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Topics at the DRS Late stages stellar evolution White dwarfs Hot massive stars & extragalactic stellar astronomy Binaries with massive companions X-ray astronomy, neutron stars, black holes & AGN
Late stages of stellar evolution
SN Iaprogenitors
Chemical composition
Kinematics,Hypervelocit
y stars
Stephan Geier
Heiko HirschUli Heber
Christian Schmitt
White dwarf rotation
Alfred Tillich
pulsations
Hot massive stars & extragalactic stellar astronomy
NLTE model
atmospheres
Galactic abundance gradients
Chemical composition
Fernanda Nieva
Markus Firnstein
Norbert PrzybillaBA
Supergiants
Florian Schiller
White dwarfs
Diffusion Magnetic fields
Klaus Unglaub
Irmela Bues
Binaries with massive components
Horst Drechsel
Light curves
Large Magellanic
cloud
Stefan Nesslinger
Neutron stars, black holes & AGNNeutron
stars, black holes &AGN
Jörn Wilms
Cygnus X-1
Manfred Hanke
Observations
Optical spectroscopy: ESO, Calar Alto, Keck UV spectroscopy: HST & FUSE X-ray: XMM, Chandra, Suzaku, RXTE γ-ray: INTEGRAL Imaging & Astrometry Future: eRosita, SIMBOL-X
Education
Lecture courses for - Physics undergraduates (1. year) - Physics graduates - student teachers - non-physics graduates (mostly computer science) Lab course (Praktikum): 60 students/year Numerics course
Plate Archive
more than 40000 plates photographic monitoring (Felderplan with Sonneberg & Potsdam) from Bamberg: 1921 – 1960 Boyden-station (South Africa): 1963-1974 more than 12000 plates plate scanning since 2003 collaboration with Tsvetkov et al. (Bulgarian Academy of Sciences)
Public Outreach
Public observations, guided tours, slide shows and public lectures: 700-2000 people/year
Collaborations
Komponenten der Galaxis
Buser
Dark matter
Very old stars
Old starsYoung &
old stars
Quantitative
Spektralanalyse
Komplexe
Modelatome:
Schwere Elemente
Model Atmosphere
Atmospheric Parameters Teff, logg, [M/H]
Input
DETAILStatistical Equilibrium
&Radiative Transference
Rij = Rij(J)
Iteration until S
i = Si-1
S= S(ni)
Occupation numbers ni for each
* f line components* Statistical Weightscol and rad
Line profiles of the atom
Output DETAILInput SURFACE
ji
ijjijji
ijiji C+Rn=C+Rn )()(
1*)( iii S+S=J
)(),(),( τPτPτT e
Voigt profile
Abundan
ce
SURFACE
Model AtomLevels:
*Excitation Potentials*Statistical Weights*Ionization States
Transitions:*Oscillator Strength
*Photoionization cross sections*Excitation and Ionization
cross sections
F
lux
Elementhäufigkeiten
Heiße Sterne: Ultravioletspektroskopie: HST
Elementhäufigkeiten:
- Unterhäufigkeiten leichter Elemente- Überhäufigkeiten schwerer Elemente
im Vergleich zur Sonne
Asteroseismologie
Nichtradiale Pulsationen
Hyper-velocity star
Definition:
- Raumgeschwindigkeit übersteigt lokale Entweichgeschwindigkeit
Stern ist nicht mehr an Galaxis gebunden
- Entweichgeschwindigkeit von der Galaxis: ca. 500km/s