Article
Astronomy & Astrophysics
Ronan Hix, Chong-Chong He, Massimo Ricotti
Summary: In this study, we performed numerical simulations of turbulent molecular clouds with varying initial magnetic field strength. We found that increasing the strength of the magnetic field leads to a transition from unimodal to bimodal star formation. The strongly magnetized clouds exhibit a two-phase star formation process, with the second phase producing only low-mass stars. This bimodality may have implications for understanding the origin of multiple stellar populations in massive globular clusters.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Donghee G. Nam, Christoph Federrath, Mark R. Krumholz
Summary: It is found that reducing the turbulence index from 2 to 1 leads to a flatter high-mass region of the IMF, resulting in the formation of more massive stars. Comparing these simulations with the predictions of three IMF theories, it is concluded that the theory by Padoan and Nordlund matches the simulations most accurately, while the other theories either fail to reproduce the main results or require modifications.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
P. Padoan, V-M Pelkonen, M. Juvela, T. Haugbolle, A. Nordlund
Summary: Characterizing pre-stellar cores in star-forming regions is crucial for testing theoretical models of star formation. However, extracting real cores from dust-continuum observations is challenging due to projection effects. This study examines core extraction in both idealized column-density maps and synthetic ALMA observations. It finds that derived core masses are unreliable, with a weak correlation between synthetic ALMA and three-dimensional cores. Proper guidance from realistic simulations is essential for using ALMA observations at kpc distances to test star formation models.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
David Guszejnov, Michael Y. Grudic, Philip F. Hopkins, Stella S. R. Offner, Claude-Andre Faucher-Giguere
Summary: The study finds that protostellar jets play a crucial role in setting the mass scale of stars, with resulting stellar masses being significantly higher in the absence of jets. Jets disrupt the accretion flow around protostars, allowing gas to fragment and form additional stars, leading to a decrease in mean stellar mass.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Piyush Sharda, Anish M. Amarsi, Kathryn Grasha, Mark R. Krumholz, David Yong, Gen Chiaki, Arpita Roy, Thomas Nordlander
Summary: According to star formation models, the metal-poor initial mass function (IMF) may differ significantly in metal-poor gas clouds, leading to variations in the characteristic mass of IMF with metallicity. Some observational data suggest that the ratios of C and O elements in metal-poor systems do not follow solar scaling, which could have a significant impact on IMF and the star formation process.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Yingjie Cheng, Robert A. Gutermuth, Stella Offner, Mark Heyer, Hans Zinnecker, S. Thomas Megeath, Riwaj Pokhrel
Summary: We present a new SOFIA/FORCAST mid-infrared survey of luminous protostars and crowded star-forming environments in Cygnus X. By combining data from Spitzer, UKIDSS, and SOFIA/FORCAST, we derive bolometric luminosities for over 1000 sources in the region and identify 63 new luminous protostar candidates. Our study reveals an excess of high luminosity sources in regions of high stellar density or gas column density.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Lewis R. Prole, Paul C. Clark, Ralf S. Klessen, Simon C. O. Glover
Summary: This study presents simulations on the formation of primordial stars, revealing the relationship between sink particle creation density, number of sinks, and their mass. It also shows the impact of resolution on the initial mass function. The findings suggest that previous studies may have overestimated the masses of primordial stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
David Guszejnov, Michael Y. Grudic, Stella S. R. Offner, Claude-Andre Faucher-Giguere, Philip F. Hopkins, Anna L. Rosen
Summary: This study presents simulations that investigate the origin of the stellar initial mass function (IMF) in star formation processes. It finds that stellar radiation and protostellar jet physics play a major role in determining the IMF, while the impact of stellar winds and supernovae is minor. Additionally, the study explores the effects of initial conditions on the IMF and reveals that turbulence and magnetization primarily influence the high-mass slope of the IMF.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Lewis R. Prole, Paul C. Clark, Ralf S. Klessen, Simon C. O. Glover, Ruediger Pakmor
Summary: The study suggests that the inclusion of magnetic fields in numerical simulations of Pop III star formation is largely unimportant, as the fields cannot suppress gas fragmentation and increased resolution.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Y. Pouteau, F. Motte, T. Nony, R. Galvan-Madrid, A. Men'shchikov, S. Bontemps, J. -F. Robitaille, F. Louvet, A. Ginsburg, F. Herpin, A. Lopez-Sepulcre, P. Dell'Ova, A. Gusdorf, P. Sanhueza, A. M. Stutz, N. Brouillet, B. Thomasson, M. Armante, T. Baug, M. Bonfand, G. Busquet, T. Csengeri, N. Cunningham, M. Fernandez-Lopez, H. -L. Liu, F. Olguin, A. P. M. Towner, J. Bally, J. Braine, L. Bronfman, I. Joncour, M. Gonzalez, P. Hennebelle, X. Lu, K. M. Menten, E. Moraux, K. Tatematsu, D. Walker, A. P. Whitworth
Summary: This study observed the W43-MM2&MM3 mini-starburst ridge and found that the high-mass end of its core mass function (CMF) is different from the canonical initial mass function (IMF), showing a top-heavy feature. The results challenge the universality of the IMF and suggest the need for more robust functions to predict the IMF.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Y. Pouteau, F. Motte, T. Nony, M. Gonzalez, I. Joncour, J. -F. Robitaille, G. Busquet, R. Galvan-Madrid, A. Gusdorf, P. Hennebelle, A. Ginsburg, T. Csengeri, P. Sanhueza, P. Dell'Ova, A. M. Stutz, A. P. M. Towner, N. Cunningham, F. Louvet, A. Men'shchikov, M. Fernandez-Lopez, N. Schneider, M. Armante, J. Bally, T. Baug, M. Bonfand, S. Bontemps, L. Bronfman, N. Brouillet, D. Diaz-Gonzalez, F. Herpin, B. Lefloch, H-L Liu, X. Lu, F. Nakamura, Q. Nguyen Luong, F. Olguin, K. Tatematsu, M. Valeille-Manet
Summary: This study investigates the impact of environment on the shape of the core mass function (CMF) and explores variations in the core distributions with cloud characteristics. The research focuses on the W43-MM2&MM3 mini-starburst and finds that its CMF deviates from the Salpeter slope. The findings suggest a connection between the cloud structure and the high-mass end of the CMF.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Joshua J. Ziegler, Thomas D. P. Edwards, Anna M. Suliga, Irene Tamborra, Shunsaku Horiuchi, Shin'ichiro Ando, Katherine Freese
Summary: In this study, we explore the common assumption in astrophysics that the stellar initial mass function (IMF) is universal across all galaxies. By comparing a canonical broken-power-law IMF and a non-universal IMF, we find that the non-universal IMF has a significant impact on the star formation rate density and the supernova core-collapse rate, but only slight effects on other observables. Currently available data do not show a clear preference for a universal or non-universal IMF, but improved measurements at higher redshifts may provide better discernment.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Jamie D. Smith, James E. Dale, Sarah E. Jaffa, Martin G. H. Krause
Summary: This study investigates the impact of different turbulence driving methods on star formation in molecular clouds. The results show that externally driven turbulence produces star clusters that are more consistent with observations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Justin Kin Jun Hew, Christoph Federrath
Summary: This study presents novel 3D magnetohydrodynamic simulations of a laser-driven shock propagating into a stratified multiphase medium, investigating the post-shock turbulent magnetic field amplification via the turbulent dynamo mechanism. The results indicate that the growth rate of the magnetic field is consistent with the theoretical predictions for compressive turbulence driving in subsonic, compressible turbulence.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Thales A. Gutcke, Ruediger Pakmor, Thorsten Naab, Volker Springel
Summary: The LYRA project introduces a high-resolution galaxy formation model that can be used in cosmological simulations to study stellar formation and supernova feedback mechanisms. It demonstrates the significant role of clustered supernovae in enhancing feedback effectiveness in low-density material. The model's ability to directly respond to stellar evolution and spatially distributed energy deposition has implications for galactic mass and metal retention.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
C. Gieser, H. Beuther, D. Semenov, A. Ahmadi, S. Suri, T. Moeller, M. T. Beltran, P. Klaassen, Q. Zhang, J. S. Urquhart, Th. Henning, S. Feng, R. Galvan-Madrid, V. de Souza Magalhaes, L. Moscadelli, S. Longmore, S. Leurini, R. Kuiper, T. Peters, K. M. Menten, T. Csengeri, G. Fuller, F. Wyrowski, S. Lumsden, A. Sanchez-Monge, L. Maud, H. Linz, A. Palau, P. Schilke, J. Pety, R. Pudritz, J. M. Winters, V. Pietu
Summary: This study focuses on characterizing the physical and chemical properties of massive stars in the process of formation with high spatial resolution. A variety in molecular richness is observed in the high-mass star-forming regions, which can be explained by differences in age. The derived density and temperature power-law distributions are well-constrained, providing insights into the evolution of these regions.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
L. Moscadelli, H. Beuther, A. Ahmadi, C. Gieser, F. Massi, R. Cesaroni, A. Sanchez-Monge, F. Bacciotti, M. T. Beltran, T. Csengeri, R. Galvan-Madrid, Th. Henning, P. D. Klaassen, R. Kuiper, S. Leurini, S. N. Longmore, L. T. Maud, T. Moeller, A. Palau, T. Peters, R. E. Pudritz, A. Sanna, D. Semenov, J. S. Urquhart, J. M. Winters, H. Zinnecker
Summary: By combining data from the NOrthern Extended Millimeter Array large project CORE and the Protostellar Outflows at the EarliesT Stages (POETS) survey, researchers were able to connect large-scale events such as clump fragmentation and mass flows with the physical processes identified at small scales, specifically, accretion and ejection in disk-jet systems. High-angular resolution, centimeter and millimeter interferometric observations in thermal tracers, combined with Very Long Baseline Interferometry of molecular masers, are valuable in studying high-mass star formation.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
H. Beuther, C. Gieser, S. Suri, H. Linz, P. Klaassen, D. Semenov, J. M. Winters, Th. Henning, J. D. Soler, J. S. Urquhart, J. Syed, S. Feng, T. Moeller, M. T. Beltran, A. Sanchez-Monge, S. N. Longmore, T. Peters, J. Ballesteros-Paredes, P. Schilke, L. Moscadelli, A. Palau, R. Cesaroni, S. Lumsden, R. Pudritz, F. Wyrowski, R. Kuiper, A. Ahmadi
Summary: The study focused on the dynamical and fragmentation properties of two young high-mass star-forming regions, revealing 29 cores mainly located along filament-like structures. The findings suggest a mass-size relation based on different temperature assumptions, with implications of thermal Jeans fragmentation and dynamical cloud collapse within the regions.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
C. Gieser, H. Beuther, D. Semenov, S. Suri, J. D. Soler, H. Linz, J. Syed, Th. Henning, S. Feng, T. Moeller, A. Palau, J. M. Winters, M. T. Beltran, R. Kuiper, L. Moscadelli, P. Klaassen, J. S. Urquhart, T. Peters, S. N. Longmore, A. Sanchez-Monge, R. Galvan-Madrid, R. E. Pudritz, K. G. Johnston
Summary: The study aims to characterize the physical and chemical properties of fragmented cores during the earliest evolutionary stages in very young star-forming regions. Results show that both regions contain a cluster of young stellar objects, and strong molecular emission is observed in some locations, which may be associated with bipolar outflows or colliding flows.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Jessica Speedie, Ralph E. Pudritz, A. J. Cridland, Farzana Meru, Richard A. Booth
Summary: ALMA observations of protoplanetary discs have revealed dust ring/gap structures that can be explained by the presence of planets. Simulations show that in high viscosity discs, inward migration prevails and forms compact planetary systems, while in low viscosity discs, low mass planets can migrate outward before eventually migrating inward.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Meteorology & Atmospheric Sciences
R. A. Khan, N. K. R. Kevlahan
Summary: Accurate modeling of tsunami waves requires complete data and appropriate mathematical models. However, data is often lacking or inaccurate, making it difficult to capture the dynamics of nonlinear waves. In this study, we demonstrate the feasibility of variational data assimilation for recovering initial conditions and verify its convergence using numerical simulations. We compare different configurations of observation points and assess their impact on convergence. These results are a first step towards more accurate tsunami forecasts.
Article
Biology
Klaus Paschek, Kai Kohler, Ben K. D. Pearce, Kevin Lange, Thomas K. Henning, Oliver Trapp, Ralph E. Pudritz, Dmitry A. Semenov
Summary: The origin of life on early Earth might be closely related to the formation of ribose in carbonaceous chondrites, which is a crucial component of the RNA world. Through laboratory experiments and theoretical calculations, researchers found that the aqueous formose reaction could produce a significant amount of ribose in carbonaceous chondrites. This discovery sheds light on the possible synthesis of life-building blocks on Earth.
Article
Astronomy & Astrophysics
Ben K. D. Pearce, Karan Molaverdikhani, Ralph E. Pudritz, Thomas Henning, Kaitlin E. Cerrillo
Summary: The origin of life on Earth is believed to involve the early appearance of RNA, an information-containing molecule. This study suggests that the basic building blocks of RNA could have been delivered by carbon-rich meteorites or produced in the early Earth's atmosphere. By constructing a model of the early Earth's atmosphere, the researchers found that HCN, a molecule important for RNA synthesis, could have rained out into warm little ponds. They also calculated the resulting abundances of nucleobases and other molecules important for RNA formation. The study suggests that adenine, a nucleobase, could have been delivered to the ponds by meteorites, but its concentration would decrease over time due to various factors.
ASTROPHYSICAL JOURNAL
(2022)
Article
Oceanography
Nicholas K. -R. Kevlahan, Francis J. Poulin
Summary: The study investigates the influence of baroclinic mode on wind-driven western boundary current turbulence, and finds that it introduces an energy spectrum component typical of stratified three-dimensional ocean flows. The first baroclinic mode may be primarily responsible for the submesoscale turbulence energy spectrum of the oceans.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2022)
Article
Astronomy & Astrophysics
Matthew Alessi, Ralph E. Pudritz
Summary: Recent surveys have found that protoplanetary discs have lower levels of turbulence than expected, and magnetized disc winds may play a dominant role in angular momentum transport. This has important implications for the process of planet formation. By computing the physical and chemical evolution of discs and the formation and migration of planets, researchers have found that populations produced from discs with different levels of turbulence and winds strength fit better with observations, compared to populations with constant values. These models suggest a substantial population of super Earths at specific orbital radii, as well as distinct populations of hot Jupiter and warm Jupiter planets.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Meteorology & Atmospheric Sciences
P. H. Lauritzen, N. K. R. Kevlahan, T. Toniazzo, C. Eldred, T. Dubos, A. Gassmann, V. E. Larson, C. Jablonowski, O. Guba, B. Shipway, B. E. Harrop, F. Lemarie, R. Tailleux, A. R. Herrington, W. Large, P. J. Rasch, A. S. Donahue, H. Wan, A. Conley, J. T. Bacmeister
Summary: This paper provides a derivation of the total energy equations for the atmospheric components of Earth System Models (ESMs) and discusses the conceptual challenges and practical difficulties in achieving energy balance. It diagnoses the major errors in energy balance using a realistic climate simulation and proposes future research directions to improve thermodynamic formulations and conservation principles.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2022)
Article
Astronomy & Astrophysics
Klaus Paschek, Dmitry A. Semenov, Ben K. D. Pearce, Kevin Lange, Thomas K. Henning, Ralph E. Pudritz
Summary: Prebiotic molecules have been discovered in carbonaceous chondrites, which are essential for the origin of life. The delivery of these molecules onto early Earth could have triggered the polymerization of the first RNA molecules. This study investigates the formation of RNA and DNA nucleobases inside planetesimals of carbonaceous chondrites and suggests that the synthesis of prebiotic organic matter can be explained by radiogenic heating, aqueous chemistry, and a reduced initial volatile content.
ASTROPHYSICAL JOURNAL
(2023)
Article
Meteorology & Atmospheric Sciences
R. A. Khan, N. K. R. Kevlahan
Summary: This study uses second order adjoint variational analysis to explore the sensitivity of surface wave errors to observations, and its application in bathymetry reconstruction. The results indicate that higher sensitivity of surface wave reconstruction errors to observations is associated with larger errors in bathymetry reconstruction and larger amplitudes of bathymetry profiles, while sensitivity decreases with broader observation coverage.
TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY
(2022)
Article
Geosciences, Multidisciplinary
Nicholas K-R Kevlahan, Florian Lemarie
Summary: This paper introduces wavetrisk-2.1, an ocean model compatible with the wavetrisk atmosphere model. The model utilizes wavelet-based dynamically adaptive core and solves the incompressible ocean equations using multilayer rotating shallow water formulation. It incorporates a semi-implicit free surface formulation and volume penalization to handle barotropic-baroclinic mode splitting and coastlines boundary conditions.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2022)
Article
Meteorology & Atmospheric Sciences
R. A. Khan, N. K. R. Kevlahan
Summary: This study utilizes second order adjoint variational analysis to investigate the sensitivity of surface wave errors to observational perturbations, as well as the correlation between bathymetry reconstruction errors and perturbations in the data assimilation scheme parameters. The research findings demonstrate that the sensitivity of surface wave errors to observations decreases with a wider coverage of the observation network over the bathymetry.
TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY
(2022)