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Related papers: On the Origin of the Salpeter Slope for the Initia…

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The origin of the stellar initial mass function (IMF) is one of the most debated issues in astrophysics. Here, we explore the possible link between the quasi-universal filamentary structure of star-forming molecular clouds and the origin of…

Astrophysics of Galaxies · Physics 2019-08-28 Philippe André , Doris Arzoumanian , Vera Könyves , Yoshito Shimajiri , Pedro Palmeirim

We propose a functional form for the IMF, the L_3 IMF, which is a natural heavy-tailed approximation to the log-normal distribution. It is composed of a low-mass power law and a high mass power-law which are smoothly joined together. Three…

Astrophysics of Galaxies · Physics 2015-06-12 Thomas Maschberger

Several observational and theoretical indications suggest that the initial mass function (IMF) becomes increasingly top-heavy (i.e., overabundant in high-mass stars with mass $m > 1M_{\odot}$) with decreasing metallicity and increasing gas…

Astrophysics of Galaxies · Physics 2020-12-15 Hosein Haghi , Ghasem Safaei , Akram Hasani Zonoozi , Pavel Kroupa

Our recent determination of a Salpeter slope for the IMF in the field of 30 Doradus (Selman and Melnick 2005) appears to be in conflict with simple probabilistic counting arguments advanced in the past to support observational claims of a…

Astrophysics · Physics 2009-11-13 Fernando J. Selman , Jorge Melnick

We use the ZFIRE survey (http://zfire.swinburne.edu.au) to investigate the high mass slope of the initial mass function (IMF) for a mass-complete (log10(M$_*$/M$_\odot$)~9.3) sample of 102 star-forming galaxies at z~2 using their H$\alpha$…

A growing fraction of Simple Stellar Population (SSP) models, in an aim to create more realistic simulations capable of including stochastic variation in their outputs, begin their simulations with a distribution of discrete stars following…

Astrophysics of Galaxies · Physics 2015-06-18 Bogdan Popescu , M. M. Hanson

Recent observations indicate a lower Halpha to FUV ratio in dwarf galaxies than in brighter systems, a trend that could be explained by a truncated and/or steeper IMF in small galaxies. However, at low star formation rates (SFRs), the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Michele Fumagalli , Robert L. da Silva , Mark R. Krumholz

We introduce a new dual power law (DPL) probability distribution function for the mass distribution of stellar and substellar objects at birth, otherwise known as the initial mass function (IMF). The model contains both deterministic and…

Solar and Stellar Astrophysics · Physics 2018-05-23 Karl Heinz Hoffmann , Christopher Essex , Shantanu Basu , Janett Prehl

There are various ways of measuring the slope of the upper end of the IMF. Arguably the most direct of these is to place stars on the H-R diagram and compare their positions with stellar evolutionary models. Even so, the masses one infers…

Solar and Stellar Astrophysics · Physics 2010-08-10 Philip Massey

(abridged) The case can be made for a rather universal stellar IMF form that can be approximated by a two-part power-law function in the stellar regime. However, there exists a possible hint for a systematic variation with metallicity. A…

Astrophysics · Physics 2007-05-23 Pavel Kroupa

Massive stars define the upper limits of the star formation process, dominate the energetics of their local environs, and significantly affect the chemical evolution of galaxies. Their role in starburst galaxies and the early Universe is…

Astrophysics · Physics 2015-11-11 Donald F. Figer

Peaks and lulls in the star formation rate (SFR) over the history of the Galaxy produce plateaux and declines in the present day mass function (PDMF) where the main-sequence lifetime overlaps the age and duration of the SFR variation. These…

Astrophysics · Physics 2009-11-13 Bruce G. Elmegreen , John Scalo

the present paper, we propose that the stellar initial mass distributions as known as IMF are best fitted by $q$-Weibulls that emerge within nonextensive statistical mechanics. As a result, we show that the Salpeter's slope of $\sim$2.35 is…

Solar and Stellar Astrophysics · Physics 2019-05-22 D. B. de Freitas , R. T. Eufrasio , M. M. F. Nepomuceno , J. R. P. da Silva

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

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 low-mass end of the stellar Initial Mass Function (IMF) is constrained by focusing on the baryon-dominated central regions of strong lensing galaxies. We study in this letter the Einstein Cross (Q2237+0305), a z=0.04 barred galaxy whose…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Ignacio Ferreras , Prasenjit Saha , Dominik Leier , Frederic Courbin , Emilio E. Falco

The present paper extends our previous theory of the stellar initial mass function (IMF) by including the time-dependence, and by including the impact of magnetic field. The predicted mass spectra are similar to the time independent ones…

Astrophysics of Galaxies · Physics 2015-06-15 Patrick Hennebelle , Gilles Chabrier

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…

The debate about the universality of the stellar initial mass function (IMF) revolves around two competing lines of evidence. While measurements in the Milky Way, an archetypal spiral galaxy, seem to support an invariant IMF, the observed…

Observed variations in the IMF are reviewed with an emphasis on environmental density. The remote field IMF studied in the LMC by several authors is clearly steeper than most cluster IMFs, which have slopes close to the Salpeter value.…

Astrophysics · Physics 2015-11-11 Bruce G. Elmegreen