We discuss recent results from high-resolution Magellan/MIKE spectroscopy of five stars in the outskirts (up to ∼ 1 kpc) of the Tucana II ultra-faint dwarf galaxy (UFD), complemented by prior observations of seven stars closer to the galaxy’s center. These outer stars were identified via their low SkyMapper photometric metallicities and consistent Gaia DR2 proper motions, and their membership was confirmed through follow-up medium-resolution spectroscopy. The high-resolution spectroscopy presented here provides detailed chemical abundances and more precise velocities, facilitating a revised dynamical analysis for signs of tidal disruption and a collective analysis of the detailed chemistry to evaluate astrophysical scenarios for the origin of the spatially extended feature. We discuss these signatures here and assess the evidence for several formation scenarios for the extended feature of Tucana II, highlighting how such studies of the outskirts of the UFD population as a whole can inform which scenarios may be preferred.

The origin of the sub-terahertz (sub-THz) component of radio emission from solar flares, which is characterized by the increase flux with frequency in the 100-400 GHz range, is considered. On the basis of equations of 1D non-LTE radiation hydrodynamics we simulated the altitude distribution of the plasma density and temperature inside the flare loop caused by the interaction of non-stationary beam of accelerated electrons in the form of a triangular pulse with the chromospheric plasma. The FLARIX numerical code was used to calculate the dynamics of the flare plasma parameters at different heights which are compared with the RADYN numerical code. We found that the characteristic heights of the formation of sub-THz emission vary over a wide range with time for both codes. The main contribution to the sub-THz emission comes from the chromospheric and transition region plasma with temperatures of 104–105K.

Almost 30 years have passed since not only the universal density distribution of dark matter (DM) halos in cosmological N-body simulations, but also the scalings between properties of DM halos represented by concentration-mass (c-M) relations are proposed. We derive the c-M relation for sub galactic halos (subhalos) of Milky Way (MW)-sized host halo using the result of the ultra-high resolution cosmological N-body simulation, Phi-4096, with a particle mass of 5.13 × 103 h−1M⊙. This c-M relation is confirmed to be consistent with a c-M relation from near the free streaming scale to the galactic scale proposed in a literature. One of our main findings is that the c-M relation can reproduce observational properties of DM halos from dwarf galaxies to clusters of galaxies. In addition, we provide a testable prediction of the density distributions of MW subhalos for future observations.

We have found strong evidence that an extended bipolar planetary nebula (PN), lying in the line-of-sight of the Galactic open cluster M37, is actually its physical member. We estimated both the PN physical properties and the properties of its progenitor from cluster studies. The progenitor mass has been found to be around 2.8 M⊙. There are only a handful of such confirmed associations and each of them provides valuable additional data to the initial-to-final-mass relation. The nebula has a major axis of 445 arcsec and a kinematical age of around 80 kyrs -the largest ever determined for a PN- suggesting that PNe in clusters do not dissipate as fast as field PNe.

Radiative transfer in spherical circumstellar silicate dust envelope was modelled with and without accounting for polarization, using the code RADMC-3D. It was found that the influence of polarization on dust temperature and the mean intensity of shortwave radiation in spherically symmetric case is negligible, but neglecting for polarization does not give sensible economy of the computing time for the given signal to noise ratio. Construction of good virtual polarization images of the object can require much more computing time than good intensity images.

The mass-anisotropy degeneracy is still one of the main issues in estimating the dark matter distribution in galaxies, especially for the commonly used 2nd-order Jeans analysis. We study the extension of spherical Jeans modeling by incorporating the 4th-order velocity moments under the assumption of dynamical equilibrium and a constant velocity anisotropy. Incorporating 4th -order moments allows stars’ line-of-sight velocity distribution (LOSVD), which is sensitive to the value of β, to be flexible, covering thin-tailed to heavy-tailed distributions that are inaccessible if only 2nd-order moments are used. We test our stellar dynamical modeling using mock data that resembles Draco dSph with either central NFW cusp or Burkert core. Using 500 sample stars, our simulations show that incorporating 4th-order moments improves the results. Typically, the velocity anisotropy is constrained ∼ 2 −3 times tighter, while it is ≲30% typical bias for the constraint of the dark matter inner density slope with both parameters being recovered within 1σ uncertainties.

The first quasars at the Reionisation Epoch, z ∼ 6-7.5, probe the early stages of supermassive black holes and host galaxy assembly. In this paper, we present recent results, exploiting VLT, ALMA and NOEMA observations, that allow us to constrain the onset of strong black hole feedback, the dust properties and star formation rates in high redshift quasars with unprecedented accuracy. These results highlight the strategic importance of ALMA high frequency (i.e. Band 9 and 8) observations to obtain a reliable overview of the host galaxy and supermassive black hole growth out to the highest redshifts.

The Sun and solar-type stars exhibit irregular cyclic variations in their magnetic activity over long time scales. To understand this irregularity, we employed the flux transport dynamo models to investigate the behavior of one solar mass star at various rotation rates. To achieve this, we have utilized a mean-field hydrodynamic model to specify differential rotation and meridional circulation, and we have incorporated stochastic fluctuations in the Babcock–Leighton source of the poloidal field to capture inherent fluctuations in the stellar convection. Our simulations successfully demonstrated consistency with the observational data, revealing that rapidly rotating stars exhibit highly irregular cycles with strong magnetic fields and no Maunder-like grand minima. On the other hand, slow rotators produce smoother cycles with weaker magnetic fields, long-term amplitude modulation, and occasional extended grand minima. We observed that the frequency and duration of grand minima increase with the decreasing rotation rate. These results can be understood as the tendency of a less supercritical dynamo in slow rotators to be more prone to produce extended grand minima. We further explore the possible existence of the dynamo in the subcritical regime in a Babcock–Leighton-type framework and in the presence of a small-scale dynamo.

A family of unidentified infrared emission (UIE) bands is widely observed in planetary nebulae. We suggest that the carriers of the UIE bands are mixed aromatic/aliphatic organic nanoparticles (MAONs) synthesized over thousand-year time scales in the nebulae. The possible chemical pathways of synthesis is discussed. These organics are ejected into the interstellar medium and could have enriched the primordial Solar System, leading to the reservoir of complex organics in comets, asteroids, planetary satellites, and interplanetary dust particles.

Optical spectra of the Very Late Thermal Pulse (VLTP) object V4334 Sgr have shown a rapidly changing spectrum resulting from shocks in the outflow, which created a new bipolar nebula inside the old nebula. We see C II and C III emission lines emerging typical of a [WC 11-10]-type star. The strong increase of [O III] and [S III] emission lines indicate the possible onset of photoionisation in the new ejecta.

We here present 0.02–0.04″ resolution ALMA observation of the compact obscured nucleus (CON) of IRAS 17578-0400. A dusty torus within the nucleus, approximately 4 pc in radius, has been uncovered, exhibiting a usually flat spectral index at ALMA band 3, likely due to the millimeter corona emission from the central supermassive black hole (SMBH). The dense gas disk, traced by 13CO(1-0), spans 7 pc in radius and suggests an outflow driven by a disk wind due to its asymmetrical structure along the minor axis. Collimated molecular outflows (CMO), traced by the low-velocity components of the HCN(3-2) and HCO+(3-2) lines, align with the minor axis gas disk. Examination of position-velocity plots of HCN(3-2) and HCO+(3-2) reveals a flared dense gas disk extended a radius of ∼60 pc, infalling and rotating at speeds of about 200 km s−1 and 300 km s−1 respectively. A centrifugal barrier, located around 4 pc from the dynamical center, implies an SMBH mass of approximately 108 Mȯ, consistent with millimeter corona emission estimates. The CMO maintains a steady rotation speed of 200 km s−1 over the 100 pc scale along the minor axis. The projected speed of the CMO is about 80 km s−1, corresponding to around ∼500 km s−1, assuming an inclination angle of 80°. Such a kinematics structure of disk-driven collimated rotating molecular outflow with gas supplies from a falling rotating disk indicates that the feedback of the compact obscured nucleus is likely regulated by the momentum transfer of the molecular gas that connects to both the feeding of the nuclear starburst and supermassive black hole.

The central parsec of AGN is a key region for the launching of winds, and near-infrared interferometry is a unique tool for its study. With GRAVITY at the VLT interferometer, we can now spatially resolve not just the hot dust continuum on milliarcsecond ‘torus’ scales through imaging but also the broad-line region (BLR) on microarcsecond scales through spectro-astrometry. We have mapped the kinematics of the BLR in seven nearby AGN, measured sizes of the hot dust for seventeen AGN, and reconstructed dust images for two AGN. BLR kinematics has allowed us to measure the BLR size and supermassive black hole mass independent of reverberation mapping. The ongoing GRAVITY+ upgrade will greatly enhance the sensitivity and sky coverage of GRAVITY, and first results demonstrate its power for AGN science at z∼2 and beyond.

The discovery in JWST data of numerous bright galaxies at Cosmic Dawn, along with the identification of potentially “Universe-breaking” massive galaxies, is reshaping our understanding of galaxy formation, and raise questions about how rapidly galaxies assembled their mass in the early Universe. In parallel with follow-up studies, significant progress can be achieved by characterizing the brightest and most massive galaxies observed when the universe was 200 − 400 million years older, likely the most immediate descendants of the tantalizing objects observed at z > 10. In this talk, we will present the first results from a NIRSpec IFU R100 program targeting 12 bright, especially high-mass galaxies at just approximately 750Myr of cosmic time (6.5 < z < 8.5). Remarkably, this sample also benefits from [CII] and dust continuum estimates from the recent ALMA large program REBELS, making this a unique sample in the panorama of high-redshift studies. Leveraging the JWST’s high spatial and spectral resolution across a broad wavelength range, from the rest-frame UV to rest-frame optical, we can reconstruct spatially-resolved maps of their stellar and gas content. These maps enable us to interpret them in terms of in-situ mass assembly, merger-driven star formation, and star-formation history. We will also provide a brief outlook on their formation histories as inferred from gas-phase metallicities, but will leave most of the discussion to a companion, more in-depth presentation. These results will ultimately allow us to assess the star formation efficiency in massive galaxies at early epochs.

We present a radial velocity and model atmosphere analysis of both components of the spectroscopic binary central star of NGC 1514, based on high-resolution, high-signal-to-noise-ratio spectrograms taken with the CFH and Subaru telescopes at Maunakea, Hawaii. Together with the Gaia parallax and other data from the literature, all this information permits to determine the basic stellar parameters (Teff, L, log g, masses) of both binary components. This allows us to empirically test the theoretical post-AGB mass-luminosity relation.

We present analysis of the evolution of subsurface flows in and around active regions with peculiar magnetic configurations and compare their characteristics with the normal active regions. We also study the zonal and meridional components of subsurface flows separately in different polarity regions separately to better understand their role in flux migration. We use the techniques of local correlation tracking and ring diagrams for computing surface and subsurface flows, respectively. Our study manifests an evidence that the meridional component of the flows near anti-Hale active regions is predominantly equatorward which disagrees with the poleward flow pattern seen in pro-Hale active regions. We also find clockwise or anti-clockwise flows surrounding the anti-Joy active regions depending on their locations in the Southern or Northern hemispheres, respectively.

The radiative mode of AGN feedback, operated through outflows, plays an essential role in the evolution of galaxies. Quasar outflows are detected as blue-shifted broad absorption lines in the UV/optical spectra of quasars. Thanks to the Sloan digital sky survey, 100,000 broad absorption line quasars are available now for ensemble statistical studies. This rich dataset has also enabled us to identify some peculiar cases of these sources. By quantifying the BAL fraction in radio-loud BAL quasars, our studies demonstrate a clear trend of increasing BAL fraction as the viewing angle approaches an edge-on orientation, favoring the orientation model of BAL quasars. Also, by contrasting the properties of BAL quasars with appearing and disappearing BAL troughs, our analysis suggests that the extreme variations in BAL troughs are driven by ionization changes.

We show that, contrary to simple predictions, most AGNs show at best only a small increase of lags with increasing wavelength in the J, H, K, and L bands. We suggest that a possible cause of this near simultaneity from the near-IR to the mid-IR is that the hot dust is in a hollow bi-conical outflow of which we preferentially see the near side. In the proposed model sublimation or re-creation of dust (with some delay relative luminosity variations) along our line of sight in the hollow cone as the flux varies could be a factor in explaining the AGN changing-look phenomenon (CL). Variations in the dust obscuration can help explain changes in relationship of Hβ time delay on Luv variability. The relative wavelength independence of IR lags simplifies the use of IR lags for estimating cosmological parameters.

We report spectroscopic confirmation of a z = 3.757 ± 0.0011 massive $({\rm{log}}({{\rm{M}}_*}/{M_ \odot }) = 10.86_{ - 0.03}^{ + 0.09})$ quiescent galaxy with 11 hours of Keck/MOSFIRE K-band observations. This galaxy was selected from the FENIKS survey, which uses deep Gemini/Flamingos-2 Kb Kr imaging optimized for increased sensitivity to galaxies with strong Balmer/4000 Å breaks. Its rest-frame colors are consistent with a ∼1 Gyr old stellar population. This places it as one of the oldest objects at these redshifts, and challenges the notion that quiescent galaxies at z > 3 are all young post-starbursts. The star formation history suggests that its progenitor was in place by z ∼4 −7, reaching 1010.6 Mȯ by z ∼ 5, which we have confirmed using ultra-deep medium resolution spectroscopy from JWST. These results are in line with the rapid formation and quenching timescales reported for similar massive quiescent galaxies at z > 3, implying extreme baryonic physics within the first billion years of cosmic history.

In this contribution, we present the results from proper motion measurements across the Large Magellanic Cloud (LMC) using data from the VISTA survey of the Magellanic Cloud system (VMC). Using the derived proper motions, we modelled the structure of the LMC and analysed its internal kinematics. Within the central parts of the LMC, we found observational evidence for elongated orbits parallel to the bar’s major axis, which are considered to provide the main contribution for the support of a bar structure. A peculiar kinematic structure in the outer regions of the LMC hints toward stripped material from the Small Magellanic Cloud. We further introduce an observational campaign utilising the Hubble Space Telescope to precisely measure the proper motions of star clusters within the LMC. These motions, combined with radial velocities and 3D positions will be used to trace the gravitational potential of the LMC.