2004AJ....128..202S


Query : 2004AJ....128..202S

2004AJ....128..202S - Astron. J., 128, 202-210 (2004/July-0)

Keck spectroscopy of two young globular clusters in the merger remnant NGC 3921.

SCHWEIZER F., SEITZER P. and BRODIE J.P.

Abstract (from CDS):

Low-resolution, ultraviolet-to-visual spectra of two candidate globular clusters in the merger remnant NGC 3921 (czLG=6021 km/s) are presented. These two clusters of apparent magnitude V~22.2 (MV~-12.5) lie at projected distances of about 5 kpc (0.9 Reff) from the center and move with halo-type radial velocities relative to the local galaxy background. Their spectra show strong Balmer absorption lines [EW(Hβ-Hδ)=11-13 Å] indicative of main-sequence turnoffs dominated by A-type stars. Comparisons with model-cluster spectra computed by Bruzual & Charlot and others yield cluster ages in the range of 200-530 Myr, and metallicities about solar to within a factor of three. Given their small half-light radii (Reff≲5 pc) and ages corresponding to ∼102 core-crossing times, these clusters are gravitationally bound and hence indeed young globulars. Assuming that they had Chabrier-type initial mass functions, their estimated current masses are (2.3±0.1)x106M☉and (1.5±0.1)x106M☉, respectively, or roughly half the mass of ω Cen. Since NGC 3921 itself shows many signs of being a 0.7±0.3 Gyr old protoelliptical, these two young globulars of roughly solar metallicity and their many counterparts observed with the Hubble Space Telescope provide supporting evidence that, in the process of forming elliptical-like remnants, major mergers of gas-rich disks can also increase the number of metal-rich globular clusters.

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Journal keyword(s): Galaxies: Abundances - Galaxies: Formation - Galaxies: Individual: NGC Number: NGC 3921 - Galaxies: Interactions - Galaxies: Star Clusters

Simbad objects: 19

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Number of rows : 19
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 1275 Bla 03 19 48.1599902040 +41 30 42.108850836   13.10 12.48 11.09   ~ 4243 3
2 NGC 1316 rG 03 22 41.789 -37 12 29.52 9.81 9.15 8.53 7.66   ~ 1491 1
3 PG 0823+546 HS* 08 26 49.6108286760 +54 28 00.333515460   14.09 14.32 14.63   sdOC 33 0
4 Ton 21 WD* 09 42 50.6352905952 +26 00 59.844255084   14.18 14.53     DA.7 43 0
5 NGC 3256 Sy2 10 27 51.284 -43 54 13.55   11.83 11.33 10.62 11.9 ~ 920 2
6 NGC 3597 EmG 11 14 41.9796496464 -23 43 39.573399828   13.62   12.46   ~ 134 1
7 NGC 3610 GiG 11 18 25.2827189856 +58 47 10.433735988   11.4       ~ 327 0
8 S96 25 Gl? 11 51 01.192 +55 04 41.72     21.91     ~ 3 0
9 S96 1 Gl? 11 51 05.763 +55 04 42.39     22.17     ~ 5 0
10 S96 2 Gl? 11 51 06.633 +55 04 55.51     22.31     ~ 4 0
11 NGC 3921 LIN 11 51 06.8803989360 +55 04 43.414457484   13.4 12.64     ~ 260 1
12 [SMW96] 54 Gl? 11 51 07.075 +55 04 45.68     21.64     ~ 2 0
13 NGC 4038 EmG 12 01 53.002 -18 52 03.32   10.91   9.74 11.0 ~ 1364 1
14 NAME Antennae IG 12 01 53.170 -18 52 37.92           ~ 1749 0
15 NGC 4039 GiP 12 01 53.51 -18 53 10.3   11.08   9.77   ~ 1173 1
16 NGC 4365 GiG 12 24 28.228 +07 19 03.07   11.5       ~ 871 0
17 NAME Centaurus A BLL 13 25 27.61521044 -43 01 08.8050291   8.18 6.84 6.66   ~ 4774 3
18 NGC 7252 AGN 22 20 44.7748209648 -24 40 41.909518200 12.26 12.46 12.06 11.57   ~ 720 1
19 NAME Local Group GrG ~ ~           ~ 9325 0

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