Growth and evolution of continental lithosphere by cycles of oceanic subductions – Evidence from seismic anisotropy supported by petrologic and geochemical findings

<p><span><span>Formation and evolution of the continental lithosphere, one of the ILP research themes, still belongs to fundamental questions often debated within different geoscience disciplines. We emphasize the role of mantle lithosphere that forms the biggest volume of continents, but is often overlooked, particularly in geologic interpretations of tectonic processes. Investigation of seismic anisotropy from propagation of teleseismic P and S waves in three dimensions (3D) provides a unique constraint on tectonic fabrics and character of past and present-day deformations. We collect independent findings from seismology, petrology and geochemistry to support our 3D anisotropic model of mantle lithosphere with tilted symmetry axes, derived from data of passive seismic experiments organised in tectonically different domains of Archean, Proterozoic and Phanerozoic provinces of Europe. We delimit the extent of lithosphere domains and their boundaries according to c</span><span>hanges in orientation of the large-scale anisotropy, associated with a systematic preferred orientation of olivine, originally formed by mantle convection in the oceanic mantle lithosphere and “frozen” deep in continents</span><span>.</span></span></p><p><span><span>We explain the oriented dipping fabrics in the continental mantle lithosphere by successive subductions of ancient oceanic plates and their accretions enlarging a primordial continent core, consequent supercontinent break-ups and assemblages of wandering micro-plates to create the patchwork structure of the present-day continents. Supporting arguments for such model arise from petrologic and geochemical studies indicating that continental peridotites formed in oceanic environments and became “continental” after significant thickening or underthrusting. Combining seismological, petrologic and geochemical findings can help to bridge the gap between the different viewpoints and evoke further discussions on growth mechanisms and evolution of the continental lithosphere. Data gathered during new large-scale passive seismic experiments, like AlpArray, AdriaArray, PACASE and related projects, including </span><span>CoLiBrI - Continental Lithosphere: a Broadscale Investigation, </span><span>will provide </span><span>new exciting materials for studies of </span><span>f</span><span>ormation and evolution of the continental lithosphere.</span></span></p>

First detection of the 448 GHz ortho-H2O line at high redshift: probing the structure of a starburst nucleus at z = 3.63

Submillimeter rotational lines of H2O are a powerful probe in warm gas regions of the interstellar medium (ISM), tracing scales and structures ranging from kiloparsec disks to the most compact and dust-obscured regions of galactic nuclei. The ortho-H2O(423 − 330 line at 448 GHz, which has recently been detected in a local luminous infrared galaxy, offers a unique constraint on the excitation conditions and ISM properties in deeply buried galaxy nuclei because the line requires high far-infrared optical depths to be excited. In this letter, we report the first high-redshift detection of the 448 GHz H2O(423–330) line using ALMA in a strongly lensed submillimeter galaxy (SMG) at z = 3.63. After correcting for magnification, the luminosity of the 448 GHz H2O line is ∼106 L⊙. In combination with three other previously detected H2O lines, we build a model that resolves the dusty ISM structure of the SMG, and find that it is composed of a ∼1 kpc optically thin (optical depth at 100 μm τ100 ∼ 0.3) disk component with a dust temperature Tdust ≈ 50 K that emits a total infrared power of 5 × 1012 L⊙ with a surface density ΣIR = 4 × 1011 L⊙ kpc−2, and a very compact (0.1 kpc) heavily dust-obscured (τ100 ≳ 1) nuclear core with very warm dust (100 K) and ΣIR = 8 × 1012 L⊙ kpc−2. The H2O abundance in the core component, XH2O ∼ (0.3–5) × 10−5, is at least one order of magnitude higher than in the disk component. The optically thick core has the characteristic properties of an Eddington-limited starburst, providing evidence that radiation pressure on dust is capable of supporting the ISM in buried nuclei at high redshifts. The multicomponent ISM structure revealed by our models illustrates that dust and molecules such as H2O are present in regions that are characterized by highly differing conditions and scales, extending from the nucleus to more extended regions of SMGs.

EDGE: the mass–metallicity relation as a critical test of galaxy formation physics

ABSTRACT We introduce the ‘Engineering Dwarfs at Galaxy Formation’s Edge’ (EDGE) project to study the cosmological formation and evolution of the smallest galaxies in the Universe. In this first paper, we explore the effects of resolution and sub-grid physics on a single low-mass halo ($M_{\rm halo}=10^{9}{\, \rm M}_\odot$), simulated to redshift z = 0 at a mass and spatial resolution of $\sim 20{\, \rm M}_\odot$ and ∼3 pc. We consider different star formation prescriptions, supernova feedback strengths, and on-the-fly radiative transfer (RT). We show that RT changes the mode of galactic self-regulation at this halo mass, suppressing star formation by causing the interstellar and circumgalactic gas to remain predominantly warm (∼104 K) even before cosmic reionization. By contrast, without RT, star formation regulation occurs only through starbursts and their associated vigorous galactic outflows. In spite of this difference, the entire simulation suite (with the exception of models without any feedback) matches observed dwarf galaxy sizes, velocity dispersions, V-band magnitudes, and dynamical mass-to-light-ratios. This is because such structural scaling relations are predominantly set by the host dark matter halo, with the remaining model-to-model variation being smaller than the observational scatter. We find that only the stellar mass–metallicity relation differentiates the galaxy formation models. Explosive feedback ejects more metals from the dwarf, leading to a lower metallicity at a fixed stellar mass. We conclude that the stellar mass–metallicity relation of the very smallest galaxies provides a unique constraint on galaxy formation physics.

The demographics of central massive black holes in low-mass early-type galaxies

The existence intermediate mass black holes (IMBH, MBH ≲ 106M⊙) at the centers low-mass galaxies with stellar masses between (1–10)×10M⊙ are key to constraining the origin of black hole (BH) seeds and understanding the physics deriving the co-evolution of central BHs and their host galaxies. However, finding and weighing IMBH is challenging. Here, we present the first observational evidence for such IMBHs at the centers of the five nearest early-type galaxies (D < 3.5 Mpc, ETGs) revealed by adaptive optics kinematics from Gemini and VLT and high-resolution HST spectroscopy. We find that all five galaxies appear to host IMBHs with four of the five having masses below 1 million M⊙ and the lowest mass BH being only ∼7,000 M⊙. This work provides a first glimpse of the demographics of IMBHs in this galaxy mass range and at velocity dispersions < 70 km/s, and thus provides an important extension to the bulge mass and galaxy dispersion scaling relations. The ubiquity of central BHs in these galaxies provides a unique constraint on BH seed formation scenarios, favoring a formation mechanism that produces an abundance of low-mass seed BHs.

Extended tuple constraint type as a complex integrity constraint type in XML data model - definition and enforcement

A database management system (DBMS) is based on a data model whose concepts are used to express a database schema. Each data model has a specific set of integrity constraint types. There are integrity constraint types, such as key constraint, unique constraint and foreign key constraint that are supported by most DBMSs. Other, more complex constraint types are difficult to express and enforce and are mostly completely disregarded by actual DBMSs. The users have to manage those using custom procedures or triggers. eXtended Markup Language (XML) has become the universal format for representing and exchanging data. Very often XML data are generated from relational databases and exported to a target application or another database. In this context, integrity constraints play the essential role in preserving the original semantics of data. Integrity constraints have been extensively studied in the relational data model. Mechanisms provided by XML schema languages rely on a simple form of constraints that is sufficient neither for expressing semantic constraints commonly found in databases nor for expressing more complex constraints induced by the business rules of the system under study. In this paper we present a classification of constraint types in relational data model, discuss possible declarative mechanisms for their specification and enforcement in the XML data model, and illustrate our approach to the definition and enforcement of complex constraint types in the XML data model on the example of extended tuple constraint type.

An Empirical Approach to Performance Criteria for Manipulation

Empirical performance criteria based on geometric and physical properties are commonly used for real-time decision-making (and design) of redundant anthropomorphic manipulators (serial) or workcells (parallel) performing high level tasks while avoiding obstacles, providing safety, and responding to human commands. This requires configuration management of these complex systems by prioritizing candidate configurations relative to quantifiable secondary objectives with clear physical meanings. Clarity is addressed by using position, inertial, kinetic, and potential energy (gravity and deformation) based metrics that are crisply defined from system and input parameters. Scaling differences among derived performance metrics require normalization to determine their relative import and inclusion in multicriteria decision-making techniques. Large dimensional spaces mean statistically reduced representations are necessary to decipher their relative import and allow an operator without extensive robotic knowledge to use them effectively and independent of a redundancy resolution technique (RRT). We propose two global norms: the unit norm and the average norm for a broad set of performance criteria that quantify these systems’ unique constraint, transmission, and energy characteristics. These norms are then used to select relevant criteria for operational decision-making based on intuitive operator commands instead of abstract mathematical notions. Additionally, a modified RRT is presented that is more robust with respect to changes during operation in the secondary objectives, which allows for greater flexibility when formulating new criteria. Results are illustrated using a variety of new and existing criteria on an anthropomorphic dual-arm system.

Phylogenetic Analysis and its Application in Evolutionary Paleobiology

Each of the perspectives on the fossil record represented by contributions to this short course (and many that are not) can claim a legitimate share of the mantle of “Analytical Paleontology,” earned by combining rigor and insight to provide some unique constraint on our understanding of the history of life. Dare I claim more for phylogeny? Certainly not, if “more” suggests that phylogeny is some final synthesis, complete unto itself, sought by all, and needing no further justification. Such a posture would make phylogenetic inference an end in itself, and, although it may sometimes appear that phylogeneticists have this in mind, I will argue here that it is the service role of phylogenetic analysis that makes it important in shaping our knowledge of evolution. Interpretation of the phylogenetic relationships of the organisms we study has profound implications for virtually all of our other ways of handling data from the fossil (or Recent) record.