NGC 253 is one of the closest starburst galaxies to the Milky Way and as such it has been studied in detail across the electromagnetic spectrum. Recent observations have detected the first extragalactic class I methanol masers at 36 and 44 GHz and the first extragalactic HC3N (cyanoacetylene) masers in this source. Here we discuss the location of the masers with respect to key morphological features within NGC 253 and the association between the masers and the ongoing starburst.

The Megamaser Cosmology Project (MCP) measures the Hubble Constant by determining geometric distances to circumnuclear 22 GHz H2O megamasers in galaxies at low redshift (z < 0.05) but well into the Hubble flow. In combination with the recent, exquisite observations of the Cosmic Microwave Background by WMAP and Planck, these measurements provide a direct test of the standard cosmological model and constrain the equation of state of dark energy. The MCP is a multi-year project that has recently completed observations and is currently working on final analysis. Based on distance measurements to the first four published megamasers in the sample, the MCP currently determines H0 = 69.3 ± 4.2 km s−1 Mpc−1. The project is finalizing analysis for five additional galaxies. When complete, we expect to achieve a ~4% measurement. Given the tension between the Planck prediction of H0 in the context of the standard cosmological model and astrophysical measurements based on standard candles, the MCP provides a critical and independent geometric measurement that does not rely on external calibrations or a distance ladder.

We introduce the newly developed database of circumstellar maser sources. Until now, the compilations comprehensively including the three major maser species in evolved stars (i.e., SiO, H2O, OH) has been practically limited only to the Benson’s catalog (Benson et al. 1990), which was published more than a quarter of a century ago. For OH masers alone, there exists the University of Hamburg (UH) database, but there is no updated compilation work for H2O and SiO masers. In order to utilize the information of masers in actual studies, it is highly desirable to have a database containing all the three masers. We are currently constructing a database covering SiO, H2O and OH masers. This database consists of a web-service, which accesses compiled maser observations in available archives and combines them with the data we newly collected and IR databases. The archives currently used are the OH maser archive from Engels & Bunzel (2015), and H2O and SiO archives, which are currently under construction. So far, the information of about 27,000 observations (about 10,000 objects) has been implemented. We also have a plan to extend the database by including higher transitions and other types of objects, such as young stellar objects, in future. In this paper, we briefly summarize, (1) outline of the data collected, and (2) future development plans of the eDAMS system. The URL of the database is as follows: http://maserdb.ins.urfu.ru/

Matter in neutron star cores reaches extremely high densities, forming states of matter that cannot be generated in the laboratory. The Equation of State (EOS) of the matter links to macroscopic observables, such as mass M and radius R, via the stellar structure equations. A promising technique for measuring M and R exploits hotspots (burst oscillations) that form on the stellar surface when material accreted from a companion star undergoes a thermonuclear explosion. As the star rotates, the hotspot gives rise to a pulsation, and relativistic effects encode information about M and R into the pulse profile. However the burst oscillation mechanism remains unknown, introducing uncertainty when inferring the EOS. I review the progress that we are making towards cracking this long-standing problem, and establishing burst oscillations as a robust tool for measuring M and R. This is a major goal for future large area X-ray telescopes.

We present the results of a search for strong single radio pulses emitted by magnetars and for FRB signals in the fields of magnetars observed at the Parkes radio telescope within the NAPA project P626. Unsurprisingly, given the short total observing time, no extragalacic FRB signal was found up to a DM of 3000 pc/cm3. Two strong pulses dispersed at the DM of the known radio magnetar J1550–5418 where found, one occurring at the same time of an X-ray burst. This result is potentially interesting in the framework of magnetar models for FRBs.

The Bulge Asymmetries and Dynamical Evolution (BAaDE) project aims to map the positions and velocities of up to ~20,000 late-type stars with SiO maser emission along the full Galactic plane, with a large concentration in the Galactic Bulge and inner Galaxy. Both J = 1 → 0 and J = 2 → 1 transitions using the Very Large Array (VLA) and the Atacama Large Millimeter Array (ALMA) are being observed. In the VLA observing setup, in addition to the 28SiO, v = 1 and v = 2J = 1 → 0 maser transitions, the bandwidth was wide enough to include the J = 1 → 0 transitions of the rare isotopologues of the SiO molecule in both the ground and vibrationally excited states: 29SiO, v = 0, 30SiO, v = 0, 29SiO, v = 1, and 29SiO, v = 2. Approximately 10% of the initial ~3500 targets of the project show maser emission from at least one of these lines. Some of these stars (with isotopic maser emission) show high radial velocities which implies that they are indeed in the Galactic Bulge or inner Galaxy (i.e. not foreground objects). We present line profiles, refined detection statistics, and the implications of the detection of the isotopic maser emission on pumping schemes that have been previously presented.

The dwarf galaxies in the Local Group (LG) reveal a surprising amount of spatial structuring. In particular, almost all non-satellite dwarfs belong to one of two planes that show a very pronounced symmetry. In order to determine if these structures in the LG are dynamically stable or, alternatively, if they only represent transient alignments, proper motion measurements of these galaxies are required. A viable method to derive proper motions is offered by VLBI studies of 22-GHz water (and 6.7-GHz methanol) maser lines in star-forming regions.

In 2016, in the framework of the Early Science Program of the Sardinia Radio Telescope (SRT), we have conducted an extensive observational campaign to map the entire optical body of all the LG dwarf galaxies that belong to the two planes, at C and K band, in a search for methanol and water maser emission.

Here, we outline the project and present its first results on 3 targets, NGC 6822, IC 1613, and WLM. While no luminous maser emission has been detected in these galaxies, a number of interesting weaker detections has been obtained, associated with particularly active star forming regions. In addition, we have produced deep radio continuum maps for these galaxies, aimed at investigating their star forming activity and providing an improved assessment of star formation rates in these galaxies.

Methanol masers at 6.7 GHz are the brightest of class II methanol masers and have been found exclusively towards massive star forming regions. These masers can thus be used as a unique tool to probe the early phases of massive star formation. We present here the SED studies of 284 methanol masers chosen from the MMB catalogue, which falls in the Hi-GAL range (|l| ≤ 60°, |b| ≤ 1°). The masers are studied using the ATLASGAL, MIPSGAL and Hi-GAL data at wavelengths ranging from 24−870 micrometers. A single grey body component fit was used to model the cold dust emission whereas the emission from the warm dust is modelled by a black body. The clump properties such as isothermal mass, FIR luminosity and MIR luminosity were obtained using the best fit parameters of the SED fits. We discuss the physical properties of the sources and explore the evolutionary stages of the sources having 6.7 GHz maser emission in the timeline of high mass star formation.

The nearest millisecond pulsar PSR J0437–4715 is the ideal target to constrain the dense matter equation of state using the lightcurve modelling method. Our analysis combining XMM-Newton, NuSTAR, and ROSAT observations removed ambiguities in the spectral modelling of the surface emission from PSR J0437–4715. Furthermore, the NuSTAR observation demonstrated that the non-thermal hard tail emission was pulsed at the pulsar spin period. These features are crucial to model the lightcurve and to measure the radius of the neutron star. This conference proceeding is based on the publication Guillot et al. (2016).

In our attempt to investigate the basic active galactic nucleus (AGN) paradigm requiring a centrally located supermassive black hole (SMBH), a close to Keplerian accretion disk and a jet perpendicular to its plane, we have searched for radio continuum in galaxies with H2O megamasers in their disks. We observed 18 such galaxies with the Very Large Baseline Array in C band (5 GHz, ~2 mas resolution) and we detected 5 galaxies at 8 σ or higher levels. For those sources for which the maser data is available, the positions of masers and those of the 5 GHz radio continuum sources coincide within the uncertainties, and the radio continuum is perpendicular to the maser disk’s orientation within the position angle uncertainties.

We present polarimetric observations of the 4 ground-state transitions of OH, toward a sample of maser-emitting planetary nebulae (PNe) using the Australia Telescope Compact Array. This sample includes confirmed OH-emitting PNe, confirmed and candidate H2O-maser-emitting PNe. Polarimetric observations provide information related to the magnetic field of these sources. Maser-emitting PNe are very young PNe and magnetic fields are a key ingredient in the early evolution and shaping process of PNe. Our preliminary results suggest that magnetic field strengths may change very rapidly in young PNe.

Slow pulsars show a great deal of qualitative and quantitative regularity in the structure of their radio emission beams as described by the core/double-cone model; however, millisecond pulsars (MSPs) have shown little. It is thus arresting to encounter a 2.7-s MSP with what appears to be a double-cone/core profile—and even more so to find that the arrangement of the cones around the core suggest aberration/retardation emission heights that are very reasonable. This and several other pulsars then represent rare opportunities for analysis and raise questions about why a few MSPs show such orderly beam structure while so many do not.

Multi-decade observing campaigns of the globular clusters 47 Tucanae and M15 have led to an outstanding number of discoveries. Here, we report on the latest results of the long-term observations of the pulsars in these two clusters. For most of the pulsars in 47 Tucanae we have measured, among other things, their higher-order spin period derivatives, which have in turn provided stringent constraints on the physical parameters of the cluster, such as its distance and gravitational potential. For M15, we have studied the relativistic spin precession effect in PSR B2127+11C. We have used full-Stokes observations to model the precession effect, and to constrain the system geometry. We find that the visible beam of the pulsar is swiftly moving away from our line of sight and may very soon become undetectable. On the other hand, we expect to see the opposite emission beam sometime between 2041 and 2053.

Using quasi-simultaneous observations of 86 stars with known SiO maser emission, we searched for systematic differences between the strengths of the 43 and 86 GHz v=1 maser lines. Although for individual stars there is wide scatter between the line strengths spanning nearly an order of magnitude, there is no evidence of a systematic difference between these line strengths for the entire sample.

The aim of this work is to explore the connection between variability in single pulse intensity and periodic switching of the position angle (PA) of the linear polarisation and how this relates to the radio emission mechanism. There are five pulsars reported in the literature for which the PA is seen to periodically change in tandem with the variability in their pulse shapes. This behaviour is seemingly incompatible with two well established models of the radio emission mechanism. The purpose of this study is to investigate in a systematic way whether this phenomenon is common or if only happens in special cases, using a high-quality sample of pulsar data observed with the Parkes telescope. We show that the connection between polarisation variability and intensity variability is more common than previously expected.

The linearly polarized component of a pulsar signal at different radio frequencies can help to constrain the parallel component of the magnetic field along the line of sight. In this work we measured the polarimetric properties of the pulsars in the globular cluster 47 Tucanae and we report the Rotation Measure (RM) for 13 of them. A gradient in the RM values of the pulsars across the cluster is detected suggesting the presence of significant variations in the magnetic field across the very small angular scales associated with the lines of sight to the pulsars in 47 Tucanae. Both magnetic fields located in the globular cluster or in the Galactic disk in the direction of the cluster are taken into consideration. However, more detailed modelling of the dynamics of the cluster and deeper observations with the MeerKAT and/or the SKA1 radio telescopes are necessary to discriminate among the models.

We present a brief overview of MeerTRAP, a real-time, fully commensal survey for pulsars and fast transients with the MeerKAT radio telescope in South Africa. MeerTRAP will combine the excellent sensitivity of MeerKAT with an unprecedented amount of on-sky time in order to significantly extend the parameter space covered by similar, previous or ongoing, surveys with other radio telescopes. Here, we will give a brief overview of the project.

PSRSalsa is a versatile open-source pulsar data-analysis project designed to obtain a comprehensive picture of the radio properties of your pulsar of choice. Here its usefulness is demonstrated through the analysis of the radio pulsar B1839–04, thereby revealing the extremely rare phenomenon of “bi-drifting” where the drift direction of subpulses is systematically different in different pulse profile components.

We calculate the luminosity of the synchrotron radiation from the vicinity of the light cylinder. We find that even if the thermal emission from the entire surface is included as the seed photon, the γ-ray to X-ray flux ratio for young pulsars is significantly higher than the observations. For these pulsars, most of γ-ray photons may be absorbed in the magnetosphere.

The Galactic Center contains large amounts of molecular and ionized gas as well as a plethora of energetic objects. Water masers are an extinction-insensitive probe for star formation and thus ideal for studies of star formation stages in this highly obscured region. With the Australia Telescope Compact Array, we observed 22 GHz water masers in the entire Central Molecular Zone with sub-parsec resolution as part of the large SWAG survey: “Survey of Water and Ammonia in the Galactic Center”. We detect of order 600 22 GHz masers with isotropic luminosities down to ~10−7 L⊙. Masers with luminosities of ≳10−6 L⊙ are likely associated with young stellar objects. They appear to be close to molecular gas streamers and may be due to star formation events that are triggered at pericenter passages near Sgr A*. Weaker masers are more widely distributed and frequently show double line features, a tell-tale sign for an origin in evolved star envelopes.