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Deep Hubble Space Telescope observations of star clusters in NGC 1275

Carlson, Matthew N. and Holtzman, Jon A. and Watson, Alan M. and Grillmair, Carl J. and Mould, Jeremy R. and Ballester, Gilda E. and Burrows, Christopher J. and Clarke, John T. and Crisp, David and Evans, Robin W. and Gallagher, John S., III and Griffiths, Richard E. and Hester, J. Jeff and Hoessel, John G. and Scowen, Paul A. and Stapelfeldt, Karl R. and Trauger, John T. and Westphal, James A. (1998) Deep Hubble Space Telescope observations of star clusters in NGC 1275. Astronomical Journal, 115 (5). pp. 1778-1790. ISSN 0004-6256. http://resolver.caltech.edu/CaltechAUTHORS:20150122-093027737

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Abstract

We present an analysis of compact star clusters in deep Hubble Space Telescope Wide Field Planetary Camera 2 images of NGC 1275. B- and R-band photometry of roughly 3000 clusters shows a bimodality in the B-R colors, suggesting that distinct old and young cluster populations are present. The small spread in the colors of the blue clusters is consistent with the hypothesis that they are a single-age population, with an inferred age of 0.1 to 1 Gyr. The luminosity function shows increasing numbers of blue clusters to the limit of our photometry, which reaches several magnitudes past the turnover predicted if the cluster population is identical to current Galactic globular clusters seen at a younger age. The blue clusters have a spatial distribution that is more centrally peaked than that of the red clusters. The individual clusters are slightly resolved, with core radii ≾0.75 pc if they have modified Hubble profiles. We estimate the specific frequencies of the old and young populations and discuss the uncertainties in these estimates. We find that the specific frequency of the young population in NGC 1275 is currently larger than that of the old population and will remain so as the young population evolves, even if the majority of the low-mass clusters are eventually destroyed. If the young population formed during a previous merger, this suggests that mergers can increase the specific frequency of globular clusters in a galaxy. However, the presently observed young population likely contains too few clusters to have a significant impact on the overall specific frequency as it will be observed in the future.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1086/300334DOIArticle
http://iopscience.iop.org/1538-3881/115/5/1778/PublisherArticle
ORCID:
AuthorORCID
Grillmair, Carl J.0000-0003-4072-169X
Mould, Jeremy R.0000-0003-3820-1740
Additional Information:© 1998 American Astronomical Society. Received 1997 November 17; revised 1998 January 22. This work was supported in part by NASA under contract NAS 7-918 to the Jet Propulsion Laboratory and by a grant to M. N. C. from the New Mexico Space Grant Consortium.
Group:Infrared Processing and Analysis Center (IPAC)
Funders:
Funding AgencyGrant Number
NASANAS 7-918
New Mexico Space Grant ConsortiumUNSPECIFIED
Subject Keywords:galaxies, active; galaxies, star clusters
Record Number:CaltechAUTHORS:20150122-093027737
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20150122-093027737
Official Citation:Deep Hubble Space Telescope Observations of Star Clusters in NGC 1275 Matthew N. Carlson et al. 1998 The Astronomical Journal 115 1778
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:53984
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:22 Jan 2015 18:14
Last Modified:05 Oct 2017 20:58

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