Chandra spectroscopy of N157B -- a young composite supernova remnant in a superbubble
Abstract
We present Chandra ACIS observations of SNR N157B a young supernova remnant located in the 30 Doradus star-formation region of the Large Magellanic Cloud This remnant contains the most energetic pulsar known dot E 4 8 times 10 38 erg s -1 cm -2 which is surrounded by a bright nonthermal nebula that likely represents a toroidal pulsar wind terminal shock observed edge-on We confirm the non-thermal nature of the comet-shaped X-ray emission feature and show that the spectral steepening of this feature away from the pulsar is quantitatively consistent with synchrotron cooling of shocked pulsar particles flowing downstream at a bulk velocity close to the speed of light Around the cometary nebula we unambiguously detect a thermal component which accounts for about 1 3 of the total 0 5 -- 10 keV flux from the remnant This thermal component is distributed among various clumps of metal-enriched plasma embedded in the low surface brightness X-ray-emitting diffuse gas The relative metal enrichment pattern suggests that the mass of the supernova progenitor is sim20M odot A comparison of the X-ray data with a recent sl HST optical image suggests that the explosion site is close to a dense cloud against which a reflection shock is launched The interaction between this reflection shock and the nebula has likely produced both its cometary shape and the surrounding thermal emission enhancement SNR N157B is apparently expanding into the low density and hot interior of a nearby superbubble formed by the young OB association
- Publication:
-
36th COSPAR Scientific Assembly
- Pub Date:
- 2006
- Bibcode:
- 2006cosp...36.3444C