Astrophys. J., 596, 240-252 (2003/October-2)
Kinematic masses of super-star clusters in M82 from high-resolution near-infrared spectroscopy.
McCRADY N., GILBERT A.M. and GRAHAM J.R.
Abstract (from CDS):
Using high-resolution (R∼22,000) near-infrared (1.51-1.75 µm) spectra from Keck Observatory, we measure the kinematic masses of two super-star clusters in M82. Cross-correlation of the spectra with template spectra of cool evolved stars gives stellar velocity dispersions of σr=15.9±0.8 km/s for J0955505+694045 (MGG-9) and σr=11.4±0.8 km/s for J0955502+694045 (MGG-11). The cluster spectra are dominated by the light of red supergiants and correlate most closely with template supergiants of spectral types M0 and M4.5. King model fits to the observed profiles of the clusters in archival Hubble Space Telescope/Near-Infrared Camera and Multi-Object Spectometer images give half-light radii of rhp=2.6±0.4 pc for MGG-9 and rhp=1.2±0.17 pc for MGG-11. Applying the virial theorem, we determine masses of 1.5±0.3x106 M☉for MGG-9 and 3.5±0.7x105 M☉ for MGG-11 (where the quoted errors include σr, rhp, and the distance). Population synthesis modeling suggests that MGG-9 is consistent with a standard initial mass function (IMF), whereas MGG-11 appears to be deficient in low-mass stars relative to a standard IMF. There is, however, evidence of mass segregation in the clusters, in which case the virial mass estimates would represent lower limits.
Galaxies: Individual: Messier Number: M82 - Galaxies: Nuclei - Galaxies: Starburst - Galaxies: Star Clusters - Infrared: Galaxies
Table 3, Figs 1, 6: MGG JHHMMSSs+DDMMSS N=20 = MGG A (Nos F, L), MGG a N=10 among (Nos b-t), MGG NNa (Nos 1a-1c) + N=7 among (Nos 3-11).
Table 3: In the format JHHMMMSSs+DDMMSS there is a misprint for all minutes of Dec: The correct Dec is +6940 (and not 49').
View the reference in ADS
To bookmark this query, right click on this link: simbad:2003ApJ...596..240M and select 'bookmark this link' or equivalent in the popup menu