Propagation effects have been central to pulsar research and indeed were an integral part of the pulsar discovery and its prologue. I will summarize the early deduction process for establishing pulsar distances and refinements to the distance scale and modeling of the Galaxy in electron density and magnetic field. This will lead to the analogous current situation of understanding distances and media for extragalactic radio bursts. The role of magnetoionic media in precision pulsar timing and surveys for transients will be summarized. Finally, going full circle, searches for extraterrestrial intelligence (LGMs) also require attention to propagation effects.

A strong outburst of 6.7 GHz methanol maser occurred in the high-mass young stellar object (HMYSO) G24.33+0.14 between November 2010 and January 2013. The target was observed with the Torun 32 m radio telescope as a part of a long-term monitoring programme. Almost all twelve spectral features from 108 to 120 km s−1 varied synchronously with time delays between the flux minima of about two weeks. This may indicate that the variability is driven by global changes in the pump rate. The flare peaks of the two features with the highest relative amplitude of 40-60 are delayed by about 2.5 months while their profiles undergo essential transformation with a velocity drift of 0.23 km s−1yr−1. This may suggest that the variability is caused by a rapid increase of the pump rate and excitation of a large portion of the HMYSO environment by an accretion event.

International LOFAR stations, equipped with powerful backends, can be used as individual telescopes, and provide data sets complementary to those obtained with the LOFAR Core. Such “local mode” observations are particularly adapted to monitoring observations, where the advantage of having a high observing cadence (one observation per week) outweighs the reduced sensitivity of a single station when compared to the full array. With such observations, it is possible to monitor the temporal evolution of the pulsars’ behaviour via its dispersion, scattering, intensity, and profile shape. We present recent studies performed in the LOFAR low band (10-90 MHz).

As first realised in the late 1980s, methanol masers come in two varieties, termed Class I and Class II. While Class II masers had observationally been extensively studied in the past, until recently relatively little attention was paid to Class I methanol masers due to their low luminosities compared to other maser transitions. In this review, we will focus on the recent progress in our understanding of Class I methanol masers both from an observational and from a theoretical point of view.

Follow-up of unidentified Fermi sources has expanded the number of known galactic-field “black widow” and “redback” millisecond pulsar binaries from four to nearly 30. Several systems observed by Chandra, XMM-Newton, Suzaku, and NuSTAR exhibit double-peaked X-ray orbital modulation. This is attributed to synchrotron emission from electrons accelerated in an intrabinary shock and Doppler boosting by mildly relativistic bulk flow. We briefly discuss the rich complexity of these systems, their astrophysical utility, and open questions.

For fifty years astronomers have been searching for pulsar signals in observational data. Throughout this time the process of choosing detections worthy of investigation, so called ‘candidate selection’, has been effective, yielding thousands of pulsar discoveries. Yet in recent years technological advances have permitted the proliferation of pulsar-like candidates, straining our candidate selection capabilities, and ultimately reducing selection accuracy. To overcome such problems, we now apply ‘intelligent’ machine learning tools. Whilst these have achieved success, candidate volumes continue to increase, and our methods have to evolve to keep pace with the change. This talk considers how to meet this challenge as a community.

We summarize a long-term monitoring of 11 periodic 6.7 GHz methanol masers and a search for new periodic sources. Observations were carried out with the Torun 32 m telescope. Periods of observed sources range from 29 to 658 days and the data consist of more than 10 observed cycles for most of the masers. Inspection of archival data resulted in identification of 3 new periodic sources while 2 new periodic objects were found in observations started in 2014.

We will report the activities of the VERA single-dish observations. We are carrying out single-dish observations with two purposes. The first purpose is the monitoring of known H2O maser sources. At present, we are carrying out monitoring observations for 312 H2O maser sources at intervals of two months. The second purpose is the search for new water maser sources. We selected 901 target sources from the AKARI FIS Bright Source Catalogue. We found 61 new H2O maser sources.

Scintillation arcs provide an unprecedented degree of detail into the scattering of radio waves from pulsars. We review evidence that has emerged over the last fifteen years that: a) the scattering of many nearby pulsars is dominated by one or several relatively thin “screens” of material, b) the resulting image on the sky is highly linear, with axial ratios at least as high as 10:1, and c) this arrangement is persistent for at least one source (B1133+16) for at least 25 years. We expand on the idea of Pen and Levin (2014) and previous authors that such scattering may be caused by linear sheets of plasma seen nearly edge-on. Further analysis of such scintillation arcs, including new work on multi-frequency, multi-epoch observations, should help elucidate the astrophysical nature of these ubiquitous scattering entities, which are currently not convincingly linked with any known structures.

Braking indices are used to describe the evolution of pulsars rotation, and can offer insights into the braking mechanism that dominates the slow down. Here we discuss the main difficulties associated with measuring braking indices and the complexity of interpreting these measurements. Considering recent braking index measurements on pulsars with large and regular glitches, we comment on the significant effects that the loosely coupled superfluid inside pulsars might have on their spin evolution.

Theoretical simulations have shown that magnetic fields play an important role in massive star formation: they can suppress fragmentation in the star forming cloud, enhance accretion via disc and regulate outflows and jets. However, models require specific magnetic configurations and need more observational constraints to properly test the impact of magnetic fields. We investigate the magnetic field structure of the massive protostar IRAS18089-1732, analysing 6.7 GHz CH3OH maser MERLIN observations. IRAS18089-1732 is a well studied high mass protostar, showing a hot core chemistry, an accretion disc and a bipolar outflow. An ordered magnetic field oriented around its disc has been detected from previous observations of polarised dust. This gives us the chance to investigate how the magnetic field at the small scale probed by masers relates to the large scale field probed by the dust.

1E 161348-5055 (1E 1613), the source at the center of the supernova remnant RCW 103, has defied any easy classification since its discovery, owing to its long-term variability (a factor of ~ 100 in flux on time scales from months to years) and a periodicity of 6.67 hr with a variable light curve profile across different flux levels. On June 2016, 1E 1613 emitted a magnetar-like millisecond burst of hard X-rays accompanied with a factor ~ 100 brightening in the persistent soft X-ray emission. The duration and spectral decomposition of the burst, the discovery of a hard X-ray tail in the spectrum, and the long-term outburst history suggest that 1E 1613 is an isolated magnetar and the periodicity of 6.67 hr is the rotational spin period, making 1E 1613 the slowest neutron star ever detected.

Ring−like sources of 6.7 GHz methanol maser emission were discovered a decade ago with the European VLBI Network. In the past years we have been incessantly working to understand the nature of these rings. In general, the methanol rings do not coincide with H II regions nor they show 22 GHz water maser emission. Here, we present a proper motion study over a time baseline up to 10.5 years for the first sub-sample of methanol maser rings. Our findings suggest that in three targets G23.207−00.377, G23.389+00.185, and G23.657−00.127, such rings form in outflows or even in winds close to the central sources, and the masers trace slow proper motions of a few km s−1 typically.

Here, we present initial results from the ALFABURST radio transient survey, which is currently running in a commensal mode with the ALFA receiver at the Arecibo telescope. We observed for a total of 1400 hours and have detected single pulses from known pulsars but did not detect any FRBs. The non-detection of FRBs is consistent with the current FRB sky rates.

The “CepHeus-A Star formation and proper Motions” (CHASM) survey is a large project consisting of a combination of astrometric Very Long Baseline Array (VLBA) and Jansky Very Large Array (VLA) observations, to map both the stellar and dense molecular gas components in the star-forming region Cepheus A. With the VLBA, we make use of the CH3OH and H2O maser emission in the vicinity of Cepheus A HW2, in order to measure accurate proper motions and parallax distances to both T Tauri stars and massive young stellar objects (YSOs) belonging to the same star-forming region. With the Jansky VLA, we make use of the interstellar thermometer NH3, in order to image the molecular clump surrounding Cepheus A HW2 and to determine its physical conditions. By combining these informations all together, we can provide, for instance, a direct measurement of the Bondi-Hoyle accretion radius for a massive young star, namely, HW2.

In this paper, we present our study on multi-frequency scatter-broadening observations of a large sample of pulsars, made using the Ooty Radio Telescope (ORT) and the Giant Metrewave Radio Telescope (GMRT). For each pulsar, the scatter-broadening time scales (τsc) have been estimated at different observing frequencies and the dependence of τsc with the observing frequency, i.e., the frequency scaling index (α) has been obtained. We report estimates of α for a set of 39 pulsars, of which 31 are completely new and provide the first-time measurement on about 50% of the sample. This enhanced sample suggests that almost 65% of the pulsars have an α much lower than the conventional value of 4.4 for a Kolmogorov type turbulence spectrum, and a considerably large scattering strength. An increase in scattering strength is observed with the distance to the pulsar in the Galaxy.

We report on interferometric observations of a face-on accretion system around the high mass young stellar object, G353.273+0.641. The innermost accretion system of 100-au radius was resolved in a 45-GHz continuum image taken with the Jansky Very Large Array. Our SED analysis indicated that the continuum could be explained by optically-thick dust emission. 6.7 GHz CH3OH masers associated with the same system were also observed with the Australia Telescope Compact Array. The masers showed a spiral-like, non-axisymmetric distribution with a systematic velocity gradient. The line-of-sight velocity field is explained by an infall motion along a parabolic streamline that falls onto the equatorial plane of the face-on system. The streamline is quasi-radial and reaches the equatorial plane at a radius of 16 au. The physical origin of such a streamline is still an open question and will be constrained by the higher-resolution thermal continuum and line observations with ALMA long baselines.

Our 2015-2016 ALMA 1.3 to 0.87 mm observations (resolution ~200 au) of the massive protocluster NGC6334I revealed that an extraordinary outburst had occurred in the dominant millimeter dust core MM1 (luminosity increase of 70×) when compared with earlier SMA data. The outburst was accompanied by the flaring of ten maser transitions of three species. We present new results from our recent JVLA observations of Class II 6.7 GHz methanol masers and 6 GHz excited OH masers in this region. Class II masers had not previously been detected toward MM1 in any interferometric observations recorded over the past 30 years that targeted the bright masers toward other members of the protocluster (MM2 and MM3=NGC6334F). Methanol masers now appear both toward and adjacent to MM1 with the strongest spots located in a dust cavity ~1 arcsec (1300 au) north of the MM1B hypercompact HII region. In addition, new excited OH masers appear on the non-thermal source CM2. These data reveal the dramatic effects of episodic accretion onto a deeply-embedded high mass protostar and demonstrate its ongoing impact on the surrounding protocluster.

The Square Kilometre Array will be an amazing instrument for pulsar astronomy. While the full SKA will be sensitive enough to detect all pulsars in the Galaxy visible from Earth, already with SKA1, pulsar searches will discover enough pulsars to increase the currently known population by a factor of four, no doubt including a range of amazing unknown sources. Real time processing is needed to deal with the 60 PB of pulsar search data collected per day, using a signal processing pipeline required to perform more than 10 POps. Here we present the suggested design of the pulsar search engine for the SKA and discuss challenges and solutions to the pulsar search venture.

High-mass young stellar objects (HMYSO) displaying methanol maser flux variability probably trace a variety of phenomena such as accretion events, magnetospheric activity, stellar flares and stellar wind interactions in binary systems. A long-term monitoring of the 6.7 GHz methanol line in a large sample of HMYSOs has been undertaken to characterize the variability patterns and examine their origins. The majority of the masers show significant variability on time-scales between a week and a few years. High amplitude short flares of individual features occurred in several HMYSOs. The maser features with low luminosity tend to be more variable than those with high luminosity. The variability of the maser features increases when the bolometric luminosity the powering star decreases. Statistical analysis of basic properties of exciting objects and the variability measures supports an idea that burst activity of methanol masers is driven mainly by changes in the infrared pumping rate.