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Journal articles on the topic 'Accretion; gravitational'

Author: Grafiati

Published: 3 June 2025

Last updated: 31 July 2025

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1

Cattorini, Federico, Sofia Maggioni, Bruno Giacomazzo, Francesco Haardt, Monica Colpi, and Stefano Covino. "Misaligned Spinning Binary Black Hole Mergers in Hot Magnetized Plasma." Astrophysical Journal Letters 930, no. 1 (2022): L1. http://dx.doi.org/10.3847/2041-8213/ac6755.

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Abstract We present general relativistic magnetohydrodynamical simulations of equal-mass spinning black hole binary mergers embedded in a magnetized gas cloud. We focus on the effect of the spin orientation relative to the orbital angular momentum on the flow dynamics, mass accretion rate, and Poynting luminosity. We find that, across the inspiral, the gas accreting onto the individual black holes concentrates into disklike overdensities whose angular momenta are oriented toward the spin axes and that persist until merger. We identify quasiperiodic modulations occurring in the mass accretion r

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BOGOVALOV, S. V., and S. R. KELNER. "ACCRETION AND PLASMA OUTFLOW FROM DISSIPATIONLESS DISCS." International Journal of Modern Physics D 19, no. 03 (2010): 339–65. http://dx.doi.org/10.1142/s0218271810016373.

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We consider the specific case of disc accretion for negligibly low viscosity and infinitely high electric conductivity. The key component in this model is the outflowing magnetized wind from the accretion disc, since this wind effectively carries away angular momentum of the accreting matter. Assuming magnetic field has variable polarity in the disc (to avoid magnetic flux and energy accumulation at the gravitational center), this leads to radiatively inefficient accretion of the disc matter onto the gravitational center. In such a case, the wind forms an outflow, which carries away all the en

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Lau, Mike Y. M., Ryosuke Hirai, Ilya Mandel, and Christopher A. Tout. "Expansion of Accreting Main-sequence Stars during Rapid Mass Transfer." Astrophysical Journal Letters 966, no. 1 (2024): L7. http://dx.doi.org/10.3847/2041-8213/ad3d50.

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Abstract Accreting main-sequence stars expand significantly when the mass accretion timescale is much shorter than their thermal timescales. This occurs during mass transfer from an evolved giant star onto a main-sequence companion in a binary system and is an important phase in the formation of compact binaries including X-ray binaries, cataclysmic variables, and gravitational-wave sources. In this study, we compute 1D stellar models of main-sequence accretors with different initial masses and accretion rates. The calculations are used to derive semianalytical approximations to the maximum ex

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Rehman, H., and G. Abbas. "Accretion around a hairy black hole in the framework of gravitational decoupling theory." Chinese Physics C 47, no. 12 (2023): 125106. http://dx.doi.org/10.1088/1674-1137/ad010e.

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Abstract We investigate astrophysical accretion onto a static and spherically symmetric hairy black hole within the framework of gravitational decoupling. To achieve this goal, we examine the accretion procedure for several types of perfect fluids, including polytropic fluid and ultra-stiff, ultra-relativistic, radiation, and sub-relativistic isothermal fluids. Moreover, we determine the critical or sonic points for numerous fluid forms that are accreting onto the black hole by utilizing the Hamiltonian dynamical approach. Additionally, the closed form of the solutions are presented for a numb

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Gittins, Fabian, and Nils Andersson. "Population synthesis of accreting neutron stars emitting gravitational waves." Monthly Notices of the Royal Astronomical Society 488, no. 1 (2019): 99–110. http://dx.doi.org/10.1093/mnras/stz1719.

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ABSTRACT The fastest-spinning neutron stars in low-mass X-ray binaries, despite having undergone millions of years of accretion, have been observed to spin well below the Keplerian break-up frequency. We simulate the spin evolution of synthetic populations of accreting neutron stars in order to assess whether gravitational waves can explain this behaviour and provide the distribution of spins that is observed. We model both persistent and transient accretion and consider two gravitational-wave-production mechanisms that could be present in these systems: thermal mountains and unstable rmodes.

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Toscani, Martina, Giuseppe Lodato, and Rebecca Nealon. "Gravitational wave emission from unstable accretion discs in tidal disruption events." Monthly Notices of the Royal Astronomical Society 489, no. 1 (2019): 699–706. http://dx.doi.org/10.1093/mnras/stz2201.

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Abstract Gravitational waves can be emitted by accretion discs if they undergo instabilities that generate a time varying mass quadrupole. In this work we investigate the gravitational signal generated by a thick accretion disc of 1 M⊙ around a static supermassive black hole of 106 M⊙, assumed to be formed after the tidal disruption of a solar type star. This torus has been shown to be unstable to a global non-axisymmetric hydrodynamic instability, the Papaloizou–Pringle instability, in the case where it is not already accreting and has a weak magnetic field. We start by deriving analytical es

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Heigl, S., A. Burkert, and M. Gritschneder. "Accretion-driven turbulence in filaments – I. Non-gravitational accretion." Monthly Notices of the Royal Astronomical Society 474, no. 4 (2017): 4881–93. http://dx.doi.org/10.1093/mnras/stx3145.

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Townsley, Dean M., and Lars Bildsten. "Physical Interpretation of Dwarf Nova Primary Effective Temperatures." International Astronomical Union Colloquium 194 (2004): 192–93. http://dx.doi.org/10.1017/s0252921100152431.

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AbstractWe have undertaken a theoretical study of the impact of the accumulating envelopes on the thermal state of the underlying white dwarf (WD). This has allowed us to find the equilibrium WD core temperatures, the classical nova ignition masses and the thermal luminosities for WDs accreting at rates of 10–11 – 10–8M⊙ yr–1. These accretion rates are most, appropriate to WDs in cataclysmic variables (CVs) of (Porb ≲ 7 hr), many of which accrete sporadically as Dwarf Novae. Over twenty Dwarf Novae have been observed in quiescence, when the accretion rate is low and the WD photosphere is detec

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BECERRA, L. M., J. A. RUEDA, and R. RUFFINI. "SPH simulations of the induced gravitational collapse." Astronomical and Astrophysical Transactions, Volume 33, Numéro 3 (December 15, 2022): 265–72. http://dx.doi.org/10.17184/eac.7529.

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In the induced gravitational collapse (IGC) paradigm, a carbon–oxygen (CO) star collapses and explodes in a supernova (SN) in the presence of a binary companion, a neutron star (NS). The material ejected in the explosion is gravitationally attracted by the NS, triggering a hypercritical accretion process onto it. For compact systems, the accretion rate could be high enough for the NS to reach its critical mass, collapse in a black hole (BH) and emit an energetic (energy release $\gtrsim 10^{52}$ erg) gamma-ray burst (GRB). With the aim to identify the separatrix of systems in which a BH is for

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Horák, Jiří, and Vladimír Karas. "Intensity and polarization light-curves from radiatively-driven clouds." Proceedings of the International Astronomical Union 2, S238 (2006): 381–82. http://dx.doi.org/10.1017/s1743921307005558.

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AbstractWe study linear polarization from scattering of light on a cloud of relativistic electrons. We assume that the cloud is hovering above an accretion disc, or it is in an accelerated motion underthe combined influence of the radiation and gravitational fields near an accreting black hole. Atfirst we derive simple and general analytical formulae for the Stokes parameters. These formulae are then used in calculations of the temporal evolution of the observed signal.We find that higher-order images can significantly enhance the observed flux. Possible targets where the effect should be sear

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Dobyns, York H. "Gravitational accretion of hot dark matter." Astrophysical Journal 329 (June 1988): L5. http://dx.doi.org/10.1086/185165.

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12

TOHLINE, JOEL E., and JOHN W. WOODWARD. "Global Gravitational Instabilities in Accretion Disksa." Annals of the New York Academy of Sciences 675, no. 1 (1992): 31–40. http://dx.doi.org/10.1111/j.1749-6632.1992.tb56787.x.

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Vorobyov, Eduard I., Vardan G. Elbakyan, Kazuyuki Omukai, Takashi Hosokawa, Ryoki Matsukoba, and Manuel Guedel. "Accretion bursts in low-metallicity protostellar disks." Astronomy & Astrophysics 641 (September 2020): A72. http://dx.doi.org/10.1051/0004-6361/202038354.

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Aims. The early evolution of protostellar disks with metallicities in the Z = 1.0 − 0.01 Z⊙ range was studied with a particular emphasis on the strength of gravitational instability and the nature of protostellar accretion in low-metallicity systems. Methods. Numerical hydrodynamics simulations in the thin-disk limit were employed that feature separate gas and dust temperatures, and disk mass-loading from the infalling parent cloud cores. Models with cloud cores of similar initial mass and rotation pattern but distinct metallicity were considered to distinguish the effect of metallicity from t

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Kosakowski, Alekzander, Matti Dorsch, Warren R. Brown, Thomas Kupfer, Fatma Ben Daya, and Mukremin Kilic. "A New LISA-detectable Type Ia Supernova Progenitor in the Southern Sky: SMSS J1138−5139." Astrophysical Journal 987, no. 2 (2025): 205. https://doi.org/10.3847/1538-4357/add1cf.

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Abstract We present the discovery and analysis of a nearby eclipsing ultracompact accreting binary SMSS J1138−5139, the first well-constrained LISA-detectable Type Ia supernova progenitor. Our time-series optical spectroscopy identifies its orbital period through radial velocity monitoring at P orb,RV = 27.682 minutes , twice the photometric period seen in 2 minute cadence data from TESS Sector 37. We model our optical spectroscopy together with new simultaneous multiband time-series photometry from Gemini to place constraints on the binary parameters. Our light-curve modeling finds that SMSS

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Kato, Mariko, Hideyuki Saio, and Izumi Hachisu. "A light curve model of V2491 Cyg: Classical nova outburst on a cool and massive white dwarf." Publications of the Astronomical Society of Japan 73, no. 4 (2021): 1137–51. http://dx.doi.org/10.1093/pasj/psab064.

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Abstract The classical nova V2491 Cyg was once suggested to be a recurrent nova. We have broadly reproduced the light curve of V2491 Cyg by a nova outburst model on a cold 1.36 M⊙ white dwarf (WD), which strongly suggests that V2491 Cyg is a classical nova outbursting on a cold very massive WD rather than a recurrent nova outbursting on a warmer WD like the recurrent nova RS Oph. In the long-term evolution of a cataclysmic binary, an accreting WD has settled to a thermal equilibrium state with the balance of gravitational energy release and neutrino loss. The central temperature of the WD is u

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Laune, JT, Rixin 日新 Li 李, and Dong Lai. "Migration of Accreting Planets and Black Holes in Disks." Astrophysical Journal 975, no. 2 (2024): 296. http://dx.doi.org/10.3847/1538-4357/ad7117.

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Abstract Nascent planets are thought to lose angular momentum (AM) to the gaseous protoplanetary disk via gravitational interactions, leading to inward migration. A similar migration process also applies to stellar-mass black holes (BHs) embedded in the disks of active galactic nuclei. However, AM exchange via accretion onto the planet/BH may strongly influence the migration torque. In this study, we perform 2D global hydrodynamic simulations of an accreting planet/BH embedded in a disk, where AM exchange between the planet/BH and disk via gravity, accretion, pressure, and viscosity are consid

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Nishikori, H., M. Machida, and R. Matsumoto. "Magnetic Activity Following Re-Accretion on to Galaxies." Symposium - International Astronomical Union 217 (2004): 174–76. http://dx.doi.org/10.1017/s0074180900197396.

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We carried out global three-dimensional magnetohydrody-namical (MHD) simulations of galactic gaseous disks re-accreting intergalactic plasma. As the initial condition, we assume that a rotating slender torus is formed at 10kpc from the galactic center. We assume a gravitational potential generated by bulge stars, disk stars and dark matters. Numerical results indicate that magnetorotational instability (MRI) growing in the torus amplifies magnetic fields and generates turbulence. The Maxwell stress enhanced by turbulent magnetic fields drives mass accretion of the disk gas. The amplification o

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Leahy, D. A. "An Accretion Column Model for the Accreting Pulsar Hercules X-1." Symposium - International Astronomical Union 218 (2004): 447–48. http://dx.doi.org/10.1017/s007418090018163x.

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A model is developed here to reproduce the pulse shape of Her X-1. The 35-day cycle of pulse shape changes during the 35-day Her X-1 cycle “High – Low – Short High – Low” is caused by varying obscuration of the emission region by the accretion disk. The observed sequence of pulse shape changes imply a pencil beam from the near pole and a fan beam from the far pole. Using a newly developed code for modeling accretion column emission, including accurate treatment of gravitational light-bending effects, the observed pulse shape of Her X-1 is modeled here.

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Cardoso, Vitor, and Caio F. B. Macedo. "Drifting through the medium: kicks and self-propulsion of binaries within accretion discs and other environments." Monthly Notices of the Royal Astronomical Society 498, no. 2 (2020): 1963–72. http://dx.doi.org/10.1093/mnras/staa2396.

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ABSTRACT Compact binaries are within the reach of gravitational and electromagnetic wave detectors, and are important for our understanding of astrophysical environments and the composition of compact objects. There is a vast body of work devoted to the evolution of such binaries in background media, such as in common-envelope evolution, accretion discs and dark matter mini spikes. Here, we explore further gravitationally bound binaries evolving within an environment. We show that dissipative effects such as gravitational drag and accretion impart a momentum to the centre of mass (CM) of asymm

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Takahashi, M. "8.12. MHD accretion in a black hole magnetosphere." Symposium - International Astronomical Union 184 (1998): 367–68. http://dx.doi.org/10.1017/s0074180900085259.

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To explain the activity of active galactic nuclei or compact X-ray sources, I consider a black hole magnetosphere in the center of these objects. The considering black hole magnetosphere is composed of a massive black hole with surrounding fluids and magnetic fields, and rotates rapidly. Because of the strong gravitation and the rapid rotation, both an accretion and a wind/jet would be generated from plasma sources (e.g., an accretion disk and its corona). The outgoing flow carries the angular momentum from the plasma source effectively, and then the accretion would go on stationary, releasing

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Bisikalo, D. V., and A. G. Zhilkin. "Shock propagation in accretion discs around merging black holes: self-similar solution." Monthly Notices of the Royal Astronomical Society 494, no. 4 (2020): 5520–33. http://dx.doi.org/10.1093/mnras/staa1088.

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ABSTRACT To date, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo gravitational wave detectors have registered several events due to merging binary black holes. It is considered that black holes are surrounded by the circumbinary accretion disc therefore such events must be followed by perturbation of the disc and an increase in the flux of electromagnetic radiation from these objects. Our recent numerical investigations have shown that the heating of matter caused by a shock wave leads to an increase in luminosity. This shock wave arises in the accretion disc due

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Collin, Suzy, and Jean-Paul Zahn. "Accretion Disks and Star Formation." Symposium - International Astronomical Union 194 (1999): 246–55. http://dx.doi.org/10.1017/s0074180900162072.

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It is generally admitted that at distances larger than ˜ 104 gravitational radii accretion disks in AGN form a torus made of high velocity gaseous interacting clouds with a small filling factor. We propose here a completely different model for this region, in which unstable fragments give rise to protostars, all becoming massive stars after a rapid stage of accretion. These stars explode as supernovae, which produce strong outflows perpendicular to the disk and induce an outward transfer of angular momentum, as shown by the numerical simulations of Rozyczka, Bodenheimer and Lin (1995). So the

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Singh, N., B. Haskell, D. Mukherjee, and T. Bulik. "Asymmetric accretion and thermal ‘mountains’ in magnetized neutron star crusts." Monthly Notices of the Royal Astronomical Society 493, no. 3 (2020): 3866–78. http://dx.doi.org/10.1093/mnras/staa442.

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ABSTRACT Accreting neutron stars (NSs) are one of the main targets for continuous gravitational wave searches, as asymmetric accretion may lead to quadrupolar deformations, or ‘mountains’, on the crust of the star, which source gravitational wave (GW) emission at twice the rotation frequency. The GW torque may also impact on the spin evolution of the star, possibly dictating the currently observed spin periods of NSs in low-mass X-ray binaries and leading to the increased spin-down rate observed during accretion in PSR J1023+0038. Previous studies have shown that deformed reaction layers in th

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Degollado, Juan Carlos. "Electromagnetic and gravitational signatures of accretion into black holes." International Journal of Modern Physics D 24, no. 09 (2015): 1542004. http://dx.doi.org/10.1142/s0218271815420043.

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In this paper, the gravitational and electromagnetic signals due to accretion of charged fluids into a Schwarzschild black hole is revisited. We set up the perturbed Einstein equations and Maxwell equations coupled to the fluid equations on a stationary black hole as a system of differential equations that can be integrated as an initial value problem. We numerically investigate cases in which we varied the properties of the fluid. Our scenario may provide an electromagnetic counterpart to gravitational waves in many situations of interest, enabling easier extraction and verification of gravit

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Haemmerlé, L., R. S. Klessen, L. Mayer, and L. Zwick. "Maximum accretion rate of supermassive stars." Astronomy & Astrophysics 652 (August 2021): L7. http://dx.doi.org/10.1051/0004-6361/202141376.

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Context. The formation of the most massive quasars observed at high redshifts requires extreme inflows of gas down to the length scales of the central compact object. Aims. Here we estimate the maximum inflow rate allowed by gravity down to the surface of supermassive stars, the possible progenitors of these supermassive black holes. Methods. We use the continuity equation and the assumption of spherical symmetry and free fall to derive the maximum allowed inflow rates for various density profiles. We apply our approach to the mass–radius relation of rapidly accreting supermassive stars to est

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Klessen, Ralf S., Thomas Peters, Robi Banerjee, Mordecai-Mark Mac Low, Roberto Galván-Madrid, and Eric R. Keto. "Modeling High-Mass Star Formation and Ultracompact H ii Regions." Proceedings of the International Astronomical Union 6, S270 (2010): 107–14. http://dx.doi.org/10.1017/s1743921311000251.

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AbstractMassive stars influence the surrounding universe far out of proportion to their numbers through ionizing radiation, supernova explosions, and heavy element production. Their formation requires the collapse of massive interstellar gas clouds with very high accretion rates. We discuss results from the first three-dimensional simulations of the gravitational collapse of a massive, rotating molecular cloud core that include heating by both non-ionizing and ionizing radiation. Local gravitational instabilities in the accretion flow lead to the build-up of a small cluster of stars. These low

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Kuiper, R., and T. Hosokawa. "First hydrodynamics simulations of radiation forces and photoionization feedback in massive star formation." Astronomy & Astrophysics 616 (August 2018): A101. http://dx.doi.org/10.1051/0004-6361/201832638.

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Aims. We present the first simulations of the formation and feedback of massive stars which account for radiation forces as well as photoionization feedback (along with protostellar outflows). In two different accretion scenarios modeled, we determine the relative strength of these feedback components and derive the size of the reservoir from which the forming stars gained their masses. Methods. We performed direct hydrodynamics simulations of the gravitational collapse of high-density mass reservoirs toward the formation of massive stars including self-gravity, stellar evolution, protostellar

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Mineshige, Shin, Takashi Hosokawa, Mami Machida, and Ryoji Matsumoto. "Gravitational-Wave Radiation from Magnetized Accretion Disks." Publications of the Astronomical Society of Japan 54, no. 5 (2002): 655–60. http://dx.doi.org/10.1093/pasj/54.5.655.

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Vorobyov, E. I., and Shantanu Basu. "Self-regulated gravitational accretion in protostellar discs." Monthly Notices of the Royal Astronomical Society 381, no. 3 (2007): 1009–17. http://dx.doi.org/10.1111/j.1365-2966.2007.12321.x.

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Liu, Tong, and Li Xue. "Gravitational Instability in Neutrino Dominated Accretion Disks." Chinese Physics Letters 28, no. 12 (2011): 129802. http://dx.doi.org/10.1088/0256-307x/28/12/129802.

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Karjalainen, Raine, and Heikki Salo. "Gravitational accretion of particles in Saturn's rings." Icarus 172, no. 2 (2004): 328–48. http://dx.doi.org/10.1016/j.icarus.2004.05.022.

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Bosch-Ramon, V. "3D hydrodynamical simulations of the impact of mechanical feedback on accretion in supersonic stellar-mass black holes." Astronomy & Astrophysics 660 (March 30, 2022): A5. http://dx.doi.org/10.1051/0004-6361/202142821.

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Context. Isolated stellar-mass black holes accrete gas from their surroundings, often at supersonic speeds, and can form outflows that may influence the accreted gas. The latter process, known as mechanical feedback, can significantly affect the accretion rate. Aims. We use hydrodynamical simulations to assess the impact of mechanical feedback on the accretion rate when the black hole moves supersonically through a uniform medium. Methods. We carried out three-dimensional (3D) hydrodynamical simulations of outflows fueled by accretion that interact with a uniform medium, probing scales equival

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Wang, Joan Jing, and Hsiang-Kuang Chang. "Orbital motion and quasi-quantized disk around rotating neutron stars." International Journal of Modern Physics D 23, no. 06 (2014): 1450053. http://dx.doi.org/10.1142/s0218271814500539.

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In accreting neutron star (NS) low-mass X-ray binary (LMXB) systems, NS accretes material from its low-mass companion via a Keplerian disk. In a viscous accretion disk, inflows orbit the NS and spiral in due to dissipative processes, such as the viscous process and collisions of elements. The dynamics of accretion flows in the inner region of an accretion disk is significantly affected by the rotation of NS. The rotation makes NS, thus the spacetime metric, deviate from the originally spherical symmetry, and leads to gravitational quadrupole, on one hand. On the other hand, a rotating NS drags

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Vicente, Rodrigo, Vitor Cardoso, and Miguel Zilhão. "Dynamical friction in slab geometries and accretion discs." Monthly Notices of the Royal Astronomical Society 489, no. 4 (2019): 5424–35. http://dx.doi.org/10.1093/mnras/stz2526.

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ABSTRACT The evolution of planets, stars, and even galaxies is driven, to a large extent, by dynamical friction of gravitational origin. There is now a good understanding of the friction produced by extended media, either collisionless or fluid-like. However, the physics of accretion or protoplanetary discs, for instance, is described by slab-like geometries instead, compact in one spatial direction. Here, we find, for the first time, the gravitational wake due to a massive perturber moving through a slab-like medium, describing e.g. accretion discs with sharp transitions. We show that dynamic

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Sur, Ankan, and Brynmor Haskell. "Gravitational waves from mountains in newly born millisecond magnetars." Monthly Notices of the Royal Astronomical Society 502, no. 4 (2021): 4680–88. http://dx.doi.org/10.1093/mnras/stab307.

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ABSTRACT In this paper, we study the spin-evolution and gravitational-wave luminosity of a newly born millisecond magnetar, formed either after the collapse of a massive star or after the merger of two neutron stars. In both cases, we consider the effect of fallback accretion; and consider the evolution of the system due to the different torques acting on the star, namely the spin-up torque due to accretion and spin-down torques due to magnetic dipole radiation, neutrino emission, and gravitational-wave emission linked to the formation of a ‘mountain’ on the accretion poles. Initially, the spi

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Chen, Yi-Xian, Yan-Fei Jiang, Jeremy Goodman, and Eve C. Ostriker. "3D Radiation Hydrodynamic Simulations of Gravitational Instability in AGN Accretion Disks: Effects of Radiation Pressure." Astrophysical Journal 948, no. 2 (2023): 120. http://dx.doi.org/10.3847/1538-4357/acc023.

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Abstract We perform 3D radiation hydrodynamic local shearing-box simulations to study the outcome of gravitational instability (GI) in optically thick active galactic nuclei (AGNs) accretion disks. GI develops when the Toomre parameter Q T ≲ 1, and may lead to turbulent heating that balances radiative cooling. However, when radiative cooling is too efficient, the disk may undergo runaway gravitational fragmentation. In the fully gas-pressure-dominated case, we confirm the classical result that such a thermal balance holds when the Shakura–Sunyaev viscosity parameter (α) due to the gravitationa

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Keto, Eric. "Observational constraints on angular momentum transfer during gravitational collapse*." Symposium - International Astronomical Union 147 (1991): 438–39. http://dx.doi.org/10.1017/s0074180900239922.

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A simple calculation of the expected spectral signatures of model protostellar accretion flows suggests how the rotation curve of the accretion disk may be deduced from radio frequency molecular line observations. We compare synthetic observations with actual data to derive rotation curves, braking torques, and minimum magnetic field energies required to effect the braking.

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Keto, Eric. "Observational constraints on angular momentum transfer during gravitational collapse*." Symposium - International Astronomical Union 147 (1991): 438–39. http://dx.doi.org/10.1017/s0074180900199309.

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A simple calculation of the expected spectral signatures of model protostellar accretion flows suggests how the rotation curve of the accretion disk may be deduced from radio frequency molecular line observations. We compare synthetic observations with actual data to derive rotation curves, braking torques, and minimum magnetic field energies required to effect the braking.

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Philatov, Vladimir, Lubov Boltnova, and Ksenya Vandysheva. "Generalization of study experience of Ural ore deposits by method of tectonophysical analysis gravitational field." E3S Web of Conferences 177 (2020): 02001. http://dx.doi.org/10.1051/e3sconf/202017702001.

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Gravity is important in the history of Earth 's formation and evolution. Gravitational accretion, gravitational differentiation of Earth matter by density. Gravitational accretion, gravity differentiation of the Earth 's substance in density, its movement and other processes deform the Earth 's crust, contribute to the formation in it of different scale, shape and metallogenical specialization of plicative and disjunctive structures, with which genetically and spatially related deposits of different minerals. The link between gravity and deformation of the geological medium is its density inho

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Sochora, Vjaceslav, Vladimír Karas, Jirí Svoboda, and Michal Dovciak. "BEYOND THE STANDARD MODEL OF THE DISC–LINE SPECTRAL PROFILES FROM BLACK HOLE ACCRETION DISCS." Acta Polytechnica 54, no. 4 (2014): 300–304. http://dx.doi.org/10.14311/ap.2014.54.0301.

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The strong gravitational field of a black hole has distinct effects on the observed profile of a spectral line from an accretion disc near a black hole. The observed profile of the spectral line is broadened and skewed by a fast orbital motion and redshifted by a gravitational field. These effects can help us to constrain the parameters of a system with a black hole, both in active galactic nuclei and in a stellar-mass black hole. Here we explore the fact that an accretion disc emission can be mathematically imagined as a superposition of radiating accretion rings that extend from the inner ed

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M. Becerra, Laura, Carlo Bianco, Chris Fryer, Jorge Rueda, and Remo Ruffini. "On the Induced Gravitational Collapse." EPJ Web of Conferences 168 (2018): 02005. http://dx.doi.org/10.1051/epjconf/201816802005.

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The induced gravitational collapse (IGC) paradigm has been applied to explain the long gamma ray burst (GRB) associated with type Ic supernova, and recently the Xray flashes (XRFs). The progenitor is a binary systems of a carbon-oxygen core (CO) and a neutron star (NS). The CO core collapses and undergoes a supernova explosion which triggers the hypercritical accretion onto the NS companion (up to 10-2 M⊙s-1). For the binary driven hypernova (BdHNe), the binary system is enough bound, the NS reach its critical mass, and collapse to a black hole (BH) with a GRB emission characterized by an isot

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Wachlin, F. C., S. Vauclair, G. Vauclair, and L. G. Althaus. "Fingering convection in accreting hydrogen white dwarfs." EAS Publications Series 82 (2019): 183–87. http://dx.doi.org/10.1051/eas/1982018.

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The accretion of heavy material from debris disk on the surface of hydrogen-rich white dwarfs induces a double diffusivity instability known as the fingering convection. It leads to an efficient extra mixing which brings the accreted material deeper in the star than by considering only mixing in the surface dynamical convection zone, in a time scale much shorter than that of gravitational settling. We performed numerical simulations of a continuous accretion of heavy material having a bulk Earth composition on the two well studied DAZ and ZZ Ceti pulsators GD 133 and G 29-38. We find that the

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Yusupova, Rosaliya M., Ramis Kh Karimov, Ramil N. Izmailov, and Kamal K. Nandi. "Accretion Flow onto Ellis–Bronnikov Wormhole." Universe 7, no. 6 (2021): 177. http://dx.doi.org/10.3390/universe7060177.

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Study of accretion onto wormholes is rather rare compared to that onto black holes. In this paper, we consider accretion flow of cosmological dark energy modeled by barotropic fluid onto the celebrated Ellis–Bronnikov wormhole (EBWH) built by Einstein minimally coupled scalar field ϕ, violating the null energy condition. The accreting fluid is assumed to be phantom, quintessence, dust and stiff matter. We begin by first pointing out a mathematical novelty showing how the EBWH can lead to the Schwarzschild black hole under a complex Wick rotation. Then, we analyze the profiles of fluid radial v

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Roubíček, Tomáš, and Ulisse Stefanelli. "Modelling of planetary accretion and core-mantle structure formation." Journal of Physics A: Mathematical and Theoretical 57, no. 45 (2024): 455701. http://dx.doi.org/10.1088/1751-8121/ad75d9.

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Abstract We advance a thermodynamically consistent model of self-gravitational accretion and differentiation in planets. The system is modeled in actual variables as a compressible thermoviscoelastic fluid in a fixed, sufficiently large domain. The supply of material to the accreting and differentiating system is described as a bulk source of mass, volume, impulse, and energy localized in some border region of the domain. Mass, momentum, and energy conservation, along with constitutive relations, result in an extended compressible Navier–Stokes-Fourier-Poisson system. The centrifugal and Corio

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Fabian, A. C. "Probing General Relativity with Accreting Black Holes." Proceedings of the International Astronomical Union 8, S290 (2012): 3–12. http://dx.doi.org/10.1017/s1743921312019096.

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AbstractMost of the X-ray emission from luminous accreting black holes emerges from within 20 gravitational radii. The effective emission radius is several times smaller if the black hole is rapidly spinning. General Relativistic effects can then be very important. Large spacetime curvature causes strong lightbending and large gravitational redshifts. The hard X-ray, power-law-emitting corona irradiates the accretion disc generating an X-ray reflection component. Atomic features in the reflection spectrum allow gravitational redshifts to be measured. Time delays between observed variations in

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Paraskevas, Evangelos Achilleas, and Leandros Perivolaropoulos. "Gravitational Wave Signatures Induced by Dark Fluid Accretion in Binary Systems." Universe 11, no. 2 (2025): 62. https://doi.org/10.3390/universe11020062.

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We investigate the impact of dark fluid accretion on gravitational waveforms emitted by a compact binary system consisting of a supermassive black hole and a stellar-mass black hole. Using a Lagrangian framework with 1 PN and 2.5 PN corrections, we analyze the effects of the spherically symmetric accretion of a fluid with steady-state flow, including those characterized by an equation of state parameter resembling dark energy, on the binary’s dynamics. We validate our approach by comparing it with previous studies in the common region of validity and extend the analysis to include both local e

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Heigl, S., M. Gritschneder, and A. Burkert. "Accretion-driven turbulence in filaments II: effects of self-gravity." Monthly Notices of the Royal Astronomical Society 495, no. 1 (2020): 758–70. http://dx.doi.org/10.1093/mnras/staa1202.

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ABSTRACT We extend our previous work on simulations with the code ramses on accretion-driven turbulence by including self-gravity and study the effects of core formation and collapse. We show that radial accretion on to filaments drives turbulent motions which are not isotropic but radially dominated. In contrast to filaments without gravity, the velocity dispersion of self-gravitating filaments does not settle in an equilibrium. Despite showing similar amounts of driven turbulence, they continually dissipate their velocity dispersion until the onset of core formation. This difference is conne

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Lambiase, Gaetano, Leonardo Mastrototaro, Reggie C. Pantig, and Ali Övgün. "Probing Schwarzschild-like black holes in metric-affine bumblebee gravity with accretion disk, deflection angle, greybody bounds, and neutrino propagation." Journal of Cosmology and Astroparticle Physics 2023, no. 12 (2023): 026. http://dx.doi.org/10.1088/1475-7516/2023/12/026.

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Abstract In this paper, we investigate Schwarzschild-like black holes within the framework of metric-affine bumblebee gravity. We explore the implications of such a gravitational setup on various astrophysical phenomena, including the presence of an accretion disk, the deflection angle of light rays, the establishment of greybody bounds, and the propagation of neutrinos. The metric-affine bumblebee gravity theory offers a unique perspective on gravitational interactions by introducing a vector field that couples to spacetime curvature. We analyze the behavior of accretion disks around Schwarzs

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Begelman, Mitchell C., and Joseph Silk. "Magnetic fields catalyse massive black hole formation and growth." Monthly Notices of the Royal Astronomical Society: Letters 526, no. 1 (2023): L94—L99. http://dx.doi.org/10.1093/mnrasl/slad124.

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ABSTRACT Large-scale magnetic fields in the nuclear regions of protogalaxies can promote the formation and early growth of supermassive black holes (SMBHs) by direct collapse and magnetically boosted accretion. Turbulence associated with gravitational infall and star formation can drive the rms field strength toward equipartition with the mean gas kinetic energy; this field has a generic tendency to self-organize into large coherent structures. If the poloidal component of the field (relative to the rotational axis of a star-forming disc) becomes organized on scales ≲r and attains an energy of

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Cardoso, Vitor, and Andrea Maselli. "Constraints on the astrophysical environment of binaries with gravitational-wave observations." Astronomy & Astrophysics 644 (December 2020): A147. http://dx.doi.org/10.1051/0004-6361/202037654.

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Aims. The dynamics of coalescing compact binaries can be affected by the environment in which the systems evolve, leaving detectable signatures in the emitted gravitational signal. In this paper, we investigate the ability of gravitational-wave detectors to constrain the nature of the environment in which compact binaries merge. Methods. We parametrized a variety of environmental effects by modifying the phase of the gravitational signal emitted by black hole and neutron star binaries. We infer the bounds on such effects by current and future generations of interferometers, studying their depe

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