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Near-infrared spectroscopic observations in the range 0.8-2.4¼m are used to study the kinematics and excitation mechanisms of Molecular Hydrogen and [FeII] lines in a sample of AGNs. The width of H2 lines is narrower than [FeII] lines, therefore they do not originate from the same parcel of gas. The molecular emission is found to be purely thermal but with heating processes which vary among the objects. A clear correlation between H2/Br³ and [FeII] 1.257¼m/Pa² is found for our sample objects supplemented with data from the literature. The correlation of these line ratios is a useful diagnostic tool in the NIR to separate emitting line objects by their level of nuclear activity.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html [ABSTRACT FROM PUBLISHER]

In this work we investigate the stellar population, metallicity distribution and ionized gas in the elliptical galaxy NGC 5044, using long-slit spectroscopy and a stellar population synthesis method. We found differences in the slope of FeI and Mg2 lines gradients, which suggests an enhancement of ± elements, particularly towards the central region. The stellar population synthesis shows that the contribution, at »5870, of the most metallic and old stellar population ($Z/Z_\odot \sim 0.0$ and 1010year) is dominant in NGC 5044. The presence of a non-thermal ionization source, such as a low-luminosity AGN and/or shock ionization, is implied by the large values of the ratio [NII]/H± observed in all sampled regions. However, the emission lines observed in the external regions indicate the presence of an additional ionization source, probably hot, post-AGB stars.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html [ABSTRACT FROM PUBLISHER]

The spectroscopic properties of a sample of nine Seyfert 1, six NLS1, 26 Seyfert 2, and three starburst galaxies have been studied at mid-infrared wavelengths in order to determine if the frequency of detection of the brightest emission lines and the continuum shape are correlated with the degree of activity. The raw data were obtained from the Spitzer Infrared Spectrograph (IRS) archive and reduced with the pipeline (version 17.2). The spectra of the galaxies were grouped by type of activity. We conclude through this study that in general the continuum shape of the active galactic nuclei (AGN) is flat between 5 μm and 12 μm, and strong variations are found at longer wavelengths in this sample. [ABSTRACT FROM PUBLISHER]