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@PHDTHESIS{Kleiner:622204,
author = {Kleiner, Tobias Kai},
othercontributors = {Berge, David and Kowalski, Marek and Wilms, Joern},
title = {{I}nvestigating the {M}icroquasar {SS} 433 and the
{P}e{V}atron {C}andidate {MGRO} {J}1908+06 with a {N}ovel
{E}xtended {S}ource {A}nalysis {M}ethod},
school = {Humboldt-Universität zu Berlin},
type = {Dissertation},
publisher = {Humboldt-Universität zu Berlin},
reportid = {PUBDB-2025-00242},
pages = {213},
year = {2024},
note = {Dissertation, Humboldt-Universität zu Berlin, 2023},
abstract = {The origins of galactic Very-high energy; 100 GeV < E < 100
TeV (VHE) and Ultra-high energy; 100 TeV < E(VHE) cosmic
rays remain largely unknown. However, recent studies suggest
the existence of numerousgalactic sources known as
PeVatrons, which have the ability to accelerate particles up
to Petaelectronvolt (PeV)energies. These PeVatron candidates
include Pulsar wind nebulae (PWNe), Supernova remnants
(SNRs) aswell as micro-quasars. Investigating the gamma-ray
emission at Gigaelectronvolt (GeV) and Teraelectronvolt(TeV)
energies from these sources provides valuable insights into
their physical properties and accelerationmechanisms. In the
scope of this thesis, we analyse data from the Very
Energetic Radiation Imaging TelescopeArray System (VERITAS)
gamma-ray observatory, which consists of an array of four
12-meter Imagingatmospheric Cherenkov telescopes (IACTs)
located in Arizona. Our focus is on understanding the
propertiesof two extended galactic sources: MGRO J1908+06, a
potential PeVatron candidate whose identification is yetto
be established, and SS 433, a microquasar.We adopt for the
first time in VERITAS a 3D maximum-likelihood analysis
method as part of Gammapy toconstrain the properties of the
investigated sources using spectromorphological models. This
involves theproduction and validation of offset-dependent
Instrument response functions (IRFs), including models
thatdescribe the irreducible cosmic-ray background, and the
validation of the analysis method using observationsof the
Crab Nebula.We apply this new method to analyse the extended
gamma-ray emission from MGRO J1908+06. We determinethat the
gamma-ray emission exhibits energy-dependent morphology. By
considering proton densities inthe region and analysing the
emission characteristics, we conclude that the emission is
likely a result ofsynchrotron radiation and inverse-Compton
scattering. We explore a potential association with the
pulsarPSR J1907+0602, suggesting that it could be the
remnant of a supernova explosion where the subsequentreverse
shock expelled the pulsar, leaving behind a relic pulsar
wind nebula. To validate the 3D maximumlikelihood analysis,
we employ a mimic data method, for performing a bias
correction and for estimating theuncertainties of the
analysis method.Additionally, we report significant
gamma-ray emission from the microquasar SS 433, representing
its firstdetection in the VERITAS data. The emission
originates from the region where the jets interact with
themedium of the W50 supernova remnant. SS 433, an X-ray
binary system in the Milky Way, consists of ablack hole and
an orbiting A-type star and exhibits two powerful jets.
Through 3D analyses, we determinethat the gamma-ray
emissions at the jet termination lobes exhibit an extended
and elongated structure. In amultiwavelength analysis, we
explore various scenarios to explain the origin of the
gamma-ray emission,employing models that describe the
particle populations responsible for the emission. Based on
the estimatedjet power of SS 433, a leptonic origin for the
observed gamma-ray emissions is favoured. Furthermore,
wefind no significant gamma-ray emission from the black hole
region and no evidence of variable gamma-ray emissions.
Envisioning the future of gamma-ray astronomy, we conduct
simulations to optimize thecharacteristics of Cherenkov
Telescope Array (CTA), the next-generation IACT.
Specifically, we focus onaddressing telescope shadowing
effects and optimizing the placement of the illuminators.},
keywords = {VERITAS (Other) / CTA (Other) / 3D Analysis (Other) /
PeVatron (Other) / MGRO J1908+06 (Other) / Microquasar
(Other) / SS 433 (Other) / VERITAS (Other) / CTA (Other) /
3D Analysis (Other) / PeVatron (Other) / MGRO J1908+06
(Other) / Microquasar (Other) / SS 433 (Other) / 530 Physik
(Other) / 520 Astronomie und zugeordnete Wissenschaften
(Other)},
cin = {$Z_CTA$ / $Z_VER$},
cid = {$I:(DE-H253)Z_CTA-20210408$ / $I:(DE-H253)Z_VER-20210408$},
pnm = {613 - Matter and Radiation from the Universe (POF4-613)},
pid = {G:(DE-HGF)POF4-613},
experiment = {EXP:(DE-H253)VERITAS-20170101 / EXP:(DE-H253)CTA-20150101},
typ = {PUB:(DE-HGF)11},
urn = {urn:nbn:de:kobv:11-110-18452/29497-4 },
doi = {10.3204/PUBDB-2025-00242},
url = {https://bib-pubdb1.desy.de/record/622204},
}