AAS 197, January 2001
Session 78. Nearby Galaxies I
Display, Wednesday, January 10, 2001, 9:30am-7:00pm, Exhibit Hall

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[78.13] GALSPEC: A Tool for Computing the Spectra of Star-Forming Galaxies of Low Metallicity

S. R. Heap (NASA's GSFC), I. Hubeny (AURA, GSFC), T. M. Lanz (U. Md., GSFC), D. J. Lindler (ACC Inc., GSFC)

The far-ultraviolet spectral region is rich in diagnostics of star formation in galaxies; it gives information not only about the star-forming complex, but also about the dust and circumstellar gas. We have therefore developed a tool, called GALSPEC, for computing far-UV spectra of star-forming galaxies. The user controls the process through a graphical user interface (GUI) by specifying the input parameters for the stars, dust, and gas.

GALSPEC computes the integrated spectrum of a star-forming complex, given the rate of star formation, metallicity (0.2 Z\odot or 0.5 Z\odot), and IMF upper mass limit. To compute the integrated spectrum, GALSPEC makes use of a library of stellar spectra composed of observed spectra from HST and model spectra calculated with the TLUSTY/SYNSPEC program (Hubeny & Lanz 1995).

GALSPEC then applies wavelength-dependent extinction according to Calzetti's starburst extinction law.

The mechanical luminosity from massive stars and supernovae sweeps up interstellar material thereby forming an expanding shell with a central cavity. GALSPEC computes the absorption spectrum of the shell using the CLOUDSPEC program (Hubeny 2000), a combination of Ferland's CLOUDY program and SYNSPEC.

This work was supported by the STIS GTO program at Goddard and by STScI grants (GO 7437, AR 7985).

The author(s) of this abstract have provided an email address for comments about the abstract: heap@srh.gsfc.nasa.gov

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