The helicity of cellular convective flows in a horizontal layer of compressible fluid (gas) heated from below and rotating about a vertical axis is studied using finite-difference numerical simulations. The medium is assumed to be polytropically stratified. An initial thermal perturbation is introduced so as to produce a system of Bénard-type hexagonal convection cells. The flow gradually becomes less ordered, and the mean helicity grows initially and decreases sharply after the substantial chaotisation of the flow. Given the Rayleigh and Prandtl numbers, the maximum value reached by the mean helicity increases with the decrease of the polytrope index and has a maximum at a certain rotational velocity of the layer.

The results of search for meteor showers associated with the asteroids crossing the Earthfs orbit and moving on comet-like orbits are given. It was shown that among 2872 asteroids discovered till 1.01.2005 and belonging to the Apollo and Amor groups, 130 asteroids have associated meteor showers and, therefore, are the extinct cometary nuclei.

The interstellar medium in galactic halos is described as a consequence of feedback mechanisms from processes related to star-formation in the disk. The presence of gas in galactic halos is also expected due to accretion of gas from the circumgalactic environment. The observational evidence for gas in galactic halos - from the hot X-ray emitting coronal phase to cool molecular gas and dust - is reviewed and discussed in the context of current models of the ISM and the “infall vs. outflow“ debate.

The heritage of astronomy in Australia has proven an effective communication medium. By interpreting science as a social and cultural phenomenon new light is thrown on challenges, such as the dispersal of instruments and problems identifying contemporary astronomy heritage. Astronomers are asked to take note and to consider the communication of astronomy now and in the future through a tangible heritage legacy.

Advances in both digital processing devices and in technologies to sample the focal and aperture planes of radio antennas is enabling observations of the radio sky with high spectral and spatial resolution combined with large bandwidth and field of view. As a consequence, survey mode radio astronomy generating vast amounts of data and involving globally distributed collaborations is fast becoming a primary tool for scientific advance. The Square Kilometre Array (SKA) will open up a new frontier in data intensive astronomy. Within the next few years SKA precursor telescopes will demonstrate new technologies and take the first major steps toward the SKA. Projects that path find the scientific journey to the SKA with these and other telescopes are currently underway and being planned. The associated exponential growth in data require us to explore new methodologies for collaborative end-to-end execution of data intensive observing programs.

The presence of μG-level magnetic fields associated with the intracluster medium of galaxy clusters is now widely acknowledged. Our knowledge of their properties has greatly improved in the recent years thanks to both new radio observations and the developments of new techniques to interpret data.

We present the preliminary analysis of clustering of a sample of 1157 radio-identified galaxies from Machalski & Condon (1999). We found that for separations 2–15 h−1 Mpc their redshift space autocorrelation function ξ(s) can be approximated by the power law with the correlation length ~3.75h−1 Mpc and slope γ ~ 1.8. The correlation length for radiogalaxies is found to be lower and the slope steeper than the corresponding parameters of the control sample of optically observed galaxies. Analysis the projected correlation function Ξ(r) displays possible differences in the clustering properties between active galactic nuclei (AGN) and starburst (SB) galaxies.

We report a pair of oppositely directed sudden impulses (SI), in the geomagnetic field (ΔX), at ground stations, called SI+ – SI− pairs, that occurred between 1835 UT and 2300 UT on 23 April 1998. The SI+ – SI− pair, was well correlated with corresponding variations in the solar wind density, while solar wind velocity and the southward component of the interplanetary magnetic field (Bz) did not show any correspondence. This event had no source on the visible solar disk but was associated with a rear-side fast partial halo coronal mass ejection (CME) and an optically occulted M1.4 class solar flare behind the west limb. This event was unique in that one could clearly identify variations in ΔX at ground stations with solar wind parameters.

Under the standard model extension (SME) framework, Lorentz invariance is tested in five binary pulsars: PSR J0737-3039, PSR B1534+12, PSR J1756-2251, PSR B1913+16 and PSR B2127+11C. By analyzing the advance of periastron, we obtain the constraints on a dimensionless combination of SME parameters that is sensitive to timing observations. The results imply no evidence for the break of Lorentz invariance at 10−10 level, one order of magnitude larger than previous estimation.

One of the most outstanding predictions of the radial migration theory was a progressive increase in the age of the stellar populations toward the galaxy outskirts. This gradual change in the age is caused by a net flux of old stars formed in the inner disk moving toward the outskirts. Thanks to the fact that the age of stellar populations can be interpreted in terms of colors, this prediction was confirmed observationally a few years ago with deep surface brightness profiles of a large sample of nearby galaxies. Our group has now taken a step forward on this as we have explored the properties of the stellar populations beyond the star formation threshold using ultra deep data from SDSS Stripe82. These data allowed us to study the faint outskirts of disks in detail down to a surface brightness level of 30 mag/arcsec2 in the r'-band. At these surface brightness levels spiral galaxies reveal new and exciting structural components which could not have been seen by regular SDSS imaging: outer disks extend farther out, tidal streams and satellites become visible. We will present deep color profiles of the regions of the galaxies where the disks starts to be confused with the stellar haloes. We confront these colors with model predictions. For some galaxies, the very outer regions are so red that conventional IMFs can not explain their colors. We will discuss whether our new results can be explained within the radial migration scheme.

cD galaxies are supergiant elliptical galaxies found generally in the central parts of rich clusters, which have an extended halo-like component (envelope) in addition to the underlying de Vaucouleurs-Sérsic elliptical galaxy-like component. This envelope can extend to radial distances of > 500 kpc (Oemler 1976, Schombert 1988). There have been many theories to explain the formation of these envelopes. These include tidal stripping, where material is stripped from neighbouring galaxies; mergers and fusions, where the envelope is built up hierarchically by successive mergers with large and small galaxies; primordial origin, where the envelope is formed at the same time as the rest of the elliptical galaxy (which appears to be related to theories of early formation of the largest galaxies); and cooling flows: in clusters with X-ray emission there is often a minimum temperature in the centre interpreted as a flow of cooling gas towards the centre of the cluster, where the gas can cool sufficiently, forming stars. The colours of the stars in the envelopes will be affected by their process of formation and subsequent evolution.

For the purposes of the discussion of IAU follow up on Resolution B5, adopted at the GA in Rio de Janiero in 2009, reference is made here to the resolution itself and the background which led to its proposal and adoption by the IAU.

We report our new results of the magnetic field (B) morphologies toward W51 North, traced with the linear polarization of the dust continuum at wavelengths of 870 μm. The B morphologies are resolved with an angular resolution of typically 1” using the Submillimeter Array (SMA). Dense structures with a number density 105 to 107 cm−3 are traced. In comparison, the B morphologies of sources at different evolutionary stages, from the collapsing core in W51 e2 (Tang et al. 2009a) and part of Orion BN/KL (Tang et al. 2010) to the ultra-compact HII region G5.89-0.39 (Tang et al. 2009b) clearly exhibit different morphologies, likely suggesting different roles of the B fields at different stages.

The presence of matter with angular momentum, in the form of a fallback disk around a young isolated neutron star will determine its evolution. This leads to an understanding of many properties of different classes of young neutron stars, in particular a natural explanation for the period clustering of AXPs, SGRs and XDINs. The spindown or spinup properties of a neutron star are determined by the dipole component of the magnetic field. The natural possibility that magnetars and other neutron stars may have different strengths of the dipole and higher multipole components of the magnetic field is now actually required by observations on the spindown rates of some magnetars. This talk gives a broad overview and some applications of the fallback disk model to particular neutron stars. Salient points are: (i) A fallback disk has already been observed around the AXP 4U 0142+61 some years ago. (ii) The low observed spindown rate of the SGR 0418+5729 provides direct evidence that the dipole component of the field is in the 1012G range. All properties of the SGR 0418+5729 at its present age can be explained by spindown under torques from a fallback disk. (iii) The anomalous braking index of PSR J1734-3333 can also be explained by the fallback disk model which gives the luminosity, period, period derivative and the period second derivative at the present age. (iv) These and all applications to a variety of other sources employ the same disk physics and evolution, differing only in the initial conditions of the disk.

Recent observations reveal that a cool disk may survive in the innermost stable circular orbit (ISCO) for some black hole X-ray binaries in the low/hard state. The spectrum is characterized by a power law with a photon index Γ ~ 1.5-2.1 in the range of 2-10 keV and a weak disk component with temperature of ~ 0.2 keV. The formation of such a cool disk in the most inner region of black hole X-ray binaries at the low/hard state is investigated within the framework of disk accretion fed by condensation of hot corona. We also calculate the emergent spectra of the inner disk and corona. It's found that our model can very well explain the spectral features of GX 339-4 and Cyg X-1, in which the thin disk may exist at ISCO in the low/hard state.

Spectral classifications and color temperatures based on narrow-band TiO/CN photometry are given for ten dM stars that are known to be planet hosts.

We use the full spectrum fitting ability of ULySS, with the Pegase.HR stellar population model to fit the observed spectra of 40 brightest cluster galaxies in order to determine whether a single or a composite stellar population provided the most probable representation of the star formation history (SFH). We find that some galaxies in the sample have more complex SFHs.

The project Galactic Cold Cores is studying the early stages of Galactic star formation using far-infrared and sub-millimetre observations of dust emission. The Planck satellite has located many sources of cold dust emission that are likely to be pre-stellar clumps in interstellar clouds. We have mapped a sample of Planck-detected clumps with the Herschel satellite at wavelengths 100-500 μm. Herschel has confirmed the Planck detections of cold dust and have revealed a significant amount of sub-structure in the clumps. The cloud cores have colour temperatures in the range of 10–15 K. However, star formation is often already in progress with cold clumps coinciding with mid-infrared point sources. In less than half of the cases, the cloud morphology is clearly dominated by filamentary structures. The sources include both nearby isolated globules and more distant, massive clouds that may be off-the-plane counterparts of infrared dark clouds.

The Herschel observations have been completed and the processed maps will be released to the community in 2013.

The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is under construction and will be commissioned in September 2016. A low frequency 7-beam receiver working around 400 MHz is proposed for FAST early science. It will be optimized for a whole FAST sky drift-scan pulsar survey. Simulations show that about 1500 new normal pulsars will be discovered, as while as about 200 millisecond pulsars.

Ultra-Luminous X-ray sources are accreting black holes that might represent strong evidence of the Intermediate Mass Black Holes (IMBH), proposed to exist by theoretical studies but with no firm detection (as a class) so far. We analyze the best X-ray timing and spectral data from the ULX in NGC 5408 provided by XMM-Newton. The main goal is to study the broad-band noise variability of the source. We found an anti-correlation of the fractional root-mean square variability versus the intensity of the source, similar to black-hole binaries during hard states.