galaxy stellar mass function

galaxy stellar mass function
Name	Galaxy stellar mass function
Field	Astrophysics, Cosmology, Extragalactic astronomy
Introduced	1970s–1990s
Notable examples	Schechter function, double Schechter

galaxy stellar mass function is the statistical distribution describing the number density of galaxies as a function of stellar mass in a cosmological volume. It connects observational programs and theoretical frameworks by linking measurements from instruments and surveys to predictions from models of structure formation and baryonic physics. The function provides a cornerstone for interpreting results from facilities, collaborations, and missions in extragalactic research across redshift and environment.

Definition and mathematical form

The galaxy stellar mass function is typically parametrized by analytic forms such as the Schechter function originally applied in studies by Paul Schechter and often extended to double-Schechter forms used in analyses by groups associated with Sloan Digital Sky Survey, Two Micron All Sky Survey, COSMOS survey, and Hubble Space Telescope programs. In common notation the single Schechter expression uses parameters phi*, M*, and alpha familiar from work connected to Max Planck Institute for Astrophysics projects and interpretations by researchers at Harvard–Smithsonian Center for Astrophysics and California Institute of Technology. The double Schechter adds an additional slope and normalization to capture distinct contributions from passive populations studied by teams at Space Telescope Science Institute and star-forming populations characterized in papers from European Southern Observatory collaborations.

Measurement methods and observational surveys

Mass function determinations rely on multiwavelength photometry and spectroscopy from facilities such as Hubble Space Telescope, James Webb Space Telescope, Keck Observatory, Very Large Telescope, Subaru Telescope, and millimeter arrays like Atacama Large Millimeter/submillimeter Array. Surveys including Sloan Digital Sky Survey, COSMOS survey, DEEP2 Redshift Survey, Galaxy And Mass Assembly, and CANDELS deliver photometric catalogs and spectroscopic redshifts used by teams at University of Cambridge, Princeton University, University of Tokyo, and University of California, Berkeley to estimate stellar masses through population-synthesis fitting codes developed with influences from Charles Steidel and groups at Max Planck Society. Methods incorporate stellar population models from groups influenced by Gustavo Bruzual, Stromback-style treatments, initial mass functions like choices motivated by Edwin Salpeter, Pavel Kroupa, and Gilles Chabrier, and dust attenuation laws employed in analyses from NASA Goddard Space Flight Center teams. Techniques for volume correction and completeness use frameworks derived in part from cosmological parameters measured by Planck (spacecraft), with clustering information supplied by projects linked to Dark Energy Survey and Baryon Oscillation Spectroscopic Survey collaborations.

Evolution with redshift and cosmic time

Empirical studies trace the stellar mass function from the local Universe probed by Sloan Digital Sky Survey to high-redshift measurements from Hubble Space Telescope and James Webb Space Telescope deep fields, with interpretations advanced by groups at Carnegie Institution for Science and Institute for Advanced Study. Observations indicate mass-dependent growth where massive systems associated with groups and clusters cataloged in Abell catalogue evolve differently from low-mass systems cataloged in surveys of the Local Group, consistent with theoretical predictions from teams at Lawrence Berkeley National Laboratory and Flatiron Institute. Results feed into constraints on cosmic star-formation history studies connected to work by J. Richard Gott and empirical compilations often cited alongside outcomes from WMAP and Planck (spacecraft) cosmology analyses.

Relation to galaxy properties and environment

The shape of the mass function correlates with galaxy bimodality explored in studies by researchers associated with Columbia University, Yale University, and Imperial College London that separate star-forming and quiescent populations. Environmental dependence appears when comparing field populations identified in COSMOS survey with cluster members cataloged by Rosat and optical cluster searches tied to Mauna Kea Observatories, reflecting processes discussed in literature from Max Planck Institute for Astronomy and University of Arizona. Connections to morphology, emission-line properties, and active nuclei link mass-function features to results from collaborations involving European Space Agency, National Radio Astronomy Observatory, and investigators such as those affiliated with University of Oxford and University of Chicago.

Theoretical models and interpretation

Semi-analytic models and hydrodynamic simulations from teams at Max Planck Institute for Astrophysics, IllustrisTNG consortium, EAGLE project, and groups at Princeton University and University of California, Santa Cruz compare predicted mass functions to observations to probe feedback from supernovae and active galactic nuclei studied by groups at NASA Ames Research Center and Harvard–Smithsonian Center for Astrophysics. Halo abundance matching techniques developed by researchers at University of Pennsylvania and University of Barcelona link stellar masses to dark-matter halos characterized in simulations run on facilities like National Energy Research Scientific Computing Center. Outcomes inform theories on gas accretion, mergers, and quenching discussed in monographs and reviews connected to California Institute of Technology and Rutgers University researchers.

Systematic uncertainties and biases

Uncertainties arise from choices of initial mass function informed by Edwin Salpeter, Pavel Kroupa, and Gilles Chabrier prescriptions; stellar population synthesis models influenced by Gustavo Bruzual; photometric redshift systematics typified in comparisons between COSMOS survey and DEEP2 Redshift Survey; and cosmic variance given survey footprints from Hubble Space Telescope deep fields and wide-area programs like Sloan Digital Sky Survey and Dark Energy Survey. Calibration of stellar masses depends on assumptions tested in intercomparisons by groups at Max Planck Society and European Southern Observatory while observational selection effects linked to instrumentation from Keck Observatory and Very Large Telescope impose biases that propagate into theoretical inferences used by collaborations at Flatiron Institute and Lawrence Berkeley National Laboratory.

Category:Extragalactic astronomy