Skip to main content Accessibility help
×
Home

A new method to estimate the ages of globular clusters: the case of NGC 3201

  • A. Calamida (a1), G. Bono (a2) (a3), P. B. Stetson (a4), M. Dall'Ora (a5), M. Monelli (a6), C. E. Corsi (a3), P. G. Prada Moroni (a7), S. Degl'Innocenti (a7), A. Dotter (a8), C. Brasseur (a8), P. Amico (a1), E. Marchetti (a1), R. Buonanno (a2), A. Di Cecco (a2), S. D'Odorico (a1), I. Ferraro (a3), G. Iannicola (a3), M. Nonino (a7), M. Romaniello (a1), N. Sanna (a2), D. A. Vandenberg (a8), M. Zoccali (a9) and A. Walker (a10)...

Abstract

We devised a new method to estimate globular cluster absolute ages by adopting the knee of the bending of the lower main-sequence (MS) in the Near-Infrared (NIR) J, J - Ks color-magnitude diagram. The color difference between this feature and the Turn-Off point is strongly correlated to the cluster age. This method is marginally affected by distance and reddening uncertainties, and by the possible occurrence of differential reddening. Furthermore, the knee location does not depend on the cluster age and it is a robust theoretical prediction. We adopted accurate J, Ks-band photometry collected with both MAD/VLT and SOFI/NTT for the Galactic globular cluster NGC 3201 to identify the location of the knee at J~19.90 ±0.03 and J-Ks ~0.76±0.02 mag. The comparison with different sets of cluster isochrones, transformed adopting different Color–Temperature–Relations (CTRs), shows that the models are slightly redder than the observations for J > 19 mag. This difference could be due to the presence of a calibration drift or to a problem of the CTRs in this magnitude range.

    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      A new method to estimate the ages of globular clusters: the case of NGC 3201
      Available formats
      ×

      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      A new method to estimate the ages of globular clusters: the case of NGC 3201
      Available formats
      ×

      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      A new method to estimate the ages of globular clusters: the case of NGC 3201
      Available formats
      ×

Copyright

References

Hide All
Belokurov, V., et al. 2007, ApJ, 658, 337
Bono, G., et al. 2008, ApJ, 686, L87
Brott, I. & Hauschildt, P. H. 2005, ESASP, 576, 565
Buonanno, R., et al. 1998, ApJ, 501, L33
Cardelli, J. A., Clayton, , & G. C., , Mathis, J. S. 1989, ApJ, 345, 245
Cariulo, P., Degl'Innocenti, S., & Castellani, V. 2004, A&A 421, 1121
Casetti-Dinescu, D. I., et al. 2007, AJ, 134, 103
Castellani, V. 1999, in Globular clusters, 10th Canary Islands Winter School of Astrophysics, 109
Castellani, V. & Degl'Innocenti, S. 1999, A&A, 344, 97
Covey, K. R., et al. 2003, PASP, 115, 819
Chaboyer, B. 1998, PhR, 307, 23
De, Angeli, et al. 2005, AJ, 130, 116
Dotter, A., et al. 2007, AJ, 134, 376
Dotter, A., et al. 2008, ApJS, 178, 89
Fitzpatrick, E. L. 1999, PASP, 111, 63
Gilmozzi, R. & Spyromilio, J. 2007, Msngr, 127, 11
Gratton, R., Sneden, C., & Carretta, E. 2004, ARA&A, 42, 385
Grillmair, C. J. 2006, ApJ, 651, 29
Harris, W. E. 2003, Catalog of Parameters for Milky Way Globular Clusters: The Database Hamilton: McMaster Univ., http://physun.physics.mcmaster.ca/~harris/mwgc.dat
Kraft, R. & Ivans, I. 2003, PASP, 115, 143
Layden, A. C. & Sarajedini, A. 2003, AJ, 125, 208
Mazur, B., Krzemiski, W., & Thompson, I. B. 2003, MNRAS, 340, 1205
Marchetti, E., et al. 2006, SPIE, 6272, 21
Piersimoni, A., Bono, G., & Ripepi, V. 2002, AJ, 124, 1528
Pulone, L. et al. 1998, ApJ, 492, 41
Pulone, L., De Marchi, G., & Paresce, F. 1999, A&A, 342, 440
Pritzl, B. J., Venn, K. A., & Irwin, M. 2005, AJ, 130, 2140
Renzini, A. 1991, otci.conf., 131
Rosenberg, A., et al. 1999, AJ, 118, 230
Rutledge, , et al. 1997, PASP, 109, 907
Saumon, D., et al. 1994, ApJ, 424, 333
Saumon, D. & Marley, M. S. 2008, ApJ, 689, 1327
Stetson, P. B. 1994, PASP, 106, 250
Stetson, P. B., et al. 1999, AJ, 117, 247
Vandenberg, D., Stetson, P. B., & Bolte, M. 1996, ARA&A, 34, 461
Vandenberg, D., et al. 2002, ApJ, 571, 487
Vandenberg, D. & Clem, J. L. 2003, AJ, 126, 778
Vandenberg, D., et al. 2008, ApJ, 675, 746
van den Bergh, S. 1993, AJ, 105, 971
Zoccali, M., et al. 2000, ApJ, 538, 289
Zoccali, M., et al. 2003, A&A, 399, 931
MathJax
MathJax is a JavaScript display engine for mathematics. For more information see http://www.mathjax.org.

Keywords

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed