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27/10/2025, 09:00
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Florian Kühnel (MPP & LMU Munich)27/10/2025, 09:05
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Gia Dvali27/10/2025, 09:30
The "memory burden" effect implies that the black hole's quantum information load, which is invisible in black hole's ground state and traditionally has not been paid the deserved attention, exerts macroscopic effects on perturbed black holes. First, it tends to stabilize a black hole against the Hawking evaporation, leading to dramatic consequences for PBH dark matter. Even more...
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Sebastian Zell (Ludwig Maximilian University & Max Planck Institute for Physics, Munich)27/10/2025, 09:55
Mounting theoretical evidence suggests that the information stored in black holes suppresses their decay rate. This quantum effect of memory burden opens up a new window for small primordial black holes (PBHs) below $10^{15}\,{\rm g}$ as dark matter candidates. In this talk, I show that the smooth transition from semi-classical evaporation to the memory-burdened phase strongly impacts...
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Manuel Ettengruber (Max-Planck-Institut für Physik (Werner-Heisenberg-Institut))27/10/2025, 10:10
The fundamental scale of gravity could be significantly lower than the Planck scale due to the existence of a large number of particle species. This would also mean that processes exceeding this energy scale could produce black holes. In this talk, I will discuss two consequences of such a situation: first, the production of micro black holes in the corona of active galactic nuclei, together...
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Prof. Dieter Lüst27/10/2025, 10:50
We briefly revisit mechanisms for primordial black hole (PBH) production, namely inflation, phase transitions, and cosmic strings, in the context of the Dark Dimension Scenario, which is motivated by Swampland principles. Applying quantum gravity constraints, we demonstrate that any viable mechanism inevitably leads to the formation of five-dimensional PBHs. We comment on the observational...
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Ivano Basile (Max Planck Institute for Physics)27/10/2025, 11:15
The thermodynamics of large black holes is reliably described by semiclassical quantum gravity, and contains the seeds of holography. Generically, it cannot be extrapolated beyond the validity of gravitational effective field theory. In some special regimes this is possible, and leads to novel constraints on weakly coupled completions of gravity. I will present the framework and discuss how...
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Matilda Delgado (MPP & Harvard U.)27/10/2025, 11:30
Charged black hole solutions, which are ubiquitous in string theory, provide a natural setting for thought experiments probing the ultraviolet (UV) structure of quantum gravity. I will review recent progress in understanding how UV scales emerge in Effective Field Theories of quantum gravity, and explain how the attractor mechanism of charged black holes offers a controlled way to access UV...
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Carmine Montella (Max Planck Institute for Physics)27/10/2025, 11:45
Black holes remain one of the most fascinating windows into the quantum nature of gravity, yet their entropy is not fully captured by semiclassical considerations. Supersymmetric black holes, in particular, provide a controlled laboratory to explore subtle quantum effects and gain insights into more general black hole dynamics. In this work, we investigate genuinely non-perturbative...
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M. Sten Delos (Max Planck Institute for Astrophysics)27/10/2025, 13:15
Dark matter could consist of primordial black holes (PBHs). I present the first simulation of structure formation with PBH dark matter that self-consistently incorporates collisional few-body effects, post-Newtonian orbit corrections, orbital decay due to gravitational radiation, and black-hole mergers. An interesting phenomenology emerges in this simulation. Many-body interactions eject PBHs...
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Valentin Thoss (Ludwig-Maximilians-Universität München)27/10/2025, 13:40
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Frank Eisenhauer (MPE)27/10/2025, 13:55
Black Holes are among the most mysterious objects in the Universe. They are so massive and compact that nothing - not even light - can escape their gravity. Our presentation will give an update on the overwhelming observational evidence for an extremely heavy and compact object in the Galactic Centre, for which a supermassive black hole is the best explanation. Using the world's largest...
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Felix Mang (Max Planck Institute for Extraterrestrial Physics)27/10/2025, 14:20
Resolving the rich structure in the central 0.1 x 0.1’’ in the Galactic Center allows tracing stars orbiting the central massive black hole SgrA*. Serving as test particles in a strong gravitational field, these S-stars are susceptible to effects of General Relativity. With its unmatched astrometric precision, the interferometric beam-combiner GRAVITY has already facilitated in the past a...
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Matteo Sadun Bordoni (Max Planck Institute for Extraterrestrial Physics)27/10/2025, 15:00
Since 2016, the GRAVITY interferometer at ESO’s Very Large Telescope has provided astrometric data with unprecedented accuracy for the S-stars orbiting Sagittarius A*, providing a powerful means to probe the gravitational potential surrounding the supermassive black hole at the center of our Galaxy. Notably, we have detected the in-plane, prograde Schwarzschild precession of the orbit of the...
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Diogo Ribeiro (Max Plank Institute for Extraterrestrial Physics)27/10/2025, 15:15
Photons emitted from near ultra-compact objects carry information not only about their emission environment but also about the spacetime geometry around such objects. In the case of Sagittarius A*, the supermassive black hole at the centre of the Milky Way, the detected emission in the Near Infrared can flare to ten times its quiescent flux and be resolved temporally and spatially by the...
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Ildar Khabibullin (USM LMU, MPA)27/10/2025, 15:30
Extended X-ray emission observed in the direction of several molecular clouds in the Central Molecular Zone (CMZ) of our Galaxy exhibits spectral and temporal properties consistent with the `X-ray echo' scenario. It postulates that the observed signal is a light-travel-time delayed reflection of a short ($δt<$1.5 yr) and bright ($L_{\rm X}>10^{39}~{\rm erg~s^{-1}}$) flare, most probably...
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Simran Joharle (Max Planck Institute for Extraterrestrial Physics)27/10/2025, 15:45
Sagittarius A*, the supermassive black hole at the center of our Galaxy, offers a unique laboratory to study black hole accretion at extremely low rates. Understanding what material is available to feed it, and how that material interacts with its accretion zone, is key to understanding black hole feeding mechanisms more broadly. Many gas clumps of the order of a few Earth Solar masses have...
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Valeriya Korol (Max Planck for Astrophysics)27/10/2025, 16:20
Gravitational-wave observations have opened a new window onto compact objects across the Universe. The Laser Interferometer Space Antenna (LISA) is a flagship European-led mission that will explore the intermediate-frequency gravitational-wave spectrum between 0.1 and 100 mHz. With its unique discovery potential, LISA will detect an exceptionally rich variety of sources, from stellar binaries...
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Antoine Mérand (European Southern Observatory)27/10/2025, 16:45
Stellar evolution models predict that our galaxy should be filled with hundred of millions of isolated stellar-mass black holes (ISBH), yet only one has been detected conclusively as of today. Microlensing is the only method to detect ISBH, and only spatially resolving the event can break the degeneracy between distance and mass to the lens. I will present the latest developments in predicting...
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Aleksandra Olejak (Max Planck Institute for Astrophysics)28/10/2025, 09:00
Recent discoveries of puzzling electromagnetic transients in galactic centers, such as quasi-periodic eruptions and oscillations, point to a new class of stellar-mass objects interacting with supermassive black holes (SMBH). One compelling scenario is that stars gradually spiral inward through gravitational-wave emission and eventually transfer mass to the SMBH, forming stellar extreme mass...
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Daniel Kresse (Max Planck Institute for Astrophysics)28/10/2025, 09:25
Stellar-mass black holes (BHs) are formed in the collapse of massive stars. The detailed pathways to BH formation are, however, still under active debate. In my talk, I will present results from a set of three-dimensional (3D) neutrino-hydrodynamics simulations of BH formation in failed core-collapse supernova explosions (sometimes called "unnovae"). Because failed supernovae lack a bright...
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Jakob Stegmann (Max Planck Institute for Astrophysics)28/10/2025, 09:40
There is growing evidence that a substantial fraction of the compact object mergers detected through gravitational waves merge with non-zero eccentricity or large spin-orbit misalignment. In particular, recent evidence for an eccentric neutron star-black hole (NSBH) merger and NSBHs with anti-aligned BH spins challenge leading formation scenarios to date. Residual eccentricity rules out...
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Silvia Popa (MPA)28/10/2025, 09:55
Among the over 200 gravitational wave detections reported so far, GW231123 is a remarkable event that not only holds the record for the most massive black hole merger, but also exhibits extreme spins. Its origin is actively debated. Proposed scenarios include dynamical formation involving a sequence of mergers, Population III stars, accretion in an AGN disk and also more exotic explanations...
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Andrea Merloni (MPE)28/10/2025, 10:35
The statistical properties of Supermassive Black Holes in the local Universe provide both direct and indirect constraints on theoretical models of BH formation, growth and co-evolution with their host galaxies. In this talk, I will present studies of the local distribution of X-ray selected AGN carried out thanks to the largest survey of the kind, the eROSITA All-Sky Survey. I will focus in...
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Catarina Aydar (Max Planck Institute for Extraterrestrial Physics)28/10/2025, 11:00
Unraveling the mysteries of supermassive black holes and their relationship with their host galaxies is challenging and requires a proper disentanglement of the emission from the Active Galactic Nucleus (AGN) and the stellar populations. When observing the same AGN in different phases of its activity, some properties obtained from its optical spectra should be consistent, as the mass of the...
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Ms Khushboo - (LMU)28/10/2025, 11:15
Recent JWST mid-infrared observations of the central ~50pc region of the Seyfert 2 nucleus in the galaxy NGC 7582 have revealed prominent ice absorption features. Such icy bands have not been included in existing AGN or starburst dust radiative transfer models. In particular, template spectra from AGN model libraries severely underestimate the mid-infrared flux when compared with the JWST...
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Almudena Prieto (IAC & Munich Observatory)28/10/2025, 11:30
I discuss the relevance of high ionisation coronal lines as genuine tracers of the ionising continuum in galactic nuclei, and in turn of the spectral shape and temperature of the accretion disk, hence of the BH mass. On the basis of bona-fide BH masses from reverberation mapping and the strong infrared coronal line [Si VI] 1.96 um, a tight correlation between the excitation of the gas and...
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Taro Shimizu (MPE)28/10/2025, 11:45
We present the first sample of cosmic noon quasars with spatially resolved broad-line regions (BLRs) and dynamical black hole mass measurements using GRAVITY+. Through deep integrations with GRAVITY+, we detect the differential phase signal across the H$\alpha$ broad emission line which allows for detailed kinematic modeling of the BLR. We find BLR sizes systematically smaller by a factor of...
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Lazaros Souvaitzis (Max Planck Institute for Astrophysics)28/10/2025, 13:10
The most massive galaxies in the Universe also host the largest black holes, with masses of $10^9 \: \mathrm{M_{\odot}}$ and above (SMBHs). During their hierarchical assembly, these galaxies accreted many low-mass galaxies across cosmic time, possibly hosting IMBHs. They have experienced only a few major mergers at low redshift. If some of these IMBHs migrate to the galactic center, they may...
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Stefano de Nicola28/10/2025, 13:25
Ultramassive black holes, with masses > 10^10 solar masses, sit at the very top of the black hole mass spectrum. These objects are rare and can’t be identified using standard scaling relations like the classic BH-sigma relation, which underestimate black hole masses at the high-mass end. Instead, the size of the core — a light-deficient central region compared to an inward extrapolation of the...
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Justo Gonzalez (European Southern Observatory)28/10/2025, 13:40
AGN feedback has become a standard ingredient in cosmological simulations to help regulate the development of cooling flows and star formation from the scales of galaxies to groups and clusters. However, it is difficult to fine-tune the feedback efficiency to reproduce the observed cool-core fractions at all scales. In the paper "How the cool-core population transitions from galaxy groups to...
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Luca Sala (C2PAP/LMU/USM)28/10/2025, 13:55
The mass and spin of massive black holes (BHs) at the centre of galaxies evolve due to gas accretion and mergers with other BHs. Besides affecting the evolution of relativistic jets, the BH spin determines the efficiency with which the BH radiates energy.
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I implemented a sub-resolution prescription for cosmological, hydrodynamical simulations that models the evolution of the BH spin,... -
Volker Springel (MPA)28/10/2025, 14:30
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Jelena Ritter (Max Planck Institute for Astrophysics)28/10/2025, 14:55
Extended Ly-alpha nebulae observed around quasars trace the cool gas
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within the multiphase circumgalactic medium and can provide key insights
into the complex interplay between gas dynamics and active galactic
nuclei (AGN) feedback. However, the connection between this cool phase
and the cold molecular gas around the host galaxies remains largely
unexplored. In this talk, I leverage ALMA... -
Raquel Ruiz Valença (Universidade de São Paulo)28/10/2025, 15:10
Quasars are the most luminous type of AGN currently known, detectable across a vast range of redshifts extending beyond $z=7$. Thus, increasing the number of known quasars is essential for studying the accretion mechanisms of supermassive black holes, the evolution of galaxies, and the large-scale structure of the Universe, among others.
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Over the last four decades, spectroscopic surveys have... -
Ric Davies (MPE)28/10/2025, 15:25
We present the first near-infrared interferometric data of the broad line region of a QSO at z=4. GRAVITY+ detects a differential phase signal tracing the spatially resolved kinematics for both the H$\beta$ and H$\gamma$ lines. Fitting these lines simultaneously shows that 80% of the HI line emission in the broad line region originates in an outflow with a velocity up to $10^4$ km/s, oriented...
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Sunmyon Chon (MPA)28/10/2025, 15:40
The formation of supermassive black holes (SMBHs) is one of the biggest challenges in astrophysics. The Direct Collapse (DC) model provides seed BHs with a mass of 10^5 Msun and explains the origin of high-redshift SMBHs. It has been assumed that these seed BHs can only form in primordial gas, a restrictive condition that yields too few seeds to explain the observed population. We investigate...
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Ruancun Li (Max-Planck-Institute for Extraterrestrial Physics)28/10/2025, 16:15
The early growth of high-redshift quasars and their host galaxies raises critical questions about their cosmic evolution. We exploit the angular resolution and sensitivity of NIRCam to investigate the host galaxies of 31 quasars at $4 < z <7$ drawn from multiple JWST surveys. Using a new multi-band forward-modeling code (\textsc{GalfitS}) that incorporates physically motivated priors, we...
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Dr Irham Taufik Andika (Ludwig-Maximilians-University Munich)28/10/2025, 16:30
The formation channels of the first supermassive black holes (SMBHs) at z > 6 remain elusive, as current observations are dominated by the most luminous quasars, representing only the tip of the population. To uncover fainter quasars, gravitational lensing provides a uniquely effective natural telescope, extending the accessible luminosity range and offering essential probes of black hole...
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Seok-Jun Chang (Max Planck Institut für Astrophysik)28/10/2025, 16:45
Little Red Dots (LRDs), compact galaxies at z > 5 discovered by JWST, show hydrogen Balmer lines with broad wings (>1000 km/s), absorption features, and asymmetric profiles, indicating extremely dense hydrogen gas. When the broad components of Balmer lines are analyzed using standard AGN methods, they imply supermassive black holes with unusually high black hole–to–stellar mass ratios....
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Hannah Übler (MPE)28/10/2025, 17:00
JWST has discovered an unexpected ubiquity of massive, active black holes at high redshift. Understanding their formation and the properties of their host galaxies is an ongoing endeavour. I will present first results from BlackTHUNDER, a JWST/NIRSpec-IFS Large Program to study broad-line AGN and their immediate surroundings during the first few billion years of cosmic history. Specifically, I...
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