Search

We present and discuss new high-sensitivity and resolution radio-continuum images of the Small Magellanic Cloud (SMC) at $lambda$=20~cm($u$=1.4~GHz). The new images were created by merging 20-cm radio-continuum archival data, from the Australian Telescope Compact Array and the Parkes radio-telescope. Our images span from $sim$10arcsec to $sim$150arcsec in resolution and sensitivity of r.m.s.$geq$0.5~mJy/beam. These images will be used in future studies of the SMC's intrinsic sources and its overall extended structure.

We present a detailed study and results of new Australia Telescope Compact Array (ATCA) observations of supernova remnant SNR J0527-6549. This Large Magellanic Cloud (LMC) object follows a typical supernova remnant (SNR) horseshoe morphology with a diameter of D=(66$imes$58)$pm$1~pc which is among the largest SNRs in the LMC. Its relatively large size indicates older age while a steeper than expected radio spectral index of $alpha$=-0.92$pm$0.11 is more typical of younger and energetic SNRs. Also, we report detections of regions with a high order of polarization at a peak value of $sim$ 54 per cent $pm$ 17 per cent at 6~cm.

We present the 100 strongest 1.4~GHz point sources from a new mosaicimage in the direction of the Large Magellanic Cloud (LMC). The observationsmaking up the mosaic were made using Australia Telescope Compact Array (ATCA)over a ten year period and were combined with Parkes single dish data at 1.4 GHz to complete the image for short spacing. An initial list of co-identifications within 10arcsec at 0.843, 4.8 and 8.6 GHz consisted of 2682 sources. Elimination of extended objects and artifact noise allowed the creation of a refined list containing 1988 point sources. Most of these are presumed to be background objects seen through the LMC; a small portion may represent compact HII regions, young SNRs and radio planetary nebulae. For the 1988 point sources we find a preliminary average spectral index ($alpha$) of -0.53 and present a 1.4 GHz image showing source locationin the direction of the LMC.

We present 11 spectra from 12 candidate radio sources co-identified with known planetary nebulae (PNe) in the Large Magellanic Cloud (LMC). Originally found in Australia Telescope Compact Array (ATCA) LMC surveys at 1.4, 4.8 and 8.64~GHz and confirmed by new high resolution ATCA images at 6 and 3~cm (4arcsec/2arcsec), these complement data recently presented for candidate radio PNe in the Small Magellanic Cloud (SMC). Their spectra were obtained using the Radcliffe 1.9-meter telescope in Sutherland (South Africa). All of the optical PNe and radio candidates are within 2arcsec and may represent a population of selected radio bright sample only. Nebular ionized masses of these objects are estimated to be as high as 1.8~$M_odot$, supporting the idea that massive PNe progenitor central stars lose much of their mass in the asymptotic giant branch (AGB) phase or prior. We also identify a sub-population (33\%) of radio PNe candidates with prominent ionized iron emission lines.

We present the results of new moderate resolution ATCA observations of SNR. We found that this SNR exhibits a mostly typical appearance with rather steep and curved $alpha$=--0.81$pm$0.18 and D=43$imes$31$pm$1~pc. Regions of high polarisation were detected, including unusually strong ($sim$70\%) region corresponding to the northern breakout. Such a strong polarisation in breakout regions has not been observed in any other SNR.

We present preliminary results from spectral observations of four (4) candidate radio sources co-identified with known planetary nebulae (PNe) in the Small Magellanic Cloud (SMC). These were made using the Radcliffe 1.9-meter telescope in Sutherland, South Africa. These radio PNe were originally found in Australia Telescope Compact Array (ATCA) surveys of the SMC at 1.42 and 2.37~GHz, and were further confirmed by new high resolution ATCA images at 6 and 3 cm (4arcsec/2arcsec). Optical PNe and radio candidates are within 2arcsec and may represent a sub-population of selected radio bright objects. Nebular ionized masses of these objects may be 2.6~$M_odot$ or greater, supporting the existence of PNe progenitor central stars with masses up to 8 $M_odot$.

With an increasing number of contact binary discoveries and the recognition that luminous red novae are the result of contact binary merger events, there has been a significant increase in the number of light curve solutions appearing in the literature. One key element of such solutions is assigning and fixing the effective temperature of the primary component (T1). Sometimes the expectation that the assigned temperature will significantly alter light curve solution is exaggerated even though theoretical considerations suggest that the absolute value of T1 has little influence on the geometric elements of the light curve solution. In this study, we show that assigning T1 over a range of 1000 K has no significant influence on the light curve solutions of two extreme low mass ratio contact binary systems. In addition, we explore the use of photometric spectral energy distribution as a potential standard for assigning T1 in the absence of spectroscopic observations.

We present an analysis of a new Australia Telescope Compact Array (ATCA) radio-continuum observation of supernova remnant (SNR) G1.9+0.3, which at an age of ~181±25 years is the youngest known in the Galaxy. We analysed all available radio-continuum observations at 6-cm from the ATCA and Very Large Array. Using this data we estimate an expansion rate for G1.9+0.3 of 0.563%±0.078% per year between 1984 and 2009. We note that in the 1980's G1.9+0.3 expanded somewhat slower (0.484% per year) than more recently (0.641% per year). We estimate that the average spectral index between 20-cm and 6-cm, across the entire SNR is α={0.72±0.26 which is typical for younger SNRs. At 6-cm, we detect an average of 6% fractionally polarised radio emission with a peak of 17%§3%. The polarised emission follows the contours of the strongest of X-ray emission. Using the new equipartition formula we estimate a magnetic field strength of B≈273μG, which to date, is one of the highest magnetic field strength found for any SNR and consistent with G1.9+0.3 being a very young remnant.

We present and discuss a new catalogue of 48 compact Hii regions in the Small Magellanic Cloud (SMC) and a newly created deep 1420 MHz (λ=20 cm) radio-continuum image of the N19 region located in the southwestern part of the SMC. The new images were created by merging 1420 MHz radiocontinuum archival data from the Australian Telescope Compact Array. The majority of these detected radio compact Hii regions have rather flat spectral indices which indicates, as expected, that the dominant emission mechanism is of thermal nature.

We present a study of new Australian Telescope Compact Array (ATCA) observations of supernova remnant, SNR J0536-6735. This remnant appears to follow a shell morphology with a diameter of D=36x29 pc (with 1 pc uncertainty in each direction). There is an embedded HII region on the northern limb of the remnant which made various analysis and measurements (such as flux density, spectral index and polarisation) difficult. The radio-continuum emission followed the same structure as the optical emission, allowing for extent and flux density estimates at 20 cm. We estimate the surface brightness at 1 GHz of 2.55x10−21 Wm−2 Hz−1 sr−1 for the SNR. Also, we detect a distinctive radio-continuum point source which confirms the previous suggestion of this remnant being associated with pulsar wind nebula (PWN). The tail of this remnant is not seen in the radio-continuum images and is only seen in the optical and X-ray images.

We present a series of new high-sensitivity and high-resolution radio-continuum images of M31 at λ=20 cm (ν=1.4 GHz). These new images were produced by merging archived 20 cm radio-continuum observations from the Very Large Array (VLA) telescope. Images presented here are sensitive to rms=60 μJy and feature high angular resolution (

We present and discuss new high-sensitivity and resolution radiocontinuum images of the Small Magellanic Cloud (SMC) at λ=20 cm (ν=1.4 GHz). The new images were created by merging 20-cm radio-continuum archival data, from the Australian Telescope Compact Array and the Parkes radio-telescope. Our images span from ～10"to ～150" in resolution and sensitivity of r.m.s.≥0.5 mJy/beam. These images will be used in future studies of the SMC’s intrinsic sources and its overall extended structure.

We present a new catalogue of radio-continuum sources in the field of the Small Magellanic Cloud (SMC). This catalogue contains sources previously not found in 2370 MHz (λ=13 cm) with sources found at 1400 MHz (λ=20 cm) and 843 MHz (λ=36 cm). 45 sources have been detected at 13 cm, with 1560 sources at 20 cm created from new high sensitivity and resolution radio-continuum images of the SMC at 20 cm from paper I. We also created a 36 cm catalogue to which we listed 1689 radio-continuum sources.

We present new 6 and 3-cm radio-continuum maps of the Small Magellanic Cloud (SMC), created with the "peeling" technique and a joint deconvolution. The maps have resolutions of 3000 and 2000 and r.m.s., noise of 0.7 and 0.8 mJy/beam at 6 and 3 cm, respectively. These maps will be used for future studies of the SMC's radio source population and overall extended structure.

We present two new catalogues of radio-continuum sources in the field of the Small Magellanic Cloud (SMC). These catalogues contain sources found at 4800 MHz (λ=6cm) and 8640 MHz (λ=3cm). Some 457 sources have been detected at 3cm with 601 sources at 6cm created from new high-sensitivity and resolution radio-continuum images of the SMC from Crawford et al. (2011).