Parameter mismatches,variable delay times and synchronization in time-delayed systems

We investigate synchronization between two unidirectionally linearly coupled chaotic non-identical time-delayed systems and show that parameter mismatches are of crucial importance to achieve synchronization. We establish that independent of the relation between the delay time in the coupled systems and the coupling delay time, only retarded synchronization with the coupling delay time is obtained. We show that with parameter mismatch or without it neither complete nor anticipating synchronization occurs. We derive existence and stability conditions for the retarded synchronization manifold. We demonstrate our approach using examples of the Ikeda and Mackey-Glass models. Also for the first time we investigate chaos synchronization in time-delayed systems with variable delay time and find both existence and sufficient stability conditions for the retarded synchronization manifold with the coupling delay lag time. Also for the first time we consider synchronization between two unidirectionally coupled chaotic multi-feedback Ikeda systems and derive existence and stability conditions for the different anticipating, lag, and complete synchronization regimes.Comment: 12 page

Near-IR Atlas of S0-Sa galaxies (NIRS0S)

An atlas of Ks-band images of 206 early-type galaxies is presented, including 160 S0-S0/a galaxies, 12 ellipticals, and 33 Sa galaxies. A majority of the Atlas galaxies belong to a magnitude-limited (mB<12.5 mag) sample of 185 NIRS0S (Near-IR S0 galaxy Survey) galaxies. To assure that mis-classified S0s are not omitted, 25 ellipticals from RC3 classified as S0s in the Carnegie Atlas were included in the sample. The images are 2-3 mag deeper than 2MASS images. Both visual and photometric classifications are made. Special attention is paid to the classification of lenses, coded in a systematic manner. A new lens-type, called a 'barlens', is introduced. Also, boxy/peanut/x-shaped structures are identified in many barred galaxies, even-though the galaxies are not seen in edge-on view, indicating that vertical thickening is not enough to explain them. Multiple lenses appear in 25% of the Atlas galaxies, which is a challenge to the hierarchical evolutionary picture of galaxies. Such models need to explain how the lenses were formed and survived in multiple merger events that galaxies may have suffered during their lifetimes. Following the early suggestion by van den Bergh, candidates of S0c galaxies are shown, which galaxies are expected to be former Sc-type spirals stripped out of gas.Comment: 67 pages (include 16 figures and 6 tables). Accepted to MNRAS 2011 June 1

Chaos synchronization in time-delayed systems with parameter mismatches and variable delay times

Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 , Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Adaptive synchronization in chaotic laser diodes subject to optical feedback(s)

Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 , Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal