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Related papers: The Salpeter IMF and its descendants

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The stellar initial mass function (sIMF) describes the distribution of stellar masses formed in a single star formation event in a molecular cloud clump. It is fundamental to astrophysics and cosmology, shaping our understanding of…

Over the past years observations of young and populous star clusters have shown that the stellar initial mass function (IMF) can be conveniently described by a two-part power-law with an exponent alpha_2 = 2.3 for stars more massive than…

Astrophysics of Galaxies · Physics 2010-11-10 Carsten Weidner , Jan Pflamm-Altenburg , Pavel Kroupa

The stellar initial mass function (IMF) describes the distribution of stellar masses that form in a given star formation event. The long main-sequence lifetimes of low-mass stars mean that the IMF in this regime (below $\sim 1…

The initial mass function (IMF) describes the distribution of stellar masses in a population of newly born stars and is amongst the most fundamental concepts in astrophysics. It is not only the direct result of the star formation process…

Solar and Stellar Astrophysics · Physics 2026-02-12 Amery Gration , Robert G. Izzard , Payel Das

We suggest that the intrinsic, stellar initial mass function (IMF) follows a power-law slope gamma=2, inherited from hierarchical fragmentation of molecular clouds into clumps and clumps into stars. The well-known, logarithmic Salpeter…

Astrophysics of Galaxies · Physics 2015-05-30 M. S. Oey

An essential component of galaxy formation theory is the stellar initial mass function (IMF), that describes the parent distribution of stellar mass in star forming regions. We present observational evidence in a sample of early-type…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 I. Ferreras , F. La Barbera , R. R. de Carvalho , I. G. de la Rosa , A. Vazdekis , J. Falcon-Barroso , E. Ricciardelli

Understanding the processes that determine the stellar Initial Mass Function (IMF) is a critical unsolved problem, with profound implications for many areas of astrophysics. In molecular clouds, stars are formed in cores, gas condensations…

Obtaining accurate measurements of the initial mass function (IMF) is often considered to be the key to understanding star formation, and a universal IMF is often assumed to imply a universal star formation process. Here, we illustrate that…

Astrophysics of Galaxies · Physics 2015-05-14 M. B. N. Kouwenhoven , S. P. Goodwin

The measured star-formation rates (SFRs) of galaxies comprise an important constraint on galaxy evolution and also on their cosmological boundary conditions. Any available tracer of the SFR depends on the shape of the mass-distribution of…

Astrophysics of Galaxies · Physics 2021-12-22 Pavel Kroupa , Tereza Jerabkova

Observations and theory of the IMF are briefly reviewed. Slight variations have been observed, although they are difficult to prove unambiguously. Most detailed theoretical models reproduce the IMF, but because they use different…

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

Observations of normal galactic star-forming regions suggest there is widespread near-uniformity in the initial stellar mass function (IMF) in spite of diverse physical conditions. Fluctuations may come largely from statistical effects and…

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

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

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 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

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

The stellar initial mass function (IMF) of early-type galaxies is the combination of the IMF of the stellar population formed in-situ and that of accreted stellar populations. Using as an observable the effective IMF $\alpha_{IMF}$, defined…

Astrophysics of Galaxies · Physics 2017-01-18 Alessandro Sonnenfeld , Carlo Nipoti , Tommaso Treu

It has frequently been suggested that the stellar IMF in galaxies was top-heavy at early times. This would be plausible physically if the IMF depends on a mass scale such as the Jeans mass that was higher at earlier times because of the…

Astrophysics · Physics 2009-10-30 Richard B. Larson

In a probabilistic framework of the interpretation of the initial mass function (IMF), the IMF cannot be arbitrarily normalized to the total mass, M, or number of stars, N, of the system. Hence, the inference of M and N when partial…

Cosmology and Nongalactic Astrophysics · Physics 2013-07-02 Miguel Cervino , Carlos Romann-Zuniga , Amelia Bayo , Valentina Luridiana , Nestor Sanchez , Enrique Perez

The initial mass function (IMF) is a construct that describes the distribution of stellar masses for a newly formed population of stars. It is a fundamental element underlying all of star and galaxy formation, and has been the subject of…

Astrophysics of Galaxies · Physics 2025-03-26 Diego Salvador , Andrew Hopkins , Matt Owers , Themiya Nanayakkara , Scott Croom

We test the hypothesis that the initial mass function (IMF) is determined by the density probability distribution function (PDF) produced by supersonic turbulence. We compare 14 simulations of star cluster formation in 50 solar mass…

Astrophysics of Galaxies · Physics 2016-12-07 David Liptai , Daniel J. Price , James Wurster , Matthew R. Bate