Schleicher, Dominik R. G.

[["dc.bibliographiccitation.firstpage","1676"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Monthly Notices of the Royal Astronomical Society"],["dc.bibliographiccitation.lastpage","1676"],["dc.bibliographiccitation.volume","504"],["dc.contributor.author","Navarrete, Felipe H"],["dc.contributor.author","Schleicher, Dominik R G"],["dc.contributor.author","Käpylä, Petri J"],["dc.contributor.author","Schober, Jennifer"],["dc.contributor.author","Völschow, Marcel"],["dc.contributor.author","Mennickent, Ronald E"],["dc.date.accessioned","2021-08-12T07:45:14Z"],["dc.date.available","2021-08-12T07:45:14Z"],["dc.date.issued","2021"],["dc.identifier.doi","10.1093/mnras/stab836"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/88402"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-448"],["dc.relation.eissn","1365-2966"],["dc.relation.iserratumof","/handle/2/75283"],["dc.relation.issn","0035-8711"],["dc.title","Erratum: Magnetohydrodynamical origin of eclipsing time variations in post-common-envelope binaries for solar mass secondaries"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.subtype","erratum_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Monthly Notices of the Royal Astronomical Society"],["dc.bibliographiccitation.lastpage","17"],["dc.bibliographiccitation.volume","446"],["dc.contributor.author","Schober, Jennifer"],["dc.contributor.author","Schleicher, Dominik R. G."],["dc.contributor.author","Klessen, Ralf S."],["dc.date.accessioned","2018-11-07T10:03:45Z"],["dc.date.available","2018-11-07T10:03:45Z"],["dc.date.issued","2015"],["dc.description.abstract","The evolution of magnetic fields in galaxies is still an open problem in astrophysics. In nearby galaxies the far-infrared-radio correlation indicates the coupling between magnetic fields and star formation. The correlation arises from the synchrotron emission of cosmic ray electrons travelling through the interstellar magnetic fields. However, with an increase of the interstellar radiation field (ISRF), inverse Compton scattering becomes the dominant energy loss mechanism of cosmic ray electrons with a typical emission frequency in the X-ray regime. The ISRF depends on the one hand on the star formation rate and becomes stronger in starburst galaxies, and on the other hand increases with redshift due to the higher temperature of the cosmic microwave background. With a model for the star formation rate of galaxies, the ISRF, and the cosmic ray spectrum, we can calculate the expected X-ray luminosity resulting from the inverse Compton emission. Except for galaxies with an active galactic nucleus the main additional contribution to the X-ray luminosity comes from X-ray binaries. We estimate this contribution with an analytical model as well as with an observational relation, and compare it to the pure inverse Compton luminosity. Using data from the Chandra Deep Field Survey and far-infrared observations from Atacama Large Millimeter/Submillimeter Array, we then determine upper limits for the cosmic ray energy. Assuming that the magnetic energy in a galaxy is in equipartition with the energy density of the cosmic rays, we obtain upper limits for the magnetic field strength. Our results suggest that the mean magnetic energy of young galaxies is similar to the one in local galaxies. This points towards an early generation of galactic magnetic fields, which is in agreement with current dynamo evolution models."],["dc.identifier.doi","10.1093/mnras/stu1999"],["dc.identifier.isi","347518300001"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/38543"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Oxford Univ Press"],["dc.relation.issn","1365-2966"],["dc.relation.issn","0035-8711"],["dc.title","X-ray emission from star-forming galaxies - signatures of cosmic rays and magnetic fields"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","99"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","The Astrophysical Journal"],["dc.bibliographiccitation.volume","754"],["dc.contributor.author","Schober, Jennifer"],["dc.contributor.author","Schleicher, Dominik R. G."],["dc.contributor.author","Federrath, Christoph"],["dc.contributor.author","Glover, Simon C. O."],["dc.contributor.author","Klessen, Ralf S."],["dc.contributor.author","Banerjee, Robi"],["dc.date.accessioned","2018-11-07T09:07:49Z"],["dc.date.available","2018-11-07T09:07:49Z"],["dc.date.issued","2012"],["dc.description.abstract","We study the amplification of magnetic fields during the formation of primordial halos. The turbulence generated by gravitational infall motions during the formation of the first stars and galaxies can amplify magnetic fields very efficiently and on short timescales up to dynamically significant values. Using the Kazantsev theory, which describes the so-called small-scale dynamo-a magnetohydrodynamical process converting kinetic energy from turbulence into magnetic energy-we can then calculate the growth rate of the small-scale magnetic field. Our calculations are based on a detailed chemical network and we include non-ideal magnetohydrodynamical effects such as ambipolar diffusion and Ohmic dissipation. We follow the evolution of the magnetic field up to larger scales until saturation occurs on the Jeans scale. Assuming a weak magnetic seed field generated by the Biermann battery process, both Burgers and Kolmogorov turbulence lead to saturation within a rather small density range. Such fields are likely to become relevant after the formation of a protostellar disk and, thus, could influence the formation of the first stars and galaxies in the universe."],["dc.identifier.doi","10.1088/0004-637X/754/2/99"],["dc.identifier.isi","000306666700020"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/25888"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Iop Publishing Ltd"],["dc.relation.issn","0004-637X"],["dc.title","THE SMALL-SCALE DYNAMO AND NON-IDEAL MAGNETOHYDRODYNAMICS IN PRIMORDIAL STAR FORMATION"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","531"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Astronomische Nachrichten"],["dc.bibliographiccitation.lastpage","536"],["dc.bibliographiccitation.volume","334"],["dc.contributor.author","Schleicher, Dominik R. G."],["dc.contributor.author","Latif, A. H. M. Mahbub"],["dc.contributor.author","Schober, Jennifer"],["dc.contributor.author","Schmidt, Wolfram"],["dc.contributor.author","Bovino, Stefano"],["dc.contributor.author","Federrath, Christoph"],["dc.contributor.author","Niemeyer, J."],["dc.contributor.author","Banerjee, R."],["dc.contributor.author","Klessen, Ralf S."],["dc.date.accessioned","2018-11-07T09:22:39Z"],["dc.date.accessioned","2020-07-09T08:55:45Z"],["dc.date.available","2018-11-07T09:22:39Z"],["dc.date.available","2020-07-09T08:55:45Z"],["dc.date.issued","2013"],["dc.description.abstract","We explore the amplification of magnetic fields in the high-redshift Universe. For this purpose, we perform high-resolution cosmological simulations following the formation of primordial halos with \\sim10^7 M_solar, revealing the presence of turbulent structures and complex morphologies at resolutions of at least 32 cells per Jeans length. Employing a turbulence subgrid-scale model, we quantify the amount of unresolved turbulence and show that the resulting turbulent viscosity has a significant impact on the gas morphology, suppressing the formation of low-mass clumps. We further demonstrate that such turbulence implies the efficient amplification of magnetic fields via the small-scale dynamo. We discuss the properties of the dynamo in the kinematic and non-linear regime, and explore the resulting magnetic field amplification during primordial star formation. We show that field strengths of \\sim10^{-5} G can be expected at number densities of \\sim5 cm^{-3}."],["dc.identifier.doi","10.1002/asna.201211898"],["dc.identifier.isi","000325862900007"],["dc.identifier.scopus","2-s2.0-84879824861"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/66910"],["dc.identifier.url","http://www.scopus.com/inward/record.url?eid=2-s2.0-84879824861&partnerID=MN8TOARS"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.eissn","0004-6337"],["dc.relation.issn","1521-3994"],["dc.title","Magnetic fields during high redshift structure formation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","114504"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Physical Review Letters"],["dc.bibliographiccitation.volume","107"],["dc.contributor.author","Federrath, Christoph"],["dc.contributor.author","Chabrier, G."],["dc.contributor.author","Schober, Jennifer"],["dc.contributor.author","Banerjee, R."],["dc.contributor.author","Klessen, Ralf S."],["dc.contributor.author","Schleicher, Dominik R. G."],["dc.date.accessioned","2018-11-07T08:51:47Z"],["dc.date.available","2018-11-07T08:51:47Z"],["dc.date.issued","2011"],["dc.description.abstract","We study the growth rate and saturation level of the turbulent dynamo in magnetohydrodynamical simulations of turbulence, driven with solenoidal (divergence-free) or compressive (curl-free) forcing. For models with Mach numbers ranging from 0.02 to 20, we find significantly different magnetic field geometries, amplification rates, and saturation levels, decreasing strongly at the transition from subsonic to supersonic flows, due to the development of shocks. Both extreme types of turbulent forcing drive the dynamo, but solenoidal forcing is more efficient, because it produces more vorticity."],["dc.identifier.doi","10.1103/PhysRevLett.107.114504"],["dc.identifier.isi","000294783900005"],["dc.identifier.pmid","22026677"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22019"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1079-7114"],["dc.relation.issn","0031-9007"],["dc.title","Mach Number Dependence of Turbulent Magnetic Field Amplification: Solenoidal versus Compressive Flows"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.journal","Monthly Notices of the Royal Astronomical Society"],["dc.contributor.author","Navarrete, Felipe H"],["dc.contributor.author","Schleicher, Dominik R G"],["dc.contributor.author","Käpylä, Petri J"],["dc.contributor.author","Schober, Jennifer"],["dc.contributor.author","Völschow, Marcel"],["dc.contributor.author","Mennickent, Ronald E"],["dc.date.accessioned","2020-12-10T18:19:32Z"],["dc.date.available","2020-12-10T18:19:32Z"],["dc.date.issued","2019"],["dc.identifier.doi","10.1093/mnras/stz3065"],["dc.identifier.eissn","1365-2966"],["dc.identifier.issn","0035-8711"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/75283"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.relation.haserratum","/handle/2/75283"],["dc.title","Magneto-hydrodynamical origin of eclipsing time variations in post-common-envelope binaries for solar mass secondaries"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","066412"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW E"],["dc.bibliographiccitation.volume","86"],["dc.contributor.author","Schober, Jennifer"],["dc.contributor.author","Schleicher, Dominik R. G."],["dc.contributor.author","Bovino, Stefano"],["dc.contributor.author","Klessen, Ralf S."],["dc.date.accessioned","2018-11-07T09:02:11Z"],["dc.date.available","2018-11-07T09:02:11Z"],["dc.date.issued","2012"],["dc.description.abstract","The present-day Universe is highly magnetized, even though the first magnetic seed fields were most probably extremely weak. To explain the growth of the magnetic field strength over many orders of magnitude, fast amplification processes need to operate. The most efficient mechanism known today is the small-scale dynamo, which converts turbulent kinetic energy into magnetic energy leading to an exponential growth of the magnetic field. The efficiency of the dynamo depends on the type of turbulence indicated by the slope of the turbulence spectrum v(l) proportional to l(I),where v(l) is the eddy velocity at a scale l. We explore turbulent spectra ranging from incompressible Kolmogorov turbulence with I = 1/3 to highly compressible Burgers turbulence with I = 1/2. In this work, we analyze the properties of the small-scale dynamo for low magnetic Prandtl numbers Pm, which denotes the ratio of the magnetic Reynolds number, Rm, to the hydrodynamical one, Re. We solve the Kazantsev equation, which describes the evolution of the small-scale magnetic field, using the WKB approximation. In the limit of low magnetic Prandtl numbers, the growth rate is proportional to Rm((1-I)/(1+I)). We furthermore discuss the critical magnetic Reynolds number Rm(crit), which is required for small-scale dynamo action. The value of Rm(crit) is roughly 100 for Kolmogorov turbulence and 2700 for Burgers. Furthermore, we discuss that Rm(crit) provides a stronger constraint in the limit of low Pm than it does for large Pm. We conclude that the small-scale dynamo can operate in the regime of low magnetic Prandtl numbers if the magnetic Reynolds number is large enough. Thus, the magnetic field amplification on small scales can take place in a broad range of physical environments and amplify week magnetic seed fields on short time scales. DOI: 10.1103/PhysRevE.86.066412"],["dc.identifier.doi","10.1103/PhysRevE.86.066412"],["dc.identifier.isi","000312838400007"],["dc.identifier.pmid","23368064"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/24617"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1539-3755"],["dc.title","Small-scale dynamo at low magnetic Prandtl numbers"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","023010"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW E"],["dc.bibliographiccitation.volume","92"],["dc.contributor.author","Schober, Jennifer"],["dc.contributor.author","Schleicher, Dominik R. G."],["dc.contributor.author","Federrath, Christoph"],["dc.contributor.author","Bovino, Stefano"],["dc.contributor.author","Klessen, Ralf S."],["dc.date.accessioned","2018-11-07T09:53:22Z"],["dc.date.available","2018-11-07T09:53:22Z"],["dc.date.issued","2015"],["dc.description.abstract","The origin of strong magnetic fields in the Universe can be explained by amplifying weak seed fields via turbulent motions on small spatial scales and subsequently transporting the magnetic energy to larger scales. This process is known as the turbulent dynamo and depends on the properties of turbulence, i.e., on the hydrodynamical Reynolds number and the compressibility of the gas, and on the magnetic diffusivity. While we know the growth rate of the magnetic energy in the linear regime, the saturation level, i.e., the ratio of magnetic energy to turbulent kinetic energy that can be reached, is not known from analytical calculations. In this paper we present a scale-dependent saturation model based on an effective turbulent resistivity which is determined by the turnover time scale of turbulent eddies and the magnetic energy density. The magnetic resistivity increases compared to the Spitzer value and the effective scale on which the magnetic energy spectrum is at its maximum moves to larger spatial scales. This process ends when the peak reaches a characteristic wave number k(star) which is determined by the critical magnetic Reynolds number. The saturation level of the dynamo also depends on the type of turbulence and differs for the limits of large and small magnetic Prandtl numbers Pm. With our model we find saturation levels between 43.8% and 1.3% for Pm >> 1 and between 2.43% and 0.135% for Pm << 1, where the higher values refer to incompressible turbulence and the lower ones to highly compressible turbulence."],["dc.identifier.doi","10.1103/PhysRevE.92.023010"],["dc.identifier.isi","000359054400007"],["dc.identifier.pmid","26382506"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/36317"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","1550-2376"],["dc.relation.issn","1539-3755"],["dc.title","Saturation of the turbulent dynamo"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","026303"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","PHYSICAL REVIEW E"],["dc.bibliographiccitation.volume","85"],["dc.contributor.author","Schober, Jennifer"],["dc.contributor.author","Schleicher, Dominik R. G."],["dc.contributor.author","Federrath, Christoph"],["dc.contributor.author","Klessen, Ralf"],["dc.contributor.author","Banerjee, Robi"],["dc.date.accessioned","2018-11-07T09:13:30Z"],["dc.date.available","2018-11-07T09:13:30Z"],["dc.date.issued","2012"],["dc.description.abstract","The small-scale dynamo is a process by which turbulent kinetic energy is converted into magnetic energy, and thus it is expected to depend crucially on the nature of the turbulence. In this paper, we present a model for the small-scale dynamo that takes into account the slope of the turbulent velocity spectrum v(l) proportional to l(v), where l and v(l) are the size of a turbulent fluctuation and the typical velocity on that scale. The time evolution of the fluctuation component of the magnetic field, i. e., the small-scale field, is described by the Kazantsev equation. We solve this linear differential equation for its eigenvalues with the quantum-mechanical WKB approximation. The validity of this method is estimated as a function of the magnetic Prandtl number Pm. We calculate the minimal magnetic Reynolds number for dynamo action, Rm(crit), using our model of the turbulent velocity correlation function. For Kolmogorov turbulence (v = 1/ 3), we find that the critical magnetic Reynolds number is Rm(crit)(K) approximate to 110 and for Burgers turbulence (v = 1/ 2) Rm(crit)(B) approximate to 2700. Furthermore, we derive that the growth rate of the small-scale magnetic field for a general type of turbulence is Gamma proportional to Re(1-v)/(1+v) in the limit of infinite magnetic Prandtl number. For decreasing magnetic Prandtl number (down to Pm greater than or similar to 10), the growth rate of the small-scale dynamo decreases. The details of this drop depend on the WKB approximation, which becomes invalid for a magnetic Prandtl number of about unity."],["dc.identifier.doi","10.1103/PhysRevE.85.026303"],["dc.identifier.isi","000299994400003"],["dc.identifier.pmid","22463313"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/27194"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Physical Soc"],["dc.relation.issn","2470-0053"],["dc.relation.issn","2470-0045"],["dc.title","Magnetic field amplification by small-scale dynamo action: Dependence on turbulence models and Reynolds and Prandtl numbers"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","L19"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","The Astrophysical Journal"],["dc.bibliographiccitation.volume","797"],["dc.contributor.author","Federrath, Christoph"],["dc.contributor.author","Schober, Jennifer"],["dc.contributor.author","Bovino, Stefano"],["dc.contributor.author","Schleicher, Dominik R. G."],["dc.date.accessioned","2018-11-07T09:31:10Z"],["dc.date.available","2018-11-07T09:31:10Z"],["dc.date.issued","2014"],["dc.description.abstract","The turbulent dynamo may explain the origin of cosmic magnetism. While the exponential amplification of magnetic fields has been studied for incompressible gases, little is known about dynamo action in highly compressible, supersonic plasmas, such as the interstellar medium of galaxies and the early universe. Here we perform the first quantitative comparison of theoretical models of the dynamo growth rate and saturation level with three-dimensional magnetohydrodynamical simulations of supersonic turbulence with grid resolutions of up to 1024(3) cells. We obtain numerical convergence and find that dynamo action occurs for both low and high magnetic Prandtl numbers Pm = nu/eta = 0.1-10 (the ratio of viscous to magnetic dissipation), which had so far only been seen for Pm >= 1 in supersonic turbulence. We measure the critical magnetic Reynolds number, Rm(crit) = 129(-31)(+43), showing that the compressible dynamo is almost as efficient as in incompressible gas. Considering the physical conditions of the present and early universe, we conclude that magnetic fields need to be taken into account during structure formation from the early to the present cosmic ages, because they suppress gas fragmentation and drive powerful jets and outflows, both greatly affecting the initial mass function of stars."],["dc.identifier.doi","10.1088/2041-8205/797/2/L19"],["dc.identifier.isi","000347462000007"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/31481"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Iop Publishing Ltd"],["dc.relation.issn","2041-8213"],["dc.relation.issn","2041-8205"],["dc.title","THE TURBULENT DYNAMO IN HIGHLY COMPRESSIBLE SUPERSONIC PLASMAS"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]