Other
Scientific paper
May 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011aas...21813311y&link_type=abstract
American Astronomical Society, AAS Meeting #218, #133.11; Bulletin of the American Astronomical Society, Vol. 43, 2011
Other
Scientific paper
The colors of globular clusters (GCs) in most large elliptical galaxies are bimodal. Based on the observed linear relations between GC colors and their metallicities, the bimodality is taken as evidence of two GC subsystems with different metallicities in each galaxy and has led to a number of theories in the context of galaxy formation. More recent observations and modeling of GCs, however, suggest that colors likely trace metallicities in a subtly nonlinear manner. The nonlinearity could even transform a broad, unimodal metallicity spread into a strongly bimodal color distribution. Despite the far-reaching implications, whether color-metallicity relations (CMRs) are nonlinear and whether the nonlinearity indeed causes the color bimodality are still open questions. Given that the spectroscopic refinement of CMRs is still very challenging, we here propose a new photometric tool to probe the possible nonlinear nature of CMRs. In essence, a color distribution of GCs is a "projected” distribution of their metallicities based on a given CMR. Since the form of CMRs hinges on which color is used, the shape of color distributions varies depending significantly on colors in use. Among other optical colors, the u-band colors (e.g., u-g and u-z) are theoretically predicted to exhibit the most distinctive CMRs from other preferred CMRs (e.g., for g-z). As a case study, we performed the HST/WFPC2 archival u-band photometry for the M87 GC system with confirmed color bimodality. We show that any weak yet discernible feature on CMRs is amplified appreciably on the color domain by the projection effect, and hence, under the assumption of the nonlinear CMRs, the u-band color distributions are significantly different and readily distinguishable from those under the assumption of the conventional linear CMRs. With more data, this method will support or rule out the nonlinear-CMR scenario for GC color bimodality with high confidence.
Cho Jungyeon
Chung Chih-Ching
Kim Hungsoo
Lee Seongsu
Sohn Sangmo Tony
No associations
LandOfFree
Color Bimodality of Extragalactic Globular Clusters: A Test for the Nonlinear Color-Metallicity Relation Scenario via the u-band Colors does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Color Bimodality of Extragalactic Globular Clusters: A Test for the Nonlinear Color-Metallicity Relation Scenario via the u-band Colors, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Color Bimodality of Extragalactic Globular Clusters: A Test for the Nonlinear Color-Metallicity Relation Scenario via the u-band Colors will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1738734