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\title{THE SPECTRAL ENERGY DISTRIBUTION OF NORMAL STARBURST\\
~\\
AND ACTIVE GALAXIES}

\author{Henrique R.\ Schmitt\/\thanks{Also Space Telescope Science
Institute, 3700 San Martin Drive, Baltimore, MD 21218.}\morethanks{CNPq
Fellow.}\\
\\
Departamento de Astronomia\\
\\
IF-UFRGS\\
\\
CP 15051, CEP91501-970\\
\\
Porto Alegre, RS, Brazil\\
\and
Anne L.\ Kinney\/\thanks{Also Department of Physics and Astronomy, The Johns
Hopkins University, Baltimore, MD 21218.} and
Daniela Calzetti\\
\\
Space Telescope Science Institute\\
\\
3700 San Martin Drive\\
\\
Baltimore, MD 21218\\
\and
Thaisa Storchi-Bergmann\\
\\
Departamento de Astronomia\\
\\
IF-UFRGS\\
\\
CP 15051, CEP91501-970\\
\\
Porto Alegre, RS, Brazil}

\tobe{August 1997}{Astronomical Journal}
\recacc{15 February 1997}{12 May 1997}
\maketitle
\abstract{
We present the results of an extensive literature search of
multiwavelength data for a sample of 59~galaxies, consisting of
26~Starbursts, 15~Seyfert~2's, 5~LINER's, 6~normal spirals and 7~normal
elliptical galaxies. The data include soft X-ray fluxes, ultraviolet
and optical spectra, near, mid/far infrared photometry and radio
measurements, selected to match as closely as possible the IUE aperture
(10\arcsec$\times$20\arcsec). The galaxies are separated into 6~groups with
similar characteristics, namely, Ellipticals, Spirals, LINER's, Seyfert~2's,
Starbursts of Low and High reddening, for which we create average
spectral energy distributions (SED).

The individual groups SED's are normalized to the
$\lambda$7000~\AA\ flux and compared, looking for similarities and
differences among them. We find that the SED's of Normal Spirals and
Ellipticals are very similar over the entire energy range, and fainter
than those of all other groups. LINER's SED's are similar to those of
Seyfert~2's and Starbursts only in the visual to near-IR waveband,
being fainter in the remaining wavebands. Seyfert~2's are similar to
Starbursts in the radio to near-IR waveband, fainter in the visual to
ultraviolet, but stronger in the X-rays. Low and High reddening
Starbursts are similar along the entire SED, differing in the
ultraviolet, where Low reddening Starbursts are stronger, and in the
mid/far IR where they are fainter.

We have also collected multiwavelength data for 4~HII regions, a
thermal supernova remnant, and a non-thermal supernova remnant (SNR),
which are compared with the Starburst SED's. The HII regions and
thermal SNR's have similar SED's, differing only in the X-ray and far
infrared. The non-thermal SNR SED is a flat continuum, different from
all the other SED's. Comparing the SED's of Starbursts and HII regions
we find that they are similar in the mid/far IR parts of the
spectrum, but HII regions are fainter in the radio and X-rays.
Starbursts are also stronger than HII regions in the visual and near-IR
parts of the spectrum, due to the contribution from old stars to
Starbursts.

The bolometric fluxes of the different types of galaxies are calculated
integrating their SED's. These values are compared with individual
waveband flux densities, in order to determine the wavebands which
contribute most to the bolometric flux. In Seyfert~2's, LINER's and
Starbursts, the mid/far IR emission are the most important
contributers to the bolometric flux, while in normal Spirals and
Ellipticals this flux is dominated by the near-IR and visual
wavebands. Linear regressions were performed between the bolometric
and individual band fluxes for each kind of galaxy. These fits can be
used ine the calculation of the bolometric flux for other objects of
similar activity type, but with reduced waveband information.}