10 research outputs found
Near-infrared probing of embedded structures in starburst and Seyfert galaxies
Surface photometry in the J and K' bands of 15 southern Seyfert or starburst
galaxies is presented. The detailed central morphology and structural
properties of these objects were analyzed by fitting ellipses to isophotes. New
central peculiar structures have been identified like, for instance, three
double-barred systems (ESO 215-G031; ESO 320-G030; ESO 443-G017), one object
with a nested nuclear spiral structure at the center of a primary bar (NGC
5135), one object with a nuclear bar without evidence of a large-scale bar (NGC
4941), and one galaxy with a likely dissolved secondary bar within a primary
one (ESO 508-G005). The J-K' radial profile proved to be reasonably well linked
with the presence of a starburst, but not with the Seyfert activity. For
significant starbursts, the central J-K' value is 0.3-1.5 magnitude larger than
the disc one.Comment: 19 pages, 10 figures, accepted for publication in A&A
Dynamics of embedded bars and the connection with AGN. I. ISAAC/VLT stellar kinematics
We present new stellar kinematical profiles of four galaxy hosts of active galactic nuclei, using the CO bandhead around 2.3 micron with the ISAAC/VLT spectrograph. We find that the nuclear bars or discs, embedded in large-scale primary bars, have all a decoupled kinematics, in the sense that the maximum of the rotational velocity occurs in the nuclear region. In three cases (NGC 1097, NGC 1808 and NGC 5728), the velocity dispersion displays a significant drop at the nucleus, a rarely observed phenomenon. We also detect kinematical asymmetries (m=1 mode) along the nuclear bar major-axis of NGC 1808 and NGC 5728, dynamical counterparts of corresponding asymmetries in the surface brightness. We have derived simple dynamical models in an attempt to fit the kinematics of each galaxy and reconstruct the full velocity field. For all four targets, the fits are good, and confirm the presence of the decoupled nuclear components. These models cannot however reproduce the observed central drop in the dispersion. We suggest that this drop is due to a transient cold nuclear disc, fuelled by gas inflow along the bar, that has recently formed new stars
Dynamics of embedded bars and the connection with AGN
We present new stellar kinematical profiles of four galaxy hosts of active galactic nuclei, using
the 12CO bandhead around 2.3 ÎĽm with the ISAA
Optical Multifrequency Scanning Probe Microscopy
We present the design and numerical optimization of an all-polymer fiber as a luminescent solar concentrator. Large-area, lightweight, and flexible fabrics constructed of such fibers are a low-cost solar-energy harvesting alternative useful for mobile applications. © 2012 OSA
In Situ Generation of Surface Plasmon Polaritons Using a Near-Infrared Laser Diode
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