X-Ray Emission from Multi-Phase Shock in the Large Magellanic
Cloud Supernova Remnant N49
Sangwook Park*, David N. Burrows*, Gordon P. Garmire*, John A. Nousek*,
John P. Hughes**, and Rosa Murphy Williams***
* Department of Astronomy and Astrophysics, Pennsylvania State University,
525 Davey Laboratory, University Park, PA. 16802
** Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ. 08854-8109
***Department of Astronomy, B619E - LGRT, University of Massachusetts,
Amherst, MA 01003
Accepted for the publication in The Astrophysical Journal (v586 n1 March
20, 2003)
ABSTRACT
The supernova remnant (SNR) N49 in the Large Magellanic Cloud
has been observed with the Advanced CCD Imaging Spectrometer
(ACIS) on board the Chandra X-Ray Observatory. The superb
angular resolution of the Chandra/ACIS images resolves a
point source, the likely X-ray counterpart of soft
gamma-ray repeater SGR 0526-66, and the diffuse filaments
and knots across the SNR. These filamentary features represent
the blast wave sweeping through the ambient interstellar medium
and nearby dense molecular clouds. We detect metal-rich ejecta
beyond the main blast wave shock boundary in the southwest of the
SNR, which appear to be explosion fragments or ``bullets''
ejected from the progenitor star. The detection of strong H-like
Si line emission in the eastern side of the SNR requires multi-phase
shocks in order to describe the observed X-ray spectrum, whereas
such a multi-phase plasma is not evident in the western side. This
complex spectral structure of N49 suggests that the postshock
regions toward the east of the SNR might have been reheated by the
reverse shock off the dense molecular clouds while the blast
wave shock front has decelerated as it propagates into the dense
clouds. The X-ray spectrum of the detected point-like source is
continuum dominated and can be described with a power law of
Gamma ~ 3. This provides a confirmation that this point-like
X-ray source is the counterpart of SGR 0526-66 in the quiescent state.
Preprint (astro-ph/0211552)