2001AJ....121.3100D


Query : 2001AJ....121.3100D

2001AJ....121.3100D - Astron. J., 121, 3100-3113 (2001/June-0)

Near-infrared imaging of the central regions of metal-poor inner spheroid globular clusters.

DAVIDGE T.J.

Abstract (from CDS):

JHK images obtained with the Canada-France-Hawaii Telescope adaptive optics bonnette are used to investigate the near-infrared photometric properties of red giant branch (RGB) and horizontal-branch (HB) stars in eight metal-poor globular clusters with RGC≤2 kpc. The slope of the RGB on the (K, J-K) CMDs confirms the metal-poor nature of these clusters, four of which (NGC 6287, 6293, 6333, and 6355) are found to have metallicities that are comparable to M92. The luminosity functions of RGB stars in inner spheroid and outer halo clusters have similar slopes, although there is a tendency for core-collapsed clusters to have slightly flatter luminosity functions than noncollapsed clusters. The distribution of red HB stars on the (K, J-K) CMDs of inner spheroid clusters with [Fe/H]~-1.5 is very different from that of clusters with [Fe/H]~-2.2, suggesting that metallicity is the main parameter defining HB content among these objects. The RGB bump is detected in four of the inner spheroid clusters, and this feature is used to compute distances to these objects. Finally, the specific frequency of globular clusters in the inner Galaxy is discussed in the context of the early evolution of the bulge. Based on the ratio of metal-poor to metal-rich clusters in the inner Galaxy it is suggested that the metal-poor clusters formed during an early intense burst of star formation. It is also demonstrated that if the globular cluster formation efficiency for the inner Galaxy is similar to that measured in other spheroidal systems, then the main body of the bulge could have formed from gas that was chemically enriched in situ; hence, material from a separate pre-enriched reservoir, such as the disk or outer halo, may not be required to form the bulge.

Abstract Copyright: ∼

Journal keyword(s): Galaxy: Center - Galaxy: General - Infrared Radiation - Stars: General - stars: late type

Simbad objects: 15

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Number of rows : 15
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026
#notes
1 NGC 288 GlC 00 52 45.24 -26 34 57.4   10 8.13     ~ 1130 0
2 NGC 4147 GlC 12 10 06.149 +18 32 31.78   11.45 10.74     ~ 616 0
3 M 13 GlC 16 41 41.634 +36 27 40.75     5.8     ~ 2291 0
4 M 19 GlC 17 02 37.69 -26 16 04.6   8.45 5.57     ~ 406 1
5 NGC 6287 GlC 17 05 09.4906767360 -22 42 28.099250172   11.49 10.30     ~ 240 0
6 NGC 6293 GlC 17 10 10.42 -26 34 54.2           ~ 309 0
7 M 92 GlC 17 17 07.39 +43 08 09.4     6.52     ~ 2240 0
8 M 9 GlC 17 19 11.78 -18 30 58.5   9.36 8.42     ~ 348 0
9 NGC 6355 GlC 17 23 58.65 -26 21 12.3   12.46 11.05     ~ 183 0
10 NGC 6401 GlC 17 38 36.93 -23 54 31.5   11.31 10.71     ~ 203 0
11 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 16269 0
12 NAME Baade Window reg 18 03.5 -30 01           ~ 643 3
13 NGC 6522 GlC 18 03 34.08 -30 02 02.3           ~ 569 0
14 NGC 6642 GlC 18 31 54.23 -23 28 34.1   11.30 10.24     ~ 240 0
15 M 15 GlC 21 29 58.33 +12 10 01.2           ~ 3274 0

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