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Related papers: The Initial Mass Function in the Extended Ultravio…

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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

The stellar initial mass function (IMF) is expressed by $\phi(m) \propto m^{-\alpha}$ with the slope $\alpha$, and known as the poorly-constrained but very important function in studies of star and galaxy formation. There are no sensible…

Astrophysics of Galaxies · Physics 2023-04-13 Shohei Aoyama , Masami Ouchi , Yuichi Harikane

The non-detection of zero-metallicity stars in ultra-faint dwarf galaxies (UFDs) can be used to constrain the Initial Mass Function (IMF) of the first (PopIII) stars by means of a statistical comparison between available data and…

Astrophysics of Galaxies · Physics 2021-03-31 Martina Rossi , Stefania Salvadori , Ása Skúladóttir

It is now well-established that the stellar initial mass function (IMF) can be determined from the absorption line spectra of old stellar systems, and this has been used to measure the IMF and its variation across the early-type galaxy…

Astrophysics of Galaxies · Physics 2017-03-22 Charlie Conroy , Pieter van Dokkum , Alexa Villaume

Many results in modern astrophysics rest on the notion that the Initial Mass Function (IMF) is universal. Our observations of HI selected galaxies in the light of H-alpha and the far-ultraviolet (FUV) challenge this notion. The flux ratio…

The stellar initial mass function (IMF) is among the most fundamental distributions in astrophysics, defined as the mass spectrum of stars produced in a single star-formation event. Even in the solar neighbourhood, where measurements can be…

Astrophysics of Galaxies · Physics 2026-04-15 Yu-Ting Wang , Chao Liu , Jiadong Li

Recent results on the non-universality of the Initial Mass Function (IMF) have shown strong evidence of IMF variations with galaxy velocity dispersion, with a corresponding impact on other stellar population parameters, line indices and…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Anna Ferré-Mateu , Alexandre Vazdekis , Ignacio G. de la Rosa

Analyses of strong gravitational lenses, galaxy-scale kinematics, and absorption line stellar population synthesis (SPS) have all concluded that the stellar initial mass function (IMF) varies within the massive early-type galaxy (ETG)…

Astrophysics of Galaxies · Physics 2017-11-29 Alexa Villaume , Jean Brodie , Charlie Conroy , Aaron J. Romanowsky , Pieter van Dokkum

We obtain constraints on the slope of a universal stellar initial mass function (IMF) over a range of cosmic star-formation histories (SFH) using z=0.1 luminosity densities in the range from 0.2 to 2.2 microns. The age-IMF degeneracy of…

Astrophysics · Physics 2011-05-05 I. K. Baldry , K. Glazebrook

We present a pilot method to estimate the high-mass initial mass function (IMF) across the arm, interarm, and spur regions in galaxies and apply it to NGC 628. We extracted star-forming complexes (SFCs) from H$\alpha$ VLT/MUSE and UVIT (FUV…

Astrophysics of Galaxies · Physics 2025-06-24 S Amrutha , Mousumi Das

Stellar population studies of massive early-type galaxies (ETGs) suggest that the stellar initial mass function may not be universal. In particular, the centres of ETGs seem to contain an excess of low-mass dwarf stars compared to our own…

Astrophysics of Galaxies · Physics 2024-02-12 Taniya Parikh , Roberto Saglia , Jens Thomas , Kianusch Mehrgan , Ralf Bender , Claudia Maraston

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

The heavyweight stellar initial mass function (IMF) observed in the cores of massive early-type galaxies (ETGs) has been linked to formation of their cores in an initial swiftly-quenched rapid starburst. However, the outskirts of ETGs are…

Astrophysics of Galaxies · Physics 2017-04-19 Padraig D. Alton , Russell J. Smith , John R. Lucey

We investigate the time evolution and spatial variation of the stellar initial mass function (IMF) in star-forming disk galaxies by using chemodynamical simulations with an IMF model depending both on local densities and metallicities…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Kenji Bekki , Gerhardt R. Meurer

The distribution of stellar masses that form in one star-formation event in a given volume of space is called the initial mass function (IMF). The IMF has been estimated from low-mass brown dwarfs to very massive stars. Combining IMF…

Astrophysics · Physics 2009-11-07 Pavel Kroupa

[abridged] We aim to constrain the stellar initial mass function (IMF) during the epoch of reionization. To this purpose, we build up a semi-empirical model for the reionization history of the Universe, based on various ingredients: the…

Astrophysics of Galaxies · Physics 2024-03-14 A. Lapi , G. Gandolfi , L. Boco , F. Gabrielli , M. Massardi , B. S. Haridasu , C. Baccigalupi , A. Bressan , L. Danese

Observations with JWST have revealed an unexpected high abundance of bright z>10 galaxy candidates. We explore whether a stellar initial mass function (IMF) that becomes increasingly top-heavy towards higher redshifts and lower gas-phase…

We present new observations of the nuclear star cluster in the central parsec of the Galaxy with the adaptive optics assisted, integral field spectrograph SINFONI on the ESO/VLT. Our work allows the spectroscopic detection of early and late…

The stellar initial mass function (IMF) describes the mass distribution of stars at the time of their formation and is of fundamental importance for many areas of astrophysics. The IMF is reasonably well constrained in the disk of the Milky…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Pieter van Dokkum , Charlie Conroy

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