The international Araucaria Project aims to provide an improved local calibration of the extragalactic distance scale out to distances of a few Megaparsecs. We present a brief, up-to-date review of different results and ongoing projects to (i) better understand the Baade–Wesselink projection factor used in distance determinations based on Cepheids, and (ii) improve the eclipsing-binary technique of distance determination using CHARA/VEGA interferometric observations.

We investigated the environment of the infrared dust bubbles S51 (Zhang & Wang 2012a), N68 (Zhang & Wang 2012b), and N131 (Zhang et al. 2012) from catalogue of Churchwell et al. (2006), and searched for evidence of triggered star formation.

Merging neutron star (NS) binaries may be detected by ground-based gravitational wave (GW) interferometers (e.g. LIGO/VIRGO) within this decade and may also generate electromagnetic radiation detectable by wide-field, fast imaging telescopes that are coming online. The GWs can provide new constraint on the NS equation of state (including mass-radius relation and the related nuclear symmetry energy). This paper reviews various hydrodynamical and electrodynamical processes in coalescing NS binaries, with focus on the pre-merger phase.

We have combined the semi-analytic galaxy formation model of Guo et al. (2011) with a novel particle-tagging technique to predict galaxy surface brightness profiles in a representative sample of ~1900 massive dark matter haloes (1012–1014 M⊙) from the Millennium II ΛCDM N body simulation. We focus on the outer regions of galaxies and stars accreted in mergers. Our simulations cover scales from the stellar haloes of Milky Way-like galaxies to the ‘cD envelopes’ of groups and clusters, and resolve low surface brightness substructure such as the tidal streams of dwarf galaxies. We find that the spatial distribution of stars in low surface brightness regions is tightly correlated with DM halo mass and that collisionless merging during the hierarchical assembly of galaxies largely determines the structure of spheroidal stellar components. Our ΛCDM model agrees well with the available data.

High speed photometry of several accreting binaries was obtained using the McDonald Observatory 2.1m telescope and ARGOS CCD photometer. A broad-band filter (BVR) was used in order to maximize flux and maintain a short (1-10s) integration time on faint targets. Such observations obtained over several years allow for variability study over time scales covering many orders of magnitude. Observations and analysis for several binaries are summarized.

We present detailed models of the edge-on protoplanetary disk ESO Hα 569 (SSTgbs J111110.7-764157) from resolved scattered light images from HST and a complete spectral energy distribution. Data was obtained as part of an HST campaign to catalogue edge-on disks around young stars in nearby star forming regions (HST program 12514, PI: Karl Stapelfeldt). We confirm that this object is an optically thick edge-on disk around a young star with an outer radius of 125 AU. Using full radiative transfer models, we probe the distribution of dust grains and overall shape of the disk (inclination, scale height, dust mass, maximum particle size, inner radius, flaring exponent and surface/volume density exponent).

Coronal Mass Ejections (CMEs) are one of the most violent phenomena found on the Sun. One model to explain their occurrence is the flux rope ejection model where these magnetic structures firt form in the solar corona then are ejected to produce a CME. We run simulations coupling two models. The Global Non-Linear Force-Free Field (GNLFFF) evolution model to follow the quasi-static formation of a flux rope and MHD simulations for the production of a CME through the loss of equilibrium and ejection of this flux rope in presence of solar gravity and density stratification. Our realistic multi-beta simulations describe the CME following the flux rope ejection and highlight the decisive role played by the gravity stratification on the CME propagation speed.

Detections of massive extrasolar moons are shown feasible with the Kepler space telescope. Kepler's findings of about 50 exoplanets in the stellar habitable zone naturally make us wonder about the habitability of their hypothetical moons. Illumination from the planet, eclipses, tidal heating, and tidal locking distinguish remote characterization of exomoons from that of exoplanets. We show how evaluation of an exomoon's habitability is possible based on the parameters accessible by current and near-future technology.

We report the latest results of 225 GHz atmospheric opacity measurements from two Arctic sites; one on high coastal terrain near the Eureka weather station, on Ellesmere Island, Canada, and the other at the Summit Station near the peak of the Greenland icecap. This is a campaign to search for a site to deploy a new telescope for submillimeter Very Long Baseline Interferometry and THz astronomy in the northern hemisphere. Since 2011, we have obtained 3 months of winter data near Eureka, and about one year of data at Summit Station. The results indicate that these sites offer a highly transparent atmosphere for observations in submillimeter wavelengths. Summit Station is particularly excellent, and its zenith opacity at 225 GHz is statistically similar to the Atacama Large Milllimeter/submillimeter Array site in Chile. In winter, the opacity at Summit Station is even comparable to that observed at the South Pole.

W51 Main/South is one of the brightest and richest high-mass star-forming regions (SFR) in the complex W51. It is known to host many ultra-compact HII (UCHII) regions thought to be the site of massive young stellar objects. Maser emission from various species is also found in the region. We have performed MERLIN astrometric observations of excited-OH maser emission at 6.035 GHz and Class II methanol maser emission at 6.668 GHz towards W51 to investigate the relationship between the maser emission and the compact continuum sources in this SFR complex. Here we present the astrometric distributions of both 6.668-GHz methanol and 6.035-GHz excited-OH maser emission in the W51 Main/South region. The location of maser emission in the two lines is compared with that of previously published OH groundstate emission. The interesting coherent velocity and spatial structure observed in the methanol maser distribution as well as the relationship of the masers to infall or outflow in the region are discussed. It appears that the masers are excited by multiple objects potentially at different stages of evolution.

In this paper we first discuss observational evidence of longitudinal concentrations of magnetic activity in the Sun and rapidly rotating late-type stars with outer convective envelopes. Scenarios arising from the idea of rotationally influenced anisotropic convective turbulence being the key physical process generating these structures are then presented and discussed - such effects include the turbulent dynamo mechanism, negative effective magnetic pressure instability (NEMPI) and hydrodynamical vortex instability. Finally, we discuss non-axisymmetric stellar mean-field dynamo models, the results obtained with them, and compare those with the observational information gathered up so far. We also present results from a pure α2 mean-field dynamo model, which show that time-dependent behavior of the dynamo solutions can occur both in the form of an azimuthal dynamo wave and/or oscillatory behavior related to the alternating energy levels of the active longitudes.

Next year the second generation instrument SPHERE will begin science operations at the Very Large Telecope (ESO). This instrument will be dedicated to the search for exoplanets through the direct imaging techniques, with the new generation extreme adaptive optics. In this poster, we present the performances of one of the focal instruments, the Infra-Red Dual-beam Imaging and Spectroscopy (IRDIS). All the results have been obtained with tests in laboratory, simulating the observing conditions in Paranal. We tested several configurations using the sub-system Integral Field Spectrograph (IFS) in parallel and simulating long coronographic exposures on a star, calibrating instrumental ghosts, checking the performance of the adaptive optics system and reducing data with the consortium pipeline. The contrast one can reach with IRDIS is of the order of 10−6 at 0.5 arcsec separation from the central star.

In order to answer this question, we examine the relationship between the two sites of maser activity in G357.96-0.16. We also propose future observations for examining the dust properties of this interesting region of massive star formation.

Improvement of the calibration of the Cepheid period–luminosity relation (Leavitt's Law) is one of the main challenges to improve the accuracy of the Hubble constant, H0. Many parallax-of-pulsation methods are promising but have not yet delivered sufficiently accurate distances: observational biases, such as the projection factor, still dominate. We propose a global parallax-of-pulsation method, combining all observables (photometry, spectroscopy, and interferometry), to (i) reduce statistical errors, (ii) use the redundancy among observables to validate our approach, and (iii) achieve 2% accuracy for individual Cepheid distances.

The nebular remnant of RS Ophiuchi was modelled using combined HST/ACS imaging and ground-based spectroscopy on day 155 after outburst as a two component bipolar expansion with a low velocity innermost hour-glass over density and a more extended high velocity dumbbell structure. The model was evolved to a much later date, day 455 after outburst, when second epoch HST images were secured. However, due to the lack of simultaneous ground-based spectroscopy the evolved model was much harder to constrain. One suggestion put forward was that the dumbbell structure expanded linearly while the inner hour-glass showed signs of deceleration. Archival data in the form of ground-based spectroscopy on day 415 were subsequently obtained. These new data suggest indeed that a non-linear expansion of the system occurred.

I present recent results studying flare emission in magnetars. Strong quasi-periodic oscillations observed in the tail of giant magnetar flares are frequently interpreted as evidence for global seismic oscillations. I demonstrate that such a global oscillation is not directly observable in the lightcurve. New work suggests the amplitude for the strongest QPO stays nearly constant in the rotation phases where it is observed, which I argue suggests it is produced by an additional emission process from the star.

We present a map of CO clumps of Lynds 935 and investigate their physical properties.

Project Dwarf is a new observing campaign focused on the detection of substellar companions to low-mass (composed of late-type, subdwarf (sd) or/and white dwarf (WD) components) detached eclipsing binaries using minima timing. The crucial condition for the object selection for this campaign is possibility to determine times of the minima with high precision. This is naturally fullfilled for eclipsing binaries with deep and narrow minima or systems hosting a WD component showing fast ingress or egress.

The observing project includes three groups of close eclipsing binaries indicating presence of substellar circum-binary components:

1. (i) systems with K or/and M dwarf components

2. (ii) systems with hot subdwarf (sd) and M dwarf components

3. (iii) systems with white dwarf (WD) component(s).

We report observations of a filament eruption, two-ribbon flare, and coronal mass ejection (CME) that occurred in Active Region NOAA 10898 on 6 July 2006. The filament was located South of a strong sunspot that dominated the region. In the evolution leading up to the eruption, and for some time after it, a counter-clockwise rotation of the sunspot of about 30 degrees was observed. We suggest that the rotation triggered the eruption by progressively expanding the magnetic field above the filament. To test this scenario, we study the effect of twisting the initially potential field overlying a pre-existing flux rope, using three-dimensional zero–β MHD simulations. We consider a magnetic configuration whose photospheric flux distribution and coronal structure is guided by the observations and a potential field extrapolation. We find that the twisting leads to the expansion of the overlying field. As a consequence of the progressively reduced magnetic tension, the flux rope quasi-statically adapts to the changed environmental field, rising slowly. Once the tension is sufficiently reduced, a distinct second phase of evolution occurs where the flux rope enters an unstable regime characterized by a strong acceleration. Our simulation thus suggests a new mechanism for the triggering of eruptions in the vicinity of rotating sunspots.

The evolution of size and shape of massive quiescent galaxies over cosmic history has been challenging to explain within standard models of galaxy assembly. Several mechanisms have been proposed to explain the size growth of these systems, including major mergers, expansion, and late accretion via a series of minor mergers. The central mass density is shown to be an excellent tool for discriminating between different evolutionary scenarios. We present here the analysis performed on a spectroscopic sample of ~500 quiescent systems with stellar masses M*>1010 M⊙ spanning the redshift range 0.2<z<2.7 for which we calculate stellar mass densities within central 1 kpc and show that this quantity evolves linearly with redshift. Our results do not change when only systems at constant number density are considered in order to account for the mass growth during mergers and to relate progenitors to their descendants. Discrepancy between our findings and other recent studies performed on an order of magnitude smaller samples emphasizes the need for larger homogeneous spectroscopic samples to be used in such analysis.