Skip to main content Accessibility help
×
Home

Tracing the stellar halo of an early type galaxy out to 25 effective radii

  • Marina Rejkuba (a1)

Abstract

We have used ACS and WFC3 cameras on board HST to resolve stars in the halo of NGC 5128 out to 140 kpc (25 effective radii, Reff) along the major axis and 70 kpc (13 Reff) along the minor axis. This dataset provides an unprecedented radial coverage of stellar halo properties in any galaxy. Color-magnitude diagrams clearly reveal the presence of the red giant branch stars belonging to the halo of NGC 5128 even in the most distant fields. The V-I colors of the red giants enable us to measure the metallicity distribution in each field and so map the metallicity gradient over the sampled area. The stellar metallicity follows a shallow gradient and even out at 140 kpc (25 Reff) its median value does not go below [M/H]~−1 dex. We observe significant field-to-field metallicity and stellar density variations. The star counts are higher along the major axis when compared to minor axis field located 90 kpc from the galaxy centre, indicating flattening in the outer halo. These observational results provide new important constraints for the assembly history of the halo and the formation of this gE galaxy.

    • 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.

      Tracing the stellar halo of an early type galaxy out to 25 effective radii
      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.

      Tracing the stellar halo of an early type galaxy out to 25 effective radii
      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.

      Tracing the stellar halo of an early type galaxy out to 25 effective radii
      Available formats
      ×

Copyright

References

Hide All
Bird, S., Harris, W. E., Blakeslee, J. P., & Flynn, C. 2010, A&A 524, A71
Bird, S., Flynn, C., Harris, W. E., & Valtonen, M. 2015, A&A 575, A72
Crnojević, D., Ferguson, A. M. N., & Irwin, M. J. 2013, MNRAS 432, 832
Davidge, T. J. 2002, AJ 124, 2012
Davidge, T. J. & van den Bergh, S. 2001, ApJ (Letters) 553, L133
Elson, R.A.W. 1997, MNRAS 286, 771
Ferrarese, L., Mould, J. R., & Stetson, P. B. 2007, ApJ 654, 186
Girardi, L., Groenewegen, M. A. T., Hatziminaoglou, E. & daAAAACosta, L. 2005, A&A 436, 895
Gregg, M. D., Ferguson, H. C., Minniti, D., et al. 2004, AJ, 127, 1441
Harris, G. L. H., Harris, W. E., & Poole, G. B. 1999, AJ 117, 855
Harris, G. L. H. & Harris, W. E. 2000 AJ 120, 2423
Harris, G. L. H., Rejkuba, M., & Harris, W. E. 2010, PASA 27, 475
Harris, W. E. & Harris, G. L. H. 2002, AJ 123, 3108
Harris, W. E., Harris, G. L. H., Layden, A. C., & Stetson, P. B. 2007a, AJ 134, 43
Harris, W. E., Harris, G. L. H., Layden, A. C., & Wehner, E. M. H. 2007b, ApJ 666, 903
Neumayer, N. 2010, PASA 27, 449
Peacock, M. B., Strader, J., Romanowsky, A. J., & Brodie, J. P. 2015, ApJ 800, 13
Peng, E. W., Ford, H. C. & Freeman, K. C. 2004, ApJ 602, 685
Pietrinferni, A., Cassisi, S., Salaris, M., & Castelli, F. 2006, ApJ 642, 797
Rejkuba, M., Minniti, D., Silva, D. R., & Bedding, T. 2003, A&A 411, 351
Rejkuba, M., Harris, W. E., Greggio, L., et al. 2005, ApJ 631, 262
Rejkuba, M., Greggio, L., Harris, W. E., & Harris, G. L. H. 2011, A&A 526, A123
Rejkuba, M., Harris, W. E., Greggio, L., et al. 2014, ApJ (Letters) 791, L2
Robin, A. C., Reylé, C., Derriére, S., & Picaud, S. 2003, A&A, 409, 523
Sakai, S., Madore, B. F., Freedman, W. L., et al. 1997, ApJ 478, 49
Soria, R., Mould, J. R., Watson, A. M., et al. 1996, ApJ 465, 79
Tal, T., et al. 2009, AJ 138, 1417
Wu, P-F., Tully, R. B., Rizzi, L.et al. 2014, AJ 148, 7
MathJax
MathJax is a JavaScript display engine for mathematics. For more information see http://www.mathjax.org.

Keywords

Tracing the stellar halo of an early type galaxy out to 25 effective radii

  • Marina Rejkuba (a1)

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