X-rays originate from matter under extreme conditions. These are
found in accreting binary stars, the coronae of normal stars, very
compact stars, accreting supermassive black holes, and the hot
intergalactic medium in galaxy clusters. Our group has a (i) wide
and a (ii) narrow scope: (i) We use various X-ray surveys
to build complete samples of different source distributions the sky.
(ii) We investigate certain X-ray emitters to understand the
physical processes that lead to the emission of X-rays and the formation
of broad-band spectral energy distributions. The AIP X-ray group takes
part in national and international space missions such as XMM-Newton and eROSITA.
||(+49 331 - 7499...)
|Arjen de Hoon
from left to right:
Sabine Thater, Iris Traulsen, Gabriele Schönherr, Georg Lamer, Robert
Schwarz, Ali Takey, Valentina Scipione, Axel Schwope, Adriana Pires, René Heller
OLDER PICTURES (beginning 2005 at the right end)
FORMER MEMBERS (in alphabetical order)
Ada Nebot Gomez-Moran,
X-ray Binary Stars
Cataclysmic Variables (CVs) are compact, short period, interacting binaries with a white dwarf
as the primary star. Our research interest is mainly focused on systems that harbour a strongly
magnetic white dwarf. Here the field is large enough (1-230 MegaGauss) to greatly modify the
mass transfer from the mass donating secondary. Unlike nonmagnetic CVs the infalling material
is radially channelled to a compact region, where most of the kinetic energy is released as X-ray
and cyclotron emission. We use spectral and temporal information from X-ray missions like XMM-Newton
to derive an accurate understanding of the complex accretion zone. In addition, we try to resolve
the structure of the mass flow and the heated white dwarf involving indirect imaging techniques such
as Doppler tomography, eclipse mapping and light curve modelling. Another important aspect of our
work is the evolution of compact binaries. We are currently involved in a dedicated search for the
progenitors of Cataclysmic Variables using the SLOAN/SEGUE-survey.
Most recent papers:
- The serendipituous discovery of a
short-period eclipsing polar in 2XMMp
Vogel, J.; Byckling, K.; Schwope, A.; Osborne, J. P.;
Schwarz, R.; Watson, M. G.: 2008, Astron. Astrophys. 485, 787
- The changing accretion states of
the intermediate polar MU Cam
Staude, A.; Schwope, A.D.; Schwarz, R.; Vogel, J.; Krumpe, M.;
Nebot Gomez-Moran, A.: 2008, Astron. Astrophys. 486, 899
- XMM-Newton observations of EF Eridani:
the textbook example of low-accretion rate polars
Schwope, A.D.; Staude, A.; Koester, D.; Vogel, J.: 2007, Astron. Astrophys. 469, 1027
- Paloma (RX J0524+42): the missing link
in magnetic CV evolution?
Schwarz, R.; Schwope, A. D.; Staude, A.; Rau, A.; Hasinger, G.;
Urrutia, T.; Motch, C.: 2007, Astron. Astrophys. 473, 511
An in-depth study of the pre-polar candidate WX Leo Minoris
Vogel, J.; Schwope, A.D.; Gaensicke, B.T.: 2007, Astron. Astrophys. 464, 647
A 110 MG cyclotron harmonic in the optical spectrum of RX J1554.2+2721
Schwope, A.D.; Schreiber, M.R.; Szkody, P.: 2006, Astron. Astrophys. 452, 955
- Doppler tomography of the asynchronous polar
Schwarz, R., Schwope, A.D., Staude, A., Remillard, R.A.: 2005, Astron. Astrophys. 444, 213
Active Galactic Nuclei
Active Galactic Nuclei (AGN) are fuelled by accretion of matter onto supermassive black holes.
A large part of the power generated by the accretion process is emitted as X-ray radiation.
With the extended energy range and sensitivity of the X-ray telescopes on the XMM-Newton and
Chandra satellites it became possible to observe also AGN which are heavily obscured by gas and
dust in their surrounding medium. These absorbed AGN are thought to be responsible for the hard
spectrum of the cosmic X-ray background. Our main interests are the identification and study of
AGN in X-ray surveys and spectral studies of AGN with XMM-Newton. Projects include the XMM Marano
field survey and contributions to the identification of the XMM serendipity surveys conducted by
the XMM-Newton Survey Science Centre.
- RBS1423 - a new QSO with relativistic reflection from an ionised disk
M. Krumpe, G. Lamer, A.D. Schwope, B. Husemann, 2007, A&A, accepted
- The XMM-Newton Survey in the Marano Field I.
The X-ray data and optical follow-up
M. Krumpe, G. Lamer, A.D. Schwope, S. Wagner, G. Zamorani, M. Mignoli, R. Staubert, L. Wisotzki,
G. Hasinger, 2007, A&A, 466, 41
- Strange magnification pattern in the large
separation lens SDSS J1004+4112 from optical to X-rays
G. Lamer, A. Schwope, L. Wisotzki, L. Christensen, 2006, A&A, 454, 493
Isolated Neutron Stars
Isolated Neutron stars are a new class of soft X-ray emitters discovered by ROSAT.
Their unique properties are: a soft, thermal X-ray spectrum, very little interstellar
absorption, a high ratio between X-ray and optical flux, fX/fopt > 104,
no signs of binarity, no magnetospheric emission, and no association with a supernova remnant.
Despite the expection to find thousands of those objects in the ROSAT all-sky survey, to date
only seven could be uniquely identified, now termed the Magnificent Seven.
Our group was involved in the discovery of two of them, RBS1223 and RBS1556, which were identified
as bright X-ray source with no optical counterpart down to a magnitude of 25.6 in the
ROSAT Bright Survey
(Schwope et al. (2000), Astron. Nachr. 321, 1).
The great interest in those sources arose from the fact, that these stars offer the unique opportunity
to study a neutron's star surface uncontaminated from any other emission. There is hope, to identify
spectral features in their X-ray spectra which allow to derive constraints on the equation-of-state of
Our main achievements:
The identification of RBS1223 as an isolated neutron star candidate
Schwope A.D., Hasinger G., Schwarz R., Haberl F., Schmidt M., 1999, A&A 341, L51 (1999)
The isolated neutron star candidate RXJ J1605.3+3249
Motch C., Haberl F., Zickgraf F.-J., Hasinger G., Schwope A.D., 1999, A&A 351, 177
Discovery of 5.16 s pulsations from the isolated neutron star RBS1223
V. Hambaryan, G. Hasinger, A.D. Schwope, N. Schulz, 2002, A&A 381, 98
A broad absorption feature in the X-ray spectrum of the isolated neutron star RBS1223 (1RXS J130848.6+212708)
F. Haberl, A.D. Schwope, V. Hambaryan, G. Hasinger, C. Motch, 2003, A&A 403, L19
The discovery of a large proper motion of RBS1556 from SUBARU and HST images
Motch, C., Sekiguchi, K., Haberl, F., Zavlin, V.E., Schwope, A.D., and Pakull, M.W.: 2005, A&A 429, 257
A successful fit of the pulsing X-ray signal of RBS1223 with a two-spot model
Schwope, A.D., Hambaryan, V., Haberl, F., Motch, C.: 2005, A&A 441, 597
The discovery of second absorption feature in the X-ray spectrum of RBS1223
Schwope, A.D.; Hambaryan, V.; Haberl, F.; Motch, C.: 2007, Proceedings Conf. 'Isolated Neutron Stars: From the
interior to the surface', ApSS, in press
Clusters of Galaxies
Galaxy clusters are the largest gravitational bound objects known in the univere containing several
tens to hundreds of galaxies. Their evolution strongly depends on various cosmoligical parameters and
so they are ideal objects to stress cosmological models. As this dependency gets stronger in the
higher-redshift regime, we try tho extend the sample of such objects beyond redshift z=1, which is
roughly a distance of 8.5 billion lightyears.
While in the optical range most likely found as a local overdensity of galaxies, the are detectable
as extended sources in xrays. The XMM-Newton-archive provides a very good source to look for these
extended objects and so we started a large survey relying on that archive.
A pilot study was done some time ago and proved the reliability of the method to select the objects
in xrays, do imaging in to different color-ranges in optical/IR so select the most likely high-redshift
candidates and in a third step spectroscopically confirm their distance.
This international collaboration has in combination with the Rosat deep cluster survey increased the
number of known clusters with z > 1 from six to twelve. More candidates are in the queue.
In a recent study (Takey, Schwope, and Lamer 2011),
we presented a catalogue of X-ray selected galaxy clusters and groups as a first release of the 2XMMi/SDSS Galaxy Cluster Survey.
On this site, we present a more detailed summary of this work.
The AIP 70cm-Telescope
The AIP 70 cm reflector was built in
1958 and overhauled in 1994. The telescope is equipped with a cryogenic 1k x 1k CCD. Besides the training
for students it is frequently used for scientific observations. Principal application is time resolved
photometry of cataclysmic variable stars.
eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is a X-ray telescope which will be build under the leadership of the MPE. It should perform the first imaging all-sky survey in the medium energy X-ray range up to 10 keV with an unprecedented spectral and angular resolution. The nature of the mysterious Dark Energy that is driving the Universe apart is one of the most exciting questions facing astronomy and physics today. It may be the vacuum energy providing the Cosmological Constant in Einstein's theory of General Relativity, or it may be a time-varying energy field. The solution could require a fundamental revolution in physics. Clusters of galaxies are the largest collapsed objects in the Universe. Their formation and evolution is dominated by gravity, i.e. Dark Matter, while their large scale distribution and number density depends on the geometry of the Universe, i.e. Dark Energy. X-ray observations of clusters provide information on the rate of expansion of the Universe, the fraction of mass in visible matter and the amplitude of primordial fluctuations that are the origin of clusters of galaxies and the whole structure of the universe. (press release (german)).
The XMM Survey Science Centre (SSC) is a consortium of eight European institutions , led by Leicester University. Within the XMM project, the SSC has responsibilities to develop science analysis software for XMM (jointly with ESA's XMM Science Operations Centre), to perform a pipe-line processing of all XMM observations, and to conduct a follow-up/identification programme for the XMM serendipitous X-ray survey. The AIP has the responsibility to provide the source detection software for the pipe-line processing of the XMM EPIC data.
ROSAT Results Archive (till 2001)
The ROSAT Results Archive contains results (positions, count rates, hardness ratios, extent, and variability information) on some 100,000 objects detected in more than 5000 observations performed by ROSAT. The data have undergone a thorough screening and validation process, including an automatic screening and visual inspection of all ROSAT images. About 1700 ROSAT datasets were screened at AIP.
The project was conducted in collaboration with MPE, GSFC, SAO and Leicester University.
SODART (till 2000)
SODART was a high-throughput multi-mirror X-ray twin telescope of 8m focal length with changeable detectors on slides for energies between 0.1 and 20 keV for the SPECTRUM X GAMMA satellite, an international high-energy space mission under IKI (Russia) leadership. Launch was planned for 2003, but there was never a confirmation of a schedule for a firm launch date.
ABRIXAS (till 2000)
ABRIXAS (A Broad-band Imaging X-ray All-sky Survey) was a small satellite mission which was planned to observe the X-ray sky for three years in the energy band 0.5-10 keV. One main goal of the project was to study the absorbed AGN population and its contribution to the X-ray background.
After the succesful launch of the ABRIXAS satellite on April 28th 1999 it turned out that there was a failure in the satellite's power system. On July 1st 1999 DLR has declared that the scientific mission of ABRIXAS failed.
Galaxies and Quasars home
updated: 2011, Sep. 11 by René Heller