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As most if not all stars are born in stellar clusters the shape of the mass function of the field stars is not only determined by the initial mass function of stars (IMF) but also by the cluster mass function (CMF). In order to quantify…

Astrophysics · Physics 2015-11-11 Carsten Weidner , Pavel Kroupa

We present the new technique for the determination of the low-mass slope of the stellar mass function from the pixel-space fitting of integrated light spectra. This technique is the extension of the NBursts full spectral fitting technique.…

Instrumentation and Methods for Astrophysics · Physics 2013-01-25 N. Podorvanyuk , I. Chilingarian , I. Katkov

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

We show the results of deep V and I HST photometry of 6 rich star clusters in the Large Magellanic Cloud with different ages and metallicities. The number of stars with measured magnitudes in each cluster varies from about 3000 to 10000. We…

Astrophysics · Physics 2009-11-06 B. Santiago , S. Beaulieu , R. Johnson , G. Gilmore

As an introduction of a kinematic survey of Magellanic Cloud (MC) star clusters, we report on the dynamical masses and mass-to-light ($M/L$) ratios of NGC 419 (SMC) and NGC 1846 (LMC). We have obtained more than one hundred high-resolution…

Astrophysics of Galaxies · Physics 2019-10-16 Ying-Yi Song , Mario Mateo , A. D. Mackey , Edward W. Olszewski , Ian U. Roederer , Matthew G. Walker , John I. Bailey

When an universal untruncated star cluster initial mass function (CIMF) described by a power-law distribution is assumed, the mass of the most massive star cluster in a galaxy (M_max) is the result of the size-of-sample (SoS) effect. This…

Astrophysics · Physics 2015-06-24 M. Gieles , S. S. Larsen , M. R. Haas , R. A. Scheepmaker , N. Bastian

We show that we can obtain a good fit to the present day stellar mass functions (MFs) of a large sample of young and old Galactic clusters in the range 0.1 - 10 Msolar with a tapered power law distribution function with an exponential…

Astrophysics of Galaxies · Physics 2015-05-19 Guido De Marchi , Francesco Paresce , Simon Portegies Zwart

We have undertaken the largest systematic study of the high-mass stellar initial mass function (IMF) to date using the optical color-magnitude diagrams (CMDs) of 85 resolved, young (4 Myr < t < 25 Myr), intermediate mass star clusters…

We attempt to evaluate whether the integrated galactic IMF (IGIMF) is expected to be steeper than the IMF within individual clusters through direct evaluation of whether there is a systematic dependence of maximum stellar mass on cluster…

Solar and Stellar Astrophysics · Physics 2010-09-02 C. Clarke , Th. Maschberger

We reanalyze the catalogs of molecular clouds in the Local Group to determine the parameters of their mass distributions in a uniform manner. The analysis uses the error-in-variables method of parameter estimation which accounts not only…

Astrophysics · Physics 2009-11-11 E. Rosolowsky

The dichotomy between a universal mass function (IMF) and a variable IMF which depends on local physical parameters characterises observational and theoretical stellar astronomy. In this contribution the available distributions of…

Astrophysics · Physics 2011-09-20 Lorenzo Zaninetti

In a recent preprint, Hearin et al. (2012,H12) suggest that the halo mass-richness calibration of clusters can be improved by using the difference in the magnitude of the brightest and the second brightest galaxy (magnitude gap) as an…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Surhud More

(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

We present a maximum-likelihood analysis of galaxy-galaxy lensing effects in galaxy clusters and in the field. The aim is to determine the accuracy and robustness of constraints that can be obtained on galaxy halo properties in both…

Astrophysics · Physics 2009-11-10 Marceau Limousin , Jean Paul Kneib , Priyamvada Natarajan

We present a modern machine learning approach for cluster dynamical mass measurements that is a factor of two improvement over using a conventional scaling relation. Different methods are tested against a mock cluster catalog constructed…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-15 Michelle Ntampaka , Hy Trac , Danica J. Sutherland , Nicholas Battaglia , Barnabas Poczos , Jeff Schneider

We present a thorough literature study of the most-massive star, m_max, in several young star clusters in order to assess whether or not star clusters are populated from the stellar initial mass function (IMF) by random sampling over the…

Solar and Stellar Astrophysics · Physics 2015-05-14 C. Weidner , P. Kroupa , I. Bonnell

In the Large Magellanic Cloud (LMC), there have been very few clusters observed with ages between 4 and 11 Gyr. This phenomenon is sometimes referred to as the `LMC age gap'. We constructed a model of the cluster age distribution aimed at…

Astrophysics of Galaxies · Physics 2026-05-12 Jonathan H. Klos , Andrés E. Piatti

Deep images of the galactic globular cluster M4 taken at various locations with the NIC3 and the WFPC2 cameras on HST were used to derive detailed local optical and near IR luminosity functions. White dwarfs have been detected for the first…

Astrophysics · Physics 2007-05-23 L. Pulone , G. De Marchi , F. Paresce

The luminosity function (LF) of young star clusters is often approximated by a power law function. For clusters in a wide range of galactic environments this has resulted in fit indices near -2, but on average slightly steeper. A…

Astrophysics of Galaxies · Physics 2009-08-21 M. Gieles

We present the implementation of a Bayesian formalism within the Stochastically Lighting Up Galaxies (SLUG) stellar population synthesis code, which is designed to investigate variations in the initial mass function (IMF) of star clusters.…