Initial mass function in the South-Western part of M 31

Veltchev, Todor V.; Nedialkov, P.; Borisov, G.

doi:10.1051/0004-6361:20040414

Cited by 5 publications

(6 citation statements)

References 25 publications

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“…Using a framework to infer the distribution of mass function slopes given a set of noisy measurements (Hogg et al 2010;Foreman-Mackey et al 2014), they find that the high mass slope of the IMF is best described by α h = −2.45 +0.06 −0.03 , somewhat steeper than the high mass slope of Kroupa (2001) Andrews et al (2014). This is similar to the result of Veltchev et al (2004) who found α h = −2.59 ± 0.09 (for m > ∼ 7 M ⊙ ) using colour-magnitude diagrams for 50 OB associations in the south-western region of M31.…”

Section: Stellar Clustersmentioning

confidence: 63%

The Dawes Review 8: Measuring the Stellar Initial Mass Function

Hopkins

2018

Publ. Astron. Soc. Aust.

107

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The birth of stars and the formation of galaxies are cornerstones of modern astrophysics. While much is known about how galaxies globally and their stars individually form and evolve, one fundamental property that affects both remains elusive. This is problematic because this key property, the birth mass distribution of stars, referred to as the stellar initial mass function (IMF), is a key tracer of the physics of star formation that underpins almost all of the unknowns in galaxy and stellar evolution. It is perhaps the greatest source of systematic uncertainty in star and galaxy evolution. A star's initial mass determines its luminosity, lifetime, and eventual return of material enriched by nuclear fusion back to the interstellar medium to be incorporated in later generations of stars. The distribution of stellar masses created in star formation events therefore determines the evolution of galaxies over cosmic time, and accurately measuring it is crucial. The past decade has seen a growing number and variety of methods for measuring or inferring the shape of the IMF, along with progressively more detailed simulations, paralleled by refinements in the way the concept of the IMF is applied or conceptualised on different physical scales. This range of approaches and evolving definitions of the quantity being measured has in turn led to conflicting conclusions regarding whether or not the IMF is universal. Here I review and compare the growing wealth of approaches to our understanding of this fundamental property that defines so much of astrophysics. I summarise the observational measurements from stellar analyses, extragalactic studies and cosmic constraints, and highlight the importance of considering potential IMF variations, reinforcing the need for measurements to quantify their scope and uncertainties carefully, in order for this field to progress. I present a new framework to aid the discussion of the IMF and promote clarity in the further development of this fundamental field.

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Section: Stellar Clustersmentioning

confidence: 63%

The Dawes Review 8: Measuring the Stellar Initial Mass Function

Hopkins

2018

Publ. Astron. Soc. Aust.

107

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“…Fifty OB associations summed together in M31 were found to have an IMF slope of À2:59 AE 0:09, using a combination of space-based UV and HST photometry, Two Micron All Sky Survey (2MASS) photometry at the JHK bands, and I-band photometry ( Veltchev et al 2004). The stellar masses ranged from 8 to 100 M .…”

Section: Observations Of Galaxy-integrated Imfsmentioning

confidence: 99%

On the Similarity between Cluster and Galactic Stellar Initial Mass Functions

Elmegreen¹

2006

ApJ

105

132

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The stellar initial mass functions (IMFs) for the Galactic bulge, the Milky Way, other galaxies, clusters of galaxies, and the integrated stars in the universe are composites from countless individual IMFs in star clusters and associations where stars form. These galaxy-scale IMFs, reviewed in detail here, are not steeper than the cluster IMFs except in rare cases. This is true even though low-mass clusters generally outnumber high-mass clusters and the average maximum stellar mass in a cluster scales with the cluster mass. The implication is that the mass distribution function for clusters and associations is a power law with a slope of À2 or shallower. Steeper slopes, even by a few tenths, upset the observed equality between large-and small-scale IMFs. Such a cluster function is expected from the hierarchical nature of star formation, which also provides independent evidence for the IMF equality when it is applied on subcluster scales. We explain these results with analytical expressions and Monte Carlo simulations. Star clusters appear to be the relaxed inner parts of a widespread hierarchy of star formation and cloud structure. They are defined by their own dynamics rather than by preexisting cloud boundaries.

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“…In addition, there are practical problems with star counts in external galaxies, including crowding, incompleteness, and corrections for foreground stars. Among other studies, Veltchev et al (2004) studied the IMF of M 31 and derived a slope of γ = −2.59 ± 0.09; Jamet et al (2004) found an IMF slope of γ = −2.37 ± 0.16 for the ionizing cluster of NGC 588 in the outskirts of the nearby galaxy M 33; Annibali et al (2003) analyzed the star formation history of NGC 1705 and inferred an IMF slope close to Salpeter.…”

Section: The Imf Of the Resolved Populationmentioning

confidence: 99%

“…OB associations have been discovered in some Local Group galaxies, and with the fine spatial resolution provided by the HST, it is possible to obtain the stellar IMF of those systems. Recent works include M31 (Veltchev et al 2004), M33 (González Delgado & Pérez 2000), IC10 (Hunter 2001), and IC1613 (Georgiev et al 1999). The previous work on the IMF of NGC 4214 has been based on the integrated spectrum of the galaxy (Leitherer et al 1996;Chandar et al 2005).…”

Section: Introductionmentioning

confidence: 99%

The young stellar population of NGC 4214 as observed with HST. II. Results

Úbeda,

Maíz-Apellániz,

MacKenty

2007

Preprint

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Initial mass function in the South-Western part of M 31

Cited by 5 publications

References 25 publications

The Dawes Review 8: Measuring the Stellar Initial Mass Function

The Dawes Review 8: Measuring the Stellar Initial Mass Function

On the Similarity between Cluster and Galactic Stellar Initial Mass Functions

The young stellar population of NGC 4214 as observed with HST. II. Results

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