals for a Broadly Selected Sample of Galaxies
• Structural Properties of Central Galaxies in Groups and Clusters
• The galaxy-wide IMF of dwarf late-type to massive early-type galaxies
• Extragalactic Constraints on the Initial Mass Function
• The similarity of the stellar mass fractions of galaxy groups and clusters
• Damn You, Little h! (or, Real-World Applications Of The Hubble Constant Using Observed And Simulated Data)
• Metallicity and the Universality of the IMF

Cited by in corpus (7)

• Stellar mass -- halo mass relation and star formation efficiency in high-mass halos
• Overconsumption, outflows and the quenching of satellite galaxies
• The Fornax 3D project: a two-dimensional view of the stellar initial mass function in the massive lenticular galaxy FCC 167
• Strong Gravitational Lensing and the Stellar IMF of Early-type Galaxies
• Implications of a variable IMF for the interpretation of observations of galaxy populations
• An assessment of the evidence from ATLAS3D for a variable initial mass function
• Implications of galaxy buildup for putative IMF variations in massive galaxies