This study analyzed the Doppler shift in the solar spectrum using the Interface Region Imaging Spectrograph (IRIS). Two types of oscillations were investigated: long period damp and short period damp. The researchers observed periodic perturbations in the Doppler velocity oscillations of bright points (BPs) in the chromosphere and transition region (TR). Deep learning techniques were used to examine the statistical properties of damping in different solar regions. The results showed variations in damping rates, with higher damping in coronal hole areas. The study provided insights into the damping behavior of BPs and contributed to our understanding of energy dissipation processes in the solar chromosphere and TR.

We have undertaken a deep investigation of a well defined sample of 136 PNe located in a 10×10 degree central region of the Galactic Bulge observed with the ESO VLT and supplemented by archival HST images. These studies have provided precise morphologies, major axes position angles and the most robust sample of consistently derived chemical abundances available to date. Using these data we have statistically confirmed, at 5σ, the precise PNe population that provides the PNe alignment of major axes previously suggested in the Galactic Bulge, revealed a partial solution to the sulfur anomaly and uncovered interesting morphological, abundance and kinematic features. We summarise the most significant findings here with detailed results appearing in a series of related publications.

Almost 80% of mature planetary nebulae (PNe) have non spherical symmetry. Small-scale torii, knots, filaments and jets, frequently of low-ionization, were found embedded in PNe large-scale structures. In particular, the presence of stellar jets has been investigated through morpho-kinematic studies of PNe, from narrow-band imagery and high-dispersion long-slit spectroscopic observations. However, the latter technique is limiting the understanding of the global 3D structure of the PNe. MEGARA – the optical IFU attached to the 10.4-m Gran Telescopio Canarias – provides the ideal data to study the 3D morpho-kinematic structure of PN, allowing to discover, young jets “hidden” in the nebula. The access to the early evolution and interaction of these jets with the nebular envelope give us the opportunity of elucidating the formation of the non-spherical morphologies observed in most nebulae. We will present the results obtained from the MEGARA, unveiling for the first time hidden jets embedded in the ionized nebular envelope of NGC 2392, HuBi 1, M 2-31, M 3-38.

Babcock–Leighton process, in which the poloidal field is generated through the decay and dispersal of tilted bipolar magnetic regions (BMRs), is observed to be the major process behind the generating poloidal field in the Sun. Based on this process, the Babcock–Leighton dynamo models have been a promising tool for explaining various aspects of solar and stellar magnetic cycles. In recent years, in the toroidal to poloidal part of this dynamo loop, various nonlinear mechanisms, namely the flux loss through the magnetic buoyancy in the formation of BMRs, latitude quenching, tilt quenching, and inflows around BMRs, have been identified. While these nonlinearities tend to produce a stable magnetic cycle, the irregular properties of BMR, mainly the scatter around Joy’s law tilt, make a considerable variation in the solar cycle, including grand minima and maxima. After reviewing recent developments in these topics, I end the presentation by discussing the recent progress in making the early prediction of the solar cycle.

We have identified the velocity jump (shock) features in the inner 20′ × 10′ region of M31 using the data of [O III] and H I. The identified shock features are found primarily on the leading side of the potential bar, displaying a typical pattern of bar-driven gas inflow. The shock features provide independent evidence for M31 being a barred galaxy. Our preliminary gas simulations with a barred potential of M31 can reproduce these shock features.

New large observational surveys such as Gaia are leading us into an era of data abundance, offering unprecedented opportunities to discover new physical laws through the power of machine learning. Here we present an end-to-end strategy for recovering a free-form analytical potential from a mere snapshot of stellar positions and velocities. First we show how auto-differentiation can be used to capture an agnostic map of the gravitational potential and its underlying dark matter distribution in the form of a neural network. However, in the context of physics, neural networks are both a plague and a blessing as they are extremely flexible for modeling physical systems but largely consist in non-interpretable black boxes. Therefore, in addition, we show how a complementary symbolic regression approach can be used to open up this neural network into a physically meaningful expression. We demonstrate our strategy by recovering the potential of a toy isochrone system.

Ultra-diffuse galaxies (UDGs) are spatially extended, low surface brightness stellar systems with regular elliptical-like morphology found in large numbers in galaxy clusters and groups. Studies of the internal dynamics and dark matter content of UDGs have been hampered by their low surface brightnesses. We identified a sample of low-mass early-type post-starburst galaxies, ‘future UDGs’ in the Coma cluster still populated with young stars, which will passively evolve into UDGs in the next 5–10 Gyr. We collected deep observations for a sample of low-mass early-type galaxies in the Coma cluster using MMT Binospec, which includes present-day and future UDGs. We derived their dark matter content within a half-light radius (70–95 %) and total dynamical masses (M200 = 5.5 · 109 − 1.4·1011 M⊙) assuming the Burkert density profile and assess how different proposed evolutionary channels affect dark and visible matter in UDGs. We also discuss observational methodology of present and future UDG studies.

Just like the Sun, other stars also exhibit differential rotation. Currently, the rotation profile of a star that hosts a transiting planet can be estimated if during a transits, the planet occults a spot on the photosphere of the star, causing slight variations in its light curve. By detecting the same spot during a later transit, the stellar rotation period at that latitude is determined. Here, we present the results of differential rotation for 48 stars, 13 from the spot transit mapping method, while the remaining 35 stars from other techniques. The results show that the differential rotation is correlated with the stellar mean rotation period for fast rotating stars and strongly anti-correlated for slow rotators. The transition occuring at rotation period of 5 days. On the other hand, the differential shear increases with effective temperature for fast rotating stars, but the correlation is lost for the slow rotators.

We report spectroscopic surveys of planetary nebulae (PNe) in the Milky Way and Andromeda (M31), using the 10.4-m Gran Telescopio Canarias (GTC). The spectra are of high quality and cover the whole optical range, mostly from 3650 Å to beyond 1 μm, enabling detection of nebular emission lines critical for spectral analysis and photoionization modeling. We obtained GTC spectra of 24 compact (angular diameter <5 arcsec) PNe located in the Galactic disk, ∼3–20 kpc from the Galactic centre, and that can be used to constrain stellar evolution models and derive radial abundance gradients of the Milky Way. We have observed 30 PNe in the outer halo of M31 using the GTC. These halo PNe are uniformly metal-rich and probably all evolved from low-mass stars, consistent with the conjecture that they formed from the metal-rich gas in M31 disk but were displaced to their present locations due to galaxy interactions.

We measure the enclosed Milky Way (MW) mass profile to Galactocentric distances of ∼70 and ∼50 kpc using the smooth, diffuse stellar halo samples of Bird et al. The samples are Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and Sloan Digital Sky Survey/Sloan Extension for Galactic Understanding and Exploration (SDSS/SEGUE) K giants (KG) and SDSS/SEGUE blue horizontal branch (BHB) stars with accurate metallicities. The 3D kinematics are available through LAMOST and SDSS/SEGUE distances and radial velocities and Gaia DR2 proper motions. Two methods are used to estimate the enclosed mass: 3D spherical Jeans equation and Evans et al. tracer mass estimator (TME). We remove substructure via the Xue et al. method based on integrals of motion. We evaluate the uncertainties on our estimates due to random sampling noise, systematic distance errors, the adopted density profile, and non-virialization and non-spherical effects of the halo. The tracer density profile remains a limiting systematic in our mass estimates, although within these limits we find reasonable agreement across the different samples and the methods applied. Out to ∼70 and ∼50 kpc, the Jeans method yields total enclosed masses of 4.3±0.95 (random) ±0.6 (systematic) ×1011 M⊙ and 4.1±1.2 (random) ±0.6 (systematic) ×1011 M⊙ for the KG and BHB stars, respectively. For the KG and BHB samples we find a dark matter virial mass of (random) ±0.083 (systematic) ×1012 M⊙ and (random) ±0.15 (systematic) ×1012 M⊙, respectively.

AI and deep learning techniques are beginning to play an increasing role in astronomy as a necessary tool to deal with the data avalanche. We describe an application for finding resolved Planetary Nebulae (PNe) in crowded, wide-field, narrow-band Hα survey imagery in the Galactic plane.

We review recent results that utilize planetary nebulae (PNe) to constrain galactic dynamical and chemical evolution in different environments. Planetary nebulae have become essential probes in both these aspects of galaxy evolution, and novel observations illustrate their potential. Dynamical evolutionary models need observational constraints, and PNe uniquely probe the environment far from the galactic centers. In chemical evolution, the PN progenitor population spans a broad range of formation epochs; the oldest progenitors of local PNe are contemporary with H II regions in z ∼ 2 star-forming galaxies (SFGs). The future will bring even more possibilities in these fields, especially with the advent of extremely large telescopes.

MUSE data regarding NGC 3132 were used and analysed through SATELLITE in order to obtain 2D maps of the physico-chemical parameters of the nebula. Furthermore, our results were compared with a 3D photoionisation model built with MOCASSIN with the aim to constrain its parameters. Lastly, we utilized JWST and Spitzer IR data and examined their radial distribution.

. Post-starburst galaxies (PSBs) have quenched (significant decline in star formation rate) both recently and rapidly (≲Gyr). They are thus promising in providing insights into activities that are happening at the early stage of quenching. While studies have suggested that black hole feedback in the form of active galactic nuclei (AGN) and outflows play important roles in quenching, the details of how they impact the host galaxies and their interplay with other quenching mechanisms are still not fully understood. We find that PSBs commonly show signatures of AGN activity but they appear to be weak and/or heavily obscured. These AGN might be able to drive outflows but they are likely not strong enough to remove gas from the host galaxy. Direct evidence of AGN quenching the star formation of the host galaxy is still missing and AGN likely quench by disturbing rather than expelling the gas.

Recent panoramic maps of the Magellanic system have revealed a wealth of low-surface-brightness stellar substructures surrounding both the Large and Small Magellanic Clouds (LMC/SMC); clear evidence of tidal interactions between the two Clouds, as well as with the Milky Way. The Magellanic Edges Survey (MagES), a spectroscopic survey that targets red clump and red giant branch stars across the outskirts of both Clouds, aims to characterise these features and shed light on their formation. We summarise recent results from MagES, which suggest multiple previous LMC-SMC interactions are required to fully explain the observed dynamical properties of the Clouds.

Red Supergiant stars (RSGs) are known to eject large amounts of material during this evolutionary phase. However, the processes powering the mass ejection in low- and intermediate-mass stars do not work for RSGs and the mechanism that drives the ejection remains unknown. Different mechanisms have been proposed as responsible for this mass ejection including Alfvén waves, large convective cells, and magnetohydrodynamical (MHD) disturbances at the photosphere, but so far little is known about the actual processes taking place in these objects. Here we present high angular resolution interferometric ALMA maps of VY CMa continuum and molecular emission, which resolve the structure of the ejecta with unprecedented detail. We reconstructed the 3D structure of the gas traced by the different species. It allowed us to study the morphology and kinematics of the gas traced by the different species surrounding VY CMa. Two types of ejecta are clearly observed: extended, irregular, and vast ejecta surrounding the star that are carved by localized fast outflows. The structure of the outflows is found to be particularly flat. We present a 3D reconstruction of these outflows and proof of the carving. This indicates that two different mass loss processes take place in this massive star. We tentatively propose the physical cause for the formation of both types of structures. These results provide essential information on the mass loss processes of RSGs and thus of their further evolution.

The induction and momentum equations of solar dynamo are simplified to a dynamic system for the convective Root-Mean-Square (rms) velocity and the rms magnetic field in the solar convection zone. The study of stable stationary points of this system gives a minor excess of the critical level of the dynamo and, accordingly, moderate magnetic field typically about 1 T (10 kG). A significantly lower rms magnetic field may be possible at some parameters of the system. The stable rms velocity is about 100 m/sec, and the characteristic magnetic times are about the half-period of solar rotation or about an average lifetime of sunspots. Relative magnetic energy is of order 5 kJ/kg that is about the kinetic energy. The unstable stationary points could be near zero magnetic fields as in periods of very lower solar activity similar to the Maunder minimum.

The Galactic dwarf spheroidal galaxies (dSphs) provide valuable insight into dark matter (DM) properties and its role in galaxy formation. Their close proximity enables the measurement of line-of-sight velocities for resolved stars, which allows us to study DM halo structure. However, uncertainties in DM mass profile determination persist due to the degeneracy between DM mass density and velocity dispersion tensor anisotropy. Overcoming this requires large kinematic samples and identification of foreground contamination. With 1.25 deg2 and 2394 fibers, PFS plus pre-imaging with Hyper Suprime Cam will make significant progress in this undertaking.

Nearly all intragroup (IGL) and intracluster light (ICL) comes from stars that are not bound to any single galaxy but were formed in galaxies and later unbound from them. Kinematic information on these very low surface brightness structures mostly comes from discrete tracers such as planetary nebulae and globular clusters, showing highly unrelaxed velocity distributions. Cosmological hydrodynamical simulations provide key predictions for the dynamical state of IGL and ICL and find that most IC stars are dissolved from galaxies that subsequently merge with the central galaxy. The increase of the measured velocity dispersion with radius in the outer halos of bright galaxies is a key feature to identify IGL and ICL components. In the local groups and clusters, IGL and ICL are more centrally concentrated than the galaxies, with their typical fractions that are few to ten percent, i.e. significantly lower than the average values in more evolved clusters. The properties of ICPNe, their luminosity functions and specific frequencies were key to further constraint the age (10 Gyr) and the metallicity ([M / Fe]< −1.0) of the IC/IGL. The results in the nearby clusters are briefly illustrated.

I have performed numerical hydrodynamical calculations of outflows driven by the evaporation of a pseudo-barotropic ring around a luminous central star. The outflow shapes and internal structures resemble known cylindrical nebulae. Some of the corresponding synthetic spectra show ‘Hubble’ type outflow.