Deep CCD photometry in globular clusters III. M15

Journal Article · Sat Jun 01 04:00:00 EDT 1985 · Astrophys. J., Suppl. Ser.; (United States)

DOI:https://doi.org/10.1086/191039· OSTI ID:5546643

Fahlman, G G; Richer, H B; Vandenberg, D A

CCD photometry in U, B, and V is presented for a 5' x 3' field in the globular cluster M15. The location of the main sequence in the color-magnitude diagram is found here to be significantly bluer than previous studies have indicated. The luminosity function of the cluster is studied down to V = 22.8 (Mroughly-equal7.5) and shown to be consistent with a power-law mass function, n(M) = QM/sup -alpha/ with ..cap alpha.. = 2.5 +- 1.0, to the limit of our data. The field star population brighter than V = 21.5, is examined in some detail. There appears to be about 50% more stars belonging to the disk in the field as compared with the Bahcall-Soneira standard galaxy model. The reddening to the cluster is found to be E(B-V) = 0.11 +- 0.04 from nine bright field stars. A new value for the ultraviolet excess of the cluster main-sequence stars is obtained, delta(0.6) = 0.25 +- 0.02, and confirms the well-known fact that M15 is among the metal poorest of the globular clusters.

• Research Organization: Department of Geophysics and Astronomy, University of British Columbia, Vancouver, Canada
• OSTI ID: 5546643
• Journal Information: Astrophys. J., Suppl. Ser.; (United States), Journal Name: Astrophys. J., Suppl. Ser.; (United States) Vol. 58:2; ISSN APJSA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
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CHEMICAL COMPOSITION
DISTANCE
PHOTOMETRY
SEMICONDUCTOR DEVICES
STAR CLUSTERS
STAR EVOLUTION
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