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Related papers: The IMF and its Evolution

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We investigate the effect of a metallicity-dependent stellar initial mass function (IMF), as deduced observationally by Martin-Navarro et al. (2015c), on the inferred stellar masses and star formation rates (SFRs) of a representative sample…

Astrophysics of Galaxies · Physics 2016-08-31 Bart Clauwens , Joop Schaye , Marijn Franx

We investigate the origin of a bottom-heavy stellar initial mass function (IMF) recently observed in elliptical galaxies by using chemical evolution models with a non-universal IMF. We adopt the Kroupa IMF with the three slopes (alpha_1,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Kenji Bekki

The stellar initial mass function (IMF), which is often assumed to be universal across unresolved stellar populations, has recently been suggested to be "bottom-heavy" for massive ellipticals. In these galaxies, the prevalence of…

The characteristic mass M_c in the stellar initial mass function (IMF) is about constant for most star-forming regions. Numerical simulations consistently show a proportionality between M_c and the thermal Jeans mass M_J at the time of…

Astrophysics · Physics 2009-11-13 Bruce G. Elmegreen , Ralf S. Klessen , Christine D. Wilson

I review efforts to determine the form and any lower limit to the initial mass function in the Galactic disk, using observations of low-mass stars and brown dwarfs in the field, young clusters and star forming regions. I focus on the…

Solar and Stellar Astrophysics · Physics 2015-06-05 R. D. Jeffries

Recent studies suggest that the initial mass function (IMF) of the first stars was likely to be extremely top-heavy, unlike what is observed at present. We propose a scenario to generate fragmentation to lower masses once the first massive…

Astrophysics · Physics 2009-11-07 R. Schneider , A. Ferrara , P. Natarajan , K. Omukai

One of the key mysteries of star formation is the origin of the stellar initial mass function (IMF). The IMF is observed to be nearly universal in the Milky Way and its satellites, and significant variations are only inferred in extreme…

A method is presented here 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 covering a…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-26 Daniela Calzetti , Rupali Chandar , Janice C. Lee , Bruce G. Elmegreen , Robert C. Kennicutt , Brad C. Whitmore

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

Stars do not form continuously distributed over star forming galaxies. They form in star clusters of different masses. This nature of clustered star formation is taken into account in the theory of the integrated galactic stellar initial…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Jan Pflamm-Altenburg , Pavel Kroupa

This paper revisits the classical Kennicutt method for inferring the stellar initial mass function (IMF) from the integrated light properties of galaxies. The large size, uniform high quality data set from the Sloan Digital Sky Survey DR4…

Astrophysics · Physics 2011-04-20 Erik A. Hoversten , Karl Glazebrook

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

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…

Crucial for star formation is the interplay between gravity and turbulence. The observed cloud virial parameter, $\alpha_{\mathrm{vir}}$, which is the ratio of twice the turbulent kinetic energy to the gravitational energy, is found to vary…

Astrophysics of Galaxies · Physics 2025-01-07 Sajay Sunny Mathew , Christoph Federrath , Amit Seta

[abridged] Stars are thought to be formed predominantly in clusters. The clusters are formed following a cluster initial mass function (CMF) similar to the stellar initial mass function (IMF). Both the IMF and the CMF favour low-mass…

Astrophysics of Galaxies · Physics 2012-05-31 M. R. Haas , P. Anders

Spectroscopic analyses of gravity-sensitive line strengths give growing evidence towards an excess of low-mass stars in massive early-type galaxies (ETGs). Such a scenario requires a bottom-heavy initial mass function (IMF). However, strong…

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

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

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

In this chapter, we review some historical understanding and recent advances on the Initial Mass Function (IMF) and the Core Mass Function (CMF), both in terms of observations and theories. We focus mostly on star formation in clustered…

A wealth of observations recently challenged the notion of a universal stellar initial mass function (IMF) by showing evidences in favour of a variability of this statistical indicator as a function of galaxy properties. I present…

Astrophysics of Galaxies · Physics 2020-06-17 Fabio Fontanot