Mingantu Spectral Radioheliograph (MUSER) is an aperture-synthesis imaging telescope, dedicated to observe the Sun, operating on multiple frequencies in dm to cm range. The ability of MUSER to get images and measure Stokes I and V parameters simultaneously at many frequencies in a wide band is of fundamental importance. It allows one to approach/solve such important problems as measuring the strength, geometry and dynamics of magnetic field at coronal heights. Here we consider some of the recently developed radio physics methods to be used for solving the problems. These methods allow us to obtain information that is unattainable in other areas of the electromagnetic spectrum.

The centimeter -wave bursts are simple: they are characterized by a rapid rise in intensity and a slower decline. The burst-radiation is in general smooth, usually free of details in time and frequency and is a partially polarized broadband continuum. It starts almost immediately after an associated Hα flare and originates from a source of small angular size (< 1′ arc). The smooth continuum emission of centimeter-wave bursts has been accounted for by synchrotron radiation from fast electrons accelerated during flares. I shall not attempt to give here a full description of the observational characteristics of centimeter bursts, rather I shall concentrate on certain specific features relevant to the understanding of the generating mechanism of these bursts. More than 20 years ago, centimeter bursts were studied with a spatial resolution as good as ∼ 1′ arc. Even with this resolution the presence of small scale structures on scales of 1′–4′ were observed in cm-λ bursts sources. Since that time both spatial and time resolution have steadily improved; we now have a spatial resolution of ″ and time resolution of ∼ 10 ms. Such resolutions have revealed smaller scale structures of a few arc seconds and more complexity in burst sources. At the same time soft x-ray observations, particularly from Skylab, with resolution better than 5″ (e.g. Kahler et al. 1975; Vorpahl et al. 1975) have given new information about the flare phenomenon. Because of the close association of soft x-ray and cm-λ burst sources, these observations are particularly important for a proper understanding of the generating mechanism of cm-λ bursts, acceleration of electrons and the origin of solar flares.

Methanol and water masers indicate young stellar objects. They often exhibit flares, and a fraction shows periodic activity. Several mechanisms might explain this behavior but the lack of concurrent infrared (IR) data complicates the identification of its cause. Recently, 6.7 GHz methanol maser flares were observed, triggered by accretion bursts of high-mass YSOs which confirmed the IR-pumping of these masers. This suggests that regular IR changes might lead to maser periodicity. Hence, we scrutinized space-based IR imaging of YSOs associated with periodic methanol masers. We succeeded to extract the IR light curve from NEOWISE data for the intermediate mass YSO G107.298+5.639. Thus, for the first time a relationship between the maser and IR variability could be established. While the IR light curve shows the same period of ~34.6 days as the masers, its shape is distinct from that of the maser flares. Possible reasons for the IR periodicity are discussed.

This review summarises current knowledge of the chemical composition of PopI WR stars, concentrating on work carried out in this area since the last IAU, No. 49, symposium devoted to this stellar class (Bappu & Sahade 1973). Earlier reviews of this topic are found in Gebbie & Thomas (1968). The dichotomy of the WR stars into the WN and WC sequences (Beals 1934) has generally been qualitatively interpreted as arising because of gross differences in the C and N abundances: WN stars which exhibit emission lines of predominantly He and N ions with little evidence for C, being inferred as C-poor objects, whilst WC stars, showing predominantly He and C lines and virtually no evidence for N being inferred as N-poor. In both sequences the visible spectra show little or no evidence for hydrogen. However, although the WR stars have been acknowledged as a class for over a century now, progress has been very slow in putting quantitative determinations of their physical and chemical properties on a firm basis, with the bulk of work in this area being conducted during the past decade. The chemical nature of the WR stars has always been a matter of considerable uncertainty, controversy and, quite often, passionate disagreement, arising from uncertainties in the interpretation of the, often ambiguous, observational material available, as well as from disagreements as to the reliability of the use of comparatively simple analytical models employed to date. Recent results strongly suggest that the WR stars are chemically evolved objects, with low H/He ratios and quite different C/N ratios in the WN and WC sequences, with some measure of agreement in these results with the chemistries predicted to arise at various stages of evolutionary theory for hot massive stars which, by one means or another, have shed much of their atmospheric material during their evolution. My purpose in this review is to summarise the investigations and results that lead to the above conclusions. §2 deals with an assessment of the atmospheric H/He ratio in both WN and WC stars: a parameter of fundamental importance in addressing their evolutionary status, as well as providing a base species with which to compare other derived chemical abundances. §3 briefly deals with the models generally employed and gives recent results for He, C and N abundances derived from both visible and UV line analyses. §4 summarises recent results from stellar evolutionary theory and in §5 compares these with those derived from observation, assessing the significance of these new results and their implications for the evolutionary status of the WR stars. Some areas for further advancement are identified.

We have acquired high spectral resolution observations (R=150,000) of the planetary nebulae NGC 7009 and NGC 6153, using bHROS on Gemini South. Observations of this type may provide a key to understanding why optical recombination lines (ORLs) yield systematically higher heavy element abundances for photoionized nebulae than do the classical forbidden collisionally excited lines (CELs) emitted by the same ions; NGC 7009 and NGC 6153 have notably high ORL/CEL abundance discrepancy factors (ADFs) of 5 and 10, respectively. Due to the opposite temperature dependences of ORLs and CELs, ORLs should be preferentially emitted by colder plasma. Our bHROS observations of NGC 7009 reveal that the [O III] 4363 Å CEL has a FWHM linewidth that is 1.5 times larger than that shown by O II ORLs in the same spectrum, despite the fact that all of these lines are emitted by the O$^{2+}$ ion. The bHROS spectra of NGC 6153 also show that its O II ORLs have significantly narrower linewidths than do the [O III] 4363 Å and 5007 Å lines but, in addition, the [O III] 4363 Å and 5007 Å lines show very different velocity profiles, implying the presence of large temperature variations in the nebula.

We review the results of HST/WFPC2 observations of a sample of 50 very-low-mass objects in the solar neighborhood (30 from our own program and 20 from the archive). Using high spatial resolution HST/WFPC2 images, we observed these objects in two filters (F814W and F675W) in order to identify close companions, measure their colours, and obtain first epoch data of the newly discovered binaries. In addition to 3 previously known binaries we discovered 3 new multiple systems. Second epoch data are required to confirm that they are real common proper motion pairs. Binary properties like multiplicity, distribution of binary separations and brightness ratios hold clues on the origin and evolution of free-floating brown dwarf binaries.

By investigating ten typical magnetic clouds (MCs) associated with large geomagnetic storms (Dst $\leq-100$ nT) from 2000 to 2003, the geoeffectiveness of MCs with various orientations is addressed. It is found that the Dst peak values during the geomagnetic storms are well estimated by applying flux rope model to these magnetic clouds. A high correlation between estimated and observed Dst values is obtained. Moreover, the effect of orientations of MCs on intensities of geomagnetic storms is studied. It is found that the favorable orientations of MCs are approximately at $\theta\sim70^{\circ}$ and $\phi\sim40^{\circ}$ in GSE coordinates to cause large geomagnetic storms. Further, by analyzing solar observations of four associated erupted filaments, the question who determine the orientations of MCs is studied. The likelihood of predicting the intensities of a geomagnetic storms several tens hours before their occurrences is also discussed.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

A preliminary account is presented of some characteristics of Fast Fine Structure, that is fine structure with time scales in the milli second range, and of the flare events in which they appear. Fast Fine Structure is found to be a fairly common phenomenon that could, but not necessarily does, appear in flare events of any importance occurring at any longitude. It may occur with any type of microwave burst (except most likely “Rise” and “Fall”). It appears more often in the more important events and it may last for only a few seconds up to many minutes. Fast Fine Structure may have any degree of circular polarization, apparently independent of its longitude position.

The orbits of the planets as represented by the JPL planetary ephemerides are now primarily determined by radio tracking of spacecraft. Analysis of the data and propagation of the orbits relies on an internally consistent set of equations of motion and propagation of radio signals including relativistic effects at the centimeter level. The planetary ephemeris data set can be used to test some aspects of the underlying theory such as estimates of PPN parameters γ and β, time variation in the gravitational constant G, rotation of the solar system relative to distant objects (Mach's principle), and place stringent limits on the possible violation of the inverse-square law.

We present a catalog of millions of radio sources, created by consolidating large-area radio and optical surveys GB6 (6cm), FIRST (20cm), NVSS (20cm), WENSS (92cm), VLSS (4m), and SDSS DR9 (optical). The region where all surveys overlap covers 3269 deg2 in the North Galactic Cap, and contains >160,000 20-cm sources, with about 12,000 detected in all five radio surveys and over one-third detected optically. Combining parameters from the sky surveys allows easy and efficient classification by radio and optical morphology and radio spectral index. The catalog is available at http://www.atnf.csiro.au/people/Amy.Kimball/radiocat.shtml.

The observational status of superluminal radio sources is reviewed, and the results for one well-studied source (3C 345) are discussed in detail. We discuss the relativistic-beam model of superluminal sources, and concentrate on one aspect, namely the geometric constraints provided by combined X-ray and proper-motion measurements.

Observations show that expanding H ii regions may trigger star formation. We discuss several aspects of this type of star formation, and try to estimate its prevalence. We show how LMC H ii regions may help us to understand what we see in our Galaxy.

The possibility of a polarization sounding of the pulsar magnetosphere is examined, using intrinsic pulsar emission as a probe signal, for modern radio telescopes operating in the meter and decameter wavelength range. Different models of the pulsar magnetosphere at altitudes higher than a radius of critical polarization are used. The propagation medium besides magnetosphere is described by the stratified model, in which each layer has its own density of free electrons and vector of magnetic induction, as well as the spatial and temporal fluctuation scales of these parameters.

The frequency dependence of the polarization parameters of the pulsar radio emission, obtained in the broad band for a selected pulse phase, will enable a sounding deep into the pulsar magnetosphere.

Recent calculations of evolutionary tracks of TP-AGB stars of different mass and metallicity by Marigo et al. (2007) have been incorporated in the Bruzual & Charlot evolutionary population synthesis models. The mass of the stellar population in HUDF galaxies at z from 1 to 3 determined from fits to the spectro-photometric data of these galaxies is 50 to 80% lower than the mass determined from the BC03 models. The ages inferred for these populations are, with exceptions, 40 to 60% of the BC03 estimates.

Cosmic rays represent a unique crossing point of high-energy astrophysics and astrochemistry. The cosmic ray ionization rate of molecular hydrogen (ζ2) measured by H3+ spectroscopy in the central parsec of the Galaxy is 2 orders of magnitude higher than that in the dense clouds outside the Galactic center. However, it is still too short, by the factor of 10,000, to agree with an extremely high ζ2 that accommodates the new γ-ray observations of Sgr A* and its environment.

The theme of this Joint Meeting of Commissions 10, 27, 40, 42, 44, and 48 is “Close Binaries and Stellar Activity”. At the time this meeting was initially conceived, we took stellar activity to mean activity such as we observe on the Sun: spots, flares, chromospheric emission, variable radio and X-ray emission, coronas, winds, and so forth. That is why the series of seven reviews presented at this meeting will deal for the most part with convective stars, in particular with the RS CVn-type and BY Dra-type stars, which we know are active in so many of these ways.

It had been planned that Steven N. Shore would review briefly the situation from a theoretical viewpoint (briefly, I say, because theoretical treatment of the problem is still in the infant stages). Reference can be made, however to the contribution he presented at I.A.U. Symposium No. 88 in Toronto.

One way to open this meeting, I hope a useful way, is simply to list some unsolved problems. Those on my list may not be equal in importance or difficulty. Different problems would no doubt appear on someone else’s list. It may even turn out that, after we have heard these reviews, a number of my unsolved problems have already been solved or soon will be, but that would be a pleasant surprise rather than a disappointment.

I review the current understanding of some key properties of the earliest growing supermassive black holes (SMBHs), as determined from the most up-to-date observations of z ≲ 5 quasars. This includes their accretion rates and growth history, their host galaxies, and the large-scale environments that enabled their emergence less than a billion years after the Big Bang. The available multi-wavelength data show that these SMBHs are consistent with Eddington-limited, radiatively efficient accretion that had to proceed almost continuously since very early epochs. ALMA observations of the hosts’ ISM reveal gas-rich, well developed galaxies, with a wide range of SFRs that may exceed ∼1000 Mȯyr−1. Moreover, ALMA uncovers a high fraction of companion, interacting galaxies, separated by < 100 kpc (projected). This supports the idea that the first generation of high-mass, luminous SMBHs grew in over-dense environments, and that major mergers may be important drivers for rapid SMBH and host galaxy growth. Current X-ray surveys cannot access the lower-mass, supposedly more abundant counterparts of these rare z ≳ 5 massive quasars, which should be able to elucidate the earliest stages of BH formation and growth. Such lower-mass nuclear BHs will be the prime targets of the deepest surveys planned for the next generation of facilities, such as the upcoming Athena mission and the future Lynx mission concept.

We give an update of the observations and analysis of G2 – the gaseous red emission-line object that is on a very eccentric orbit around the Galaxy's central black hole and predicted to come within 2400 RS in early 2014. During 2013, the laser guide star adaptive optics systems on the W. M. Keck I and II telescopes were used to obtain three epochs of spectroscopy and imaging at the highest spatial resolution currently possible in the near-IR. The updated orbital solution derived from radial velocities in addition to Br-γ line astrometry is consistent with our earlier estimates. Strikingly, even ∼ 6 months before pericenter passage there is no perceptible deviation from a Keplerian orbit. We furthermore show that a proposed “tail” of G2 is likely not associated with it but is rather an independent gas structure. We also show that G2 does not seem to be unique, since several red emission-line objects can be found in the central arcsecond. Taken together, it seems more likely that G2 is ultimately stellar in nature, although there is clearly gas associated with it.

In preparation for observations with the James Webb Space Telescope (JWST), we have identified new members of the nearby, young M dwarf sample and compiled an up to date list of these stars. Here we summarize our efforts to identify young M dwarfs, describe the current sample, and detail its demographics in the context of direct planet imaging. We also describe our investigations of the unprecedented sensitivity of the JWST when imaging nearby, young M dwarfs. The JWST is the only near term facility capable of routinely pushing direct imaging capabilities around M dwarfs to sub-Jovian masses and will provide key insight into questions regarding low-mass gas-giant properties, frequency, formation, and architectures.

Detecting the seed black holes from which quasars formed is extremely challenging; however, those seeds that did not grow into supermassive should be found as intermediate-mass black holes (IMBHs) of 100 – 105 M⊙ in local dwarf galaxies. The use of deep multiwavelength surveys has revealed that a population of actively accreting IMBHs (low-mass AGN) exists in dwarf galaxies at least out to z ˜3. The black hole occupation fraction of these galaxies suggests that the early Universe seed black holes formed from direct collapse of gas, which is reinforced by the possible flattening of the black hole-galaxy scaling relations at the low-mass end. This scenario is however challenged by the finding that AGN feedback can have a strong impact on dwarf galaxies, which implies that low-mass AGN in dwarf galaxies might not be the untouched relics of the early seed black holes. This has important implications for seed black hole formation models.