Stellar occultations by asteroids and outer solar system bodies can offer ground based observers with modest telescopes and camera equipment the opportunity to probe the shape, size, atmosphere, and attendant moons or rings of these distant objects. The essential requirements of the camera and recording equipment are: good quantum efficiency and low noise; minimal dead time between images; good horological faithfulness of the image timestamps; robustness of the recording to unexpected failure; and low cost. We describe an occultation observing and recording system which attempts to fulfil these requirements and compare the system with other reported camera and recorder systems. Five systems have been built, deployed, and tested over the past three years, and we report on three representative occultation observations: one being a 9 ± 1.5 s occultation of the trans-Neptunian object 28978 Ixion (mv =15.2) at 3 seconds per frame; one being a 1.51 ± 0.017 s occultation of Deimos, the 12 km diameter satellite of Mars, at 30 frames per second; and one being a 11.04 ± 0.4 s occultation, recorded at 7.5 frames per second, of the main belt asteroid 361 Havnia, representing a low magnitude drop (Δmv = ~0.4) occultation.

A key component of explaining the array of galaxies observed in the Universe is the feedback of active galactic nuclei, each powered by a massive black hole’s accretion disk. For accretion to occur, angular momentum must be lost by that which is accreted. Electromagnetic radiation must offer some respite in this regard, the contribution for which is quantified in this paper, using solely general relativity, under the thin-disk regime. Herein, I calculate extremised situations where photons are entirely responsible for energy removal in the disk and then extend and relate this to the standard relativistic accretion disk outlined by Novikov & Thorne, which includes internal angular-momentum transport. While there is potential for the contribution of angular-momentum removal from photons to be ≳ 1% out to ~ 104 Schwarzschild radii if the disk is irradiated and maximally liberated of angular momentum through inverse Compton scattering, it is more likely of order 102 Schwarzschild radii if thermal emission from the disk itself is stronger. The effect of radiation/scattering is stronger near the horizons of fast-spinning black holes, but, ultimately, other mechanisms must drive angular-momentum liberation/transport in accretion disks.

We compare first-order (refractive) ionospheric effects seen by the MWA with the ionosphere as inferred from GPS data. The first-order ionosphere manifests itself as a bulk position shift of the observed sources across an MWA field of view. These effects can be computed from global ionosphere maps provided by GPS analysis centres, namely the CODE. However, for precision radio astronomy applications, data from local GPS networks needs to be incorporated into ionospheric modelling. For GPS observations, the ionospheric parameters are biased by GPS receiver instrument delays, among other effects, also known as receiver DCBs. The receiver DCBs need to be estimated for any non-CODE GPS station used for ionosphere modelling. In this work, single GPS station-based ionospheric modelling is performed at a time resolution of 10 min. Also the receiver DCBs are estimated for selected Geoscience Australia GPS receivers, located at Murchison Radio Observatory, Yarragadee, Mount Magnet and Wiluna. The ionospheric gradients estimated from GPS are compared with that inferred from MWA. The ionospheric gradients at all the GPS stations show a correlation with the gradients observed with the MWA. The ionosphere estimates obtained using GPS measurements show promise in terms of providing calibration information for the MWA.

We have made near-infrared (JHK s) imaging polarimetry toward 24 bright-rimmed clouds in the southern hemisphere in order to reveal their magnetic field structures. The obtained polarization vector maps show that the magnetic field directions inside the bright rim are different from its ambient magnetic field direction, implying that magnetic field structures just inside the ionized front of the clouds are due to the gas compression by UV radiation from nearby massive star. Our investigation into the relation between the magnetic field configuration and the shape of the cloud suggests that the magnetic field configuration affects the evolution of the cloud shape.

We investigated the stellar density substructures around four metal-poor globular clusters (NGC 6266, NGC 6626, NGC 6642, and NGC 6723) in the Galactic bulge. Wide-field near-infrared (JHKs) imaging data were obtained from WFCAM of UKIRT telescope. Field stars contamination around the globular clusters was reduced by using a statistical weighted filtering algorithm. Tidal stripping stellar substructures in the form of tidal tail (NGC 6266 and NGC 6626) or small density lobes/chunk (NGC 6642 and NGC 6723) were found around the four globular clusters in the two-dimensional density contour maps. We also find the overdensity features, which deviate from the theoretical models, in the outer region of radial density profiles. The observed results imply that the four globular clusters have experienced a strong tidal force or the bulge/disk shock effect of the Galaxy.

The epoch of reionization, i.e. the phase transition of the inter-galactic medium from neutral to fully ionized, is essential for our understanding of the evolution of the Universe and the formation of the first stars and galaxies. The Grism Lens-Amplified Survey from Space (GLASS) has obtained spectra of ten thousands of objects in and behind 10 massive galaxy clusters, including the six Hubble Frontier Fields. The grism spectroscopy from GLASS results in hundreds of spectra of z ≳ 7 galaxy candidates. Taking advantage of the lensing magnification from the foreground clusters, the GLASS spectra reaches unprecedented depths in the near-infrared with observed flux limits of ~ 5 × 10−18erg/s/cm2 before correcting for the lens magnification. This has resulted in several Lyα detections at z ~ 7 and tight limits on the emission line fluxes for non-detections. From an ensemble of different photometric selections, we have assembled more than 150 z ≳ 7 galaxy candidates from six of the ten GLASS clusters. Among these more than 20 objects show emission lines consistent with being Lyα at z ≳ 7. The spatial extent of Lyα estimated from a stack of the most promising Lyα emitters at 〈z〉 = 7.2 is consistent with the spatial extent of the UV continuum emission. From the stack we obtain upper limits on the emission line ratios between prominent rest-frame UV emission lines, finding that f CIV/f Lyα ≲ 0.32 and f CIII]/f Lyα ≲ 0.23 in good agreement with values published in the literature.

Supernovae are important probes of the properties of stars at high redshifts because they can be detected at early epochs and their masses can be inferred from their light curves. Direct detection of the first cosmic explosions in the universe will only be possible with JWST, WFIRST and the next generation of extremely large telescopes. But strong gravitational lensing by massive clusters, like those in the Frontier Fields, could reveal supernovae at slightly lower redshifts now by magnifying their flux by factors of 10 or more. We find that Frontier Fields will likely discover dozens of core-collapse supernovae at 5 < z < 12. Future surveys of cluster lenses similar in scope to Frontier Fields by JWST might find hundreds of these events out to z ~ 15 - 17. Besides revealing the masses of early stars, these ancient supernovae could also constrain cosmic star formation rates in the era of first galaxy formation.

We present the first evidence of clear signatures of tidal distortions in the density distribution of the fascinating open cluster NGC 6791. We find that the 2D density map shows a clear elongation and an irregular distribution starting from ~ 300″ from the cluster center and two tails extending in opposite directions beyond the tidal radius. These features are aligned to both the absolute proper motion and to the Galactic centre directions. Accordingly we find that both the surface brightness and star count density profiles reveal a departure from a King model starting from ~ 600″. These observational evidences suggest that NGC 6791 is currently undergoing mass-loss likely due to gravitational shocking and interactions with the tidal field of the Milky Way. We derive the expected mass-loss due to stellar evolution and tidal interactions and we estimate the initial cluster mass to be Mini = (1.5 − 4.0) × 105 M ⊙.

We use three-dimensional magnetohydrodynamic (MHD) simulations to investigate the quasi-equilibrium states of galactic disks regulated by star formation feedback. We incorporate effects from massive-star feedback via time-varying heating rates and supernova (SN) explosions. We find that the disks in our simulations rapidly approach a quasi-steady state that satisfies vertical dynamical equilibrium. The star formation rate (SFR) surface density self-adjusts to provide the total momentum flux (pressure) in the vertical direction that matches the weight of the gas. We quantify feedback efficiency by measuring feedback yields, ηc ≡ P c /ΣSFR (in suitable units), for each pressure component. The turbulent and thermal feedback yields are the same for HD and MHD simulations, ηth ~ 1 and ηturb ~ 4, consistent with the theoretical expectations. In MHD simulations, turbulent magnetic fields are rapidly generated by turbulence, and saturate at a level corresponding to ηmag,t ~ 1. The presence of magnetic fields enhances the total feedback yield and therefore reduces the SFR, since the same vertical support can be supplied at a smaller SFR. We suggest further numerical calibrations and observational tests in terms of the feedback yields.

This focus meeting builds on a small conference “Galaxies meet GRBs at Cabo de Gata” held in September 2013 in Spain, which, for the first time, brought together people from the GRB and starburst communities and proved to be a great success. Focus Meeting 10 at the XXIX IAU GA was the continuation of this interdisciplinary collaboration, supported by Division J (Galaxies and Cosmology), Division D (High Energy Phenomena and Fundamental Physics) and Division G Working Group “Massive Stars”.

1. The International Astronomical Union (hereinafter referred to as the Union) is an international nongovernmental organization. Its objective is to promote the science of astronomy in all its aspects.

In the current paradigm of turbulence-regulated interstellar medium (ISM), star formation rates of entire galaxies are intricately linked to the density structure of the individual molecular clouds. This density structure is essentially encapsulated in the probability distribution function of volume densities (ρ-PDF), which directly affects the star formation rates predicted by analytic models. Contrasting its fundamental role, the ρ-PDF function has remained virtually unconstrained by observations. I describe in this contribution the recent progress in attaining observational constraints for the column density PDFs (N-PDFs) of molecular clouds that function as a proxy of the ρ-PDFs. Specifically, observational works point towards a universal correlation between the shape of the N-PDFs and star formation activity in molecular clouds. The correlation is in place from the scales of a parsec up to the scales of entire galaxies, making it a fundamental, global link between the ISM structure and star formation.

We present observations of an “EIT wave” associated with an X-class flare from 2012 July 6, the propagation of which was severely restricted by the magnetic structure of the solar corona surrounding the erupting active region. The “EIT wave” was observed by both SDO and STEREO-A, allowing a three-dimensional examination of how the propagation of the disturbance was affected both by a neighbouring coronal hole and a trans-equatorial loop system. In addition, the eruption was observed at the limb by the ground-based CoMP instrument, allowing the Doppler motion associated with the eruption and resulting coronal loop oscillation to be investigated in detail. This combination of data-sets provides a unique insight into the three-dimensional evolution of the “EIT wave” and its effects on the surrounding corona.

The main purpose of Commission 14 is to foster interactions between the astronomical community and those conducting research on atoms, molecules, and solid state particles to provide data vital to reducing and analysing astronomical observations and performing theoretical investigations.

We consider the influence of a coronal mass ejection (CME) of a solar type star on the mass loss rate of a hot Jupiter exoplanet. We have conducted 3D numerical gas-dynamic simulations of the planet's atmosphere that interacts with CME. Using the results of these simulations we have estimated the specific parameters that influence the mass loss rate. Based on the assumption that CME totally sweeps away part of the planet's gaseous envelope located outside the Roche lobe we estimated the maximum mass loss rate. Finally, we have considered the dependence of mass loss rate on the frequency of CMEs in course of star's evolution.

We studied molecular gas properties in a sample of 98 Hi - flux selected spiral galaxies within ~ 25 Mpc using the CO J = 3 − 2 line, observed with the JCMT, and subdivided into isolated, group, and Virgo subsamples. We find a larger mean H2 mass in the Virgo galaxies compared to group galaxies, despite their lower mean Hi mass. Combining our data with complementary Hα star formation rate measurements, Virgo galaxies have a longer molecular gas depletion times compared to group galaxies, perhaps due to heating processes in the cluster environment or differences in the turbulent pressure.

The XXIX IAU General Assembly took place during the golden year of the exploration of small solar system bodies. With the Rosetta ESA mission around comet 67P, NASA Dawn and New Horizons missions nearby dwarf planets Ceres and Pluto, respectively, and the NASA/Cassini mission in Saturn neighborhood, year 2015 marked an important step towards further understanding of small solar system bodies. On August 11-13, Focus meeting 9 "Highlights in the exploration of small worlds" gathered scientists of all over the world to present and discuss the spectacular results obtained from these missions, as well as recent achievements obtained from past missions, comprehensive spectroscopic surveys from space (e.g., Herschel, NEOWISE, Gaia), ground-based observations, and geochemical analyses. This meeting was also the opportunity to discuss the state of our understanding of the nature of the various populations of small bodies in the Solar System, including icy satellites, in a cosmo-chemistry perspective.

This work presents an analysis of UV spectroscopic observations from the IRIS satellite of an M1.0 class flare occurred on 12 June 2014 in active region NOAA 12087. Our analysis of the IRIS spectra and Slit-Jaw images revealed presence of a strongly redshifted chromospheric jet before the flare. We also found strong emission of the chromospheric lines, and studied the C II 1334.5 Å line emission distribution in details. A blueshift of the Fe XXI line across the flaring region corresponds to evaporation flows of the hot chromospheric plasma with a speed of 50 km/s. Although the enhancement of the C II line integrated redshift correlates with the flare X-ray emission, we classify the evaporation as of a “gentle” type because of its long time scale and subsonic velocities. Analysis of X-ray data from the RHESSI satellite showed that both, an injection of accelerated particles and a heat flux from the energy release site can explain the energetics of the observed event.