Planetary nebulae (PNe) represent the final link in the chain of the gas and dust enrichment of low- and intermediate-mass stars. We present a comprehensive study of the relevant observational data of 10 PNe of the Large Magellanic Cloud (LMC). Analysing them from the UV to the IR, we characterise the nature of the central star (CS) and the dust contribution. We link these results to the evolutionary history of these sources.

In this work we present preliminary results from a systematic search for new Local Group dwarf galaxies in the deep, wide-field Ultraviolet Near-Infrared Optical Northern Survey (UNIONS). The first major result from this work is the discovery of a candidate ultra faint dwarf galaxy, Boötes V. This satellite of the Milky Way has a physical half-light radius of , an absolute V-band magnitude of −4.5 ± 0.4 mag, and resides at a heliocentric distance of approximately 100 kpc. We also announce the discovery of a faint, compact star cluster, UNIONS 1. The end goal of this work will be to put firm constraints on the detectability and completeness of Local Group dwarf galaxies given the broad sky coverage and excellent photometric depth of UNIONS.

The Large Magellanic Cloud (LMC) has a complex dynamics driven by both internal and external processes. The external forces are due to tidal interactions with the Small Magellanic Cloud and the Milky Way, while internally its dynamics mainly depends on the stellar, gas, and dark matter mass distributions. Despite the overall complexity of the system, very often simple physical models can give us important insights about the main driving factors. Here we focus on the internal forces and attempt to model the proper motions of ∼ 106 stars in the LMC as measured by Gaia Data Release 3 with an axisymmetric dynamical model, based on the Jeans equations. We test both cored and cusped spherical Navarro-Frenk-White dark matter halos to fit the LMC gravitational potential. We find that this simple model is very successful at selecting a clean sample of genuine LMC member stars and predicts the geometry and orientation of the LMC with respect to the observer within the constraint of axisymmetry. Our Jeans dynamical models describe well the rotation profile and the velocity dispersion of the LMC stellar disc, however they fail to describe the motions of the LMC bar, which is a non-axisymmetric feature dominating the central region. We plan a triaxial Schwarzschild approach as a next step for the dynamical modelling of the LMC.

The way we look at the sky is connected to the cosmological paradigm embraced by the society we live in. On the other hand, several astronomical concepts reinforce the idea of a common humanity. Yet, scientific outreach is frequenty reaching out only to a specific part of the world population, often excluding people living in extreme social vulnerability, victims of violence and prejudice, fighting for their lives and for the right of living according to their traditions. We present two outreach projects, developed in Brazil, funded by the Office of Astronomy for Development (OAD) of the International Astronomical Union (IAU), i.e. “Under Other Skies” & “OruMbya”, which tackle the importance of ethno-astronomy, and the collaboration with leaders and cultural agents of marginalised communities. We also describe an educational project born in the favela of Cantagalo Pavão Pavãozinho (PPG), in Rio de Janeiro, during the COVID19 pandemic, which started a collaboration with local educators and artists to offer classes of astronomy and English language to children in the favela.

This presentation is an attempt to lay out, in the context of observational studies of the masses of Milky Way dwarf galaxies, what it is I think we want to do, why we want to do it, and how we go about doing it. They are my own personal opinions, and are presented here in the hope that they will stimulate others to step back and consider what are the most important scientific investigations that we should be doing, given the plethora of facilities and data available that are now available to us.

Solar winds originate from the Sun and can be classified as fast or slow. Fast solar winds come from coronal holes at the solar poles, while slow solar winds may originate from the equatorial region or streamers. Spicules are jet-like structures observed in the Sun’s chromosphere and transition region. Some spicules exhibit rotating motion, potentially indicating vorticity and Alfvén waves. Machine learning and the Hough algorithm were used to analyze over 3000 frames of the Sun, identifying spicules and their characteristics. The study found that rotating spicules, accounting for 21% at the poles and 4% at the equator, play a role in energy transfer to the upper solar atmosphere. The observations suggest connections between spicules, mini-loops, magnetic reconnection, and the acceleration of fast solar winds. Understanding these small-scale structures is crucial for comprehending the origin and heating of the fast solar wind.

We present preliminary results from our spectroscopic survey of low-luminosity early-type galaxies in the Coma cluster conducted with the Binospec spectrograph at the 6.5 m MMT. From spatially-resolved profiles of internal kinematics and stellar population properties complemented with high-resolution images, we placed several low-luminosity dEs on the fundamental plane in the low-luminosity extension of the available literature data. We also discovered unusual kpc-sized kinematically-decoupled cores in several dwarf galaxies, which had been probably formed before these galaxies entered the cluster.

I discuss Local Group galaxies from the perspective of external galaxies that define benchmark scaling relations. Making use of this information leads to a model for the Milky Way that includes bumps and wiggles due to spiral arms. This model reconciles the terminal velocities observed in the interstellar medium with the rotation curve derived from stars, correctly predicts the gradual decline of the outer rotation curve, and extrapolates well out to 50 kpc. Rotationally supported Local Group galaxies are in excellent agreement with the baryonic Tully-Fisher relation. Pressure supported dwarfs that are the most likely to be in dynamical equilibrium also align with this relation. Local Group galaxies thus appear to be normal members of the low redshift galaxy population. There is, however, a serious tension between the dynamical masses of the Milky Way and M31 and those expected from the stellar masshalo mass relation of abundance matching.

The nearby Fornax cluster (d ∼ 20 Mpc) provides an unparalleled opportunity to investigate the formation and evolution of early-type galaxies in a dense environment. Using the spectroscopic data from the ESO VLT/VIMOS spectrograph of the Fornax cluster, we have kinematically characterised the photometrically detected globular cluster (GC) candidates in the core of the cluster. We confirm a total of 777 GCs with new velocity measurements and compile the most extensive spectroscopic GC sample of 2341 objects in this environment. We used our GC radial velocity catalogue to perform dynamical mass modelling of NGC 1399, the central galaxy of the the Fornax cluster out to its 200 kpc. We find that both cusp (NFW) and core (Burkert) dark matter (DM) halo can produce the observed kinematics. Independent of the DM halo profile used, we find that inclusion of the intra-cluster GCs in mass-modelling can effect the mass-estimate.

Two planetary nebulae have sofar been observed with JWST. Both show stellar companions. The paper discusses how and what we can learn from the companions.

The controversy “dark matter vs. modified gravity” constitutes a major topic of discussion. It was proposed that dynamical friction could be used to discriminate between the two alternatives. Analytic calculations indicate that, with modified gravity, globular clusters (GCs) of low-mass galaxies experience much stronger dynamical friction than in the equivalent system with Newtonian gravity and dark matter. As a result, in modified gravity the old GCs of low mass galaxies should have already settled in the centers of the galaxies. This is not observed. Here we report on our efforts to verify the analytic results by self-consistent simulations with the MOND-type (modified Newtonian dynamics) gravity. The core stalling mechanism, that was not considered in the analytic calculations, prevents GCs to settle in centers of ultra-diffuse galaxies. For isolated dwarf galaxies, which are gas-rich objects, supernova explosions prevent the GCs from settling.

We present JWST images of NGC 6720 (the Ring Nebula), covering wavelengths from 1.6 μm to 25 μm. The bright shell is strongly fragmented with some 20 000 dense globules, bright in H2, with a characteristic diameter of 0.2 arcsec and density nH∼105–106cm−3. The shell contains a narrow ring of polycyclic aromatic hydrocarbon (PAH) emission. H2 is found throughout the shell and also in the halo. The central cavity is filled with high ionization gas and shows two linear structures seen in projection against the cavity. The central star is located 2 arcsec from the emission centroid of the cavity and shell. Linear features (‘spikes’) extend outward from the ring, pointing away from the central star. Around ten low-contrast, regularly spaced concentric arc-like features are present; they suggest orbital modulation by a low-mass companion with a period of about 280 yr. A previously known much wider companion is located at a projected separation of about 15 000 au; we show that it is an M2–M4 dwarf. NGC 6720 is therefore a triple star system. These features, including the multiplicity, are similar to those seen in the Southern Ring Nebula (NGC 3132) and may be a common aspect of such nebulae.

As a relatively active region, ephemeral region (ER) exhibits highly complex pattern of magnetic flux emergence. We aim to study detailed secondary flux emergences (SFEs) which we define as bipoles that their locations close to ERs and finally coalesce with ERs after a period. We study the SFEs during the whole process from emergence to decay of 5 ERs observed by the Helioseismic and Magnetic Imager (HMI) aboard Solar Dynamics Observatory (SDO). We find that the maximum unsigned magnetic flux for each of the ERs is around 1020 Mx. All ERs have tens of SFEs with an average emerging magnetic flux of approximately 5×1018 Mx. The frequency of normalized magnetic flux for all the SFEs follows a power law distribution with an index of -2.08. The majority of SFEs occur between the positive and negative polarities of ER, and their growth time is concentrated within one hour. The magnetic axis of SFEs also exhibits a random characteristic. We suggest that the relationship between SFEs and ERs can be understood by regarding the photospheric magnetic field observations as cross-sections of an emerging magnetic structure. Tracking the ERs’ evolution, we propose that the flux emergences are partially emerged Ω-loops, and that the SFEs in ERs may be sequent emergences from the bundle of flux tube of ERs.

Flux emergence at different spatial scales and with different amounts of flux has been studied using radiative magnetohydrodynamics (rMHD) simulations. We use the radiative MHD code MURaM to simulate the emergence of an untwisted magnetic flux tube of ephemeral region scale with a density nonuniformity into a background atmosphere with a small unipolar open field. We find that the tube rises to the photosphere, forming complex loop structures seen in synthetic Atmospheric Imaging Assembly(AIA) 171 Å images. The atmosphere reaches 105 K at 3Mm above the surface. Our simulation provides a reference example of a less twisted ephemeral region emergence and the atmospheric response.

The inherent stochastic and nonlinear nature of the solar dynamo makes the strength of the solar cycles vary in a wide range, making it difficult to predict the strength of an upcoming solar cycle. Recently, our work has shown that by using the observed correlation of the polar field rise rate with the peak of polar field at cycle minimum and amplitude of following cycle, an early prediction can be made. In a follow-up study, we perform SFT simulations to explore the robustness of this correlation against variation of meridional flow speed, and against stochastic fluctuations of BMR tilt properties that give rise to anti-Joy and anti-Hale type anomalous BMRs. The results suggest that the observed correlation is a robust feature of the solar cycle and can be utilized for a reliable prediction of peak strength of a cycle at least 2 to 3 years earlier than the minimum.

In the last two decades, some arguments have accumulated for a more important mass ratio of the Large Magellanic Cloud (LMC) to the Milky Way (MW) than was previously thought, up to a value of 10% or more. This implies that the LMC has a measurable influence on the dynamics in the MW stellar halo, including both stellar densities and kinematics, as observed by Conroy et al. (2021) and Petersen and Peñarrubia (2021). While this merger has been previously reproduced using N-body simulations (see, e.g., Garavito-Camargo et al. 2019), I exploit here the results of a recent study (Rozier et al. 2022) which aimed at modelling the merger via linear response theory (LRT). More specifically, we integrated the linearized collisionless Boltzmann-Poisson system of partial differential equations using a methodology known as the matrix method. Our results display the same large scale behaviour as state-of-the-art simulations, with a dipolar over/underdense pattern related to the reflex motion of the MW, and an overdense wake trailing behind the LMC. Using LRT, I show that the response’s self-gravity can be neglected, implying a direct proportionality between the LMC to MW mass ratio and the amplitude of the relative density variations of the MW stellar halo. However, these overdensities may also depend on other model parameters, such as the structure of the MW potential (including a dark matter component), the initial stellar halo density, as well as its internal kinematics. I focus on the latter source of degeneracy, showing how the stellar halo’s velocity anisotropy impacts its response to the LMC. Interestingly enough, it appears that the density of the dipolar response is insensitive to the stellar halo’s initial velocity anisotropy, and can therefore represent an efficient probe of the LMC to MW mass ratio.

The objective of our study was the spectroscopic analysis of the PN NGC 3242, which contains a pair of low-ionization structures (LISs). For our analysis, MUSE data were used in conjunction with the SATELLITE code for a spectroscopic analysis in two spatial dimensions. Additionally, infrared images from Spitzer Space Telescope (SST) were employed to search for potential H2 emission at the LISs. The preliminary results revealed that the electron temperature calculated from [N II] diagnostics lines is approximately 12,000 K at the LISs, while the thorough examination of MUSE data has led to the identification of the [C I] 8727 Å emission line emitted only from the LISs. This result may imply that LISs are the optical counterpart of a dense molecular core. Spitzer’s data didn’t reveal the existence of H2 at LISs, but three rings were identified around the main body of the PN.

This study focuses on investigating planetary nebulae (PNe) within the dwarf galaxy VCC 1249, located in the halo of the early-type galaxy (ETG) M49, by utilizing data obtained from the Multi-Unit Spectroscopic Explorer (MUSE). The integral-field spectroscopy capabilities of MUSE enable the identification of individual planetary nebulae. The interaction of VCC 1249 with the cluster-dominant galaxy M49 in the Virgo Subcluster B is driving this project, as it offers a unique opportunity to explore how high-density environments influence the properties and fate of low-mass galaxies. To identify potential PNe candidates within VCC 1249, the method proposed by Roth et al. (2021) is employed. Through this approach, ten candidates exhibiting features consistent with PNe properties have been identified.

The grand minimum in the Sun’s activity is a distinctive mode characterized by a magnetic lull that almost completely lacks the emergence of sunspots on the solar surface for an extended duration. The factors driving this transition of an otherwise magnetically active star into a quiescent phase, the processes occurring within the solar interior and across the heliosphere during this period, and the mechanisms leading to the eventual resurgence of surface magnetic activity remain enigmatic. However, there have been sustained efforts in the past few decades to unravel these mysteries by employing a combination of observation, reconstruction and simulation of solar magnetic variability. Here, we summarize recent research on the solar grand minimum and highlight some outstanding challenges – both intellectual and practical – that necessitate further investigations.