Symbiotic stars (SySts) are long-period interacting binaries composed of a hot compact star, an evolved giant star, and a tangled network of gas and dust nebulae. Presently, we know 252 SySts in the Milky Way and 62 in external galaxies. However, these numbers are still in striking contrast with the predicted population of SySts in our Galaxy. In this contribution, I present the concept and the early results from RAMSES II (Raman Search for Extragalactic Symbiotic Stars), a Gemini/GMOS Upgrade Project which makes use of the Raman OVI 6830Å band as a powerful photometric tool to identify new SySts, within and beyond the Galaxy.

The spiral galaxy M 83, an SB(rs)b at only 4.5 Mpc, is a privileged case for study of the detailed physics on spatial scales of a tenth of a parsec. With 3-D spectroscopic observations using CIRPASS on Gemini-S, we studied the ionized gas properties in J-band with spatial resolution of 0.″5 (Figure 1). The Paβ velocity field shows two dynamical centers, neither of them coincident with the bulge center, identified with the optical nucleus (ON) and the hidden nucleus (HN), with masses, within a radius of 10 pc, of MON = (1.8±0.4)× 107M⊙ and MHN = (1.0±0.4)× 107M⊙. Using the Paβ equivalent width together with population synthesis models, we are able to estimate the ages of both mass concentrations, TON = 8 Myr and THN =6–7 Myr. Adding complexity to this puzzling scenario, we used GMOS+Gemini imaging and spectroscopy to study the radio source J133658.3–295105 (Dottori et al. 2008) and find that Hα emission at the position of this source is redshifted by ~130 km s−1 with respect to an M 83 H II region, leading us to face the possibility of that we are witnessing the ejection of an object by gravitational recoil from the M 83 nucleus. A fit to the X-ray spectrum obtained Chandra supports the association between this source and the disk of M 83 by the presence of the Fe Kα line at 6.7 keV.

NGC 1241 is a Sy 2 galaxy with a 1.4 kpc circumnuclear ring (CNR) of star formation revealed in Paα. A 0.3 kpc long Paα emitting bar centered on the nucleus is present, apparently without associated absorption features. GEMINI (+QUIRC+Hokupa) IR pixel-photometry reveals instead an azimuthally symmetric (J−Ks) color which is redder at the nucleus than at the CNR. This property may well be due to the increasing importance of dust when going from the ring inward into the nucleus. Nevertheless the (V−H) color does not indicate special absorption conditions in the nucleus with respect to the CNR, and no absorption features are evident, as normally expected near emitting bars. Then, we propose as an alternative explanation an excess of C-stars in the nuclear region which decreases outwards until reaching the CNR and its colors. We have compared the pixel color-magnitude diagram with the 2-MASS (J−Ks) vs. Ks diagram for the Large Magellanic Cloud: about 5×102 C-stars and 2.5×104 AGB Oxygen-rich stars inside r∼50 pc, are enough to reproduce the observed nuclear tip in the diagram. This stars would release gas that, gravitationally bounded, pollutes the nuclear environment and could amount 10−2 to 10−1 M$_{\odot}$ yr−1 of fuel for the central engine during the lifetime of stars with masses 2 M$_{\odot}\lt M_{CStars} \lt 6{\rm M}_{\odot}$. This scenario may also explain the observed increased strength of the CN-bands in the stellar populations of Sy 2 nuclei, and the recent claim of a significant contribution of intermediate age stars to the optical continuum of low luminosity AGNs.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We report the status of our study of the central region of M 83. Recently a binary mass concentration at the nucleus was suggested by Thatte et al. (2000), and we determined the possible position of the optically hidden mass concentration with 2D Hα kinematics. We continue our study of this region trough IR 3D spectroscopy performed with CIRPASS, attached to the Gemini South telescope. Almost 1500 spectra were obtained, centered in the wavelength 1.3 μm. The velocity field in a region of 13″ × 9″ around the optical nucleus is resolved, with 0.36″ (6.4 pc) sampling. We confirm that the optical nucleus of M 83 is not located at the most important center of symmetry of the velocity field. The largest black hole that could fit to the circular motion in this kinematic center should have a mass less than $2\times10^7M_{\odot}$.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We present spectroscopic observations of the peculiar system AM1003-435, which is composed of two strong interacting galaxies, and numerical simulations of the encounter between the galaxies, following the dynamical evolution of the stellar and gaseous components.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

We have analyzed the frequency and properties of the nuclear activity in two samples of galaxies, with and without circumnuclear rings and spirals (CNRs). We discuss the relevance of the results in the framework of the AGN feeding processes and some results are: (i) bright companion galaxies seem not to be important for the appearance of CNRs, therefore these would be more related to intrinsic properties of the host galaxies or to minor merger processes; (ii) the proportion of strong bars in AGN galaxies with a CNR is higher than the expected rate of strongly barred AGN galaxies from the sample of Ho and co-workers; (iii) the incidence of Seyfert activity coeval with CNRs is clearly larger than the expected rate from the morphological distribution of the host galaxies; (iv) the rate of Sy 2 to Sy 1 in galaxies with CNRs is larger than the expected proportion for galaxies without CNRs; this proportion would be in the opposite sense as expected from the geometric paradigm of the classical unified model for AGNs, but supports a scenario where Sy 2 activity is linked to circumnuclear star formation.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html