Relativistic radiation hydrodynamics

Diese Arbeit befasst sich mit der Erweiterung der klassischen (nicht-relativistischen) Gleichungen der Strahlungshydrodynamik auf den relativistischen Formalismus. Beginnend mit einer kurzen Darstellung des relevanten Wissens der speziellen Relativitätstheorie, im ersten Kapitel, wird im zweiten Kapitel, ein kovarianter Formalismus der Größen der Strahlungshydrodynamik, erörtert. Dieser theoretische Teil beruht vor allem auf den Arbeiten von Mihalas ([MWM84]) und Castor ([Cas04]). Im Anschluss daran werden die Gleichungen der relativistischen Strahlungshydrodynamik in ihrer konservativen Schreibweise hergeleitet. Damit sind sie bereit für die Diskretisierung und ihre Implementierung in den bestehenden SHD-Code. Zusätzlich zur Beschreibung der Diskretisierung und des verwendeten SHD-Codes (Kapitel 4) wird ein weiteres Hauptaugenmerk auf die Berechnung der Ableitungen der Gleichungen gelegt. Dies wird mit Hilfe von MATHEMATICA bewerkstelligt, wobei ein alternativer Weg zur ursprünglichen Version (von Matthias Kittel) vorgestellt wird.This work deals with the extension of the classical non-relativistic radiation hydrodynamic equations to their relativistic form. Starting with a recapitulation of some basic knowledge of special relativity (chapter 1), a covariant formalism of the quantities of radiation hydrodynamics is derived (chapter 2). Based on these fundamentals the equations of relativistic radiation hydrodynamics (RRHD) are obtained in their conservative form (chapter 3) and hence ready for the discretization and their implementation in the RHD-code (chapter 4). Chapter 4 also deals with the calculation of derivatives with MATHEMATICA and shows some alternative ways (to the original version established by Matthias Kittel) to deal with them. It must also be noted that the theoretical part of this work is mostly based on the work of Mihalas ([MWM84]) and Castor ([Cas04])

Holograms of Conformal Chern-Simons Gravity

We show that conformal Chern-Simons gravity in three dimensions has various holographic descriptions. They depend on the boundary conditions on the conformal equivalence class and the Weyl factor, even when the former is restricted to asymptotic Anti-deSitter behavior. For constant or fixed Weyl factor our results agree with a suitable scaling limit of topologically massive gravity results. For varying Weyl factor we find an enhancement of the asymptotic symmetry group, the details of which depend on certain choices. We focus on a particular example where an affine u(1) algebra related to holomorphic Weyl rescalings shifts one of the central charges by 1. The Weyl factor then behaves as a free chiral boson in the dual conformal field theory.Comment: 5

All stationary axi-symmetric local solutions of topologically massive gravity

We classify all stationary axi-symmetric solutions of topologically massive gravity into Einstein, Schr\"odinger, warped and generic solutions. We construct explicitly all local solutions in the first three sectors and present an algorithm for the numerical construction of all local solutions in the generic sector. The only input for this algorithm is the value of one constant of motion if the solution has an analytic centre, and three constants of motion otherwise. We present several examples, including soliton solutions that asymptote to warped AdS.Comment: 42 pages, 9 figures. v2: Changed potentially confusing labelling of one sector, added references. v3: Minor changes, matches published versio

The MUSICA IASI CH4 and N2O products and their comparison to HIPPO, GAW and NDACC FTIR references

This work presents the methane (CH4) and nitrous oxide (N2O) products as generated by the IASI (Infrared Atmospheric Sounding Interferometer) processor developed during the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water). The processor retrieves CH4 and N2O with different water vapour and water vapour isotopologues (as well as HNO3) and uses a single a priori data set for all the retrievals (no variation in space and time). Firstly, the characteristics and errors of the products are analytically described. Secondly, the products are comprehensively evaluated by comparisons to the following reference data measured by different techniques and from different platforms as follows: (1) aircraft CH4 and N2O profiles from the five HIAPER Pole-to-Pole Observation (HIPPO) missions; (2) continuous in situ CH4 and N2O observations performed between 2007 and 2017 at subtropical and mid-latitude highmountain observatories (Izaña Atmospheric Observatory and Jungfraujoch, respectively) in the framework of the WMO–GAW (World Meteorological Organization–Global Atmosphere Watch) programme; (3) ground-based FTIR (Fouriertransform infrared spectrometer) measurements made between 2007 and 2017 in the framework of the NDACC (Network for the Detection of Atmospheric Composition Change) at the subtropical Izaña Atmospheric Observatory, the mid-latitude station of Karlsruhe and the Kiruna polar site. The theoretical estimations and the comparison studies suggest a precision for the N2O and CH4 retrieval products of about 1.5–3% and systematic errors due to spectroscopic parameters of about 2 %. The MUSICA IASI CH4 data offer a better sensitivity than N2O data. While for the latter the sensitivity is mainly limited to the UTLS (upper troposphere–lower stratosphere) region, for CH4 we are able to prove that at low latitudes the MUSICA IASI processor can detect variations that take place in the free troposphere independently from the variations in the UTLS region.We demonstrate that the MUSICA IASI data qualitatively capture the CH4 gradients between low and high latitudes and between the Southern Hemisphere and Northern Hemisphere; however, we also find an inconsistency between low- and high-latitude CH4 data of up to 5 %. The N2O latitudinal gradients are very weak and cannot be detected. We make comparisons over a 10-year time period and analyse the agreement with the reference data on different timescales. The MUSICA IASI data can detect day-to-day signals (only in the UTLS), seasonal cycles and long-term evolution (in the UTLS and for CH4 also in the free troposphere) similar to the reference data; however, there are also inconsistencies in the long-term evolution connected to inconsistencies in the used atmospheric temperature a priori data. Moreover, we present a method for analytically describing the a posteriori-calculated logarithmic-scale difference of the CH4 and N2O retrieval estimates. By correcting errors that are common in the CH4 and N2O retrieval products, the a posteriori-calculated difference can be used for generating an a posteriori-corrected CH4 product with a theoretically better precision than the original CH4 retrieval products. We discuss and evaluate two different approaches for such a posteriori corrections. It is shown that the correction removes the inconsistencies between low and high latitudes and enables the detection of day-to-day signals also in the free troposphere. Furthermore, they reduce the impact of short-term atmospheric dynamics, which is an advantage, because respective signals are presumably hardly comparable to model data. The approach that affects the correction solely on the scales on which the errors dominate is identified as the most efficient, because it reduces the inconsistencies and errors without removing measurable real atmospheric signals. We give a brief outlook on a possible usage of this a posterioricorrected MUSICA IASI CH4 product in combination with inverse modelling

The MUSICA IASI CH4 and N2O products and their comparison to HIPPO, GAW and NDACC FTIR references

This work presents the methane (CH4) and nitrous oxide (N2O) products as generated by the IASI (Infrared Atmospheric Sounding Interferometer) processor developed during the project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water). The processor retrieves CH4 and N2O with different water vapour and water vapour isotopologues (as well as HNO3) and uses a single a priori data set for all the retrievals (no variation in space and time). Firstly, the characteristics and errors of the products are analytically described. Secondly, the products are comprehensively evaluated by comparisons to the following reference data measured by different techniques and from different platforms as follows: (1) aircraft CH4 and N2O profiles from the five HIAPER Pole-to-Pole Observation (HIPPO) missions; (2) continuous in situ CH4 and N2O observations performed between 2007 and 2017 at subtropical and mid-latitude high-mountain observatories (Izaña Atmospheric Observatory and Jungfraujoch, respectively) in the framework of the WMO–GAW (World Meteorological Organization–Global Atmosphere Watch) programme; (3) ground-based FTIR (Fourier-transform infrared spectrometer) measurements made between 2007 and 2017 in the framework of the NDACC (Network for the Detection of Atmospheric Composition Change) at the subtropical Izaña Atmospheric Observatory, the mid-latitude station of Karlsruhe and the Kiruna polar site.This work has strongly benefited from funding by the European Research Council under FP7/(2007–2013)/ERC grant agreement no. 256961 (project MUSICA); by the Deutsche Forschungsgemeinschaft for the project MOTIV (Geschäftszeichen SCHN 1126/2-1); by the Ministerio de Economía y Competitividad from Spain trough the projects CGL2012-37505 (project NOVIA) and CGL2016-80688-P (project INMENSE); by the Ministerio de Educación, Cultura y Deporte (programa “José Castillejo”, CAS14/00282); and by EUMETSAT under its Fellowship Programme (project VALIASI)

CRETA (Centrum fürreflektierte Textanalyse)– FachübergreifendeMethodenentwicklung in denDigital Humanities

This paper will present the concept of the newly established Stuttgart DH Center CRETA, which unites very different text-oriented disciplines such as literature, linguistics, history, political science, and philosophy, and which, on the other hand, not only applies methods and modeling techniques from machine learning, computational linguistics, and computer graphic visualization, but has begun to integrate them into a common DH methodology of deep reflective text analysis. Such a further development of the method inventory of the Digital Humanities is a long way and needs many participants. However, we can already illustrate aspects of the conception with case studies of scenarios from ongoing digital humanities projects, and it seems important to us to put the approach up for broad discussion