We are conducting a wide-angle Hα survey of the southern sky at CTIO using a robotic CCD camera. The survey consists of 283 fields covering the sky from δ = −90° to δ = +10°, with the same centers as those in the IRAS Sky Survey Atlas. As of July 1, 1998, it was about 45% complete. When all the images are obtained and fully processed, the survey will be made available to the scientific community on the web and on CD-ROM.

We present the results of an HI aperture synthesis mosaic of the Large Magellanic Cloud (LMC), made by combining data from 1344 separate pointing centers using the Australia Telescope Compact Array (ATCA). The resolution of the mosaiced image is 1′ (15 pc, using a distance to the LMC of 50 kpc).

We use the spatial power spectrum for a statistical study of HI in the SMC in order to probe the intrinsic topology of the ISM. A remarkable power-law fit to the spatial power spectrum was found, supporting an alternative ISM model having a fractal nature resulting from interstellar turbulence.

3D computer simulations are used to discuss shapes, expansion velocties, masses and fragmentation of expanding shells in the LMC.

A narrow-band translator and filter system has been constructed for the Parkes Multibeam receiver. This brief note outlines the characteristics of the system and indicates the range of new projects that will be possible in studies of the Magellanic Clouds.

Despite a strong UV radiation field, the Large Magellanic Cloud (LMC) shows a relatively large abundance of cool HI gas. Neither CO- nor [CII]-lines have been detected in most of these regions in previous surveys. The energy balance of these cool clouds, of which some are located in warm surroundings, is still an open question. The improved resolution and sensitivity of the ISO telescope compared to previous measurements offers a unique opportunity to study the heating and cooling of these clouds in the LMC. Here we present first results of an investigation of the dominant cooling line, [CII] (158 μm), toward cool HI clouds.

Studying the cool atomic phase of the interstellar medium is of special significance as cool atomic clouds can become the raw material for star formation and so determine the evolution of the whole galaxy. The cool atomic interstellar medium of the Large Magellanic Cloud (LMC) seems to be quite different from that in the Milky Way. In three 21 cm absorption line surveys using the Australia Telescope Compact Array (ATCA) the physical properties of the cool atomic hydrogen in the LMC and the halo of the Magellanic Clouds have been studied. Here we present the results of the third HI absorption line survey. A detailed investigation of the cool HI has been done toward the supergiant shell LMC4, the surroundings of 30 Doradus and in the direction of the eastern steep HI boundary. The data have been compared with survey 2 (Dickey et al. 1994) to probe the cool gas fraction for these different regions of the LMC and to study the differences of the cool atomic phase of the LMC and that of the Milky Way.

In the Milky Way, the 12CO J = 1 → 0 line traces the molecular gas content. The conversion factor, XGAL, between the H2 column density, N(H2), and the velocity integrated intensity of CO, I(CO), has been measured via the virial theorem or via γ-ray emission (Solomon et al. 1987; Bloemen et al. 1986; Digel et al. 1997; and references therein).

How can we apply XGAL to other galaxies where the metallicities are different from that of our Galaxy? The metallicity dependence of the conversion factor has been an issue. Cohen et al. (1988), Wilson (1995), and Arimoto, Sofue, & Tsujimoto (1996) argued that the value of X increases as the metallicity of the individual galaxy decreases. In contrast, Taylor, Kobulnicky, & Skillman (1996) showed that some low abundance galaxies have lower X.

We have observed spectral line emission from a sample of clouds in the Magellanic Clouds to investigate the effects of metallicity and FUV radiation on the physical and chemical properties of the interstellar medium. The clouds were identified by CO surveys and selected to cover a wide range of environments. We present molecular line data for five clouds in the LMC and one cloud in the SMC.

Several molecular cores in the Magellanic Clouds have been investigated. While previous works only concentrated on “warm” clouds, our study provides the first systematic study to cover different environments. Preliminary results are presented with brief discussions.

Fully sampled 12CO(J=1−0) observations of the whole extent of the LMC have been made with a linear resolution of ~ 30 pc at a detection limit of N(H2) = 2 × 1021 cm−2. In addition, several selected regions have been mapped with higher sensitivity corresponding to a detection limit of 1 × 1021 cm−2. Based on these results, a new estimate of the molecular mass in the LMC is presented.

Here we present four IRAS high resolution images of the Small Magellanic Cloud, as reconstructed by the HIRAS program using the Pyramid Maximum Entropy method (Bontekoe et al. 1994). (HIRAS is not to be confused with HiRes (Aumann et al. 1990).) The images show much more detail than in Schwering & Israel (1990). Dust temperatures range from 25–41 K (Stanimirović et al. in prep).

In the Large Magellanic Cloud (LMC) a large number of cool HI clouds have been detected with temperatures much lower than those found for atomic clouds in the Milky Way (Dickey et al. 1994; Mebold et al. 1997; Marx-Zimmer et al. 1998). Apparently, the population of cool HI clouds reaches kinetic gas temperatures down to as low as 10 or 20 K. These clouds may play an important role in the formation of stars in the LMC. We studied the association between the cool atomic gas and molecular gas in the LMC by 12CO(1–0) line observations in directions of cool HI clouds using the 15-m Swedish-ESO Submillimetre Telescope (SEST).

Based on measurements with the ORFEUS far UV echelle spectrograph, we present the first detection of H2 in absorption in the Large Magellanic Cloud (LMC) in the spectrum of the star LH 10:3120.

Both theory and observation suggest that metallicity profoundly alters the properties and structure of the Photodissociation Regions (PDRs; e.g., Madden et al. 1997). Several factors contribute to the differences between high and low metallicity systems: altered gas phase and grain surface chemistry due to the low Si, C and S elemental abundances, and diminished dust shielding because of the low dust-to-gas ratio. Since there is less dust shielding, UV photons penetrate more deeply into the molecular clouds leaving H2 unaffected but photodissociating most other molecules everywhere except in the most opaque clumps. Thus, a low-metallicity system contains large regions where hydrogen remains molecular but the usual tracers of molecular gas like CO are photodissociated.

We have made 12CO(J=1-0) observations in the LMC with NANTEN, and compared the detected giant molecular clouds (GMCs) with HII regions and stellar clusters. It is found that ~ 80% of the GMCs are associated with HII regions. The results of comparisons of the GMCs with the HII regions and the stellar clusters are presented.

Several spectra have been obtained in the 3600–10000 Å range, for the HII regions N11A and N88A in the LMC and SMC, respectively. The spectral type of their exciting star was determined and from the emission-line intensities we have derived the gas electron density and temperature, and computed the chemical abundances of He, O, N, Ne, S, and Ar. These abundances are then compared with the ones found for other HII regions in the Magellanic Clouds.

Massive stars have strong stellar winds and consequently a high mass loss during their lifetimes. Therefore they can form ring nebulae by stellar winds sweeping up the ambient medium in the main sequence phase or through wind-wind interaction or eruptions in the evolved state. We present preliminary results of a search for single bubbles and ring-nebulae around massive stars in the Large Magellanic Cloud (LMC).

Recent observations of SN 1987A made with HST/STIS show that the shock interaction of supernova debris with the innermost edge of the circumstellar ring has begun.

Supernova remnants in the Magellanic Clouds may have somewhat lower surface brightnesses at radio wavelengths than their counterparts in the Milky Way but otherwise they appear to be very similar. Balmer dominated SNRs have a lower radio luminosity than other shell remnants.