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There have been many suggestions that starbursts may play an important role in Seyfert galaxies. Recent analyses of the UV, optical, and near-IR featureless continuum (FC) in type 2 Seyfert nuclei have provided indirect evidence that the FC may be produced by a compact starburst and that this starburst may provide a power source for the pronounced far-IR excess in type 2 Seyfert galaxies. In the present paper, we present and discuss Hubble Space Telescope (HST) images and a UV spectrum plus new ground-based near-UV through near-IR spectra of Mrk 477 (=I Zw 92). This object is arguably the most powerful type 2 Seyfert nucleus in the local universe and thus offers a unique opportunity for detailed investigation of the nature of the FC. The data provide direct evidence that the observed UV through near-IR continuum in the nucleus of Mrk 477 is dominated by light from a dusty starburst. An HST image of the space-UV continuum shows that it arises in a compact (few hundred parsec) region, much smaller than the sizes of previously studied circumnuclear starbursts in Seyfert galaxies like NGC 1068. In the HST space-UV spectrum of this region, we detect strong N V λ1240 and Si IV λ1400 stellar wind lines and other weak photospheric lines from hot stars. In the optical spectrum we detect a broad emission complex around the He II λ4686 line that may be produced by an ensemble of about 30,000 Wolf-Rayet stars (WN subtype). In the near-IR spectrum we detect a strong Ca II triplet feature produced by red supergiants. Detailed comparison of the data with models implies that the nuclear starburst in Mrk 477 has an age of about 6 Myr, was of short duration (an instantaneous burst), and has solar or higher metallicity and a bolometric luminosity of ~(3 × 1010)-1011 L☉. This nuclear starburst must therefore make a significant contribution to the overall energetics of Mrk 477, even though optical spectropolarimetry demonstrates that a powerful hidden type 1 Seyfert nucleus is also present. We speculate that the compact starburst is occurring in the outer reaches of the obscuring torus that hides the type 1 Seyfert nucleus. An observational program that is underway will determine whether Mrk 477 is typical of Seyfert 2 nuclei and, thus, whether nuclear starbursts are an important part of the Seyfert phenomenon.

The ultraviolet-to-radio continuum spectral energy distributions are presented for all 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). A principal component analysis of the sample shows that most of the sample's spectral variations stem from two underlying components, one representative of a galaxy with a low infrared-to-ultraviolet ratio and one representative of a galaxy with a high infrared-to-ultraviolet ratio. The influence of several parameters on the infrared-to-ultraviolet ratio is studied (e.g., optical morphology, disk inclination, far-infrared color, ultraviolet spectral slope, and star formation history). Consistent with our understanding of normal star-forming galaxies, the SINGS sample of galaxies in comparison to more actively star-forming galaxies exhibits a larger dispersion in the infrared-to-ultraviolet versus ultraviolet spectral slope correlation. Early type galaxies, exhibiting low star formation rates and high optical surface brightnesses, have the most discrepant infrared-to-ultraviolet correlation. These results suggest that the star formation history may be the dominant regulator of the broadband spectral variations between galaxies. Finally, a new discovery shows that the 24 micron morphology can be a useful tool for parametrizing the global dust temperature and ultraviolet extinction in nearby galaxies. The dust emission in dwarf/irregular galaxies is clumpy and warm accompanied by low ultraviolet extinction, while in spiral galaxies there is typically a much larger diffuse component of cooler dust and average ultraviolet extinction. For galaxies with nuclear 24 micron emission, the dust temperature and ultraviolet extinction are relatively high compared to disk galaxies., Comment: Accepted for publication in the Astrophysical Journal; Fixed radio flux density units (mJy)

We present results of a self-consistent model of the spectral energy distribution (SED) of starburst galaxies. Two parameters control the IR SED, the mean pressure in the ISM and the destruction timescale of molecular clouds. Adding a simplified AGN spectrum provides mixing lines on IRAS color : color diagrams. This reproduces the observed colors of both AGNs and starbursts., Comment: Poster Paper for IAU 222: The Interplay among Black Holes, Stars and ISM in Galactic Nuclei

Starburst galaxies are ideal laboratories to study both the physics of massive stars and processes important in galaxy formation and evolution. Observations of starburst galaxies at UV wavelengths are crucial because only in this spectral regime can we directly observe the spectroscopic signatures of the hot, massive stars that power the emission at other wavebands. UV signatures from massive stars are mainly broad spectral features (e.g. P Cygni profiles of SiIVλ1400, and CIVλ1550) formed in the stellar winds.

We carried out a spectroscopic and photometric study of the 8 presently known B[e] -stars of the Magellanic Clouds (MC), i. e. R4 and R50 of the SMC, R66, R82, R126, Hen S12, Hen S22 and Hen S134 of the LMC. These stars are characterized by the following typical properties: a) strong Balmer emission lines, frequently with P Cygni profiles, b) permitted and forbidden emission lines predominantly of Fe II, [Fe II], [O I] etc., c) strong IR excess due to circumstellar dust. Photospheric absorption lines are usually weak or even not detectable.

We observed the galactic ring nebula NGC 7635, called the bubble nebula, by means of fluxcafibrated narrowband CCD-frames (Hαf Hβf [NII], [OIII]) and highly resolved coude-longslit spectrograms, covering the wavelength range from 6540 to 6750 A. The results (extinction, exitation, kinematics etc.) yield a picture of NGC 7635 as a wind blown shell, caused by the strong stellar wind from the 0 6.5 IIIf star BD+60°2522. An explanation is given on the physical association of the comet like features seen within the bubble nebula with the nebula itself.

The LMC star R84 (-HDE 269227 -BR 18) belongs to the group of Ofpe/WN stars believed to be closely related to the Luminous Blue Variables. Support for such a relation comes from the spectral resemblance of these stars to AG Car during visual minimum, and from the observed outburst of the Ofpe/WN star R127.

We present coordinated spectroscopic and photometric observations obtained during the present bright phase of the luminous variable star S Dor in the LMC. High resolution spectrograms in the satellite UV and in the visual range were obtained with IUE and with CASPEC (attached to the ESO 3.6-m telescope), respectively. Moreover, photometric UBVRIJHKL observations were carried out.

We present an atlas of high dispersion spectra of 24 of the brightest peculiar emission-line stars of the Magellanic Clouds.Our spectra cover the wavelength range from 3600 to 4900 Å. They have been obtained from 1970 to 1984 with the coudé spectrograph of the ESO 1.52 m telescope at La Silla, Chile. The spectral resolution is 0.4 Å for most of the spectra and 0.2 Å for the very brightest stars. Up to 11 spectra are available for one star. In addition, we have done UBVRIJHK(LM) photometry at several epochs of all stars of our sample.

The LMC star R84 (-HDE 269227 -BR 18) belongs to the group of Ofpe/WN stars believed to be closely related to the Luminous Blue Variables. Support for such a relation comes from the spectral resemblance of these stars to AG Car during visual minimum, and from the observed outburst of the Ofpe/WN star R127.The spectral analysis of R84 presented here is based on model calculations with the NLTE comoving-frame code described by Wessolowski et al. (1988) and references therein. The helium model atom was represented by 28 levels and hydrogen by 9 levels. The free model parameters were varied until the observed line profiles and the absolutely calibrated and dereddened continuum flux were reproduced. The comparison of the theoretical continuum flux distribution with the observed one yields a reddening of EB-V=0.1.

The luminous O-type star BD +60°2522 is embedded in the extended H II region S 162. Part of S 162 is NGC 7635, the striking spherically symmetric bubble nebula surrounding BD +60°2522. This star itself is unique in that it is the only known O star apparently associated with warm dust.