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The population of compact objects both Galactic and extragalactic can now be studied and verified observationally with increasing efficiency, the latter thanks to the detection of compact object mergers through gravitational waves. The formation channels of merging compact object binaries are, however, not yet fully understood, and may even vary over cosmic time. We address this problem with a population synthesis approach, including BOSSA, a new initial sampling code, to deal with the variation of initial conditions and evaluate its consequences.

Outflows are ubiquitous in various astrophysical objects, yet the mechanism responsible for generating outflows remains unclear. One possibility is that outflows are driven by large-scale magnetic fields. When dealing with magnetically driven outflows, the one-dimensional model proposed by Weber and Davis in 1967 is often employed. However, as it was originally a non-relativistic theory, this limits its application in high-energy astrophysical scenarios. This work attempts to modify the non-relativistic Bernoulli equation into its relativistic form through an analogy method, thereby applying it to relativistic outflows and comparing the results with those of classical theory. We find that when the initial temperature of the outflow is sufficiently high or when the angular velocity of rotation of the magnetic field lines is sufficiently fast, the terminal velocity of the outflow can be relativistic. The relativistically modified Bernoulli equation established in this paper could be conveniently applied in the context of extremely high-velocity outflows from different sources.

We review a general relativistic (GR) method to determine the black hole (BH) parameters: Mass-to-distance ratio, position, and recessional velocity of active galactic nuclei (AGNs) of Seyfert type, which have an accretion disk with water masers circulating around the BH. This GR method makes use of astrophysical observations: The redshifted and the blueshifted photons emitted from the aforementioned masers and their orbital position on the sky. In order to perform the estimations we implement a Bayesian statistical method to fit the above mentioned observational data. One of the main results of this work consists in analytically expressing the gravitational redshift, allowing us to quantify its magnitude for the photons emitted by the closest masers to the black holes. We present this quantity for several BHs hosted at the core of AGNs.

The kinematics within the solar vicinity have revealed interesting features relevant to both stellar and Galactic structures. This study examines three stellar associations in the Upper Scorpius and Ophiuchus regions, along with their sub-samples among Gaia DR3. The calculated kinematics and velocity ellipsoid characteristics, including the mean spatial velocity components (U, V, and W; km s⁻¹), yielding values of approximately (−5.84 ± 2.42, −16.14 ± 4.02, −7.31 ± 2.70; km s⁻¹). USC and Oph associations velocity dispersion within the ellipsoid ($��{\sigma }_i�,�\forall �i�=�1�,�2�,�3�$) was found to be (1.36 ± 0.02, 0.80 ± 0.01, 0.96 ± 0.01; km s⁻¹), their mean solar motion ($��S_{\odot }�$) was determined to be approximately 18.62 ± 4.32 km s⁻¹, convergent point coordinates ($��A_o�,�D_o�$) were (95.91 ± 0.09°, −44.42 ± 0.02°), and Oort's constants, yielding A = 17.80 ± 0.24 km s⁻¹ kpc⁻¹ and B = −9.61 ± 0.32 km s⁻¹ kpc⁻¹. Finally, the density distribution function per absolute magnitudes of USC and Oph associations is examined to obtain both luminosity and mass functions; their analysis revealed the absence of any peaks or dips as consistent with other recent studies.

Motivated by the difficulties in the quantization of spacetime, we study a q-deformed covariant algebra that imposes minimum position and momentum measurement uncertainties. We do this by invoking the Fock-Tani formalism, mainly used in atomic and nuclear physics. The results are promising for further calculation of physical predictions.

I conducted photometric observations of the cataclysmic variable LAMOST J035913.61 + 405035.0 and detected eclipses. During these observations, I recorded 14 eclipses over two groups of nights separated by 13 months. I accurately determined the orbital period of the system to be $��P_{\mathrm{orb}}�=�0.228��343��85�\pm �0.000��000��21�$ days. For the eclipses, I derived an ephemeris which is valid for a long time and suitable for studying changes in the orbital period. The out-of-eclipse magnitude of the star varied between 15.32 ± 0.02 and 17.25 ± 0.08 mag. As the brightness decreased, the eclipses became deeper and narrower. The average depth of eclipses was 1.35 ± 0.10 mag, and the average width at half-depth was 16.9 ± 0.7 min. I estimated the range of possible orbital inclinations to be between 72.8° and 76.0°, and the range of average absolute V-band magnitudes of the disc to be between 5.16 ± 0.15 and 5.44 ± 0.15 mag. Although based on the light curve from the ZTF survey, LAMOST J035913.61 + 405035.0 showed only small outbursts with amplitudes below 1.5 mag, it should be classified as a dwarf nova because the average disc brightness and mass transfer rate were below the limit of thermal instability.

This paper presents a proposal for the study of holonomy observables for the Turaev–Viro model, a model of three-dimensional Loop Quantum Gravity with a positive cosmological constant. A review of central aspects of Loop Quantum Gravity and of a categorical formalism for discrete gauge theories is presented with the intent to contextualize the Turaev–Viro model within a more general setting, which clarifies the role of the Hopf algebra $��{\mathrm{sl}}_q��(�2�,�ℂ�)��$ in its construction. The key results on spin observables for the Turaev–Viro model and on holonomy observables for the Ponzano–Regge model are presented as an effort to develop a theory of holonomy observables for the Turaev–Viro model.