We have observed the bright, magnetically active multiple star AB Doradus in a multiwavelength campaign centring around two large facility allocations in November 2006 and January, 2007. Our observations have covered at least three large flares. These flares were observed to produce significant hardening of the X-ray spectra during their very initial stages. We monitored flare-related effects using the Suzaku X-ray satellite and the Australia Telescope Compact Array (ATCA) at 3.6 and 6 cm. Observations at 11 and 21 cm were also included, but they were compromised by interference. Optical monitoring was also provided by broadband B and V photometry and some high-dispersion spectrograms. From this multiwavelength coverage we find that the observed flare effects can be mainly associated with a large active region near longitude zero. The second major X-ray and microwave flare of Jan 8, 2007 was observed with a favourable geometry that allowed its initial high-energy impulsive phase to be observed in the higher frequency range of Suzaku’s XIS detectors. The fractional circular polarisation (Stokes V/I) was measured in the uv data for the complete runs, for 25 min integrations and, at 4.80 GHz, for 5 min integrations, using the radio data of Nov 21 2006 and Jan 08 2007. Most of the full data sets showed V/I fractions from AB Dor B that were significant at greater than the 3σ level. In several of the 5 min integrations at 4.80 and 8.64 GHz this fraction reached a significance level between 3 and 9σ. Lack of angular resolution prevented identification of these high V/I values with one or other of the two low-mass red-dwarf components of AB Dor B.

In Australia a significant number of women were employed to measure and compute the position of stars for the Astrographic Catalogue at Adelaide, Sydney, Melbourne and Perth Observatories. New archival research has provided evidence that the first women employed in astronomy in Australia were engaged due to this project.

This paper focuses on Mary Emma Greayer, who was employed as a computer at Adelaide Observatory from 1890, and Charlotte Emily Fforde Peel, employed as a star measurer, computer and astrographic assistant at Melbourne Observatory from 1898. The measurement bureaux at Melbourne, Perth and Sydney Observatories are examined within the context of women working on the Astrographic Catalogue in other observatories during the late nineteenth century.

Evidence is presented that individuals, such as Greayer and Peel, were vital to the completion of the Astrographic Catalogue and other astronomical work. Furthermore, it is argued that this evidence points to women having a broader role and greater agency within observatories in Australia and in astronomy than has previously been acknowledged.

We continue the study of O-supergiants belonging to the association Cyg OB2 using moderate-resolution spectra. In this paper we present results of the modelling of the stellar atmosphere of Cyg OB2 #11. This object belongs to the spectral class Ofc, which was recently introduced and is yet small in numbers. Ofc class consists of stars with normal spectra with CIII λλ4647, 4650, 4652 emission lines of comparable intensity to those of the Of-defining lines NIII λλ4634, 4640, 4642. We combined new spectral data obtained by the 1.5-m Russian–Turkish telescope with spectra from MAST and CASU archives and determined physical parameters of the wind and chemical composition of the stellar atmosphere using cmfgen code. The estimated nitrogen abundance is lower than one in atmospheres of ‘normal’ O-supergiants (i.e. O4-6 supergiants without additional spectral index ‘n’ or ‘c’) and carbon abundance is solar. Also we find an excess in silicon. We present an illustrative comparison of our modelling results with current Geneva evolutionary models for rotating massive stars. The position on the Hertzsprung–Russell diagram corresponds to the star mass of about 50 M⊙ and age about 4.5 Myr. Moreover, we carried out the high angular resolution (~ 0.02arcsec) observations on the Russian 6-m telescope aiming to find weaker companions of this star, which did not reveal any.

We describe the development of a noise-temperature testing capability for phased-array antennas operating in receive mode from 0.7 GHz to 1.8 GHz. Sampled voltages from each array port were recorded digitally as the zenith-pointing array under test was presented with three scenes: (1) a large microwave absorber at ambient temperature, (2) the unobstructed radio sky, and (3) broadband noise transmitted from a reference antenna centred over and pointed at the array under test. The recorded voltages were processed in software to calculate the beam equivalent noise temperature for a maximum signal-to-noise ratio beam steered at the zenith. We introduced the reference-antenna measurement to make noise measurements with reproducible, well-defined beams directed at the zenith and thereby at the centre of the absorber target. We applied a detailed model of cosmic and atmospheric contributions to the radio sky emission that we used as a noise-temperature reference. We also present a comprehensive analysis of measurement uncertainty including random and systematic effects. The key systematic effect was due to uncertainty in the beamformed antenna pattern and how efficiently it illuminates the absorber load. We achieved a combined uncertainty as low as 4 K for a 40 K measurement of beam equivalent noise temperature. The measurement and analysis techniques described in this paper were pursued to support noise-performance verification of prototype phased-array feeds for the Australian Square Kilometre Array Pathfinder telescope.

We provide a set of analytic fits to the radii of pre-mainsequence stars in the mass range 0.1 < M/M ⊙ < 8.0. We incorporate the formulae in N-body cluster models for evolution from the beginning of pre-main sequence. In models with 1 000 stars and high initial cluster densities, pre-mainsequence evolution causes roughly twice the number of collisions between stars than in similar models with evolution begun only from the zero-age main sequence. The collisions are often all part of a runaway sequence that creates one relatively massive star.

I review the astrophysical insights arising from high-precision astrometric observations of X-ray binary systems, focussing primarily (but not exclusively) on recent results with very long baseline interferometry. Accurate, model-independent distances from geometric parallax measurements can help determine physical parameters of the host binary system and constrain black hole spins via broadband X-ray spectral modelling. Long-term proper motion studies, combined with binary evolution calculations, can provide observational constraints on the formation mechanism of black holes. Finally, the astrometric residuals from parallax and proper motion fits can provide information on orbital sizes and jet physics. I end by discussing prospects for future progress in this field.

Astrophysical cosmology constrains the variation of Newton’s Constant in a manner complementary to laboratory experiments, such as the celebrated lunar laser ranging campaign. Supernova cosmology is an example of the former and has attained campaign status, following planning by a Dark Energy Task Force in 2005. In this paper, we employ the full SNIa data set to the end of 2013 to set a limit on G variation. In our approach, we adopt the standard candle delineation of the redshift distance relation. We set an upper limit on its rate of change $|\dot{G}/G|$ of 0.1 parts per billion per year over 9 Gyrs. By contrast, lunar laser ranging tests variation of G over the last few decades. Conversely, one may adopt the laboratory result as a prior and constrain the effect of variable G in dark energy equation of state experiments to δw < 0.02. We also examine the parameterisation G ~ 1 + z. Its short expansion age conflicts with the measured values of the expansion rate and the density in a flat Universe. In conclusion, supernova cosmology complements other experiments in limiting G variation. An important caveat is that it rests on the assumption that the same mass of 56Ni is burned to create the standard candle regardless of redshift. These two quantities, f and G, where f is the Chandrasekhar mass fraction burned, are degenerate. Constraining f variation alone requires more understanding of the SNIa mechanism.

The transformation equations from BVRc to g′r′i′ magnitudes and vice versa for the giants were established from a sample of 80 stars collected from Soubiran et al. (2010) with confirmed surface gravity (2 ⩽ logg (cm s− 2) ⩽ 3) at effective temperatures 4000 < Teff (K) < 16000. The photometric observations, all sample stars at g′r′i′ and 65 of them at BVRc , were obtained at TÜBİTAK National Observatory (TUG) 1m (T100) telescope, on the Taurus Mountains in Turkey. The MV absolute magnitudes of the giant stars were estimated from the absolute magnitude-temperature data for the giant stars by Sung et al. (2013) using the Teff from the intrinsic colours considered in this study. The transformation equations could be considered to be valid through the ranges of the following magnitudes and colours involved: 7.10 < V 0 < 14.50, 7.30 < g′0 < 14.85, − 0.20 < (B − V)0 < 1.41, − 0.11 < (V − Rc )0 < 0.73, − 0.42 < (g′ − r′)0 < 1.15, and − 0.37 < (r′ − i′)0 < 0.47 mag. The transformations were successfully applied to the synthetic BVRc data of 427 field giants in order to obtain the g′r′i′ magnitudes and colours. Comparisons of these data with the g′r′i′ observations of giants in this study show that the mean residuals and standard deviations lie within [− 0.010, 0.042] and [0.028, 0.068] mag, respectively.

We report on the results of a long time photometric monitoring of the two metal-poor Galactic globular clusters, M22 and IC4499, searching for long-period variables (LPVs) on the upper giant branch. We detected 22 new LPVs in the field of M22 and confirmed the variability of six known variables. Periods could be determined for 16 of them. In the field of IC4499 we detected and characterised two new LPVs. Cluster membership is evaluated for all the variables based on photometry and literature data, and the location of the stars in log P-K-diagram is discussed. Our findings give further support to the presence of LPVs at metallicities as low as [Fe/H] = −1.7. The luminosity range where LPVs are found in metal-poor clusters is lower than in more metal-rich clusters.

Surface photometry at 3.6 μm is presented for 61 low surface brightness (LSB) galaxies (μo <19 3.6 μm mag arcsecs−2). The sample covers a range of luminosity from −11 to −22 in M 3.6 and size from 1 to 25 kpc. The morphologies in the mid-IR are comparable to those in the optical with 3.6 μm imaging reaches similar surface brightness depth as ground-based optical imaging. A majority of the resulting surface brightness profiles are single exponential in shape with very few displaying upward or downward breaks. The mean V − 3.6 colour of LSB is 2.3 with a standard deviation of 0.5. Colour-magnitude and two-colour diagrams are well matched to models of constant star formation, where the spread in colour is due to small changes in the star formation rate (SFR) over the last 0.5 Gyrs as also suggested by the specific SFR measured by Hα.

We investigated the space velocity components of 6 610 red clump (RC) stars in terms of vertical distance, Galactocentric radial distance and Galactic longitude. Stellar velocity vectors are corrected for differential rotation of the Galaxy which is taken into account using photometric distances of RC stars. The space velocity components estimated for the sample stars above and below the Galactic plane are compatible only for the space velocity component in the direction to the Galactic rotation of the thin disc stars. The space velocity component in the direction to the Galactic rotation (V lsr) shows a smooth variation relative to the mean Galactocentric radial distance (Rm ), while it attains its maximum at the Galactic plane. The space velocity components in the direction to the Galactic centre (U lsr) and in the vertical direction (W lsr) show almost flat distributions relative to Rm , with small changes in their trends at Rm ~ 7.5 kpc. U lsr values estimated for the RC stars in quadrant 180° < l ⩽ 270° are larger than the ones in quadrants 0° < l ⩽ 90° and 270° < l ⩽ 360°. The smooth distribution of the space velocity dispersions reveals that the thin and thick discs are kinematically continuous components of the Galaxy. Based on the W lsr space velocity components estimated in the quadrants 0° < l ⩽ 90° and 270° < l ⩽ 360°, in the inward direction relative to the Sun, we showed that RC stars above the Galactic plane move towards the North Galactic Pole, whereas those below the Galactic plane move in the opposite direction. In the case of quadrant 180° < l ⩽ 270°, their behaviour is different, i.e. the RC stars above and below the Galactic plane move towards the Galactic plane. We stated that the Galactic long bar is the probable origin of many, but not all, of the detected features.

Optical positions from the SuperCOSMOS Sky Survey have been compared in detail with accurate radio positions that define the second realisation of the International Celestial Reference Frame (ICRF2). The comparison was limited to the IIIaJ plates from the UK/AAO and Oschin (Palomar) Schmidt telescopes. A total of 1 373 ICRF2 sources was used, with the sample restricted to stellar objects brighter than BJ = 20 and Galactic latitudes |b| > 10°. Position differences showed an rms scatter of $0.16\text{ arcsec}$ in right ascension and declination. While overall systematic offsets were < $0.1\text{ arcsec}$ in each hemisphere, both the systematics and scatter were greater in the north.