A NEW EVOLUTIONARY PHASE OF SUPERNOVA REMNANT 1987A

• Main Authors: Park, Sangwook (Author), Zhekov, Svetozar A. (Author), Burrows, David N. (Author), Racusin, Judith L. (Author), Dewey, Dan (Contributor), McCray, Richard (Author)
• Other Authors: MIT Kavli Institute for Astrophysics and Space Research (Contributor)
• Format: Article
• Language: English
• Published: IOP Publishing, 2015-02-25T22:38:17Z.
• Subjects: Article
• Online Access: Get fulltext

 We have been monitoring the supernova remnant (SNR) 1987A with Chandra observations since 1999. Here we report on the latest change in the soft X-ray light curve of SNR 1987A. For the last ~1.5 yr (since day ~8000), the soft X-ray flux has significantly flattened, staying (within uncertainties) at f[subscript X] ~ 5.7 × 10[superscript -12] erg cm[superscript -2] s[superscript -1 ](corresponding to L[subscript X] ~ 3.6 × 10[superscript 36] erg s[superscript -1]) in the 0.5-2 keV band. This remarkable change in the recent soft X-ray light curve suggests that the forward shock is now interacting with a decreasing density structure, after interacting with an increasing density gradient over ~10 yr prior to day ~8000. Possibilities may include the case that the shock is now propagating beyond a density peak of the inner ring. We briefly discuss some possible implications on the nature of the progenitor and the future prospects of our Chandra monitoring observations.