A5082516154- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Adaptive optics and wavefront sensing
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Heat Transfer Mechanisms
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Mechanics and Biomechanics Studies
- Scientific Research and Discoveries
- Optical Systems and Laser Technology
- Real-time simulation and control systems
- Advanced optical system design
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Cosmology and Gravitation Theories
- Particle accelerators and beam dynamics
- Fluid Dynamics and Turbulent Flows
- Calibration and Measurement Techniques
- High-pressure geophysics and materials
- Advanced Measurement and Metrology Techniques
- Meteorological Phenomena and Simulations
National Institute for Astrophysics
2024
Osservatorio Astronomico di Padova
2018-2022
Istituto Nazionale di Fisica Nucleare, Sezione di Padova
2019-2022
University of Padua
2022
Max Planck Institute for Extraterrestrial Physics
2013-2018
Ludwig-Maximilians-Universität München
2015-2016
Optica
2013-2015
Max Planck Society
2013-2015
Stuttgart Observatory
2013
ABSTRACT We explore hierarchical black hole (BH) mergers in nuclear star clusters (NSCs), globular (GCs) and young (YSCs), accounting for both original dynamically assembled binary BHs (BBHs). find that the median mass of first- nth-generation dynamical is larger GCs YSCs with respect to NSCs because lighter are ejected by supernova kicks from lower clusters. Also, BH masses strongly affected metallicity progenitor stars: primary a merger ∼24–38 M⊙ (∼9–15 M⊙) metal-poor (metal-rich) NSCs....
Young star clusters are the most common birth-place of massive stars and dynamically active environments. Here, we study formation black holes (BHs) binary (BBHs) in young clusters, by means 6000 N-body simulations coupled with population synthesis. We probe three different stellar metallicities (Z=0.02, 0.002 0.0002) two initial density regimes (density at half-mass radius $\rho_{\rm h}\ge{}3.4\times10^4$ $\ge{1.5\times10^2}$ M$_\odot$ pc$^{-3}$ dense loose respectively). Metal-poor tend to...
Next generation ground-based gravitational-wave detectors will observe binary black hole (BBH) mergers up to redshift $z\gtrsim{}10$, probing the evolution of compact (CB) across cosmic time. Here, we present a new data-driven model estimate merger rate density (MRD) CBs, by coupling catalogs CB with observational constraints on star formation and metallicity Universe. We adopt derived from recent $N-$body population-synthesis simulations, describe MRD CBs formed in young clusters...
ABSTRACT Young star clusters are likely the most common birthplace of massive stars across cosmic time and influence formation compact binaries in several ways. Here, we simulate black hole–neutron (BHNSs) young clusters, by means binary population synthesis code MOBSE interfaced with N-body NBODY6++GPU. BHNSs formed (dynamical BHNSs) significantly more than from isolated (isolated BHNSs): ∼40 per cent dynamical BHNS mergers have a total mass >15 M⊙, while only ∼0.01 excess this...
Intermediate mass black holes (IMBHs) in the range $10^2-10^5\,\mathrm{M_{\odot}}$ bridge gap between stellar (BHs) and supermassive BHs. Here, we investigate possibility that IMBHs form young star clusters via runaway collisions BH mergers. We analyze $10^4$ simulations of dense clusters, featuring up-to-date wind models prescriptions for core collapse (pulsational) pair instability. In our simulations, only 9 out 218 binary mergers, with a $\sim{}100-140$ M$_\odot$. This channel is...
Hierarchical mergers are one of the distinctive signatures binary black hole (BBH) formation through dynamical evolution. Here, we present a fast semi-analytic approach to simulate hierarchical in nuclear star clusters (NSCs), globular (GCs) and young (YSCs). more common NSCs than they both GCs YSCs because different escape velocity. The mass distribution BBHs strongly depends on properties first-generation BBHs, such as their progenitor’s metallicity. In our fiducial model, form holes (BHs)...
ABSTRACT The detection of GW190521 by the LIGO–Virgo collaboration has revealed existence black holes (BHs) in pair-instability (PI) mass gap. Here, we investigate formation BHs PI gap via star–star collisions young stellar clusters. To avoid PI, stellar-collision product must have a relatively small core and massive envelope. We generate our initial conditions from outputs hydrodynamical simulation collision between helium burning star (∼58 M⊙) main-sequence (∼42 M⊙). allows us to take into...
We present new, deep near-infrared SINFONI @ VLT integral field spectroscopy of the gas cloud G2 in Galactic Center, from late summer 2013 and spring 2014. is visible recombination line emission. The spatially resolved kinematic data track ongoing tidal disruption. As expected for an observation near pericenter passage, roughly half 2014 found at redshifted, pre-pericenter side orbit, while other post-pericenter, blueshifted side. also orbital solution G1, which was discovered a decade ago...
Stellar winds and supernova (SN) explosions of massive stars (‘stellar feedback’) create bubbles in the interstellar medium (ISM) insert newly produced heavy elements kinetic energy into their surroundings, possibly driving turbulence. Most this is thermalized immediately removed from ISM by radiative cooling. The rest available for dynamics. In work we estimate amount feedback retained as when bubble walls have decelerated to sound speed ambient medium. We show that most star outweighs less...
We have further followed the evolution of orbital and physical properties G2, object currently falling toward massive black hole in Galactic Center on a near-radial orbit. New, very sensitive data were taken 2013 April with NACO SINFONI at ESO VLT. The "head" G2 continues to be stretched ever along orbit position–velocity space. A fraction its emission appears already emerging blueshifted side orbit, past pericenter approach. Ionized gas head is now over more than 15,000 Schwarzschild radii...
ABSTRACT Young star clusters are dynamically active stellar systems and a common birthplace for massive stars. Low-mass (∼300–103 M⊙) more numerous than characterized by two-body relaxation time-scale of few Myr: the most stars sink to cluster core interact with each other even before they give birth compact objects. Here, we explore properties black holes (BHs) binary (BBHs) formed in low-mass young clusters, means suite 105 direct N-body simulations high original fraction (100 per cent...
ABSTRACT Dynamical interactions in dense star clusters are considered one of the most effective formation channels binary black holes (BBHs). Here, we present direct N-body simulations two different cluster families: low-mass (∼500–800 M⊙) and relatively high-mass (≥5000 M⊙). We show that BBHs low- extremely lead to completely distinct populations BBH mergers. Low-mass host mainly born from evolution, while massive (chirp mass up ∼100 driven by dynamical exchanges. Tidal disruption...
The origin of the dense gas cloud G2 discovered in Galactic Center (Gillessen et al. 2012) is still a debated puzzle. might be diffuse or result an outflow from invisible star embedded it. We present hydrodynamical simulations evolution different spherically symmetric winds stellar object G2. find that interaction with ambient medium and extreme gravitational field supermassive black hole must taken into account for such source scenario. thermal pressure hot atmosphere confines wind, while...
ABSTRACT The detection of the binary black hole merger GW190521, with primary mass $85^{+21}_{-14} {\rm M}_{\odot }$, proved existence holes in theoretically predicted pair-instability gap ($\sim 60-120 \, }$) their spectrum. Some recent studies suggest that such massive could be produced by collision an evolved star a carbon–oxygen core and main sequence star. Such post-coalescence end its life avoiding regime direct collapse very envelope. It is still not clear, however, how shapes...
More and more observations indicate that young star clusters could retain imprints of their formation process. In particular, the degree substructuring rotation are possibly direct result collapse parent molecular cloud from which these systems form. Such properties can, in principle, be washed-out, but they also expected to have an impact on relaxation systems. We ran analyzed a set ten hydrodynamical simulations embedded through turbulent massive clouds. systematically studied fractality...
ABSTRACT GW190521 is the most massive binary black hole (BBH) merger observed to date, and its primary component lies in pair-instability (PI) mass gap. Here, we investigate formation of GW190521-like systems via three-body encounters young star clusters. We performed 2 × 105 simulations binary-single interactions between a BBH $\ge {60}\,$M⊙ (BH), including post-Newtonian terms up 2.5 order prescription for relativistic kicks. In our initial conditions, take into account possibility forming...
MORFEO is a post-focal adaptive optics module that forms part of the first light instrument suite for Extreme Large Telescope (ELT). The project now in Final Design Phase. In this paper, we report status project.
The gas cloud G2 is currently being tidally disrupted by the Galactic Centre supermassive black hole, Sgr A*. region around hole populated ∼30 Wolf–Rayet stars, which produce strong outflows. We explore possibility that clumps, such as G2, originate from collision of stellar winds via non-linear thin shell instability. Following an analytical approach, we study thermal evolution slabs formed in symmetric winds, evaluating whether instabilities occur, and estimating possible clump masses....
We present a new method to obtain more realistic initial conditions for N-body simulations of young star clusters. start from the outputs hydrodynamical molecular cloud collapse, in which formation is modelled with sink particles. In our approach, we instantaneously remove gas these simulation mock end gas-embedded phase, induced by stellar feedback. then enforce mass function splitting or joining particles based on their and position. Such contain consistent information spatial distribution...
Abstract We investigate the formation of circumnuclear gas structures from tidal disruption molecular clouds in galactic nuclei by means smoothed-particle hydrodynamics simulations. model as composed a supermassive black hole (SMBH) and nuclear star cluster (NSC), consider different mass ratios between two components. find that relative masses SMBH NSC have deep impact on morphology gas. Extended disks form only inside sphere influence SMBH. In contrast, compact rings naturally outside...
The dusty, ionized gas cloud G2 is currently passing the massive black hole in Galactic Center at a distance of roughly 2400 Schwarzschild radii.We explore possibility starting point within disks young stars.We make use large amount new observations order to put constraints on G2's origin.Interpreting as diffuse gas, we employ three-dimensional hydrodynamical adaptive mesh refinement (AMR) simulations with PLUTO code and do detailed comparison observational data.The presented this work...
The high velocity gradient observed in the compact cloud CO-0.40-0.22, at a projected distance of 60 pc from centre Milky Way, has led its discoverers to identify closeby mm continuum emitter, CO-0.40-0.22*, with an intermediate mass black hole (IMBH) candidate. We describe interaction between CO-0.40-0.22 and IMBH, by means simple analytical model hydrodynamical simulations. Through such calculation, we obtain lower limit CO-0.40-0.22* few $10^4 \times \; M_{\odot}$. This result tends...
Most of massive stars form in binary or higher-order systems clumpy, sub-structured clusters. In the very first phases their life, these are expected to interact with surrounding environment, before being released field when cluster is tidally disrupted by host galaxy. We present a set N-body simulations describe evolution young stellar clusters and content life. To do this, we have developed method that generates realistic initial conditions for star from hydrodynamical simulations....
ABSTRACT Star formation in molecular clouds is clumpy, hierarchically subclustered. Fractal structure also emerges hydrodynamical simulations of star-forming clouds. Simulating the realistic star clusters with a computational challenge, considering that only statistically averaged results large batches are reliable, due to chaotic nature gravitational N-body problem. While sets initial conditions for runs can be produced by formation, this prohibitively expensive terms time. Here, we address...