1 / 13

Chemical clocks for early-type galaxies in clusters

Chemical clocks for early-type galaxies in clusters Carretero, Vazdekis & Beckman. 2006, MNRAS, in press. Conrado Carretero Alejandro Vazdekis John E. Beckman. Framework: how were galaxies formed?. Our study:.

coen
Download Presentation

Chemical clocks for early-type galaxies in clusters

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chemical clocks for early-type galaxies in clusters Carretero, Vazdekis & Beckman. 2006, MNRAS, in press Conrado Carretero Alejandro Vazdekis John E. Beckman

  2. Framework: how were galaxies formed?

  3. Our study: • Detailed stellar population (SP) analysis: offer a “fossil record” of galaxy formation and evolution processes. • Based on new stellar population models and a new methodology. • We concentrate on early-type galaxies since they represent most of the luminous mass of clusters. • SAMPLE: 27 massive (250 km/s < s < 450 km/s) elliptical galaxies distributed in 4 very rich clusters (richness class 3).

  4. Ages Information obtained from SP Abundances We use certain elements as “chemical clocks”:

  5. Ages Information obtained from SP Abundances • We use certain elements as “chemical clocks”: • Mg Produced by SNe II in ~0.01 Gyr(e.g. Faber, Worthey & González 1992) • CN By intermediate-mass stars in ~0.5 Gyr (e.g. Chiappini et al. 2003) • Fe Produced, mainly, by SNe Ia in ~1 Gyr(e.g. Hughes et al. 1992) • Others…

  6. C, CN Fe Mg SFR 1 Gyr 0.01 Gyr 0.5 Gyr TODAY time Ages Information obtained from SP Abundances We use certain elements as “chemical clocks”: SP formation timescales SHORT LONG

  7. The values of the abundance ratios of those elements, measured in a galaxy, are related with the formation timescale of its stellar population. Do they depend on the environment? Ages Information obtained from SP Abundances • We use certain elements as “chemical clocks”: • Mg Produced by SNe II in ~0.01 Gyr (e.g. Faber, Worthey & González 1992) • CN By intermediate-mass stars in ~0.5 Gyr (e.g. Chiappini et al. 2003) • Fe Produced, mainly, by SNe Ia in ~1 Gyr(e.g. Hughes et al. 1992) • Others…

  8. Age Age Age Z Z Z Ages Information obtained from SP Abundances

  9. Results

  10. Our sample Coma* Virgo* * Taken from Sánchez-Blázquez et al. (2006) Results

  11. [CN/Fe] gradient with cluster mass Results [Mg/Fe] provides an upper limit for SP formation timescales (~1 Gyr) while [CN/Fe] is most suitable to discriminate between different timescales (linked to the environment) but…

  12. Results [Mg/Fe] provides an upper limit for SP formation timescales (~1 Gyr) while [CN/Fe] is most suitable to discriminate between different timescales (linked to the environment) but… … only for those galaxies with s < 300 km/s

  13. Conclusions • [CN/Fe] and [Mg/Fe] appear to be the key “chemical clocks” for infering the star formation history timescales in ellipticals. • [Mg/Fe] provides an upper limit for those formation timescales, while [CN/Fe] discriminates more finely among them. • We estimate an upper limit of <1 Gyr for those formation timescales, independently of their environment and galaxy mass. • Star formation history timescales in ellipticals depend on the environment: shorter timescales in denser environments. These differences become smaller as the galaxy mass increases.

More Related