159 research outputs found
Observations of the post shock break-out emission of SN 2011dh with XMM-Newton
After the occurrence of the type cIIb SN 2011dh in the nearby spiral galaxy M
51 numerous observations were performed with different telescopes in various
bands ranging from radio to gamma-rays. We analysed the XMM-Newton and Swift
observations taken 3 to 30 days after the SN explosion to study the X-ray
spectrum of SN 2011dh. We extracted spectra from the XMM-Newton observations,
which took place ~7 and 11 days after the SN. In addition, we created
integrated Swift/XRT spectra of 3 to 10 days and 11 to 30 days. The spectra are
well fitted with a power-law spectrum absorbed with Galactic foreground
absorption. In addition, we find a harder spectral component in the first
XMM-Newton spectrum taken at t ~ 7 d. This component is also detected in the
first Swift spectrum of t = 3 - 10 d. While the persistent power-law component
can be explained as inverse Compton emission from radio synchrotron emitting
electrons, the harder component is most likely bremsstrahlung emission from the
shocked stellar wind. Therefore, the harder X-ray emission that fades away
after t ~ 10 d can be interpreted as emission from the shocked circumstellar
wind of SN 2011dh.Comment: Accepted for publication as a Research Note in Astronomy and
Astrophysic
3D Hydrodynamic Simulations of the Galactic Supernova Remnant CTB 109
Using detailed 3D hydrodynamic simulations we study the nature of the
Galactic supernova remnant (SNR) CTB 109 (G109.1-1.0), which is well-known for
its semicircular shape and a bright diffuse X-ray emission feature inside the
SNR. Our model has been designed to explain the observed morphology, with a
special emphasis on the bright emission feature inside the SNR. Moreover, we
determine the age of the remnant and compare our findings with X-ray
observations. With CTB 109 we test a new method of detailed numerical
simulations of diffuse young objects, using realistic initial conditions
derived directly from observations. We performed numerical 3D simulations with
the RAMSES code. The initial density structure has been directly taken from
CO emission data, adding an additional dense cloud, which, when it is
shocked, causes the bright emission feature. From parameter studies we obtained
the position for an elliptical
cloud with based on the preshock density
from Chandra data and a maximum diameter of 4.54 pc, whose encounter with the
supernova (SN) shock wave generates the bright X-ray emission inside the SNR.
The calculated age of the remnant is about 11,000 yr according to our
simulations. In addition, we can also determine the most probable site of the
SN explosion. Hydrodynamic simulations can reproduce the morphology and the
observed size of the SNR CTB 109 remarkably well. Moreover, the simulations
show that it is very plausible that the bright X-ray emission inside the SNR is
the result of an elliptical dense cloud shocked by the SN explosion wave. We
show that numerical simulations using observational data for an initial model
can produce meaningful results.Comment: 9 pages, 6 figures, accepted for publication in A&
GALACTIC AND EXTRAGALACTIC SUPERNOVA REMNANTS AS SITES OF PARTICLE ACCELERATION
Supernova remnants, owing to their strong shock waves, are likely sources of Galactic cosmic rays. Studies of supernova remnants in X-rays and gamma rays provide us with new insights into the acceleration of particles to high energies. This paper reviews the basic physics of supernova remnant shocks and associated particle acceleration and radiation processes. In addition, the study of supernova remnant populations in nearby galaxies and the implications for Galactic cosmic ray distribution are discussed
Multi-Wavelength View of Supernova Remnants
This contribution gives a very short overview on the emission of supernova remnants and the processes that are responsible for both the thermal and non-thermal origins of the emission, typically observed in radio, X-rays, and up to gamma-rays. We discuss in particular the case of the Galactic SNR CTB 109. As detailed X-ray studies combined with observations in radio have shown, CTB 109 is interacting with a giant molecular cloud complex. The interaction of the SNR shock with dense interstellar clouds is responsible for both the unusual semi-circular morphology of the SNR and the bright X-ray feature inside the SNR, and, as has been shown recently, seems also to play a major role in the production of gamma-rays
ROSAT HRI catalogue of X-ray sources in the LMC region
All 543 pointed observations of the ROSAT High Resolution Imager (HRI) with
exposure times higher than 50 sec in a field of 10 deg x 10 deg covering the
Large Magellanic Cloud (LMC) were analyzed. A catalogue was produced containing
397 X-ray sources with their properties measured by the HRI. The list was
cross-correlated with the ROSAT Position Sensitive Propotional Counter (PSPC)
source catalogue presented by Haberl & Pietsch (1999), the SIMBAD data base,
and the TYCHO catalogue. 138 HRI sources are contained in the PSPC catalogue.
The spatial resolution of the HRI was higher than that of the PSPC and the
source position could be determined with errors mostly smaller than 15 arcsec
which are dominated by systematic attitude errors. 94 HRI sources were
identified with known objects based on their positional coincidence and X-ray
properties. The catalogue contains 39 foreground stars, 24 supernova remnants
(SNRs), five supersoft sources (SSSs), nine X-ray binaries (XBs), and nine AGN
well known from literature. Another eight sources were identified with known
candidates for these source classes. Additional 21 HRI sources are suggested in
the present work as candidates for SNR, X-ray binary in the LMC, or background
AGN because of their extent, hardness ratios, X-ray to optical flux ratio, or
flux variability.Comment: 22 pages, 8 figures, 4 table
XMM-Newton observation of the Galactic supernova remnant W51C (G49.1-0.1)
The supernova remnant (SNR) W51C is a Galactic object located in a strongly
inhomogeneous interstellar medium with signs of an interaction of the SNR blast
wave with dense molecular gas. Diffuse X-ray emission from the interior of the
SNR can reveal element abundances in the different emission regions and shed
light on the type of supernova (SN) explosion and its progenitor. The hard
X-ray emission helps to identify possible candidates for a pulsar formed in the
SN explosion and for its pulsar wind nebula (PWN). We have analysed X-ray data
obtained with XMM-Newton. Spectral analyses in selected regions were performed.
Ejecta emission in the bright western part of the SNR, located next to a
complex of dense molecular gas, was confirmed. The Ne and Mg abundances suggest
a massive progenitor with a mass of > 20 M_sun. Two extended regions emitting
hard X-rays were identified (corresponding to the known sources [KLS2002] HX3
west and CXO J192318.5+140305 discovered with ASCA and Chandra, respectively),
each of which has an additional point source inside and shows a power-law
spectrum with Gamma ~ 1.8. Based on their X-ray emission, both sources can be
classified as PWN candidates.Comment: 6 pages, 4 figures, accepted for publication in Astronomy and
Astrophysic
XMM-Newton view of the N 206 superbubble in the Large Magellanic Cloud
We perform an analysis of the X-ray superbubble in the N 206 HII region in
the Large Magellanic Cloud using current generation facilities to gain a better
understanding of the physical processes at work in the superbubble and to
improve our knowledge of superbubble evolution. We used XMM-Newton observations
of the N 206 region to produce images and extract spectra of the superbubble
diffuse emission. Morphological comparisons with Halpha images from the
Magellanic Cloud Emission Line Survey were performed, and spectral analysis of
the diffuse X-ray emission was carried out. We derived the physical properties
of the hot gas in the superbubble based on the results of the spectral
analysis. We also determined the total energy stored in the superbubble and
compared this to the expected energy input from the stellar population to
assess the superbubble growth rate discrepancy for N 206. We find that the
brightest region of diffuse X-ray emission is confined by a Halpha shell,
consistent with the superbubble model. In addition, faint emission extending
beyond the Halpha shell was found, which we attribute to a blowout region. The
spectral analysis of both emission regions points to a hot shocked gas as the
likely origin of the emission. We determine the total energy stored in the
bubble and the expected energy input by the stellar population. However, due to
limited data on the stellar population, the input energy is poorly constrained
and, consequently, no definitive indication of a growth rate discrepancy is
seen. Using the high-sensitivity X-ray data from XMM-Newton and optical data
from the Magellanic Cloud Emission Line Survey has allowed us to better
understand the physical properties of the N 206 superbubble and address some
key questions of superbubble evolution.Comment: 12 pages, 7 figures. Accepted for publication in A&
Chandra observation of the Galactic supernova remnant CTB 109 (G109.1-1.0)
Context: We study the X-ray emission of the Galactic supernova remnant (SNR)
CTB 109 (G109.1-1.0), which is well-known for its enigmatic half-shell
morphology both in radio and in X-rays and is associated with the anomalous
X-ray pulsar (AXP) 1E2259+586. Aims: We want to understand the origin of the
X-ray bright feature inside the SNR called the Lobe and the details of the
interaction of the SNR shock wave with the ambient interstellar medium (ISM).
Methods: The Lobe and the northeastern part of the SNR were observed with
Chandra ACIS-I. We analysed the spectrum of the X-ray emission by dividing the
entire observed emission into small regions. The X-ray emission is best
reproduced with one-component or two-component non-equilibrium ionisation
models depending on the position. In the two-component model one emission
component represents the shocked ISM and the other the shocked ejecta. Results:
We detect enhanced element abundances, in particular for Si and Fe, in and
around the Lobe. There is one particular region next to the Lobe with a high Si
abundance of 3.3 (2.6 - 4.0) times the solar value. This is the first,
unequivocal detection of ejecta in CTB 109. Conclusions: The new Chandra data
confirm that the Lobe was created by the interaction of the SNR shock and the
supernova ejecta with dense and inhomogeneous medium in the environment of SNR
CTB 109. The newly calculated age of the SNR is t ~ 1.4 x 10^4 yr.Comment: Accepted for publication in A&A. 9 pages, 10 figure
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