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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 in uence 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 in uence 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. [ABSTRACT FROM AUTHOR]

We report the discovery of a giant double-lobed (lobe-core-lobe) radio-continuum structure associated with QSO J0443.8-6141 at z=0.72. This QSO was originally identified during the follow-up of a sample of ROSAT All Sky Survey sources at radio and optical frequencies. With a linear size of ~0.77 Mpc, QSO J0443.8-6141 is classified as a giant radio source (GRS); based on its physical properties, we classify QSO J0443.8-6141 as a FR II radio galaxy. High-resolution observations are required to reliably identify GRSs; the next generation of southern-sky radio and optical surveys will be crucial to increasing our sample of these objects. [ABSTRACT FROM AUTHOR]

We use the most up-to-date Milky Way model and solar orbit data in order to test the hypothesis that the Sun's galactic spiral arm crossings cause mass extinction events on Earth. To do this, we created a new model of the Milky Way's spiral arms by combining a large quantity of data from several surveys. We then combined this model with a recently derived solution for the solar orbit to determine the timing of the Sun's historical passages through the Galaxy's spiral arms. Our new model was designed with a symmetrical appearance, with the major alteration being the addition of a spur at the far side of the Galaxy. A correlation was found between the times at which the Sun crosses the spiral arms and six known mass extinction events. Furthermore, we identify five additional historical mass extinction events that might be explained by the motion of the Sun around our Galaxy. These five additional significant drops in marine genera that we find include significant reductions in diversity at 415, 322, 300, 145 and 33 Myr ago. Our simulations indicate that the Sun has spent ~60% of its time passing through our Galaxy's various spiral arms. Also, we briefly discuss and combine previous work on the Galactic Habitable Zone with the new Milky Way model. [ABSTRACT FROM AUTHOR]

We present and discuss a new catalogue of 48 compact H II 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 radio-continuum archival data from the Australian Telescope Compact Array. The majority of these detected radio compact H II regions have rather flat spectral indices which indicates, as expected, that the dominant emission mechanism is of thermal nature. [ABSTRACT FROM AUTHOR]

We present a series of new high-sensitivity and high-resolution radio-continuum images of M31 at λ=20 cm (v=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 (<10") . A complete sample of discrete radio sources have been catalogued and analysed across 17 individual VLA projects. We identified a total of 864 unique discrete radio sources across the field of M31. One of the most prominent regions in M31 is the ring feature for which we estimated total integrated flux of 706 mJy at λ=20 cm. We compare here detected sources to those listed in Gelfand et al. (2004) at λ=92 cm and find 118 sources in common to both surveys. The majority (61%) of these sources exhibit a spectral index of a<-0.6 indicating that their emission is predominantly non-thermal in nature, that is more typical for background objects. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 30" and 20" 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. [ABSTRACT FROM AUTHOR]

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=6 cm) and 8640 MHz (λ=3 cm). Some 457 sources have been detected at 3 cm with 601 sources at 6 cm created from new high-sensitivity and resolution radio-continuum images of the SMC from Crawford et al. (2011). [ABSTRACT FROM AUTHOR]