We present ELSA, a new modular software package, written in C, to analyze and manage spectroscopic data from emission-line objects. In addition to calculating plasma diagnostics and abundances from nebular emission lines, the software provides a number of convenient features including the ability to ingest logs produced by IRAF's splot task, to semi-automatically merge spectra in different wavelength ranges, and to automatically generate various data tables in machine-readable or LaTeX format. ELSA features a highly sophisticated interstellar reddening correction scheme that takes into account temperature and density effects as well as He II contamination of the hydrogen Balmer lines. Abundance calculations are performed using a 5-level atom approximation with recent atomic data, based on R. Henry's ABUN program. Downloading and detailed documentation for all aspects of ELSA are available at the following URL:

A near-infrared survey of the Magellanic Clouds has been carried out with IRSF/SIRIUS. As a part of the results, we present a study of triggered star formation in N11 in the LMC.

Using simple physical assumptions we derived fundamental parameters including: the mass of synthesised 56Ni, the ejecta mass, and the explosion energy of Type Ia supernovae. The methods have been described in several recent publications and comparison with other methods shows general consistency.

The problems of required conditions and possible consequences of the super - compression (up to $R_m\sim 3R_E$) of the Earth's magnetosphere by giant CME are investigated by the methods of laboratory and computer simulations. A useful relation between an expected magnetopause location $R_m^*$ and the kinetic plasma energy $E_0$ of spherical plasma cloud (exploded at distance $R_0$) was obtained $R_m^*/R_0\approx 0,75/{\ae}^{1/6}$ and tested by MHD – model of Nikitin & Ponomarenko (1994) with the using their main energetic criterion of the problem ${\ae}=3E_0 R_0^3/\mu^2$ (for magnetic moment $\mu$ of point obstacle in vacuum). This relation could describe rather well an observed compression ($R_m\sim 5-6 R_E$ for CME with energy $10^{32}\, ergs$ and effective value $E_0\sim 10^{33} ergs,$ into $4\pi$) and predicts $R_m^*\leq 3R_E$ in a probable case of Mega Flare with the total energy release $\sim 10^{34}\, ergs$ and possible $E_0\sim 5\cdot 10^{34}\, ergs$ according to Kane et al. (1995) and Tsurutani et al. (2003). Some most important features of the formation such Artificial Magnetosphere (AM) structure and its possible influence onto various geospheres media (or technosphere areas) could be successfully studied in the simulative experiments at KI-1 facility of ILP with Laser Plasmas (LP) of $E_0$ up to $kJ$ and dipole $\mu\sim 10^7\, G\cdot cm^3$ as was shown by Ponomarenko et al. (2001) and Zakharov (2003). But the main problem of such planned AMEX experiment (at ${\ae}\sim 50$ for $R_0=75\, cm$) is the influence of finite value of ion magnetization $\varepsilon_m=R_L/R_m^*$ based on the ion Larmor radius $R_L=mcV_0/ezB_d,$ where $V_0\sim 100\, km/s$ is the expansion velocity of LP and $B_d$ is the initial dipole field at the point $R_m^*.$ Of coarse, $\varepsilon_m\ll 1$ in a real space conditions (excluding cases of Mercury or asteroids, explored by Omidi et al. (2004)) while in the laboratory to fulfill both need constrains ${\ae}\gg 1$ and $\varepsilon_m\ll 1$ we should use a thermonuclear plasma and devices. To overcome this problem we did a 3D/PIC – calculations by hybrid model of Kyushu University, described by Muranaka et al. (2001), to find out a critical value of $\varepsilon_m^*$ $(\approx 0,2-\!0,3),$ which need for MHD – like interaction of exploding plasmas with magnetic dipole.

The origin, structure and evolution of sunspots are investigated using a numerical model. The compressible MHD equations are solved with physical parameter values that approximate the top layer of the solar convection zone. A three dimensional (3D) numerical code is used to solve the set of equations in cylindrical geometry, with the numerical domain in the form of a wedge. The linear evolution of the 3D solution is studied by perturbing an axisymmetric solution in the azimuthal direction. Steady and oscillating linear modes are obtained.

We perform Monte Carlo calculation to determine the radiation spectra from magnetized, low angular momentum accretion flow. Magneto-hydrodynamical simulation (with angular momentum parameter lambda of about 2 Rg c) was performed by Proga & Begelman 2003. Because simulation neglect radiative cooling, we compute electron temperature separately, including ohmic heating, parametrized with small δ coefficient, ion-electron coupling, radiative cooling and advection. Radiation spectra are obtained taking into account, thermal synchrotron and bremsstrahlung radiation, self absorption and Comptonization processes.

We show which parts of the flow are responsible for characteristic spectral features and how the spectrum changes in different accretion states. We compare our results with Galactic Center black hole radiation spectra, where low angular momentum accretion is suggested. Accretion state changes seems to be a promising model for the flaring behavior of Galactic Center black hole. We also show the radiation intensity maps in radio and X-rays energy band for viewing angle i = 90°.

While Type Ia supernovae are widely used as distance indicators, the reasons for the correlation between luminosity and light curve width that allows SNe Ia to be calibratable standard candles is not yet fully understood, and in particular the details of the explosion mechanism are still the subject of heated debate. We present the results of a systematic approach that uses the high-quality data collected by the European Research Training Network “The Physics of Type Ia Supernova Explosions” to map the supernova ejecta and to infer the properties of the explosion.

We present a preliminary reconstruction of the star formation history of the Sagittarius dwarf irregular galaxy (SagDIG), a dIrr galaxy at the border of the Local Group. SagDIG is a lively star-forming dwarf galaxy with very low metallicity and an abundant gas reservoir, for which deep HST ACS observations have been obtained (Momany et al. 2005). We have built synthetic color-magnitude diagrams in the intrinsic ACS bands F606W and F814W and compared them with our HST/ACS observations to derive the global star formation history of the galaxy. We find a broad episode of star formation between 3 and 8 Gyr ago, with a low-intensity tail of star formation at older ages, and a SF enhancement in the last Gyr. An upper limit to the old populations is set by modeling the old HB. Our modeling of the color-magnitude diagram also provides some constraints on the chemical enrichment history of SagDIG.

We report the temporal evolution of the long lasting solar flare observed on June 6, 2000 (15:00 – 17:00 UT) by the Brazilian Solar Spectroscope (BSS) at INPE. We emphasize the identification of the decimetric fine structures, such as “fiber” and “zebra” emissions, including the unique case of harmonic “zebra” emissions in the decimetric band reported, radio pulsations, type III bursts and variants, recorded during this event in the frequency range of (1.2 – 1.7 GHz). The main characteristics of fine structures recorded are presented.

In this work we have studied CM Draconis, one of the least massive eclipsing binaries known. Its components are very similar, with masses and radii of about 0.23 M⊙ and 0.25 R⊙. We have analysed light curves in the R and I bands to calculate the fundamental properties of this system with accuracies better than 1%. With these results we plan to carry out a thorough test of the models, which have been found to predict smaller radii and larger effective temperatures than observed for these low-mass stars. This will also be especially interesting in the case of CM Dra since the mechanism driving magnetic activity is thought to be different from that of more massive stars. In addition, the extended time-span of the observations has led to the detection of apsidal motion. This provides a further check on models through the determination of the internal structure of the stars.

A sample of potential massive starforming regions identified at 170 m by ISO was observed in the submillimeter and millimeter regime. These observations allow us to infer physical properties of the molecular cloud cores. Two sources are presented in detail: ISOSS J23053+5953 and J183640221 show viable candidates for massive protocluster cores. Our analysis shows very low temperatures and low levels of turbulence of the major mass fraction in the molecular cloud cores besides active star formation at an early evolutionary stage. These conditions seem similar to the low mass case and may precede phases of luminous infrared emission observed towards young massive protostars.

Many clues about the galaxy assembly process lurk in the faint outer regions of galaxies. Although quantitative study of these parts has been severely limited in the past, breakthroughs are now being made thanks to the combination of wide-area star counts, deep HST imagery and 8-m class spectroscopy. I highlight here some recent progress made on deciphering the fossil record encoded in the outskirts of our nearest large neighbours, M31 and M33.

The results of long term observations of photometric ($UBV$) and spectral variability of several PNe are presented. For the most variable nebulae, IC 4997 and NGC 6572, showing both photometric and spectral changes in time, the main physical parameters ($T_{e}$, $N_{e}$ and $T_{*}$) and their time variations were estimated and discussed.

We present results from a global 3-D nonlinear simulation of magnetic dynamo action achieved by solar convection in a penetrative geometry. We include within the spherical computational domain both the bulk of the convection zone and a portion of the underlying stable layer. A tachocline of rotational shear is realized below the convection zone, where we have imposed both a hydrodynamic drag term and small thermal perturbations consistent with thermal wind balance. Thus we are capturing many of the dynamical elements thought to be essential in the operation of the global solar dynamo, including differential rotation arising from convection, magnetic pumping, and the stretching and amplification of toroidal fields within the tachocline. In the stable region, the simulation reveals that strong axisymmetric toroidal magnetic fields (about 3000 G in strength) are realized, in contrast to the mostly fluctuating fields that predominate in the convection zone. The toroidal fields in the stable region exhibit a striking antisymmetric parity akin to that observed in sunspots, with fields in the northern hemisphere largely of the opposite sign to those in the southern hemisphere. These deep toroidal fields are accompanied by mostly dipolar mean poloidal fields, whose polarity has retained the same sense over multiple years of simulated evolution.

In the framework of an ongoing ACS@HST project (HST program #10586, PI: Aloisi) we have obtained deep multi-color imaging of the very metal-poor Blue Compact Dwarf galaxy IZw18. The data were acquired in time-series fashion to allow the identification of Classical Cepheids (CCs). The main aim of this project is to constrain both the distance and the Star Formation History of the galaxy. However, as a byproduct these data also provide new insights into the properties of CCs at very low metallicities. We have identified 24 candidate CCs in IZw18. New theoretical pulsation models of CCs specifically for the low metallicity of this primordial galaxy (Z=0.0004, Y=0.24) have been computed to interpret our results.

In the course of our abundance studies over the past decade we have accumulated more than 120 high-quality, medium resolution spectra of planetary nebulae (PNe) from 3600-9600 Å using the KPNO 2.1m Goldcam CCD spectrograph and the CTIO 1.5m RC spectrograph. Results have been published in, e.g., Kwitter & Henry (1998); Henry, Kwitter & Balick (2004); and Milingo et al. (2006). We have created this website as a place where the spectra are available for graphical display, and where PN atlas information and image links are tabulated. The URL is: http://oit.williams.edu/nebulae

The SuperMACHO project has discovered light echoes from 3 ancient SNe in the LMC. These SNRs are three of the six youngest in the LMC, and are classified as likely SN Ia based on X-ray data.

The total masses of binaries are calculated on the basis of their orbital elements from the Sixth Catalog of Orbits of Visual Binary Stars. They are then compared with the values resulted from the mass-luminosity relation for the Main Sequence where as the input data are used: trigonometric parallax, total apparent magnitude of the pair (source Hipparcos Catalogue) and magnitude difference (source Hipparcos Catalogue and Photometric Magnitude Difference Catalog). It seems that for the pairs indicated as having qualitative orbital elements the agreement between the total-mass values obtained in these two ways is satisfactory.

We model the K-correction for emission lines formed on the irradiated face of companion stars in compact binaries. We compute this K-correction in a general approach as function of the mass ratio and the disc flaring angle. Our results, combined with the detection of high excitation emission lines arising from the donor star, can be used to set constraints to the masses of neutron stars and black holes in persistent Low Mass X-ray Binaries (LMXBs).

The application of our model to X1822-371 (Muñoz-Darias, Casares & Martínez-Pais 2005) lends strong support to the presence of a massive neutron star in this LMXB (i.e. MNS > 1.6M⊙). Here, we also present the K-correction for the Black Hole binary GX339-4, where we obtain a solid lower limit to the black hole mass of MBH > 5.8M⊙.

I present a brief review of some of the mid-infrared properties of interacting galaxies as these were revealed using observations from the Infrared Space Observatory and Spitzer Space Telescope over the last decade. The variation of the infrared spectral energy distribution in interacting galaxies can be used as an extinction free tracer not only of the location of the star formation activity but also of the physical mechanism dominating their energy production.‡.