Article
Astronomy & Astrophysics
Wenrui Xu, Matthew W. Kunz
Summary: In this study, the formation and early evolution of a protostellar disc from a magnetized prestellar core are investigated using non-ideal MHD simulations. The results indicate that gravitational instability plays a key role in the spreading of the disc structure and the redistribution of angular momentum within the protostar-disc system. These findings help to explain some important processes in the evolution of protostellar discs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Wenrui Xu, Matthew W. Kunz
Summary: Using a 3D radiative non-ideal magnetohydrodynamic simulation, the study investigates the formation and evolution of a young protostellar disc from a magnetized pre-stellar core, revealing a massive, weakly magnetized disc with prominent spiral arms. By constructing a predictive and quantitative physical picture based on simulation results and physical arguments, the study provides insights into the angular-momentum redistribution, thermal profile, and magnetic-field strength and braking rate in the disc, leading to the development of a simple 1D semi-analytic model of disc evolution. This hierarchical modeling approach can reliably predict disc evolution in the Class 0/I phase and circumvent the computational difficulty of direct, numerically converged simulations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Sercan Cikintoglu, K. Yavuz Eksi, Luciano Rezzolla
Summary: In this study, we investigate the general-relativistic dynamics of matter accretion and ejection on a magnetized and non-rotating neutron star. By using numerical simulations within the framework of fully general relativistic magnetohydrodynamics, we determine the relationship between the magnetospheric radius, magnetic moment, and accretion rate. We find that the material torque exhibits linear correlation with the mass-accretion rate and the strong magnetic field simulations show fluctuation similar to the observed spin fluctuations in X-ray pulsars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Multidisciplinary Sciences
Guido Roberts-Borsani, Tommaso Treu, Wenlei Chen, Takahiro Morishita, Eros Vanzella, Adi Zitrin, Pietro Bergamini, Marco Castellano, Adriano Fontana, Karl Glazebrook, Claudio Grillo, Patrick L. Kelly, Emiliano Merlin, Themiya Nanayakkara, Diego Paris, Piero Rosati, Lilan Yang, Ana Acebron, Andrea Bonchi, Kit Boyett, Marusa Bradac, Gabriel Brammer, Tom Broadhurst, Antonello Calabro, Jose M. Diego, Alan Dressler, Lukas J. Furtak, Alexei V. Filippenko, Alaina Henry, Anton M. Koekemoer, Nicha Leethochawalit, Matthew A. Malkan, Charlotte Mason, Amata Mercurio, Benjamin Metha, Laura Pentericci, Justin Pierel, Steven Rieck, Namrata Roy, Paola Santini, Victoria Strait, Robert Strausbaugh, Michele Trenti, Benedetta Vulcani, Lifan Wang, Xin Wang, Rogier A. Windhorst
Summary: In the early universe, sources of ultraviolet photons played a crucial role in ionizing intergalactic hydrogen, making the universe transparent to UV radiation. Fainter galaxies that are surrounded by neutral gas were believed to dominate the photon budget. By using the James Webb Space Telescope and gravitational lensing, the ultra-faint galaxy JD1 was spectroscopically confirmed at a redshift of z = 9.79, showing a compact and complex morphology with low stellar mass and subsolar metallicity.
Article
Astronomy & Astrophysics
Elliot M. Lynch, Gordon Ogilvie
Summary: This paper investigates the dynamical vertical structure of highly eccentric discs in tidal disruption events, finding that magnetic fields play a crucial role in the evolution of these discs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Elliot M. Lynch, Gordon Ogilvie
Summary: Current research suggests that whether tidal disruption events circularize or accrete directly as a highly eccentric disc depends sensitively on the disc thermodynamics; a coherent magnetic field has a stabilizing effect on the dynamics and can significantly alter the behavior of highly eccentric radiation-dominated discs; magnetic fields play an important role in the evolution of TDE discs.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Ryoki Matsukoba, Eduard Vorobyov, Kazuyuki Sugimura, Sunmyon Chon, Takashi Hosokawa, Kazuyuki Omukai
Summary: This study examines the role of ionizing radiation feedback based on the accretion history in two possible SMS-forming clouds extracted from cosmological simulations. The research demonstrates that despite intermittent accretion, the quiescent periods are always shorter than the Kelvin-Helmholtz time-scales, indicating that SMSs can form without being affected by ionizing radiation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
M. M. Romanova, A. Koldoba, G. Ustyugova, A. A. Blinova, D. Lai, R. V. E. Lovelace
Summary: The study shows that magnetic interaction between the star and the disc causes the disc to warp, tilt, and precess, with larger tilted discs forming as the magnetic moment of the star increases. The normal vector to the tilted discs are at different angles, and the tilted discs slowly precess over time.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Pedro H. B. Rossetto, Joerg Frauendiener, Ryan Brunet, Andrew Melatos
Summary: This paper presents the general relativistic formulation of the problem of magnetically confined mountains on neutron stars. It is found that relativistic corrections reduce the hydromagnetic deformation associated with the mountain and decrease the screening of the star's magnetic dipole moment. Numerical calculations are provided to support the findings.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Dominik R. G. Schleicher, Bastian Reinoso, Ralf S. Klessen
Summary: Numerical simulations have shown the occurrence of 'supercompetitive accretion', which refers to a situation where only the central few objects grow supermassive while a larger number of stars compete for the reservoir, with significant accretion flows. This study explores this phenomenon using analytical estimates for growth via collisions and accretion, considering both self-gravity and Bondi-Hoyle accretion. The results are validated through comparison with numerical simulations, confirming that supercompetitive accretion is a valid mechanism for the formation of very massive objects in the early Universe.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
B. Novosyadlyj, Yu. Kulinich, B. Melekh, V. Shulga
Summary: This study examines the formation and destruction of the first molecules during the Dark Ages and Cosmic Dawn, evaluating the luminosity of protogalaxy clumps (halos) in molecular lines. The impact of photodissociation processes on molecules like H-2 and HD is significant before full reionization, while the number density of helium hydride ions HeH+ shows complicated dependences on halo kinetic temperature and models of the first light. The brightness temperature evolution of individual halos in rotational lines of certain molecules does not exceed microkelvin, but detection could provide important insights into physical processes during the formation of the first stars and galaxies.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Nicolas Scepi, Mitchell C. Begelman, Jason Dexter
Summary: The rapid fluctuations in dwarf novae can be explained by ionization instability in the inner magnetized discs, leading to small, rapid heating and cooling fronts propagating back and forth in the disc, creating quasi-periodic oscillations with a period of around 1000 seconds.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
James E. Owen, Noumahn Altaf
Summary: The study demonstrates that externally photoevaporating discs produce a smooth transition from rotationally supported Keplerian discs to photoevaporative driven outflows. The penetration of ultraviolet photons predominantly determines the radius of the transition, with the strength of viscosity playing a minor role. By studying the entrainment of dust particles, rapid changes in dust properties in the transition region are observed.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Loren E. Held, George Mamatsashvili
Summary: This study investigates the effect of the large magnetic Prandtl number on the magnetorotational instability (MRI) and turbulent transport. The results show that at large Pm, the turbulent energy and stress plateau, no longer depending on Pm. The analysis of the turbulent dynamics in Fourier space helps to understand these findings.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Ghassen Rezgui, Hamed Marzougui, Taieb Lili, Reinhold Preiner, Chiara Ceccobello
Summary: Astrophysical jets are spectacular phenomena in the Universe, and understanding their launching, acceleration, and collimation processes is crucial. Our study reveals the significant role of thermal conduction in jet dynamics and its impact on jet speed, collimation, and ejection efficiency.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Christine M. Simpson, Ruediger Pakmor, Christoph Pfrommer, Simon C. O. Glover, Rowan Smith
Summary: In this study, the impact of diffusive cosmic rays (CRs) on the evolution of the interstellar medium (ISM) is explored under varying assumptions of supernova explosion environment. It is found that CR pressure and transport are important factors that strongly influence the ISM's solution state. Observable signatures such as gamma-ray emission and H i gas are also investigated, with the gamma-ray luminosity being consistent with observations but the thickness of the H i gas layer potentially being too compact.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
David J. Whitworth, Rowan J. Smith, Ralf S. Klessen, Mordecai-Mark Mac Low, Simon C. O. Glover, Robin Tress, Ruediger Pakmor, Juan D. Soler
Summary: Many studies have shown that magnetic fields can suppress star formation in molecular clouds and Milky Way like galaxies. However, most of these studies have focused on fully developed fields at saturation level, and there is little understanding of how weak initial primordial fields affect star formation in low metallicity environments. In this paper, the impact of a weak initial field on low metallicity dwarf galaxies is investigated. High-resolution AREPO simulations are performed, and the results show that the magnetic field has little impact on the global star formation rate (SFR), contrary to some previous studies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Glen H. Hunter, Paul C. Clark, Simon C. O. Glover, Ralf S. Klessen
Summary: In this study, the impact of collision speed, magnetic field inclination, and resolution on the star formation rate (SFR) in cloud-cloud collisions is investigated. A factor of 2-3 increase in the SFR is found compared to no collision simulations, with high collisional velocities, parallel magnetic field and collision axis orientation, and lower resolution leading to earlier star formation. The alignment of velocity and magnetic field is consistent in low-density environments but becomes more perpendicular as density increases, indicating the compression of the magnetic field by collapsing gas.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Lewis R. Prole, Anna T. P. Schauer, Paul C. Clark, Simon C. O. Glover, Felix D. Priestley, Ralf S. Klessen
Summary: Molecular hydrogen allows the primordial gas to cool and collapse into Population III stars. The Lyman-Werner radiation from these stars can destroy H-2 in other halos and delay further star formation. The study of selected halos shows that the IMF for masses above the brown dwarf limit is not significantly affected by the background Lyman-Werner field strength, indicating that the IMF for Pop III.2 stars is similar to the initial population of Pop III.1 stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Salome Mtchedlidze, Paola Dominguez-Fernandez, Xiaolong Du, Wolfram Schmidt, Axel Brandenburg, Jens Niemeyer, Tina Kahniashvili
Summary: In this study, the amplification mechanisms of large- and small-scale correlated magnetic fields in massive galaxy clusters were investigated using high-resolution magnetohydrodynamic cosmological zoom-in simulations. The results indicate that the amplification is more efficient for large-scale fields generated during inflation, while moderate growth is observed for seed fields generated during phase transitions. The differences between the models are imprinted on the spectral characteristics and final correlation lengths of the magnetic fields.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Karin M. Sandstrom, Eric W. Koch, Adam K. Leroy, Erik Rosolowsky, Eric Emsellem, Rowan J. Smith, Oleg V. Egorov, Thomas G. Williams, Kirsten L. Larson, Janice C. Lee, Eva Schinnerer, David A. Thilker, Ashley T. Barnes, Francesco Belfiore, F. Bigiel, Guillermo A. Blanc, Alberto D. Bolatto, Mederic Boquien, Yixian Cao, Jeremy Chastenet, Melanie Chevance, I-Da Chiang, Daniel A. Dale, Christopher M. Faesi, Simon C. O. Glover, Kathryn Grasha, Brent Groves, Hamid Hassani, Jonathan D. Henshaw, Annie Hughes, Jaeyeon Kim, Ralf S. Klessen, Kathryn Kreckel, J. M. Diederik Kruijssen, Laura A. Lopez, Daizhong Liu, Sharon E. Meidt, Eric J. Murphy, Hsi-An Pan, Miguel Querejeta, Toshiki Saito, Amy Sardone, Mattia C. Sormani, Jessica Sutter, Antonio Usero, Elizabeth J. Watkins
Summary: JWST observation of PAH emission in nearby galaxies provides deep and high-resolution views of the cold interstellar medium. PAH emission can be used as a tracer of diffuse gas surface density, offering high-resolution and high-sensitivity measurements.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
Filippo Santoliquido, Michela Mapelli, Giuliano Iorio, Guglielmo Costa, Simon C. O. Glover, Tilman Hartwig, Ralf S. Klessen, Lorenzo Merli
Summary: Population III (Pop. III) binary stars are likely responsible for the first stellar-born binary black hole (BBH) mergers in the Universe. We examine the uncertainties in the merger rate density evolution and mass spectrum of Pop. III BBHs by considering different formation histories and initial orbital properties. The primary sources of uncertainty are the orbital properties and star formation history, which significantly affect the BBH merger rate and its characteristics. Overall, the typical masses of Pop. III BBHs are larger than those of BBHs from metal-rich stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
E. Maconi, J. D. Soler, S. Reissl, P. Girichidis, R. S. Klessen, P. Hennebelle, S. Molinari, L. Testi, R. J. Smith, M. C. Sormani, J. W. Teh, A. Traficante
Summary: This study presents synthetic observations of polarized dust emission within a cavity in the interstellar medium, emphasizing the importance of studying the Local Bubble in further detail. The results suggest that the cavity acts as a translucent polarization filter due to its local density enhancement and coherent magnetic field.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
R. Dominguez, Eric W. Pellegrini, Ralf S. Klessen, Daniel Rahner
Summary: In order to replicate the evolution of embedded star clusters in 30 Doradus, particularly the compact star cluster R136 and its surroundings, we utilized the NBODY6++GPU stellar dynamics code to calculate the dynamics of stars embedded in evolving molecular clouds. By exploring clouds with various initial masses and star formation efficiencies, we were able to find the best set of parameters that can reproduce the observations. Our findings indicate the presence of multiple generations of stars in 30 Doradus, supported by measurements of mass segregation and density profile in the central region of the cluster.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Bastian Reinoso, Ralf S. Klessen, Dominik Schleicher, Simon C. O. Glover, P. Solar
Summary: The formation of supermassive stars is crucial for the development of supermassive black holes observed in the early Universe. This study investigates the formation of supermassive stars in the presence of fragmentation and the formation of star clusters. The results show that supermassive stars with masses of 10^3 and 10^4 Msun are formed through collisions and accretion, along with the presence of smaller stars in the surrounding cluster.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Nina S. Sartorio, A. Fialkov, T. Hartwig, G. M. Mirouh, R. G. Izzard, M. Magg, R. S. Klessen, S. C. O. Glover, L. Chen, Y. Tarumi, D. D. Hendriks
Summary: The properties of X-ray binaries (XRBs) arising from zero metallicity stars and their dependence on the initial mass function (IMF) of primordial stars are explored in this study. The results show that the IMF has a strong effect on the number and X-ray production efficiency of XRBs. Scaling relations between XRBs and their X-ray emission with the local star formation rate are also presented. The findings provide insights for improving X-ray feedback prescriptions in numerical simulations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Rowan J. Smith, Robin Tress, Juan D. Soler, Ralf S. Klessen, Simon C. O. Glover, Patrick Hennebelle, Sergio Molinari, Mordecai-Mark Mac Low, David Whitworth
Summary: In this study, high resolution simulations of spiral galaxies were used to investigate the distribution and correlation of the cold neutral medium (CNM) with star formation. The CNM distribution showed no strong radial dependence, but increased in spiral arms and overlapped with H-2. The CNM had a smaller vertical scale height in the outer galaxy and did not extend to extremely large radii observed in H i absorption studies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
J. Schober, M. T. Sargent, R. S. Klessen, D. R. G. Schleicher
Summary: In this study, a phenomenological model for galactic radio emission was constructed to investigate the relationship between the infrared-radio correlation (IRRC) of galaxies and their stellar mass (M-star) and redshift (z). The model results show that the IRRC is nearly independent of redshift for galaxies with intermediate to high stellar masses, but increases with redshift for low-mass galaxies. These findings have important implications for future deep radio observations.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Stefan Reissl, Ralf S. S. Klessen, Eric W. W. Pellegrini, Daniel Rahner, Rudiger Pakmor, Robert Grand, Facundo Gomez, Federico Marinacci, Volker Springel
Summary: Magnetic fields play a critical role in the formation and evolution of the Milky Way, influencing the interstellar medium and star formation process. Observations of Faraday rotation measures across the Galaxy provide insights into the magnetic field's topology and strength. By combining cosmological magnetohydrodynamic simulations with a realistic model for the local interstellar medium, researchers accurately predict the observed Faraday sky, reproducing observations at both global and local scales. These findings contribute to a better understanding of the origin of magnetic fields in our Galaxy.