601 talks across 60 sessions. Search by title, author or full text.
601 results
We have shown earlier that quantum gravity can be described in terms of wave functions on the bundle of spin connection coefficients over spacetime. The corresponding precanonical quantization procedure introduces, for dimensional reasons, an ultra-violet para…
The fast variability properties of Galactic black holes binaries can be satisfactorily explained by considering multiple physical mechanisms, such as Comptonization, reflection, variation in accretion geometry, focusing due to gravitational bending, and the ef…
The discovery of a cold (~10,000 K) disc-like structure around the super-massive black hole at the centre of the Milk Way, Sagittarius A(Sgr A), has challenged our understanding of the gas dynamics and thermodynamic state of the plasma in its immediate vicinit…
The exceptionally low mass 0.77+0.2 −0.17M⊙ inferred of the central compact object (CCO) XMMU J173203.3–344518 within the SNR HESS J1731–347, of age ≈ 4.5 kyr, challenges the standard corecollapse scenario of NS formation. The observed (likely post-AGB) star o…
I will review the properties and discuss some of the puzzling aspects of the unique binary system composed by the luminous hot subdwarf HD 49798 and a white dwarf of 1.220(8) solar masses and spin period of 13.2 s. This is one of the few massive white dwarfs w…
Recent breakthrough discoveries in multi-messenger astronomy include the first identifications of cosmological neutrino and gravitational wave sources. Among these are well-known gamma/X-ray transient sources such as active galactic nuclei and gamma-ray bursts…
We present the seven Episodes characterizing the three most powerful BdHN I. The maximum energy observed is for GRB 221009A which reaches 1x10 55 erg. New inference for the explanation of the highest energy radiation in the TeV are presented.…
Fast Radio Bursts (FRBs) are millisecond-duration, bright extragalactic bursts, whose production mechanism is still unclear. Recently, a persistent radio source (PRS) of non-thermal origin was discovered to be physically associated to two of the repeating FRB…
SOXS (Son Of X-Shooter) will be a unique spectroscopic facility built by an international consortium for the ESO-NTT 3.6-m telescope in La Silla (Chile). The design foresees a single-object, highefficiency spectrograph with a resolution-slit product of ~ 4,500…
The full proof of the nonlinear stability of Kerr consists of five papers, three written in collaboration with Jeremie Szeftel, one in collaboration with Elena and Jeremie Szeftel and another supporting paper authored by Dawei Shen. In my lecture I will descri…
In the standard cosmological model the dark matter (DM) particles are collisionless and, because of this very nature, they develop halos with the characteristic central cusp known as NFW profile. Real galaxies do not show NFW profiles but, rather, have a DM ma…
Our understanding of the mass distribution of white dwarfs remains elusive, yet it stands as a fundamental aspect of these stellar remnants that mark the final stage of the majority of stars’ lifecycles. Unravelling this distribution requires untangling the in…
This work introduces the experimental progress of the measurement of gravitational constant G at Huazhong University of Science and Technology. We intend to carry out the measurement with the silicon spheres. The surface separation between the spheres is measu…
1E 161348-5055 (1E 1613), the source at the center of the supernova remnant RCW103, has defied any easy classification since its discovery, owing to its long-term variability from months to years and a periodicity of 6.67 hr with a variable light curve profile…
Electron capture (EC) decay relies on attachment and stripping cross-sections, that in turn, depend on the atomic number of the nucleus. We revisit the impact of EC decay in the context of the high-precision cosmic-ray fluxes measured by the AMS-02 experiment.…
Since the seminal work of Jacobson, it has been known that the equations governing gravitational dynamics can be reconstructed from thermodynamics of local causal horizon. Remarkably, it is even possible to recover low energy quantum phenomenological correctio…
) A Pulsar Timing Array (PTA) exploits the remarkable rotational stability of a sample of the rapidly spinning “recycled”pulsars in order to provide the possibility to search for gravitational waves (GWs) in the ultra-long period range, between few months to f…
Large frame Ring Laser Gyroscopes which operate based on the Sagnac effect, are highly sensitive instruments used to measure angular velocity relative to fixed stars. The GINGER (Gyroscopes IN GEneral Relativity) project plans to build an array of three large…
In this talk various definitions and realizations of time are considered and compared. These realizations are clocks based on kinematics and dynamics, on electromagnetic and gravitational interactions, on classical and quantum systems. Conditions are stated fo…
In this talk, we aim to discuss the abelian features of Loop Quantum Cosmology, demonstrating that the Gauss constraint can be recast into three abelian constraints. We begin the discussion by considering nondiagonal Bianchi models, illustrating their deep con…
Gamma-ray bursts observed in high energies allow the investigation of the emission processes of these still puzzling events. Here, we investigate the peculiar GRB 090510, a short GRB with an indication of plateau emission observed by the Fermi-LAT within the c…
I will review the theoretical implications of the IXPE and multifrequency polarimetric measurements of the emission from blazars. In particular, for highly-synchrotron peaked BL Lacs current measurements show a strong frequency-dependency of the degree of pola…
We investigate the photon analogue of Fermi acceleration where a photon scatters within the shearing layers of a relativistic plasma and produces power-law-shaped spectra at high energies. It is an alternative to existing explanations of power law spectra such…
In spherical symmetry, the gravitational potential of galaxies and their halos are univocally derived from the rotational velocity profile. Thousands of galaxies are well-fitted by a universal velocity profile and thus, the gravitational profile is well known.…
Type-I X-ray bursts are powered by the unstable thermonuclear burning of accreted hydrogen and helium material on the surface of a neutron star (NS) in low-mass X-ray binary systems. They typically last for tens to hundreds of seconds, depending on the fuel co…