Description

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 (12−18µm) ISO image presented by Mirabel et al. (1998).We obtained high signal-to-noise 2.03−2.45 µm spectra of the nucleus and the obscured star cluster at R ∼ 1900. The cluster is very young (age ∼ 4 Myr), massive (M ∼ 16 × 106 M⊙), and compact (density ∼ 115 M⊙ pc−3 within a 32 pc half-light radius), assuming a Salpeter IMF (0.1−100 M⊙). Its hot stars have a radiation field characterized by Teff ∼ 39, 000 K, and they ionize a compact H ii region with ne ∼ 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 nH >∼ 105 cm−3 on scales of ∼ 200 pc, radiating LH21−0 S(1) = 9600 L⊙. (Refer to PDF file for exact formulas).

Date of creation, presentation, or exhibit

2000

Comments

European Space Agency SP-445 Also archived in: arXiv:astro-ph/9912369 v1 17 Dec 1999 AND "Star Formation from the Small to the Large Scale", Proceedings of the 33rd ESLAB Symposium. Held in Noordwijk, The Netherlands: 2-5 Nov 1999. AMG acknowledges support from a NASA GSRP grant. ISBN: 929-09-2780-1Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type

Conference Proceeding

Department, Program, or Center

School of Physics and Astronomy (COS)

Campus

RIT – Main Campus

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