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.

The link between the star formation history and [α/Fe ].

Author/s: de La Rosa, I.G.; La Barbera, F.; Ferreras, I.; de Carvalho, R.R.

Reference: 2011 MNRAS.tmpL.332D | Link

Variation of the star formation history with respect to dynamical mass (each panel <br />representing a mass bin as given in Table 2). Sketchy (theoretical) SFHs, plotted as grey Gaussian curves, are superimposed over the detailed (empirical) SFH histograms (black filled) obtained through spectral fitting. The Gaussian curves are obtained from equation 4 of Thomas et al. (2005), using our SSP-equivalent <age>_L (+ lookback time) and [alpha/Fe] values, with curves normalized to span the same area as the histograms. Arrows mark the position of the mass-weighted <age>_M, obtained from the SFH histograms. Each panel also displays M_(z<1), i.e. the stellar mass percentage formed after z=1. The grey insets at the upper-left corners are the metallicity histograms, <[Z/H]>_M, for each mass bin, with a dotted line at the solar metallicity.
Variation of the star formation history with respect to dynamical mass (each panel
representing a mass bin as given in Table 2). Sketchy (theoretical) SFHs, plotted as grey Gaussian curves, are superimposed over the detailed (empirical) SFH histograms (black filled) obtained through spectral fitting. The Gaussian curves are obtained from equation 4 of Thomas et al. (2005), using our SSP-equivalent <age>_L (+ lookback time) and [alpha/Fe] values, with curves normalized to span the same area as the histograms. Arrows mark the position of the mass-weighted <age>_M, obtained from the SFH histograms. Each panel also displays M_(z<1), i.e. the stellar mass percentage formed after z=1. The grey insets at the upper-left corners are the metallicity histograms, <[Z/H]>_M, for each mass bin, with a dotted line at the solar metallicity.

The abundance ratios between key elements such as iron and α-process elements carry a wealth of information on the star formation history (SFH) of galaxies. So far, simple chemical evolution models have linked [α/Fe ] with the SFH time-scale, correlating large abundance ratios with short-lived SFH. The incorporation of full spectral fitting to the analysis of stellar populations allows for a more quantitative constraint between [α/Fe ] and the SFH. In this letter, we provide, for the first time, an empirical correlation between [α/Fe ] (measured from spectral indices) and the SFH (determined via a non-parametric spectral-fitting method). We offer an empirical version of the iconic outline of Thomas et al., relating star formation time-scale with galaxy mass, although our results suggest, in contrast, a significant population of old (≳10 Gyr) stars even for the lowest mass ellipticals (M/dyn ˜ 3 × 1010  Msun). In addition, the abundance ratio is found to be strongly correlated with the time to build up the stellar component, showing that the highest [α/Fe ] (≳+0.2) are attained by galaxies with the shortest half-mass formation time (≲2 Gyr), or equivalently, with the smallest (≲40 per cent) fraction of populations younger than 10 Gyr. These observational results support the standard hypothesis that star formation incorporates the Fe-enriched interstellar medium into stars, lowering the high abundance ratio of the old populations.

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