Ministerio de Economía y Competitividad Gobierno de Canarias Universidad de La Laguna CSIC Centro de Excelencia Severo Ochoa

Results Gallery

Select a year: 2017 | 2016 | 2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | 2006 | 2005 | 2004 | 2003 |

· More scientific highlights from this year.

Radial variations in the stellar initial mass function of early-type galaxies.

Author/s: Martín-Navarro, I.; La Barbera, F.; Vazdekis, A.; Falcón-Barroso, J. & Ferreras, I.

Reference: 2015MNRAS.447.1033M | Link

The hypothesis of a universal initial mass function (IMF) - motivated by observations in nearby stellar systems - has been recently challenged by the discovery of a systematic variation of the IMF with the centralvelocity dispersion, σ, of early-type galaxies (ETGs), towards an excessof low-mass stars in high-σ galaxies. This trend has been derived so farfrom integrated spectra, and remains unexplained at present. To testwhether such trend depends on the local properties within a galaxy, we have obtained new, extremely deep, spectroscopic data, for three nearby ETGs, two galaxies with high σ (~300 km/s), and one lower mass system, with σ ~100 km/s. From the analysis of IMF-sensitive spectral features, we find that the IMF depends significantly ongalactocentric distance in the massive ETGs, with the enhanced fraction of low-mass stars mostly confined to their central regions. In contrast, the low-σ galaxy does not show any significant radial gradient in the IMF, well described by a shallower distribution, relative to the innermost regions of massive galaxies, at all radii. Such a result indicates that the IMF should be regarded as a local (rather than global) property, and suggests a significant difference between the formation process of the core and the outer regions ofmassive ETGs

We use our own cookies and cookies from a third party to gather statistical information to improve our services and our website. If you continue with the navigation, you are accepting the installation and use of these cookies. You can change the configuration of your browser not to accept the installation or you can obtain more information in our Cookie Policy.

OK