Bachelor / Master thesis - ECAP · Master & Bachelor thesis Winter 2018/2019 The aim of laboratory astrophysics is to prepare, control and investigate systems which beha-ve similar

Bachelor / Master thesisCTA, H.E.S.S., Fermi LAT

Winter 2018 / 2019

• X-ray phase-contrast imaging in laboratory astrophysics

• Reconstruction and evaluation of single-shot X-ray images

• Computer simulation of wave field propagation

• Deep Learning applications for H.E.S.S. data analysis

• Study of gamma-ray flare emission on months scale with Fermi-LAT

• Point source analysis with Wavelet Transform methods for H.E.S.S. and CTA

• Characterization of photosensors of CTA

• Combined data analysis with Fermi-LAT and H.E.S.S.

• Characterization of optical components in preparation for intensity interferometry with CTA

• Intensity interferometry with IceAct-telescopes and with CTA

• Search for the gamma-ray emission from astroids in the Solar system

Contact:

Prof. Dr. Stefan Funk, [email protected] 219, Erwin-Rommel-Str. 1

BachelorarbeitHerbst/Winter 2018/2019

Das Ziel der Laborastrophysik ist die Praparation, Kontrolle und Untersuchung von Systemen,die sich ahnlich zu denen mit astrophysikalischem Ursprung verhalten. Ein Beispiel fur solche La-borexperimente ist die Erzeugung von laserinduzierten Schockfronten und die Bildgebung undRekonstruktion der resultierenden Dichteverteilung mit Rontgenphasenkontrastbildgebung.Schockfronten, die nach Supernova-Explosionen auftreten, sind die Hauptkandidaten fur die Be-schleunigung der kosmischen Strahlung auf die hochsten Energien.

Entwicklung und Charakterisierung von Testphantomen fur die gitterbasier-te Rontgenphasenkontrastbildgebung in der Laborastrophysik

Ziel dieser Arbeit ist die Konzeption und Realisierung geeigneter Bildgebungsphantome, die diezu erwartenden Strukturen geschockter Medien mimiken. Anhand erster charakterisierender Mes-sungen von diesen soll das Potenzial der gitterbasierten Rontgenphasenkontrastbildgebung furdie Anforderungen der Laborastrophysik experimentell evaluiert werden.

Physikalische Themengebiete, die in dieser Arbeit behandelt werden:

• Rontgenbildgebung und Rontgenmikroskopie

• Optische Eigenschaften von Materialien

Fertigkeiten, die in dieser Arbeit erlernt werden:

• Programmierung in Matlab

• Kreatives handwerkliches Gestalten

Bei Interesse bitte melden bei:

• Max Schuster, [email protected] 214, Erwin-Rommel-Str. 1

• Prof. Dr. Gisela Anton, [email protected] 216, Erwin-Rommel-Str. 1

• Prof. Dr. Stefan Funk, [email protected] 219, Erwin-Rommel-Str. 1

Master & Bachelor thesisWinter 2018/2019

The aim of laboratory astrophysics is to prepare, control and investigate systems which beha-ve similar to those of astrophysical origin. One example of such laboratory experiments is theproduction of laser-induced shock fronts and the imaging and reconstruction of the resultingdensity distribution with X-ray phase-contrast imaging. Shock fronts occurring after superno-va explosion are the prime candidates for the acceleration of cosmic rays to the highest energies.

Reconstruction and evaluation of single-shot X-ray images

Here, data taken at PHELIX/GSI and Diamond Light Source is to be evaluated. Both beamtimeshad the aim to evaluate the single-shot imaging capabilities required in the HED-environment. Dif-ferent image reconstruction algorithms can be tested, especially regarding their suitability to copewith low contrast-to-noise ratios. Involvement in future beamtimes is possible but not required.

Physics topics related to that work:

• X-ray imaging and microscopy

• Image reconstruction

Skills acquired during this work:

• Programming with Matlab

• Working at major research facilities

Interested? Please get in touch!




Master thesisWinter 2018/2019

The aim of laboratory astrophysics is to prepare, control and investigate systems which beha-ve similar to those of astrophysical origin. One example of such laboratory experiments is theproduction of laser-induced shock fronts and the imaging and reconstruction of the resultingdensity distribution with X-ray phase-contrast imaging. Shock fronts occurring after superno-va explosion are the prime candidates for the acceleration of cosmic rays to the highest energies.

Computer simulation of wave field propagation

The simulation of X-ray phase contrast imaging setups is based on the method of wave fieldpropagation. If the construction contains focusing elements, the numerical calculation becomesvery extensive. New methods promise a higher performance. These are to be implemented andthen evaluated.

Physics topics related to that work:

• X-ray imaging and microscopy

• Numerical optics


• Programming with Matlab

• Numeric methods





Bachelor / MasterarbeitWinter 2018

Deep convolutional neural networks (CNN) are a category of machine learning that have provento be very effective in a broad range of areas, e.g. image and pattern recognition, anomaly de-tection and multi-classification. Cherenkov telescopes, such as H.E.S.S., are looking at extremeastrophysical environments by imaging the interactions of the emitted high-energy gamma-raysin the Earth atmosphere. The implementation of CNNs in the H.E.S.S. data analysis chain couldhelp resolve the fine structure in the recorded images, thereby improving the background rejecti-on (pattern recognition) rate as well as the reconstruction of events from the recorded images byapplying regression algorithms.

Deep Learning applications for H.E.S.S. data analysis

Since the first work on studying and implementing the CNN architecture were already successfullycarried out, the next steps will focus on optimizing the processes and trying to push it to its limitsby exploring new ways of application. These CNNs already gave promising results on the correctidentification of primary cosmic rays which are hard to reconstruct by using standard analysistechniques. This work will focus on the reconstruction of those primary cosmic rays by usingCNNs.

Physics topics related to this work:

• High energy astrophysics

• Ground-based gamma-ray astronomy


• Analysis of H.E.S.S. data

• Usage of modern machine learning techniques

• Programming in Python

Interested? Please get in touch:

• Matthias Buchele, [email protected] 305, Erwin-Rommel-Str. 1

• David Jankowsky, [email protected] 309, Erwin-Rommel-Str. 1


Masterarbeit

Winter 2018

Fermi Large Area Telescope (LAT) is a gamma-ray space telescope on board the NASA Fermi sa-tellite. Since its launch, in 2008, it measures gamma-ray emission from the whole sky in energiesfrom 30 MeV to above 1 TeV. At �-ray energies there are a lot of interesting objects, e.g pulsars,binary-stars and supernovae in the Galaxy, or bright sources as Active Galactic Nuclei, blazarsand Radio-galaxies outside our Galaxy. Although many sources have been detected, the mecha-nism that accelerates particles and creates photon with high energies is still under investigation.

Study of �-ray flare emission on months scale with Fermi-LAT

In order to detect and to study time variability of sources, we need analysis with different timescales. The Fermi collaboration released catalogs of sources in time-intervals of a few days orintegrated time of a few years (i.e. 4 years of data were used in the last released catalog, the3FGL), but there are not yet lists of sources that are made with a period of a few moths.

The goal of the thesis is to analyze the Fermi-LAT data for studying celestial sources with flareemission in intervals of time of a few moths.

Since one of the largest uncertainties in the sources studies, at Fermi-LAT energies, is the uncer-tainty in the diffuse background, for the analysis we will use PGWave, a background independentmethod, recently tested for performing point source analysis without the need of a diffuse model.


• High-energy astrophysics

• Space-based gamma-ray astronomy


• Modern analysis of gamma-ray data

• Monte Carlo Simulation



• Giacomo Principe, [email protected] 312, Erwin-Rommel-Str. 1

• Dr. Dmitry Malyshev, [email protected] 324, Erwin-Rommel-Str. 1


MasterarbeitWinter 2018

The High Energy Stereoscopic System (H.E.S.S.) is a system of Imaging Atmospheric CherenkovTelescopes (IACT) for the investigation of cosmic gamma rays in the photon energy range of0.03 to 100 TeV. The Cherenkov Telescope Array (CTA) is the next generation ground-basedobservatory for gamma-ray astronomy at very-high energies. It will be the world’s largest and mostsensitive high-energy gamma-ray observatory in the 20 GeV to 300 TeV band. At �-ray energiesthere are a lot of interesting objects, e.g pulsars, binary-stars and supernovae in the Galaxy, orbright sources as Active Galactic Nuclei, blazars and Radio-galaxies outside our Galaxy.

Point source analysis with Wavelet Transform methods for H.E.S.S. and CTA

The first part of thesis will be to prepare and optimize the point source analysis using Monte Carlosimulated data. The goal of the thesis is to perform a point source analysis with the H.E.S.S. data,in order to search and study new possible celestial sources, and the CTA data challenge in orderto have an expectation of the possible new sources that could be detected in the future with CTA.

Since one of the largest uncertainties in the sources studies, at high energies, is the uncertaintyin the diffuse background, for the analysis we will use Wavelet Transform. It is an innovativebackground independent method, recently tested for performing point source analysis without theneed of a diffuse model.



• Ground-based gamma-ray astronomy


• Modern analysis of gamma-ray data

• Monte Carlo Simulation



• Giacomo Principe, [email protected] 312, Erwin-Rommel-Str. 1



Bachelor / Masterarbeit

Winter 2018/2019

Das Cherenkov Telescope Array (CTA) wird das großte bodengebundene Gammastrahlungsex-periment sein, das bisher gebaut worden ist. Es wir eine Verbesserung der Sensitivitat um einenFaktor 10 im Vergleich zu den momentan exisiterenden Experimenten erreichen. Dies ist durchdas Zusammenspiel von unterschiedlichen Teleskoptypen moglich. Wir arbeiten u.a. an der Ent-wicklung der FlashCam Kamera. Hierbei liegt unser Fokus in der Optimierung, im Testen und inder Produktion der Photosensor Module sowie die Charakterisierung der Lichtsensoren (PMTs).

The Cherenkov Telescope Array (CTA) will be the largest ground-based gamma-ray experimentever built. It will reach sensitivities that are improved by 10 times with respect to currently runningexperiments. This can be achieved by the interplay of telescopes of different types. We are deeplyinvolved among others at the development of the FlashCam camera. We take an active part in theoptimization, testing and production of the photosensor modules and the characterization of thephotosensors (PMTs).

Masterarbeit: Characterization of photosensors of CTA

Die Performance einer Kamera wird stark durch die Photosensoren (PMTs) beeinflusst. Aus die-sem Grund haben wir am ECAP einen Teststand zur vollstandigen Charakterisierung von Pho-tomultipliern aufgebaut. Dieser ermoglicht die Gute der PMTs zu bestimmen. Im Rahmen derMasterarbeit wird zum einen eine vollstandige Charaketrisierung des Teststandes durchgefuhrt,um dessen Systematiken zu bestimmen. Nachdem ein tiefes Verstandnis fur den Teststand er-worben wurde, werden PMTs, die fur die zukunftigen FlashCam Kameras vermessen und derenPerformance bestimmt.

The performance of cameras strongly dependent on the photosenors (in case of FlashCam:PMTs). At ECAP we have designed and build a test setup to characterise the PMTs. This al-lows us to determine their quality. During the master thesis the test setup will be characterizedand the systematic errors will be quantified. After gaining a deep understanding of the setup,PMTs of the future FlashCam camera will be characterised.


• PD Dr. Ira Jung-Richard, [email protected] 311, Erwin-Rommel-Str. 1

• Stefan Eschbach, [email protected] 309, Erwin-Rommel-Str. 1

MasterarbeitFruhjahr/Sommer 2018

Kombinierte Datenanalyse mit Fermi-LAT und H.E.S.S.Combined data analysis with Fermi-LAT and H.E.S.S.

Das Fermi Large Area Telescope (LAT) ist ein Satellitenexperiment, welches Gammastrahlungim Energiebereich von 20 MeV bis 300 GeV detektiert. Das High Energy Stereoscopic System(H.E.S.S.) ist ein System aus funf Cherenkov-Teleskopen, welche Gammastrahlung uberhalb vonetwa 100 GeV messen konnen. Aufgrund der sich erganzenden Sensitivitat in verschiedenenEnergiebereichen ist es sinnvoll, Daten beider Experimente gleichzeitig zu analysieren. Dies sollmit Hilfe eines Open-Source-Analyseprogramms (z.B. Gammapy, siehe docs.gammapy.org) ver-sucht werden, mogliche Quellen waren etwa der Krebsnebel oder die aktiven Galaxienkerne PKS2155 und Centaurus A.

The Fermi Large Area Telescope (LAT) is a satellite experiment that detects gamma rays in theenergy range between 10 MeV and 300 GeV. The High Energy Stereoscopic System (H.E.S.S.)is an array of five Cherenkov telescopes that measure gamma rays above 100 GeV. Because thetwo instruments are sensitive in different energy ranges, it is useful to analyze data from bothexperiments simultaneously. This should be attempted using an open-source analysis tool (e.g.Gammapy, see docs.gammapy.org), possible sources include the Crab nebula as well as activegalactic nuclei such as PKS 2155 or Centaurus A.

Physikalische Themengebiete, die in dieser Arbeit behandelt werden:

• Entstehung von Gammastrahlung in astrophysikalischen Umgebungen

• Nachweis von Gammastrahlung mit satelliten- und bodengebundenen Experimenten

Fertigkeiten, die in dieser Arbeit erlernt werden:

• Einblick in die Analyse von Gammastrahlungsdaten

• Umgang mit der Analysesoftware (z.B. Gammapy)

• Programmieren mit modernen Programmiersprachen (z.B. python)


• Dr. Lars Mohrmann, [email protected] 324, Erwin-Rommel-Str. 1

• Prof. Dr. Christopher van Eldik, [email protected] 316, Erwin-Rommel-Str. 1


Bachelor/Master Thesis

Summer 2018

The Cherenkov Telescope Array (CTA) is the next-generation instrument for very-high-energy gamma-ray astronomy. There will be two sites for the northern sky (La Palma, Spain) and for the southern sky(Cerro Paranal, Chile), respectively, and from about 2019/2020 onwards observations will be carried out.In addition, it is proposed to be used as a large stellar intensity interferometer with unprecedented angularresolution.

Das Cherenkov Telescope Array (CTA) ist das Zukunftsprojekt der hochenergetischen Gammaastrono-mie, das aus zwei Standorten fur den nordlichen Himmel (La Palma, Spanien) und den sudlichen Himmel(Cerro Paranal, Chile) besteht und ab 2019/2020 die ersten Beobachtungen liefern wird. Zusatzlich wirdman es als Intensitatsinterferometer mit noch nie dagewesener Winkelauflosung verwenden.

Characterisation of optical components in preparation for intensity interferometry with CTA

Fur Intensitatsinterferometrie muss das im Teleskop fokussierte Licht schmalbandig gefiltert werden. Dazuwird es in eine optische Faser eingekoppelt, aus dem Fokus geleitet und direkt in ein System aus zweiLinsen und einem Interferenzfilter ausgekoppelt. Anschließend detektieren Photomultiplier die einzelnenPhotonen, die das System passieren. In dieser Arbeit wird das System ab der Einkopplung in die optischeFaser bis zur Detektion am PMT charakterisiert, wobei besonders die Schmalbandigkeit des gefiltertenLichts und die Verluste der einzelnen Komponenten im Vordergrund stehen.

To perform intensity interferometry, the focused light in the telescope needs to be filtered to a small op-tical bandwidth. For that, it is coupled into an optical fiber, guided out of the focal spot and outcoupleddirectly into a system which consits of two lenses and an interferometric filter. Afterwards, photomultipliersdetect the single photons which pass the system. This thesis characterises the whole system from thecoupling into the fiber to the detection with the photomultipliers, in particular the bandwidth of the filteredlight and the losses of each component.


• Intensity interferometry in astronomy

• Characterisation of optical systems

Skills acquired during this work

• Experience with and knowledge about optical systems

• Working with photomultipliers and spectrometers

• Working together in a motivated team


• Peter Deiml, [email protected], Buro 305

• Gisela Anton, [email protected], Buro 216

• Stefan Funk, [email protected], Buro 219


Summer 2018



Intensity interferometry with IceAct-telescopes

Als Vorstufe der Beobachtung mit CTA-Teleskopen von großen CTA-Teleskopen konnen auch kleine, hand-liche Linsenteleskope fur Intensitatsinterferometrie verwendet werden, wie z.B. ein oder mehrere IceAct-Teleskope, die ursprunglich fur das IceCube-Experiment am Sudpol entwickelt werden. Ziel dieser Arbeitist es, funktionierende und im Labor getestete Detektoren und Elektronik in ein IceAct-Prototypteleskop zuintegrieren und Interferometriemessungen im Labor und unter freiem Himmel durchzufuhren. Schwerpunk-te werden die Charakterisierung des Teleskops, die mechanische Justage des Detektorsystems sowie dieDurchfuhrung von Testmessungen und deren Analyse (mit existierender Software) sein.

Small and handy refractors can be used instead of the large CTA-telescopes to do intensity interfero-metry. One possiblity are IceAct-telescopes which are orginally developed for the IceCube-experiment atthe South Pole. In this thesis, working and already tested detectors and electronics are integrated in anIceAct-telescope prototype and interferometry measurements are carried out in the lab and outdoors. Thefocus is on the characterisation of the telescope, the mechanical adjustment of the detector system and thedevelopment as well as their analysis (with an existing software).



• Refractor optics, photon detection and data analysis


• Experience with and knowledge about fast photomultipliers

• Statistical analysis of large amount of data




• Gisela Anton, [email protected], Bro 216



Summer 2018



Intensit

¨

atsinterferometrie mit der CTA-Kamera FlashCAM

Intensitatsinterferometrie kann mit einzelnen Photonen (Photon counting) oder unter Verwendung des Pho-tostroms von Photomultipliern (photon current) durchgefuhrt werden, wobei unterschiedliche Detektorsy-steme eingesetzt werden. Ein mogliches System fur die Photon current Methode ist das Standardauslese-system der mittelgroßen CTA-Teleskope, die sogenannte FlashCAM. Ziel dieser Arbeit ist es, FlashCAMhinsichtlich ihres Einsatzes fur Intensitatsinterferometrie zu untersuchen und zu charakterisieren, wobeibesonderes Augenmerk auf die zeitliche Auflosung, die maximalen Photonraten, die Signalverarbeitungund die produzierte Datenrate gelegt wird.

Intensity interferometry can be done using single photons (photon counting) or the photo current of pho-tomultipliers (photon current) but different detection system are required. One option for the photo currentmethod is the standard camera electronics of the MSTs, the so called FlashCAM. This work investigatesand characterises the FlashCAM electronics in terms of its usage for intensity interferometry especially thetemporal resolution, the maximal photon rates, the signal chain and the produced amount of data are ofinterest.



• Readout electronics of CTA (FlashCAM)


• Characterisation of CTA-camera (FlashCAM) electronics

• Statistical analysis of data




• Gisela Anton, [email protected], Buro 216


Masterarbeit

Winter 2018 - 2019

Fermi Large Area Telescope (LAT) is a gamma-ray space telescope on board the NASA Fermi sa-tellite. Since its launch, in 2008, it measures gamma-ray emission from the whole sky in energiesfrom 30 MeV to above 1 TeV.

The gamma-ray emission can be separated into emission from individual sources and diffuseemission created by interactions of cosmic rays with gas and low energy photons in the Milky Waygalaxy. Interactions of cosmic rays on the surface of the Moon and the Sun make the Moon andthe Sun gamma-ray sources as well. Likewise, interactions of cosmic rays with asteroids in theasteroid belt should produce gamma-rays. The magnitude of the expected flux of gamma-raysdepends on the distribution of asteroids as a function of their mass. Since the interactions happenon the surface of the asteroids, the signal is larger, if there are a lot of small asteroids. Thusgamma-ray observations can detect or put constraints on the population of small-size asteroids,which are impossible to observe with telescopes.

Search for the gamma-ray emission from astroids in the Solar system

There exist models that predict a certain gamma-ray signal from the asteroids in the Solar system.The signal should look like a ring at the position of the asteroid belt. The project is to analyze thediffuse Fermi-LAT gamma-ray data to search for this signal and, in case of non-detection, putconstraints on the models of the distribution of asteroids as a function of their mass / size.



• Space-based gamma-ray astronomy


• Analysis of diffuse gamma-ray data





Documents

Bachelor / Master thesis - ECAP · Master & Bachelor thesis Winter 2018/2019 The aim of laboratory astrophysics is to prepare, control and investigate systems which beha-ve similar