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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20090318T000000
DTEND;TZID=Atlantic/Canary:20090318T010000
UID:iactalks-66
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/66
CREATED:2009-03-18T00:00:00+00:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:An optical/NIR survey of globular clusters in early-type galaxies
DESCRIPTION:An optical/NIR survey of globular clusters in early-type galaxi
 es\nDr. Ana Chies Santos\n\nThe colour distribution of globular cluster (G
 C) systems in the majority of galaxies is bi/multimodal in optical colours
 . It is widely accepted that multiple populations differing in metallicity
  exist implying different mechanisms/epochs of star formation, with small 
 age differences still being allowed due to the large current uncertainties
 . Recently Yoon, Yi and Lee (2006) challenged this interpretation stating 
 that the metallicity bimodality is an artifact of the horizontal branch (H
 B) morphologies that can transform a unimodal metallicity distribution in 
 a bimodal (optical) colour distribution. The combination of optical and ne
 ar-infrared (NIR) colours can in principal break the age/metallicity degen
 eracy inherent in optical colours alone, allowing  age estimates for a lar
 ge sample of GCs possible at the same time. It has been shown that the col
 ours that best represent the true metallicity distributions are the combin
 ation of optical and NIR (eg. Puzia et al. 2002, Cantiello & Blakeslee 200
 7). Therefore studying GCs in the NIR is crucial to reveal their true meta
 llicity distributions. We are currently building a homogeneous optical/NIR
  data set of GC systems in a large sample of elliptical and lenticular gal
 axies. I will present the sample, an attempt to estimate overall ages and 
 metallicities for the GC systems and the optical/NIR colour distributions.
 \n
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