Evidence in Favour of IMF Variations

Eisenhauer, F.

doi:10.1007/978-3-642-56538-0_4

Cited by 9 publications

(2 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A severe counter argument against this scenario, however, might be the frequency of stellar masses in starbursts and globular clusters. Although no firm conclusion has been reached for starbursts (Eisenhauer 2001;Gilmore 2001), there is strong evidence that these regions form proportionally fewer low mass stars with masses around 1 M ⊙ than typically observed in our Galaxy. Globular clusters, however, are known to contain a large number of such low-mass stars.…”

Section: Super Star Clusterscontrasting

confidence: 62%

Scientific Potential of Enhancing the Integral-Field Spectrometer SPIFFI with a Large Detector and High Spectral Resolution

Eisenhauer

Werf

Thatte

et al. 2002

Scientific Drivers for ESO Future VLT/VLTI Instrumentation

Self Cite

View full text Add to dashboard Cite

Abstract. SPIFFI is the near-infrared integral-field spectrometer for the VLT. Assisted by the SINFONI adaptive optics module, the instrument will be offered to the astronomical community in 2004. We outline the scientific rationale for infrared integral-field spectroscopy at the VLT, and specifically for the enhancement of SPIFFI with a larger detector and higher spectral resolution gratings. We give examples of a broad variety of astronomical research which will gain specifically from the high angular and spectral resolution provided by SPIFFI, including studies of high red-shift galax-

show abstract

Section: Super Star Clusterscontrasting

confidence: 62%

Scientific Potential of Enhancing the Integral-Field Spectrometer SPIFFI with a Large Detector and High Spectral Resolution

Eisenhauer

Werf

Thatte

et al. 2002

Scientific Drivers for ESO Future VLT/VLTI Instrumentation

Self Cite

View full text Add to dashboard Cite

show abstract

“…Another explanation for the dispersion in N/O at a given metallicity involves differing contributions from primary and secondary nitrogen, which essentially amounts to variations of the initial mass function (IMF) from galaxy to galaxy. Despite some claims of IMF variations with time and environment (e.g., Eisenhauer 2001), there is no compelling evidence that the IMF varies in local galaxies (Parker & Garmany 1993;Hill, Madore & Freedman 1994;Hunter et al 1997). Preferential oxygen loss from galaxies with high N/O and more effective oxygen retention in galaxies with low N/O may be an additional explanation for producing N/O variations at constant metallicity.…”

Section: Introductionmentioning

confidence: 96%

Chemical evolution of starburst galaxies: How does star formation proceed?

Mouhcine

Contini

2002

A&A

View full text Add to dashboard Cite

Abstract. We compute chemical evolution models to constrain the mode and the history of star formation in starburst galaxies as a whole, i.e. over a large range of mass and metallicity. To this end, we investigate the origin of the dispersion observed in the evolution of both nitrogen-to-oxygen abundance ratio and galaxy luminosity as a function of metallicity for a large sample of starburst galaxies. We find that the variation of the star formation efficiency, in the framework of continuous star formation models, produces a scatter equivalent to that observed in the N/O versus O/H diagram for low-mass Hii galaxies only. However, continous star formation models are unable to reproduce i) the scatter observed for massive starburst and UV-selected galaxies in the N/O versus O/H relation, and ii) the scatter in the MB versus O/H scaling relation observed for the whole sample of starburst galaxies. The dispersion associated with the distribution of N/O as a function of metallicity, for both low-mass and massive galaxies, is well explained in the framework of bursting star formation models. It is interpreted as a consequence of the time-delay between the ejection of nitrogen and that of oxygen into the ISM. These models also reproduce the spread observed in the luminosity-metallicity relation. Metal-rich spiral galaxies differ from metalpoor ones by a higher star formation efficiency and starburst frequency. Low-mass galaxies experienced a few bursts of star formation whereas massive spiral galaxies experienced numerous and extended powerful starbursts. Finally, we confirm previous claims (Contini et al. 2002) that UV-selected galaxies are observed at a special stage in their evolution. Their low N/O abundance ratios with respect to other starburst galaxies is well explained if they have just undergone a powerful starburst that enriched their ISM in oxygen.

show abstract

The Stellar IMF of Galactic Clusters and Its Evolution

Marchi¹,

Paresce

Zwart

The Initial Mass Function 50 Years Later

View full text Add to dashboard Cite

We show that one can obtain a good fit to the measured main sequence mass function (MF) of a large sample of Galactic clusters (young and old) with a tapered Salpeter power law distribution function with an exponential truncation. The average value of the power law index is very close to Salpeter (∼ 2.3), whereas the characteristic mass is in the range 0.1 − 0.5 M⊙ and does not seem to vary in a systematic way with the present cluster parameters such as metal abundance and central concentration. However, a remarkable correlation with age is seen, in that the peak mass of young clusters increases with it. This trend does not extend to globular clusters, whose peak mass is firmly at ∼ 0.35 M⊙ . This correlation is due to the onset of mass segregation following early dynamical interactions in the loose cluster cores. Differences between globular and younger clusters may depend on the initial environment of star formation, which in turn affects their total mass.

show abstract

Evidence in Favour of IMF Variations

Cited by 9 publications

References 31 publications

Scientific Potential of Enhancing the Integral-Field Spectrometer SPIFFI with a Large Detector and High Spectral Resolution

Scientific Potential of Enhancing the Integral-Field Spectrometer SPIFFI with a Large Detector and High Spectral Resolution

Chemical evolution of starburst galaxies: How does star formation proceed?

The Stellar IMF of Galactic Clusters and Its Evolution

Contact Info

Product

Resources

About