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Haberl F.,Max Planck Institute for Extraterrestrial Physics | Filipovic M.D.,University of Western Sydney | Bozzetto L.M.,University of Western Sydney | Crawford E.J.,University of Western Sydney | And 6 more authors.
Astronomy and Astrophysics

Context. The Large Magellanic Cloud (LMC) is rich in supernova remnants (SNRs), which can be investigated in detail with radio, optical, and X-ray observations. SNR J0453-6829 is an X-ray and radio-bright remnant in the LMC, within which previous studies revealed the presence of a pulsar wind nebula (PWN), making it one of the most interesting SNRs in the Local Group of galaxies. Aims. We study the emission of SNR J0453-6829 to improve our understanding of its morphology, spectrum, and thus the emission mechanisms in the shell and the PWN of the remnant. Methods. We obtained new radio data with the Australia Telescope Compact Array and analysed archival XMM-Newton observations of SNR J0453-6829. We studied the morphology of SNR J0453-6829 from radio, optical, and X-ray images and investigated the energy spectra in the different parts of the remnant. Results. Our radio results confirm that this LMC SNR hosts a typical PWN. The prominent central core of the PWN exhibits a radio spectral index α Core of-0.04 ± 0.04, while in the rest of the SNR shell the spectral slope is somewhat steeper with α Shell =-0.43 ± 0.01. We detect regions with a mean polarisation of P ≅ (12 ± 4)% at 6 cm and (9 ± 2)% at 3 cm. The full remnant is of roughly circular shape with dimensions of (31 ± 1) pc × (29 ± 1) pc. The spectral analysis of the XMM-Newton EPIC and RGS spectra allowed us to derive physical parameters for the SNR. Somewhat depending on the spectral model, we obtain for the remnant a shock temperature of around 0.2 keV and estimate the dynamical age to 12 000-15 000 years. Using a Sedov model we further derive an electron density in the X-ray emitting material of 1.56 cm -3, typical for LMC remnants, a large swept-up mass of 830 M ·, and an explosion energy of 7.6 × 10 50 erg. These parameters indicate a well evolved SNR with an X-ray spectrum dominated by emission from the swept-up material. © 2012 ESO. Source

De Horta A.Y.,University of Western Sydney | Filipovic M.D.,University of Western Sydney | Bozzetto L.M.,University of Western Sydney | Maggi P.,Max Planck Institute for Extraterrestrial Physics | And 12 more authors.
Astronomy and Astrophysics

Context. The supernova remnants (SNRs) known in the Large Magellanic Cloud (LMC) show a variety of morphological structures in the different wavelength bands. This variety is the product of the conditions in the surrounding medium with which the remnant interacts and the inherent circumstances of the supernova event itself. Aims. This paper performs a multi-frequency study of the LMC SNR J0530-7007 by combining Australia Telescope Compact Array (ATCA), Molonglo Observatory Synthesis Telescope (MOST), Röntgensatellit (ROSAT) and Magellanic Clouds Emission Line Survey (MCELS) observations. Methods. We analysed radio-continuum, X-ray and optical data and present a multi-wavelength morphological study of LMC SNR J0530-7007. Results. We find that this object has a shell-type morphology with a size of 215′′ × 180′′ (52 pc × 44 pc); a radio spectral index (α =-0.85 ± 0.13); with [S II]/Hα > 0.4 in the optical; and the presence of non-thermal radio and X-ray emission. Conclusions. We confirmed this object as a bona-fide shell-type SNR which is probably a result of a Type Ia supernova. © 2012 ESO. Source

Mehault J.,Laboratoire Univers Et Particules Of Montpellier | Acero F.,Laboratoire Univers Et Particules Of Montpellier | Cohen-Tanugi J.,Laboratoire Univers Et Particules Of Montpellier | Feinstein F.,Laboratoire Univers Et Particules Of Montpellier | And 3 more authors.
Proceedings of the 32nd International Cosmic Ray Conference, ICRC 2011

Extended very high energy gamma-ray emission from the direction of the W41 supernova remnant (G23.3-0.3) was first discovered by the H.E.S.S. Cherenkov telescopes and confirmed by MAGIC. However, the origin of this emission is still in debate. Different scenarios such as pulsar wind nebula or interaction with a giant molecular cloud (GMC) were proposed. Furthermore, a central compact object was detected in X-rays by XMM-Newton and recently by Chandra. This object is surrounded by a diffuse X-ray emission, supposed to be a dust halo or a pulsar wind nebula, could be the pulsar associated with W41. The discovery of high energy γ-ray emission towards W41 with Fermi LAT opens the possibility to study jointly with H.E.S.S. this region over seven decades in energy, helping us to unveil the origin of the γ-ray emission towards the W41 region. Source

Posselt B.,Pennsylvania State University | Pavlov G.G.,Pennsylvania State University | Suleimanov V.,Institute For Astronomie Und Astrophysik Tubingen | Suleimanov V.,Kazan Federal University | Kargaltsev O.,George Washington University
Astrophysical Journal

To examine the previously claimed fast cooling of the Central Compact Object (CCO) in the Cas A supernova remnant (SNR), we analyzed two Chandra observations of this CCO, taken in a setup minimizing instrumental spectral distortions. We fit the two CCO X-ray spectra from 2006 and 2012 with hydrogen and carbon neutron star atmosphere models. The temperature and flux changes in the 5.5 yr between the two epochs depend on the adopted constraints on the fitting parameters and the uncertainties of the effective area calibrations. If we allow a change of the equivalent emitting region size, R Em, the effective temperature remains essentially the same. If R Em is held constant, the best-fit temperature change is negative, but its statistical significance ranges from 0.8σ to 2.5σ, depending on the model. If we assume that the optical depth of the ACIS filter contaminant in 2012 was ±10% different from its default calibration value, the significance of the temperature drop becomes 0.8σ-3.1σ, for the carbon atmospheres with constant R Em. Thus, we do not see a statistically significant temperature drop in our data, but the involved uncertainties are too large to firmly exclude the previously reported fast cooling. Our analysis indicate a decrease of 4%-6% (1.9σ-2.9σ significance) for the absorbed flux in the energy range 0.6-6 keV between 2006 and 2012, most prominent in the ≈1.4-1.8 keV energy range. It could be caused by unaccounted changes of the detector response or contributions from unresolved SNR material along the line of sight to the CCO. © 2013. The American Astronomical Society. All rights reserved. Source

Bozzetto L.M.,University of Western Sydney | Filipovic M.D.,University of Western Sydney | Crawford E.J.,University of Western Sydney | Haberl F.,Max Planck Institute for Extraterrestrial Physics | And 11 more authors.
Monthly Notices of the Royal Astronomical Society

We report the Australia Telescope Compact Array (ATCA) and ROSAT detection of supernova remnant (SNR) J0529-6653 in the Large Magellanic Cloud (LMC) which is positioned in the projected vicinity of the known radio pulsar PSRB0529-66. In the radio continuum frequencies, this LMC object follows a typical SNR structure of a shell morphology with brightened regions in the south-west. It exhibits an almost circular shape of D= 33 × 31pc (1-pc uncertainty in each direction) and radio spectral index of α=-0.68 ± 0.03 - typical for mid-age SNRs. We also report detection of polarized regions with a peak value of ∼17 ± 7per cent at 6cm. An investigation of ROSAT images produced from merged Position Sensitive Proportional Counter (PSPC) data reveals the presence of extended X-ray emission coincident with the radio emission of the SNR. In X-rays, the brightest part is in the north-east. We discuss various scenarios with regard to the SNR-pulsar association with emphasis on the large age difference, lack of a pulsar trail and no prominent point-like radio or X-ray source. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS. Source

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