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| Paper: |
NIRSPEC Spectroscopy of a Massive Obscured Star Cluster in the Antennae Galaxies (NGC 4038/4039) |
| Volume: |
211, Massive Stellar Clusters |
| Page: |
101 |
| Authors: |
Gilbert, A. M.; Graham, J. R.; McLean, I. S.; Becklin, E. E.; Larkin, J. E.; Wilcox, M. K.; Figer, D. F.; Levenson, N. A.; Teplitz, H. I. |
| Abstract: |
We present infrared spectroscopy of the Antennae Galaxies (NGC 4038/4039) with NIRSPEC at the W. M. Keck Observatory. We imaged the star clusters in the vicinity of the southern nucleus (NGC 4039) in 0".39 seeing in K-band using NIRSPEC's slit-viewing camera. The brightest star cluster revealed in the near-IR (MK(0) -17.9) is insignificant optically, but coincident with the highest surface brightness peak in the mid-IR 12-18 mu) ISO image presented by Mirabel et al. (1998). We obtained high signal-to-noise 2.03-2.45 mu spectra of the nucleus and the obscured star cluster at R 1900. The cluster is young (age 4 Myr), massive (M 16 x106 Msun), and compact (density 115 Msun/(pc3) within a 32 pc half-light radius), assuming a Salpeter IMF (0.1-100 Msun). Its hot stars have a radiation field characterized by Teff 39000K, and they ionize a compact ion{H}{ii} region with n_e 104 cm-3. The stars are deeply embedded in gas and dust (Av 9-10 mag), and their strong FUV field powers a clumpy photodissociation region with densities n_H >= 105 cm-3 on scales of 200 pc, radiating L[H2 1-0 S(1)]= 9600 Lsun. |
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