The distribution of mass in galaxy-scale strong gravitational lenses is often modelled as an elliptical power law plus ‘external shear’, which notionally accounts for line-of-sight galaxies and cosmic shear. We argue that it does not, using three lines of evidence from the analysis of 54 galaxy-scale strong lenses: (i) strong lensing external shears do not correlate with weak lensing; (ii) the measured shear magnitudes in strong lenses (which are field galaxies) are too large (exceeding 0.05) for their environment and; (iii) the external shear position angle preferentially aligns or anti-aligns with the mass model position angle, indicating an internal origin. We argue the measured strong lensing shears are therefore systematically accounting for missing complexity in the canonical elliptical power-law mass model. If we can introduce this complexity into our lens models, this will further lensing studies of galaxy formation, dark matter and Cosmology.

In the context of hierarchical galaxy assembly, globular clusters and dwarf galaxies are indispensable probes of the formation of our Milky Way. M22 is a stellar system with chemical abundances reminiscent of an accreted dwarf galaxy such as ω Centauri but disc-like kinematics suggesting a Milky Way origin. Curiously, M22 contains a population of stars enhanced in slow neutron-capture (s-)process elements due to pollution from low-mass AGB stars. Recently, the original in-situ population stars of the Milky Way disc has been revealed to be enhanced in s-process elements. This provides a tantalizing link between the in-situ Milky Way population and the formation of M22. This talk discussed how recent high-precision chemical abundance measurements suggest that M22 may be coeval with this in-situ component, and what the formation mechanisms of this s-process population can tell us about the chemical evolution of our Galaxy before the establishment of the disc.

We present the results of KVN Key Science Program (KSP) for evolved stars, which was launched in 2014. The first phase of KSP ended in June 2020 and the second phase started in October 2020. The goal of KSP is to study the physical characteristics of the evolved stars by observing the spatial distribution and temporal variability of the stellar masers at four frequency-bands (K, Q, W and D bands). The 22 GHz H2O maser is usually observed from the outer part of circumstellar envelopes compared to the 43, 86, 129 GHz SiO masers, thus the kinematic links between these regions can be studied by the multi-frequency simultaneous observations of KSP along the stellar pulsation cycles. This eventually enable us to study the enormous mass-loss rate of evolved stars, and the accumulated results from KSP are expected to shed light on the study of the late stage of the stellar evolution.

We present the spectral and spatial evolution of H2O masers associated with IRAS 18043–2116, a well-known water fountain hosting a high-velocity collimated jet, which has been found in the observations with the 45 m telescope of Nobeyama Radio Observatory and the Australia Telescope Compact Array. We found new highest velocity components of the H2O masers, with which the resulting velocity spread of ≃ 540 km s−1 breaks the speed record of fast jets/outflows in this type of sources.

Mercury is locked in an unusual 3:2 spin-orbit resonance and as such is expected to be in a state of equilibrium called Cassini state. In that state, the angle between the spin axis and orbit normal, called obliquity, remains almost constant while the spin axis remains almost in the plane, also called Cassini plane, defined by the normal to the Laplace plane and the normal to the orbital plane. The spin axis and the orbit normal precess together with a period of about 300 kyr. The orientation of the spin axis of Mercury has been estimated using different approaches: (i) Earth-based radar observations, (ii) Messenger images and altimeter data, and (iii) Messenger radio tracking data. The different estimates all tend to confirm that Mercury occupies the Cassini state. The observed obliquity is small and close to 2 arcmin. It indicates a normalized polar moment of inertia of about 0.34. This information, combined with the existence of a liquid iron core, as evidenced by the librations, allows to constrain the interior structure of Mercury. However, the different estimates of the orientation of the spin axis locate the spin axis somewhat behind or ahead of the Cassini plane, and it is difficult to reconcile and interpret them coherently in terms of detailed interior properties. We review recent models for the obliquity and spin orientation of Mercury, which include the effects of complex orbital dynamics, tidal deformations and associated dissipation, and internal couplings related to the presence of fluid and solid cores. We discuss some implications regarding the interpretations of the orientation estimates in term of interior properties.

We present the results of high-resolution continuum and molecular line observations towards the Galactic HII region, G10.32-0.26. The continuum map with ALMA reveals the five cores with masses ranging from 2.5–9.2 Me. The results show that the brightest peak, Peak 1, is an HCHII region with an excitation temperature of : 12000 K, an electron density of 3.4×107 cm3, and a radius of 14 au. The central object is estimated to be a B0.5 star. The class II 6.7 GHz CH3OH maser coincides with Peak 1, implying class II CH3OH maser is associated with a later evolutionary stage of star formation. Using KaVA and KVN observation, we detect the class I 44 and 95 GHz CH3OH masers near the weakest peak, Peak 5. We successfully imaged class I 95 GHz CH3OH masers with VLBI for the first time. In Peak 5, the high-velocity SiO emission also exists. The continuum emission can be modelled with grey-body dust emission with Td∼30 K, and the molecular species are poor near Peak 5, suggesting Peak 5 is in an early stage of star formation.

Classical pulsating stars such as Cepheid and RR Lyrae variables exhibit well-defined Period–Luminosity relations at near-infrared wavelengths. Despite their extensive use as stellar standard candles, the effects of metallicity on Period–Luminosity relations for these pulsating variables, and in turn, on possible biases in distance determinations, are not well understood. We present ongoing efforts in determining accurate and precise metallicity coefficients of Period–Luminosity-Metallicity relations for classical pulsators at near-infrared wavelengths. For Cepheids, it is crucial to obtain a homogeneous sample of photometric light curves and high-resolution spectra for a wide range of metallicities to empirically determine metallicity coefficient and reconcile differences with the predictions of the theoretical models. For RR Lyrae variables, using their host globular clusters covering a wide range of metallicities, we determined the most precise metallicity coefficient at near-infrared wavelengths, which is in excellent agreement with the predictions of the horizontal branch evolution and stellar pulsation models.

The FU Orionis (FUor) and EX Lupi (EXor) type objects are rare pre-main sequence low-mass stars undergoing accretion outbursts. Maser emission is widespread and is a powerful probe of mass accretion and ejection on small scales in star forming region. However, very little is known about the overall prevalence of water masers towards FUors/Exors. We present results from our survey using the Effelsberg 100-m telescope to observe the largest sample of FUors and EXors, plus additional Gaia alerted sources (with the potential nature of being eruptive stars), a total of 51 targets, observing the 22.2 GHz H2O maser, while simultaneously covering the NH3 23 GHz.

We present our recent contributions to the theory of Lagrangian descriptors for discriminating ordered and deterministic chaotic trajectories. The class of Lagrangian descriptors we are dealing with is based on the Euclidean length of the orbit over a finite time window. The framework is free of tangent vector dynamics and is valid for both discrete and continuous dynamical systems. We review its last advancements and touch on how it illuminated recently Dvorak’s quantities based on maximal extent of trajectories’ observables, as traditionally computed in planetary dynamics.

Galaxy-galaxy strong lensing systems have been used in literature to test General Relativity by constraining the post-Newtonian parameter (γPPN). Nevertheless, these methods are prone to systematic errors, some of which arise from difficulties in modelling the dynamics of the lens galaxy. In this study, we address the systematic error related to the assumption of a constant anisotropy between the radial and tangential components of the velocity dispersion of stars within the lens galaxy, characterised by the parameter β. We considered two radial models for the anisotropy parameter, the Osipkov-Merritt and Mamon & Lokas, as well three Gaussian priors for constant β. Our analysis showed that the choice of β has a strong impact on the value of γPPN, with radial models leading to lower values of this parameter.

Inclination-only dependent lunisolar resonances shape the dynamics of MEO (Medium Earth Orbit) objects over secular time scales (i.e. several decades). Their main effect is to increase an object’s eccentricity, possibly up to a value where the orbit’s perigee meets the Earth’s atmosphere and friction will determine the object’s re-entry. Thus, understanding this mechanism allows the design of low-cost end-of-life disposal strategies which exploit the resonant dynamics. In this proceeding, we will summarize our results in developing an analytic theory for lunisolar resonances and the characterization of diffusion properties along them. On this topic, the techniques proposed are of interest in most problems of secular resonances encountered in Celestial Mechanics.

We analyzed the 3 mm wavelength spectral line survey of 408 clumps from the APEX telescope large area survey of the Galaxy, focusing on the methanol maser transitions. The main goals of this study are (1) to search for new methanol masers, (2) to statistically study the relationship between class I masers and shock tracers, (3) to study the properties between methanol masers and their host clumps, also as a function of their evolutionary stages and, (4) to better constrain the physical conditions using multiple co-spatial line pairs.

We present new results from a 3D modelling code for maser flares which provides the user with control over the physical conditions; maser cloud geometry and orientation; and fast runtime via parallelisation. The statistics of simulated observables suggest that achievable amplification may be dependent on viewpoints of the source and that a randomly placed observer is likely to detect an unremarkable blue- or red-shifted maser unless the line-of-sight direction is optimal for maser amplification. A preliminary model of masers towards π1 Gru based on SPH simulations also shows promising consistency with ALMA observations of high-j SiO transitions from the source.

In this work, we focus on the period-luminosity relation (PLR) of δ Sct stars, in which mode excitation and selection mechanisms are still poorly constrained, and whose structure and oscillations are affected by rotation. We review the PLRs in the recent literature, and add a new inference from a large sample of δ Sct. We highlight the difficulty in identifying the fundamental mode and show that rotation-induced surface effects can impact the measured luminosities, explaining the broadening of the PLR. We derive a tight relation between the low-order large separation and the fundamental radial mode frequency (F0) that holds for rotating stars, thus paving the way towards mode identification. We show that the PLRs we obtain for different samples are compatible with each other and with the recent literature, and with most observed δ Sct stars when taking rotation effects into account. We also find that the highest-amplitude peak in the frequency spectrum corresponds to the fundamental modein most δ Sct, thus shedding some light on their elusive mode selection mechanism.

The ALMA Project is embarking on a partner-wide initiative to at least double, and ultimately quadruple the correlated bandwidth of ALMA by @2030. This initiative is called the ALMA Wideband Sensitivity Upgrade (WSU). In this contribution, I briefly describe the main aspects of the upgrade and status. Then I provide several examples of how the WSU will enhance (sub)millimeter maser science by affording the ability to observe more diagnostic maser transitions (and thermal lines) with a single observation.

In this study, the correlation between 22 GHz water masers and other maser species with far infrared/submillimeter (FIR/sub-mm) sources is investigated. Comparing luminosity to mass ratio (L/M) of FIR/sub-mm clumps linked to different maser species, 22 GHz water masers have significantly lower L/M values than 6.7 GHz methanol and 1665 MHz OH masers. This suggests 22 GHz water masers may precede them in the evolution timeline of SFRs. The close association between water masers and FIR/sub-mm sources provides insight into maser pumping conditions and evolutionary stages.

We took profit of the availability of large catalogs of active galact nuclei (AGNs) selected in the hard X-ray from satellite missions (e. g., INTEGRAL, Swift/BAT) to investigate the relation between the occurrence of water maser emission and the X-ray properties of the nuclei on a statistically meaningful basis. Our studies demonstrate that the hard X-ray selection may significantly enhance the maser detection rate over comparably large optical or infrared surveys. Here, we report on a recent survey to search for water maser emission with the Sardinia Radio Telescope (SRT) in a sample of heavily absorbed AGN taken from the 70 months Swift/BAT catalog.