Abstract
Wide-band optical and infrared photometric measurements of the galaxies NGC 2768 (E5) and NGC 3115 (E7/S0) are used to test the efficacy of the color indices (U-V) and (U-R) as metal-abundance indicators. The color indices (U-V) and (V-K) measured along the minor axes of galaxies are compared with previously published integrated colors of globular clusters and a sample of galaxies of differing absolute magnitudes. The observations suggest that if metal-abundance variations are mainly responsible for the color changes observed for the clusters and the galaxies, they are the likely cause of intragalaxian color changes as well. A further test is provided by a comparison of observed (U-V) colors with measurements of strong atomic and molecular features at selected points along the minor axis of NGC 3115. These colors are found to be consistent with those predicted from the line-strength measurements and Faber's (1973) relations between line strength and color for a sample of E and S0 galaxies of differing luminosity. The data permit a detailed study of the surface brightness and color distribution in NGC 2768; this study provides additional support for gas-dynamical models of E-galaxy formation.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
