B[e] supergiants are known to possess circumstellar disks in which molecules and dust can form. The formation mechanism and the resulting structure of these disks is, however, still controversial. Nevertheless, to protect the disk material from the dissociating stellar radiation and to allow for dust formation in the vicinity of a luminous supergiant star, the amount of mass comprised within these disks must be huge. We study the amount of hydrogen neutral material by means of an analysis of the strong [O i] emission lines in our optical high-resolution FEROS spectra of two B[e] supergiants, the edge-on system S 65 in the SMC, and the pole-on system R 126 in the LMC. In addition, we study the possible disk dynamics of S 65, based on a simultaneous line-profile modeling. We find that the [O i] emission lines in S 65 must originate either from an outflowing disk, in which the outflow velocity is slowly decreasing outwards, or from a Keplerian rotating ring, resulting from an ejection event.

The SMC harbours a class of hot nitrogen-sequence Wolf-Rayet stars (WNE) that display only relatively weak broad He ii λ4686 emission indicative of their low mass-loss rates and which are therefore hard to detect. However, such stars are possible emitters of strong He+ Lyman continua which in turn could ionize observable He iii regions, i.e. highly excited H ii regions emitting nebular He ii λ4686 emission. We here report the discovery of a second He iii region in the SMC within OB association NGC 249 within which the weak-lined WN star SMC WR10 is embedded. SMC WR10 is of special importance since it is a single star showing the presence of atmospheric hydrogen. While analysing the spectrum in the framework of two popular, independent WR atmosphere models we found strongly discrepant predictions (by 1 dex) of the He+ continuum for the same input parameters. A second interesting aspect of the work reported here concerns the beautiful MCELS images which clearly reveal a class of strongly O iii λ5007 emitting (blue-coded) nebulae. Not unexpectedly, most of the “blue” nebulae are known Wolf-Rayet bubbles, but new bubbles around a few WRs are also detected. Moreover, we report the existence of blue nebulae without associated known WRs and discuss the possibility that they reveal weak-wind WR stars with very faint stellar He ii λ4686 emission. Alternatively, such nebulae might hint at the hitherto missing population of relatively low-mass, hot He stars predicted by massive binary evolution calculations. Such a binary system is probably responsible for the ionization of the unique He ii λ4686-emitting nebula N 44C.

At the 1998 IAU Symposium on the Magellanic Clouds, Dr. Robert Petre observed that we were reaching a time where it was possible “to study the MC SNRs at a level of detail comparable with many Galactic remnants”, while retaining the benefits of a global view in the MCs. Over the past decade, many researchers have taken advantage of these newly accessible populations. New MC-wide surveys at various wavelengths have enabled broader searches for SNR candidates, extending our census of MC SNRs to less prominent objects — older SNRs, SNRs in complex regions, et cetera. The use of light-echoes has provided a new avenue to probe young SNRs. Higher spatial and spectral resolutions in many wavelength regimes have enabled detailed studies of individual remnants, revealing progenitor types, pulsar-wind nebulae, expansion details, and environmental effects.

Perhaps the newest conceptual development is the increasing use of the MC SNRs to study physical problems of wider significance to many fields of astronomy. For example, researchers have examined the energy and hot gas inputs of MC SNRs to the ISM, including their collective effects within superbubbles, in order to evaluate their effects on stellar feedback cycles in a galaxy. Other scientists have investigated the fraction of SNR energies going to the acceleration of cosmic rays, which has significant implications for the role of SNRs in cosmic-ray production. Most recently, the onslaught of Spitzer data has led to new exploration of dust in MC SNRs, allowing us to probe dust creation, depletion, and destruction in the MC SNR populations. In summary, the study of SNRs in the MCs appears to have “come of age” over the past decade, becoming a mature field with rich potential for future scientific work.

We present mid-IR long-baseline interferometric observations of the red supergiant WOH G64 in the Large Magellanic Cloud with MIDI at the ESO's Very Large Telescope Interferometer (VLTI). Our MIDI observations of WOH G64 are the first VLTI observations to spatially resolve an individual stellar source in an extragalactic system. Our 2-D radiative transfer modeling reveals the presence of a geometrically and optically thick torus seen nearly pole-on. This model brings WOH G64 in much better agreement with the current evolutionary tracks for a 25 M⊙ star — about a half of the previous estimate of 40 M⊙ — and solves the serious discrepancy between theory and observation which existed for this object.

The Magellanic Clouds are often characterized as “irregular” galaxies, a term that implies an overall lack of organized structure. While this may be a fitting description of the Small Cloud, the Large Magellanic Cloud, contrary to popular opinion, should not be considered an irregular galaxy. It is characterized by a distinctive morphology of having an offset stellar bar and single spiral arm. Such morphology is relatively common in galaxies of similar mass throughout the local Universe, although explaining the origin of these features has proven challenging. Through a number of recent studies we are beginning to get a better grasp on what it means to be a Magellanic spiral. One key result of these works is that we now recognize that the most unique aspect of the Magellanic Clouds is not their structure, but, rather, their proximity to a larger spiral such as the Milky Way.

The Magellanic Clouds were the largest members of a group of dwarf galaxies that entered the Milky Way (MW) halo at late times. This group, dominated by the LMC, contained ~4% of the mass of the Milky Way prior to its accretion and tidal disruption, but ≈70% of the known dwarfs orbiting the MW. Our theory addresses many outstanding problems in galaxy formation associated with dwarf galaxies. First, it can explain the planar orbital configuration populated by some dSphs in the MW. Second, it provides a mechanism for lighting up a subset of dwarf galaxies to reproduce the cumulative circular velocity distribution of the satellites in the MW. Finally, our model predicts that most dwarfs will be found in association with other dwarfs. The recent discovery of Leo V (Belokurov et al. 2008), a dwarf spheroidal companion of Leo IV, and the nearby dwarf associations supports our hypothesis.

We present equivalent width measurements and limits of six diffuse interstellar bands (DIBs, λ 4428, λ 5705, λ 5780, λ 5797, λ 6284, and λ 6613) in seven damped Lyα absorbers (DLAs) over the redshift range 0.091 ≤ z ≤ 0.524, sampling 20.3 ≤ log N(Hi) ≤ 21.7. Based upon the Galactic DIB–N(H i) relation, the λ 6284 DIB equivalent width upper limits in four of the seven DLAs are a factor of 4–10 times below the λ 6284 DIB equivalent widths observed in the Galaxy, but are not inconsistent with those present in the Magellanic Clouds. Assuming the Galactic DIB–E(B − V) relation, we determine reddening upper limits for the DLAs in our sample. Based upon the E(B − V) limits, the gas-to-dust ratios, N(H i)/E(B − V), of the four aforementioned DLAs are at least ~5 times higher than that of the Galactic ISM and are more consistent with the Large Magellanic Cloud. The ratios of two other DLAs are at least a factor of a few times higher. The best constraints on reddening derive from the upper limits for the λ 5780 and λ 6284 DIBs, which yield E(B − V) ≤ 0.08 mag for four of the seven DLAs and are more consistent with the Magellanic Clouds rather than the Galaxy. Our results suggest that, in DLAs, quantities related to dust, such as reddening and metallicity, appear to have a greater impact on DIB strengths than does H i gas abundance. The molecules responsible for the DIBs in DLA selected sightlines are underabundant relative to sightlines in the Galaxy of similarly high N(H i). Using DIBs to study the ISM of DLAs provide evidence that at least some population of DLAs are more Magellanic-like than Galactic-like.

We provide a brief overview of some key issues that came out of the IAUS 256 symposium on the Magellanic System (http://www.astro.keele.ac.uk/iaus256).