The universal variability of the stellar initial mass function probed by the TIMER survey

alpha_plot_density_gamma_b

Variations in the IMF slope of a Milky Way-like galaxy. Subtle but systematic variations in the IMF are detected from the integrated spectra of NGC3351.

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Authors
Dimitri Gadotti
European Southern Observatory
University of Durham
et al.
References
A&A 684, A110 (2024)

The universality of the stellar initial mass function (IMF) is one of the most widespread assumptions in modern Astronomy and yet, it might be flawed. While observations in the Milky Way generally support an IMF that is invariant with respect to the local conditions under which stars form, measurements of massive early-type galaxies systematically point towards a non-universal IMF. To bridge the gap between both sets of evidence, in this work we measured for the first time the low-mass end of the IMF from the integrated spectra of a Milky Way-like galaxy, NGC3351. We found that the slope of the IMF in this galaxy is similar to that measured in our own galaxy. However, there are subtle yet clear and spatially coherent variations in the observed fraction of low-mass stars (i.e., in the IMF). Our results suggest that systematic variations in the IMF appear to be present in Milky Way-like galaxies.

News type
Research news
Astrophysics
General public
Undergraduate
Formation & Evolution of Galaxies (FYEG)
SEVERO OCHOA

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