We study the dynamics of a two-planet system, which evolves being in a 1/1 mean motion resonance (co-orbital motion) with non-zero mutual inclination. In particular, we examine the existence of bifurcations of periodic orbits from the planar to the spatial case. We find that such bifurcations exist only for planetary mass ratios $\rho=\frac{m_2}{m_1}<0.0205$. For ρ in the interval 0<ρ<0.0205, we compute the generated families of spatial periodic orbits and their linear stability. These spatial families form bridges, which start and end at the same planar family. Along them the mutual planetary inclination varies. We construct maps of dynamical stability and show the existence of regions of regular orbits in phase space.

I summarizes the main characteristics of a cosmological hydro-dynamical model which includes chemical evolution. In the last decade, galaxy formation models have made important progress which contribute to understand observations although there are still many open questions to be answered. Current chemo-dynamical cosmological simulations are able to reproduce global trends. They provide a suitable route to underpin physical events responsible of determining observed chemical patterns.

Stellar evolution models predict that rotation induces the mixing of chemical species, with the subsequent surface abundance anomalies relative to single non-rotating models, even during the main sequence (MS) evolution. The lack of measurable nitrogen surface enrichment in MS rotating stars, such as Be stars, has been interpreted as being in conflict with evolutionary models (e.g. Lennon et al. 2005; Hunter et al. 2008). In order to have an insight on the kind of ambient we do or we do not expect to find enriched rotating stars, we use our new population synthesis code, to produce synthetic intermediate-mass stellar populations fully accounting for stellar rotation effects, and study their evolution in time.

I report on a correlation between the saturated and non-saturated regimes of X-ray emission and the rotation sequences that have been observed in the M34 open cluster. An interpretation of this correlation in term of magnetic activity evolution in the early stage of evolution on the main sequence is presented.

We explore the relationships between the 3.3 μm polycyclic aromatic hydrocarbon (PAH) feature and active galactic nucleus (AGN) properties of a sample of 54 hard X-ray selected bright AGNs, including both Seyfert 1 and Seyfert 2 type objects, using the InfraRed Camera (IRC) on board the infrared astronomical satellite AKARI. The sample is selected from the 9-month Swift/BAT survey in the 14-195 keV band and all of them have measured X-ray spectra at E ≲ 10 keV. These X-ray spectra provide measurements of the neutral hydrogen column density (NH) towards the AGNs. We use the 3.3 μm PAH luminosity (L3.3μm) as a proxy for star formation activity and hard X-ray luminosity (L14-195keV) as an indicator of the AGN activity. We searched for possible difference of star-formation activity between type 1 (un-absorbed) and type 2 (absorbed) AGNs. Our regression analysis of log L14-195keV versus log L3.3μm shows a positive correlation and the slope seems steeper for type 1/unobscured AGNs than that of type 2/obscured AGNs. The same trend has been found for the log (L14-195keV/MBH) versus log (L3.3μm/MBH) correlation. Our analysis show that the circum-nuclear star-formation is more enhanced in type 2/absorbed AGNs than type 1/un-absorbed AGNs for low X-ray luminosity/low Eddington ratio AGNs.

Over more than twenty years, Wojtek Dziembowski and I collaborated on nearly fifty papers, which were concentrated in helioseismology through the 1980s and 1990s, but extended early into the new century. In this review, I discuss the most significant results of this collaboration and some of the underlying sociology that contributed to the intensity and longevity of our collaboration. Our work began with placing limits on the Sun's buried magnetic field and ended with extracting from the solar-cycle dependent oscillation frequency changes the roles (and net result) of competing dynamical drivers of changes in the solar diameter.

We present the first results of the new CO J = (2 − 1) observations toward the central molecular zone (CMZ) using the NANTEN2 telescope at an angular resolution of 100″. Large area coverage of 4° × 2° in l and b and a high angular resolution of 100″ enable us to investigate detailed structures of the molecular gas in the CMZ including peculiar molecular filaments perpendicularly to the Galactic plane to b > |0.5°|. The major components of the CMZ, e.g., Sgr A, Sgr B and Sgr C cloud complexes, show high CO J = (2 − 1)/J = (1 − 0) ratios around 0.9, indicating highly excited conditions of the molecular gas, while the local foreground components show less than 0.4. The molecular filaments show the typical ratios of 0.6–0.7 indicate that they are indeed located in the Galactic center.

Light echoes, light from a variable source scattered off dust, have been observed for over a century. The recent discovery of light echoes around centuries-old supernovae in the Milky Way and the Large Magellanic Cloud have allowed the spectroscopic characterization of these events, even without contemporaneous photometry and spectroscopy using modern instrumentation. Here we review the recent scientific advances using light echoes of ancient and historic transients, and focus on our latest work on SN 1987A's and Eta Carinae's light echoes.

C2, the simplest multicarbon molecule is a useful astronomical tool, because the analysis of its lines allows to determine the physical conditions in interstellar clouds. C2 abundances give information about the chemistry of interstellar clouds, especially on the pathway to the formation of long-chain carbon molecules, which may be connected with carriers of diffuse interstellar bands (Douglas 1977, Thorburn et al. 2003). Here we summarize all relations between C2 and diffuse interstellar bands (DIBs).

The Galactic central black hole and the central cluster of young stars are surrounded by a clumpy gas disk (the circumnuclear disk, CND) that rotates about them at a distance of ≃ 1 pc. The gas in this warm, turbulent, magnetized disk is ultimately likely to migrate into the central cavity and fuel future star formation and black hole accretion. We have observed two fields of approximately 20″ × 20″ in the CND at NIR wavelengths with the OSIRIS integral-field spectrometer at Keck Observatory. These two fields are located at the interface between the neutral and the ionized regions. Our data cover two H2 lines as well as the Brγ line of the Hi spectrum. The signal-to-noise ratio per spatial pixel of each line varies considerably across the field and becomes quite low in some regions. In order to avoid degrading the spatial resolution, we have developed a novel three-dimensional method to analyze the data in terms of regularized parameter maps. The method proves very efficient in retrieving all the information contained in the spectral line emission while not degrading the spatial resolution. We present this new method to analyze 3D spectroscopic data and describe our preliminary results on the structure of the ionized-neutral interface.

A new radiation-driven wind solution called δ-slow was found by Curé et al. (2011) and it predicts a mass-loss rate and terminal velocity slower than the fast solution (m-CAK, Pauldrach et al. 1986). In this work, we present our first synthetic spectra based on the δ-slow solution for the wind of B supergiant (BSG) stars. We use the output of our hydrodynamical code HYDWIND as input in the radiative transport code FASTWIND (Puls et al. 2005). In order to obtain stellar and wind parameters, we try to reproduce the observed Hα, Hβ, Hγ, Hδ, Hei 4471, Hei 6678 and Heii 4686 lines. The synthetic profiles obtained with the new hydrodynamical solutions are in good agreement with the observations and could give us clues about the parameters involved in the radiation force.

The analysis of DIB profiles was used in various attempts to discover the DIBs carriers. The broadening of the 6196 Å DIB with increasing C2 rotational temperature was reported by Kaźmierczak et al. (2009). We present the broadening of the 4763, 5780 and 6614 Å DIBs connected with higher abundance of vibrationally excited hydrogen molecule. The DIBs broadening is also correlated with increasing H2 rotational temperature on the ν=2 vibrational level. The broadening may be caused by growing population of higher rotational levels in the DIB carrier. Some DIBs, like 4964 Å, do not show any width changes with higher population of vibrationally excited H2.

The spatial distribution and kinematics of stars in the Milky Way are linked through the gravitational potential. Observations of the positions and velocities of stars can therefore be used to measure the mass distribution of the Milky Way. I review steady-state dynamical modeling approaches and illustrate their use in constraining the local matter distribution and the circular velocity curve from the kinematics of stellar tracers. In a few years, Gaia will increase the number of precise positions and velocities by multiple orders of magnitude. I describe some of the dynamical analyses that will be possible with the Gaia data and discuss some promising avenues for the optimal analysis of dynamical data.

Cepheids and RR Lyrae stars are important pulsating variable stars in distance scale work because they serve as standard candles. Cepheids follow well-defined period-luminosity (PL) relations defined for bands extending from optical to mid-infrared (MIR). On the other hand, RR Lyrae stars also exhibit PL relations in the near-infrared and MIR wavelengths. In this article, we review some of the recent developments and calibrations of PL relations for Cepheids and RR Lyrae stars. For Cepheids, we discuss the calibration of PL relations via the Galactic and the Large Magellanic Cloud routes. For RR Lyrae stars, we summarize some recent work in developing the MIR PL relations.

The surface rotation rates of young solar-type stars decrease rapidly with age from the end of the pre-main sequence though the early main sequence. This suggests that there is also an important change in the dynamos operating in these stars, which should be observable in their surface magnetic fields. Here we present early results in a study aimed at observing the evolution of these magnetic fields through this critical time period. We are observing stars in open clusters and stellar associations to provide precise ages, and using Zeeman Doppler Imaging to characterize the complex magnetic fields. Presented here are results for six stars, three in the in the β Pic association (~10 Myr old) and three in the AB Dor association (~100 Myr old).

Type IIn supernovae have bright optical emission and high bolometric luminosities. Due to their high mass loss, their are expected to have dense circumstellar interaction, thus produce bright radio and X-ray emission. We aim to carry out systematic study to understand their circumstellar interaction, mass loss properties. Here, I provide specific examples of two Type IIn supernovae, 2006jd and 2010jl.

We briefly overview the new features of PlanetPack2, the forthcoming update of PlanetPack, which is a software tool for exoplanets detection and characterization from Doppler radial velocity data. Among other things, this major update brings parallelized computing, new advanced models of the Doppler noise, handling of the so-called Keplerian periodogram, and routines for transits fitting and transit timing variation analysis.

A summary and general analysis of optical spectroscopic data for 255 Byurakan-IRAS Galaxies (BIG) obtained with BAO 2.6m, SAO 6m, OHP 1.93m telescopes, as well as SDSS DR7, DR8, and DR9 is given. The BIG sample is the result of optical identifications of IRAS PSC sources at high-galactic latitudes using the First Byurakan Survey (FBS) low-dispersion spectra. Among the 1178 objects most are spiral galaxies and there is a number of ULIRGs. All but one have emission lines; we have discovered 68 AGN and composite spectrum objects among them and the others are mostly Starburst Galaxies (SB). All possible physical characteristics have been measured and/or calculated, including physical sizes and optical and IR/FIR luminosities. The masses have been estimated based on mass-luminosity relations for spiral galaxies. As it appears, most of these objects are giant massive galaxies. Various multiwavelength (MW) data have been retrieved from recent catalogues from X-ray to radio and MW SEDs have been built, which have been matched to their optical classifications. Luminosity evolution of these objects has been studies.

In general, a tidal stream is misaligned with the orbit of its progenitor. Here we present the formation of tidal streams in angle-action space to discuss the effect of this misalignment on orbit-fitting algorithms for constraining the Galactic potential. We close by presenting and testing an alternative algorithm which more fully accounts for the dynamics of streams by using the angle-action formalism.

Massive stars play a key role in environments with very different metallicities. To interpret the role of massive stars in these systems we have to know their properties at different metallicities. The Local Group offers an excellent laboratory to this aim.