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Related papers: Initial mass function variability from the integra…

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The stellar initial mass function (IMF) in star clusters is reviewed. Uncertainties in the observations are emphasized. We suggest there is a distinct possibility that cluster IMFs vary systematically with density or pressure. Dense…

Astrophysics · Physics 2007-05-23 Bruce G. Elmegreen

The stellar initial mass function (IMF) is commonly interpreted to be a scale-invariant probability density distribution function (PDF) such that many small clusters yield the same IMF as one massive cluster of the same combined number of…

Astrophysics of Galaxies · Physics 2023-02-22 Zhiqiang Yan , Tereza Jerabkova , Pavel Kroupa

We measure the high-mass stellar initial mass function (IMF) from resolved stars in M33 young stellar clusters. Leveraging \textit{Hubble Space Telescope's} high resolving power, we fully model the IMF probabilistically. We first model the…

We study the initial mass function (IMF) of one of the most massive Galactic star-forming regions NGC 3603 to answer a fundamental question in current astrophysics: is the IMF universal, or does it vary? Using our very deep, high angular…

Astrophysics · Physics 2009-11-13 Y. Harayama , F. Eisenhauer , F. Martins

We present a method for investigating variations in the upper end of the stellar Initial Mass Function (IMF) by probing the production rate of ionizing photons in unresolved, compact star clusters with ages <~10 Myr and with different…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 D. Calzetti , R. Chandar , J. C. Lee , B. G. Elmegreen , R. C. Kennicutt , B. Whitmore

We determine an absolute calibration of the initial mass function (IMF) of early-type galaxies, by studying a sample of 56 gravitational lenses identified by the SLACS Survey. Under the assumption of standard Navarro, Frenk & White dark…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 T. Treu , M. W. Auger , L. V. E. Koopmans , R. Gavazzi , P. J. Marshall , A. S. Bolton

Recent work has suggested that the stellar initial mass function (IMF) is not universal, but rather is correlated with galaxy stellar mass, stellar velocity dispersion, or morphological type. In this paper, we investigate variations of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 A. A. Dutton , T. Treu , B. J. Brewer , P. J. Marshall , M. W. Auger , M. Barnabe , D. C. Koo , A. S. Bolton , L. V. E. Koopmans

Few topics in astronomy initiate such vigorous discussion as whether or not the initial mass function (IMF) of stars is universal, or instead sensitive to the initial conditions of star formation. The distinction is of critical importance:…

Astrophysics of Galaxies · Physics 2015-05-18 Nate Bastian , Kevin R. Covey , Michael R. Meyer

The Initial Mass Function (IMF) of early-type galaxies (ETGs) has been found to feature systematic variations by both dynamical and spectroscopic studies. In particular, spectral line strengths, based on gravity-sensitive features, suggest…

Astrophysics of Galaxies · Physics 2015-06-23 F. La Barbera , I. Ferreras , A. Vazdekis

We investigated a volume-limited sample of LAMOST main-sequence stars with masses from 0.25 to 1 $M_{\odot}$ and distances of 150-350 pc to explore how the stellar initial mass function (IMF) varies with metallicity. We corrected the…

Solar and Stellar Astrophysics · Physics 2025-11-07 Dan Qiu , Chao Liu , Jennifer A. Johnson , Jiadong Li , Bo Zhang

We present near-infrared $J$, $H$, and $K$ images of four embedded stellar clusters in the Galaxy. We find a significant fraction of pre-main-sequence stars present in at least one of the clusters. For the clusters dominated by…

Astrophysics · Physics 2008-11-26 A. Leistra , A. Cotera , J. Liebert

Much of our knowledge of galaxies comes from analysing the radiation emitted by their stars. It depends on the stellar initial mass function (IMF) describing the distribution of stellar masses when the population formed. Consequently…

The Hydra I cluster offers an excellent opportunity to study and compare the relic old stellar populations in the core of its two brightest galaxies. In addition, the differing kinematics of the two galaxies allows a test of the local…

Astrophysics of Galaxies · Physics 2023-05-17 Ilaria Lonoce , Wendy Freedman , Anja Feldmeier-Krause

The stellar initial mass function (IMF) is central to our interpretation of astronomical observables and to our understanding of most baryonic processes within galaxies. The universality of the IMF, suggested by observations in our own…

We present an investigation about the shape of the initial mass function (IMF) of early-type galaxies (ETGs), based on a joint lensing and dynamical analysis, and on stellar population synthesis models, for a sample of 55 lens ETGs…

Astrophysics of Galaxies · Physics 2015-06-22 Silvia Posacki , Michele Cappellari , Tommaso Treu , Silvia Pellegrini , Luca Ciotti

The long-standing assumption that the stellar initial mass function (IMF) is universal has recently been challenged by a number of observations. Several studies have shown that a "heavy" IMF (e.g., with a Salpeter-like abundance of low mass…

Instrumentation and Methods for Astrophysics · Physics 2015-06-17 Brendon J. Brewer , Philip J. Marshall , Matthew W. Auger , Tommaso Treu , Aaron A. Dutton , Matteo Barnabè

The ATLAS3D Survey has reported evidence for a non-universal stellar initial mass function (IMF) for early type galaxies (ETGs) (Cappellari et al. 2012, 2013b,a). The IMF was constrained by comparing stellar mass measurements from kinematic…

Astrophysics of Galaxies · Physics 2015-06-19 Bart Clauwens , Joop Schaye , Marijn Franx

Because direct measurements require resolved stellar populations including low-mass stars, determining the stellar initial mass function (IMF) has been a historically difficult problem even within our own Galaxy and impossible everywhere…

Astrophysics of Galaxies · Physics 2026-03-26 Charles L. Steinhardt , Carter Meyerhoff , Alexander J. Luening

Recent results indicate the stellar initial mass function is not a strong function of star-forming environment or ``initial conditions'' (e.g. Meyer et al. 2000). Some studies suggest that a universal IMF may extend to sub-stellar masses…

Astrophysics · Physics 2015-11-11 M. R. Meyer , J. Greissl , M. Kenworthy , D. McCarthy

Theoretical arguments and indirect observational evidence suggest that the stellar initial mass function (IMF) may evolve with time, such that it is more weighted toward high mass stars at higher redshift. Here we test this idea by…

Astrophysics · Physics 2010-01-07 Pieter van Dokkum