Cosmological Forecast for non-Gaussian Statistics in large-scale weak Lensing Surveys

Cosmic shear data contains a large amount of cosmological information encapsulated in the non-Gaussian features of the weak lensing mass maps. This information can be extracted using non-Gaussian statistics. We compare the constraining power in the $\Omega_{\mathrm{m}} - \sigma_8$ plane of three map-based non-Gaussian statistics with the angular power spectrum, namely; peak/minimum counts and Minkowski functionals. We further analyze the impact of tomography and systematic effects originating from galaxy intrinsic alignments, multiplicative shear bias and photometric redshift systematics. We forecast the performance of the statistics for a stage-3-like weak lensing survey and restrict ourselves to scales $\geq$ 10 arcmin. We find, that in our setup, the considered non-Gaussian statistics provide tighter constraints than the angular power spectrum. The peak counts show the greatest potential, increasing the Figure-of-Merit (FoM) in the $\Omega_{\mathrm{m}} - \sigma_8$ plane by a factor of about 4. A combined analysis using all non-Gaussian statistics in addition to the power spectrum increases the FoM by a factor of 5 and reduces the error on $S_8$ by $\approx$ 25\%. We find that the importance of tomography is diminished when combining non-Gaussian statistics with the angular power spectrum. The non-Gaussian statistics indeed profit less from tomography and the minimum counts and Minkowski functionals add some robustness against galaxy intrinsic alignment in a non-tomographic setting. We further find that a combination of the angular power spectrum and the non-Gaussian statistics allows us to apply conservative scale cuts in the analysis, thus helping to minimize the impact of baryonic and relativistic effects, while conserving the cosmological constraining power. We make the code that was used to conduct this analysis publicly available

Spectro-Imaging Forward Model of Red and Blue Galaxies

For the next generation of spectroscopic galaxy surveys, it is important to forecast their performances and to accurately interpret their large data sets. For this purpose, it is necessary to consistently simulate different populations of galaxies, in particular Emission Line Galaxies (ELGs), less used in the past for cosmological purposes. In this work, we further the forward modeling approach presented in Fagioli et al. 2018, by extending the spectra simulator Uspec to model galaxies of different kinds with improved parameters from Tortorelli et al. 2020. Furthermore, we improve the modeling of the selection function by using the image simulator Ufig. We apply this to the Sloan Digital Sky Survey (SDSS), and simulate $\sim157,000$ multi-band images. We pre-process and analyse them to apply cuts for target selection, and finally simulate SDSS/BOSS DR14 galaxy spectra. We compute photometric, astrometric and spectroscopic properties for red and blue, real and simulated galaxies, finding very good agreement. We compare the statistical properties of the samples by decomposing them with Principal Component Analysis (PCA). We find very good agreement for red galaxies and a good, but less pronounced one, for blue galaxies, as expected given the known difficulty of simulating those. Finally, we derive stellar population properties, mass-to-light ratios, ages and metallicities, for all samples, finding again very good agreement. This shows how this method can be used not only to forecast cosmology surveys, but it is also able to provide insights into studies of galaxy formation and evolution.Comment: 28 pages, 10 figures, accepted for publication in JCA

Die Balanced Scorecard als Instrument des Change Management

Unter Change Management werden alle Maßnahmen verstanden, die zur Initiie-rung und Umsetzung von neuen Strategien, Strukturen, Systemen und Verhal-tensweisen notwendig sind. Die Balanced Scorecard dagegen beruht auf dem Grundgedanken, finanzielle Ziele und verschiedene Leistungsperspektiven (Kunden-, interne Prozess-, Lern- und Entwicklungsperspektive) gemeinsam zu betrachten. Auf diese Weise kann die Ausgewogenheit (Balance) verschiedener Leistungsperspektiven auf einer übersichtlichen Anzeigentafel (Scorecard) ab-gebildet werden. Der Beitrag der Balanced Scorecard zum Change Manage-ment wird in dieser Diplomarbeit herausgearbeitet, da die wesentlichen zentra-len Themen des Management des Wandels von der Balanced Scorecard auf-gegriffen und zu einer Gesamtsicht verbunden werden, aus der eine umsetzba-re Strategie hergeleitet werden kann. Aufbauend auf dem theoretischen Ver-ständnis des Change Management wird die strategische und vor allem operati-ve Bewältigung von Veränderungsprozessen – teils „extern“ vorgegeben teils „intern“ als dynamische Reaktion auf Bedürfnisse, Entwicklungen und Ideen notwendig – anhand der Balanced Scorecard dargestellt. Zunächst wird der unternehmerische Wandel beschrieben. Es wird in externen und internen Wan-del unterschieden. Die Rahmenbedingungen sind es, die zu den heutigen Transformationsprozessen führen. Externe Veränderungsprozesse werden vom Markt vorgegeben. Die Vergrößerung des Marktanteils, Kundenorientierung, die Steigerung der Kundenzufriedenheit und Kundentreue sind einige kritische Er-folgsfaktoren, die ein erfolgreiches Change Management auszeichnen. Interner Wandel vollzieht sich innerhalb einer Unternehmung. Heute werden immateriel-le Werte immer wichtiger in dem Maße wie materielle Werte durch Automatisie-rung und Rationalisierung immer leichter zu schaffen sind. Kernkompetenzen, Innovationen und Lieferzeiten werden dabei zu Schlüsselfaktoren. Die Prozess-orientierung konzentriert sich dann auf diejenigen Aktivitäten, welche die Wett-bewerbsfähigkeit sichern. Am Ende der Wertschöpfung steht der Kunde. Um den Wandelprozess erfolgreich bewältigen zu können, benützt das Change Management das Projektmanagement, welches ein strukturiertes Vorgehen sicherstellt. Die Balanced Scorecard besitzt für das Change Management eine Steuerungsfunktion: sie formuliert die Vision und Strategie und setzt sie in messbare Größen um durch Kommunikation, Planung und Vorgaben und stra-tegisches Feedback und Lernen in einem Ursache-/Wirkungsmodell. Die Unter-nehmensstrategie wird mittels finanzieller und nicht-finanzieller, vorlaufender und nachlaufender Kennzahlen in wertreibende Kausalzusammenhänge aufge-löst und legt dadurch die Funktionalbeziehungen des Geschäftsmodells („theory of the firm“) offen. Die grundlegende Forderung ist, dass der Erfolg durch Inves-titionen in diverse Verbesserungen finanziell quantifizierbar sein muss. So wird aus der Geschäftsstrategie heraus über dynamische strategische Zielsetzungen und die dazu gehörigen Wandelgrößen über den Zielzeitraum sowie über die hinter den Maßnahmen liegenden Wandeltreiber eine fundamentale Dynamik betrachtet. Damit kann eine ausgewogene Darstellung des Wandelbedarfs er-reicht werden. Die Diplomarbeit zeigt, dass die Balanced Scorecard wirksam werden kann, wenn sie um Systemergänzungen erweitert wird. Dies wird im dynamischen Steuerungsgebilde berücksichtigt. So wird das Kernsteuerungs-system – die Balanced Scorecard – um ein interaktives, diagnostisches und Gebildesteuerungssystem ergänzt. Das diagnostische Steuerungssystem bein-haltet alle standardisierten Managementprozesse. Das interaktive Steuerungs-system wirkt demgegenüber als Kommunikations- und Informationssystem. Das Gebildesteuerungssystem befasst sich mit dem Veränderungsbedarf und der Anpassung an den Unternehmenskontext. Die Stärke der Balanced Scorecard zeigt sich in der Funktion eines Umsetzungs- und Wandeltreibers. Der Beitrag der Balanced Scorecard zum Change Management kann darin gesehen wer-den, wie zielgerichtet die notwendigen Maßnahmen zu Verbesserungen und Erneuerungen verwirklicht werden können. Nachteilig ist, dass die Balanced Scorecard trotz ihres Anspruchs auf Ausgewogenheit sehr stark auf eine kenn-zahlenbasierte Steuerung zielt und weiche Faktoren vernachlässigt. Ursache-/Wirkungsbeziehungen werden als allzu eindeutig angesehen und Konfliktme-chanismen erst gar nicht berücksichtigt. Zudem verleiten normative Gestal-tungsempfehlungen zu einer schablonenhaften Implementierung der Strategie. Vor allem die Wandelprozesse werden vereinfachend unterstellt indem implizit von einer „perfekten Scorecard“ ausgegangen wird und von der Hypothese, dass wenn die Balanced Scorecard erfolgreich implementiert wird sich auch das Unternehmen zu einem erfolgreichen wandelt.All measures which are necessary for the initialising and the translation into action of new strategies, structures, systems and behaviours are understood under change management. The Balanced Scorecard based on the idea that financial aims and different performance prospects (customer, internal process, learning and development prospect) look together. The balance of different performance prospects can this way be shown on a clear announcement panel (Scorecard). The contribution of the Balanced Scorecard to the change management is worked out in this master thesis since the essential central topics of the management of the change are picked up and bandaged to a complete view by the Balanced Scorecard, from which a realizable strategy can be derived. On the theoretical understanding of the change management the strategic and operative mastering of change processes partly "externally" predefined and partly "internally" necessary as a dynamic reaction to needs, developments and ideas are represented with the Balanced Scorecard. At first the entrepreneurial change is described. It is distinguished into external and internal change. It is the basic conditions which lead to today's transformation processes. External change processes are provided by the market. The extension of the market share, customer orientation, the increase of the customer satisfaction and customer loyalty are some critical success factors which honour a successful change management. Internal change takes place within a business. Today immaterial results become more and more important in the measure as material results by automation and rationalization is to provide more easily. Core competences, innovations and delivery times become key factors. The process orientation then concentrates on those activities which safeguard the competition ability. The customer stands on the end of the net product. To be able to handle the change process successfully, the change management uses the project management who guarantees a structured procedure. The Balanced Scorecard has a control function for the change management: it formulates and converts the vision and strategy in measurable sizes by communication, planning and handicaps and strategic feedback and learning in causal connections. The enterprise strategy is dissolved by means of financial and not financial, pre running and running characteristic numbers in value based causal connections and through this it makes clear the functional relations of the "theory of the firm". She is the basic demand that the success must financially be quantifiable in various improvements by investments. A balanced representation of the change need can be reached with that. The master thesis shows that the Balanced Scorecard can get effective, if she is extended by system additions. This is taken into account in the dynamic control construction. An interactive, diagnostic and dynamic control system completes the core control system, the Balanced Scorecard. The diagnostic control system contains all standardized management processes. The interactive control system works on the other hand as communication and information system. The dynamic control system deals with the change need and the adaptation to the enterprise context. The strength of the Balanced Scorecard can be seen in the function of a translation into strategy and change driver. The contribution of the Balanced Scorecard to the change management can be looked into this, how purposefully the necessary measures to improvements and renewals can be made come true. It is adverse that the Balanced Scorecard is aimed despite her claim of balance very strongly on a characteristic number based control and neglects soft factors. Cause and effect relations are esteemed too obviously and conflict mechanisms are taken into account not at all. Moreover, normative design recommendations lead to a stereotyped implementation of the strategy. The change processes are primarily simplified by supposing a "perfect Scorecard" and the hypothesis, that if the Balanced Scorecard is implemented successfully the business will be successful

Career Workshop at ETH Zurich: How to land your first job when moving from academia to industry

ISSN:0009-429

Assessing theoretical uncertainties for cosmological constraints from weak lensing surveys

Weak gravitational lensing is a powerful probe, which is used to constrain the standard cosmological model and its extensions. With the enhanced statistical precision of current and upcoming surveys, high-accuracy predictions for weak lensing statistics are needed to limit the impact of theoretical uncertainties on cosmological parameter constraints. For this purpose, we present a comparison of the theoretical predictions for the non-linear matter and weak lensing power spectra, based on the widely used fitting functions (mead and rev-halofit), emulators (EuclidEmulator, EuclidEmulator2, BaccoEmulator, and CosmicEmulator), and N-body simulations (PKDGRAV3). We consider the forecasted constraints on the ЛCDM and wCDM models from weak lensing for stage III and stage IV surveys. We study the relative bias on the constraints and their dependence on the assumed prescriptions. Assuming a ЛCDM cosmology, we find that the relative agreement on the S8 parameter is between 0.2 and 0.3σ for a stage III-like survey between the above predictors. For a stage IV-like survey the agreement becomes 1.4-3.0σ. In the wCDM scenario, we find broader S8 constraints, and agreements of 0.18-0.26σ and 0.7-1.7σ for stage III and stage IV surveys, respectively. The accuracies of the above predictors therefore appear adequate for stage III surveys, whereas the fitting functions would need improvements for future stage IV surveys. Furthermore, we find that, of the fitting functions, mead provides the best agreement with the emulators. We discuss the implication of these findings for the preparation of future weak lensing surveys, and the relative impact of theoretical uncertainties to other systematics.ISSN:0035-8711ISSN:1365-296

Towards a full wwCDM map-based analysis for weak lensing surveys

The next generation of weak lensing surveys will measure the matter distribution of the local Universe with unprecedented precision. This encourages the use of higher-order mass-map statistics for cosmological parameter inference. However, the increased quality of the data poses new challenges for map-based analyses. We extend the methodology introduced in arXiv:2006.12506 to match these requirements. Using this pipeline, we provide forecasts for the $w$CDM parameter constraints for stage 3 and stage 4 weak lensing surveys. We consider different survey setups, summary statistics and mass map filters including Starlets. The impact of baryons on the summary statistics is investigated and the necessary scale cuts are applied in the forecast. We compare the traditional angular power spectrum analysis to two extrema count statistics (peak and minima counts) as well as Minkowski functionals and the Starlet $\ell_1$-norm of the mass maps. In terms of map filters we find a preference for Starlet over Gaussian filters. Our results further suggest that using a survey setup with 10 instead of 5 tomographic redshift bins is beneficial. The addition of cross-tomographic information is found to improve the constraints on cosmology and especially on galaxy intrinsic alignment for all statistics. In terms of constraining power, we find the angular power spectrum and the peak counts to be equally matched for stage 4 surveys, followed by minima counts, the Minkowski functionals and then the Starlet $\ell_1$-norm. Combining different summary statistics significantly improves the constraints and compensates for the constraining power that is lost due to the stringent scale cuts. We identify the most `cost-effective' combination to be the angular power spectrum, peak counts and Minkowski functionals following Starlet filtering

Spectro-imaging forward model of red and blue galaxies

For the next generation of spectroscopic galaxy surveys, it is important to forecast their performances and to accurately interpret their large data sets. For this purpose, it is necessary to consistently simulate different populations of galaxies, in particular Emission Line Galaxies (ELGs), less used in the past for cosmological purposes. In this work, we further the forward modeling approach presented in Fagioli et al. 2018, by extending the spectra simulator USPEC to model galaxies of different kinds with improved parameters from Tortorelli et al. 2020. Furthermore, we improve the modeling of the selection function by using the image simulator UFIG. We apply this to the Sloan Digital Sky Survey (SDSS), and simulate similar to 157, 000 multi-band images. We pre-process and analyse them to apply cuts for target selection, and finally simulate SDSS/BOSS DR14 galaxy spectra. We compute photometric, astrometric and spectroscopic properties for red and blue, real and simulated galaxies, finding very good agreement. We compare the statistical properties of the samples by decomposing them with Principal Component Analysis (PCA). We find very good agreement for red galaxies and a good, but less pronounced one, for blue galaxies, as expected given the known difficulty of simulating those. Finally, we derive stellar population properties, mass-to-light ratios, ages and metallicities, for all samples, finding again very good agreement. This shows how this method can be used not only to forecast cosmology surveys, but it is also able to provide insights into studies of galaxy formation and evolution.ISSN:1475-751