Compact obscured nuclei (CONs) are relatively common in the centers of local (U)LIRGs, yet their nature remains unknown. Both AGN activity and extreme nuclear starbursts have been suggested as plausible nuclear power sources. The prevalence of outflows in these systems suggest that CONs represent a key phase in the nuclear feedback cycle, in which material is ejected from the central regions of the galaxy. Here, we present results from MUSE for the confirmed local CON galaxy NGC4418. For the first time we spatially map the spectral features and kinematics of the galaxy in the optical, revealing several previously unknown structures. In particular, we discover a bilateral outflow along the minor axis, an outflowing bubble, several knot structures and a receding outflow partially obscured by the galactic disk. Based on the properties of these features, we conclude that the CON in NGC4418 is most likely powered by an AGN.

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.

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.

Recent observations have established that dwarf galaxies can host black holes of intermediate mass (IMBH, 100Mȯ < MIMBH ≲ 105 Mȯ). With modern numerical models, we can test the growth of IMBHs as well as their evolutionary impact on the host galaxy. Our novel subsolar-mass (0.8 solar mass) resolution simulations of dwarf galaxies (M* = 2 × 107 Mȯ) have a resolved three-phase interstellar medium and account for non-equilibrium heating, cooling, and chemistry processes. The stellar initial mass function is fully sampled between 0.08–150 Mȯ while massive stars can form HII regions and explode as resolved supernovae. The stellar dynamics around the IMBH is integrated accurately with a regularization scheme. We present a viscous accretion disk model for the IMBH with momentum, energy, and mass conserving wind feedback. We demonstrate how the IMBH can grow from accretion of the cold and warm gas phase and how the presence of the IMBH and its feedback impacts the gas phase structure.

. 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.

We study disks and jets in various accretion states (SANE and MAD) using novel, GPU-accelerated general-relativistic magneto-hydrodynamic (GR-MHD) code which we developed, based on HARM. This code, written in CUDA-c and uses OpenMP to parallelize multi-GPU setups, allows high resolution simulations of accretion disks and the formation and structure of jets without the need of multi-node supercomputer infrastructure. A 2563 simulation is well within the reach of an Nvidia DGX-V100 server, with the computation being a factor about 100 times faster if only the CPU was used.

We use this code to examine several disk structures, wind and jet properties in the MAD and SANE states. In the MAD state, we find that the magnetic flux threading the horizon mostly depends on the spin of the BH. This implies that the jet structure and power are strong functions of the spin, with non-spinning BHs have the widest jets.

Photon-driven flows have been studied for almost a century, and a quantitative description of the radiative forces on atoms and ions is important for understanding a wide variety of systems, including active galactic nuclei (AGN). The colloquially-termed “radiation pressure” of line-driven winds plays an important role in driving outflows in these environments. Quantifying the associated forces is crucial to understanding how these flows enable interactive mechanisms within these environments, such as AGN feedback. Here we provide new calculations of the dimensionless line strength parameter due to radiation driving. For representative AGN, we calculate the photoionization balance at each step along the line of sight (LOS) to the proposed wind-launching region above the accretion disk. We then use a recently compiled database of approximately 5.6 million spectral lines to compute the strength of the line-driving force on the gas and the mass-loss rates resulting from these outflows. We also introduce a “shielding factor’’ that increases the magnitude of the accretion disk column density prior to the launch radius. This shielding factor simulates a proposed inner “failed wind” region that is thought to shield the outflowing gas from becoming over-ionized by the central source. We also revisit and formalize the role of the commonly-used ionization parameter in setting the properties of the accelerating gas.

Ram-pressure stripping (RPS) is a process known to remove gas from satellite galaxies. Recent observational studies have found an increased ratio of active galactic nuclei (AGN) among the population of RPS galaxies compared to regular galaxies in the field. To test whether ram pressure (RP) can trigger an AGN, we perform a suite of hydrodynamical wind-tunnel simulations of a massive (Mstar = 1011 Mȯ) galaxy, with inclusion of star formation, stellar feedback and high resolution up to 39 pc. We find that RP increases the inflow of gas to the galaxy centre, which in turn can result in the enhanced BH accretion, as measured by the Bondi-Hoyle model. We also estimate pressure of outflows from our accretion rates and show that AGN feedback would play an important role on the early stages of stripping, while RP itself is not so strong.

. An outflow, from the hot inner flow, in black-hole X-ray binaries is always expected due to the positive Bernoulli integral in the hot inner flow. We have demonstrated that, if one considers this outflow as the place where not only Comptonization occurs, but also radio emission, many observed correlations, including the long-standing one between radio and X-rays, can be explained with one simple model.

The connection between X-ray weakness and powerful X-ray outflows is both expected in a scenario where outflows are connected with radiation-driven winds, and observed in several sources, both in the local Universe and at high redshift. Here I present the first results of a new study of this possible connection based on a search for SDSS quasars with weak X-ray emission in serendipitous XMM-Newton observations. The selected objects have a “normal” optical/UV blue continuum, but a flat and extraordinarily weak X-ray spectrum. The availability of rest-frame optical/UV spectra allows to check for the signature of outflows in the absorption lines and/or in the profiles of the emission lines. This method could reveal the presence of a population of so-far overlooked outflowing quasars and confirm the connection between winds and X-ray weakness in quasars.

. We show that an extragalactic jet with a velocity shear gives rise to Fermi like acceleration process for photons scattering withing the shear layers of the jet. Such photons then gain energy to produce a high energy power law. These power law spectra at high energies are frequently observed in several extragalactic objects such as Gamma Ray Bursts (GRBs). We implement the model on GRBs to show that the obtained range of the photon indices are well within their observed values. The analytic results are confirmed with numerical simulations following Monte Carlo approach.

Cosmological simulations fail to reproduce realistic galaxy populations without energy injection from active galactic nuclei (AGN) into the interstellar medium (ISM) and circumgalactic medium (CGM); a process called ‘AGN feedback’. Consequently, observational work searches for evidence that luminous AGN impact their host galaxies. Here, we review some of this work. Multi-phase AGN outflows are common, some with potential for significant impact. Additionally, multiple feedback channels can be observed simultaneously; e.g., radio jets from ‘radio quiet’ quasars can inject turbulence on ISM scales, and displace CGM-scale molecular gas. However, caution must be taken comparing outflows to simulations (e.g., kinetic coupling efficiencies) to infer feedback potential, due to a lack of comparable predictions. Furthermore, some work claims limited evidence for feedback because AGN live in gas-rich, star-forming galaxies. However, simulations do not predict instantaneous, global impact on molecular gas or star formation. The impact is expected to be cumulative, over multiple episodes.

Using hydrodynamic simulations and photoionization calculations, we demonstrate that quasar emission line spectra contain information on the driving mechanism of galaxy-scale outflows. Outflows driven by a hot shocked bubble are expected to exhibit LINER-like optical line ratios, while outflows driven by radiation pressure are expected to exhibit Seyfert-like line ratios. Driving by radiation pressure also has a distinct signature in the narrow UV lines, which is detected in an HST-COS spectrum of a nearby quasar hosting a large-scale wind.

In the final phase of terrestrial planet formation, planetary embryos and planetesimals are the building blocks for the growth of rocky planets. In this investigation, we study the dynamical behaviour of a circumstellar disk in an inclined binary star system. The disk consists of 2000 planetesimals and 25 embryos and is distributed between 1 and 4 au around the primary star. To compute the gravitational interaction of the whole system, we use our recently developed GPU N-body code GANBISS. GANBISS treats all collision as perfect merging and delivers the impact parameters that will be used to distinguish between different collision outcomes.

The luminosity of the brightest stars (tip) of the red giant branch (TRGB) in the color–magnitude diagrams of old stars was used early on to introduce the ‘multiple stellar populations’ concept, in 1944, by Walter Baade. However, the precision and accuracy of the TRGB for distance estimation has not been known well for long. In the modern era, equipped with high spatial resolution imaging telescopes, the TRGB is considered an excellent standard candle for any type of resolved galaxies, thus representing a powerful probe for cosmology. The TRGB has several advantages over the classical Cepheids. I review how we can apply the TRGB in cosmology. Four science cases, from large to small scales, are presented: (1) the Hubble flow with Type Ia supernovae; (2) Virgo Cluster infall and dark matter; (3) dark galaxies; and (4) dark matter-free galaxies.

Galactic haloes in a Λ-CDM universe are predicted to host today a swarm of debris resulting from cannibalised dwarf galaxies. The chemo-dynamical information recorded in their stellar populations helps elucidate their nature, constraining the assembly history of the Galaxy. Using data from APOGEE and Gaia, we examine the chemical properties of various halo substructures, considering elements that sample various nucleosynthetic pathways. The systems studied are Heracles, Gaia-Enceladus/Sausage (GES), the Helmi stream, Sequoia, Thamnos, Aleph, LMS1, Arjuna, I’itoi, Nyx, Icarus, and Pontus. Abundance patterns of all substructures are cross-compared in a statistically robust fashion. Our results show that many halo substructures conjectured to be debris from individual accretions likely belong to either the omnipresent GES or to in situ populations, and that the Milky Way likely underwent three major mergers so far: Heracles, GES, Sagittarius dSph.

In the past decade, submillimeter surveys have been employed to define samples of gravitationally-lensed dusty star-forming galaxies (DSFGs) at z ∼ 1 − 4. These extreme objects () appear to form stars prodigiously at rates of . Using all-sky Planck and WISE surveys, and wide-area Herschel surveys, we have identified the PASSAGES sample, with some of the rarest hyper-luminous IR galaxies ever discovered. We have found that their globally-averaged star formation surface densities are always sub-Eddington, typically by an order of magnitude. This may suggest that our understanding of how radiation pressure from massive stars disrupts the collapse of molecular clouds (thereby quenching star formation) is flawed—or simply that smaller physical resolutions are necessary. With the aid of lensing, we can now capture the source-plane distribution of star formation at ∼ 100pc scales, letting us identify isolated super-Eddington regions where quenching is occurring.

Galaxy-scale strong lensing is a powerful tool in Astrophysics and Cosmology, enabling studies of massive galaxies’ internal structure, their formation and evolution, stellar initial mass function, and cosmological parameters. In this conference proceeding, we highlight key findings from the past decade in astrophysical applications of strong lensing at the galaxy scale. We then briefly summarize the present status of discovery and analyses of new samples from recent or ongoing surveys. Finally, we offer insights into anticipated developments in the upcoming era of big data shaping the future of this field, thanks to the Rubin, Euclid, and Roman observatories.

We aim to uncover the structure of the continuum and broad emission line (BEL) emitting regions in the gravitationally lensed quasar SDSS J1004+4112 through unique microlensing signatures. Analyzing 20 spectroscopic observations from 2003 to 2018, we study the striking deformations of various BEL profiles and determine the sizes of their respective emitting regions. We use the emission line cores as a baseline for no microlensing and then apply Bayesian methods to derive the sizes of the Lyα, Si IV, C IV, C III], and Mg II emitting regions, as well as of the underlying continuum-emitting sources. We find that the sizes of the emitting regions for the BELs are a few light-days across, notably smaller than in typical lensed quasars. The asymmetric distortions observed in the BELs suggest that the broad-line region lacks spherical symmetry and is likely confined to a plane. The inferred continuum emitting region sizes are larger than predictions based on standard thin-disk theory by a factor of ∼ 4. We find that the size-wavelength relation is in agreement with that of a geometrically thin and optically thick accretion disk.

This is a multi-wavelength study to examine the G45.804-0.355 massive star-forming region (SFR) and its environs. Using MeerKAT with angular resolution (θ) of 8″ at 1.28 GHz, we identify for the first time, a faint radio continuum emission core in G45.804-0.355. At 1.3 mm, ALMA observations (θ∼0″ 7) resolved the core into multiple dust continuum condensations including MM1 which was found to be the primary massive dust dense core in the region (mass Mc∼ 54.3M⊙). The dust continuum shows an arm-like extended emission within which other dense cores are situated. The velocity gradient of the MM1 core indicates that the source is associated with a rotation gas motion. The red- and blue-shifted lobes overlap at the position of MM1. The compact morphology of the 4.5 μm IR emission, the presence of spiral arms and overlapping of the red- and blue-shifted lobes suggest a face-on geometry of G45.80-40.355.