skip to main content

SciTech ConnectSciTech Connect

Title: THE REFINED SHOCK VELOCITY OF THE X-RAY FILAMENTS IN THE RCW 86 NORTHEAST RIM

A precise measurement of shock velocities is crucial for constraining the mechanism and efficiency of cosmic-ray (CR) acceleration at supernova remnant (SNR) shock fronts. The northeastern rim of the SNR RCW 86 is thought to be a particularly efficient CR acceleration site, owing to the recent result in which an extremely high shock velocity of ∼6000 km s{sup −1} was claimed. Here, we revisit the same SNR rim with the Chandra X-ray Observatory, 11 years after the first observation. This longer baseline than previously available allows us to determine a more accurate proper motion of the nonthermal X-ray filament, revealing a much lower velocity of 3000 ± 340 km s{sup −1} (and even slower at a brighter region). Although the value has dropped to one-half of that from the previous X-ray measurement, it is still higher than the mean velocity of the Hα filaments in this region (∼1200 km s{sup −1}). This discrepancy implies that the filaments bright in nonthermal X-rays and Hα emission trace different velocity components, and thus a CR pressure constrained by combining the X-ray kinematics and the Hα spectroscopy can easily be overestimated. We also measure the proper motion of the thermal X-ray filament immediately to the southmore » of the nonthermal one. The inferred velocity (720 ± 360 km s{sup −1}) is significantly lower than that of the nonthermal filament, suggesting the presence of denser ambient material, possibly a wall formed by a wind from the progenitor, which has drastically slowed down the shock.« less
Authors:
; ; ;  [1] ;  [2] ;  [3] ; ;  [4]
  1. NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States)
  2. Institute of Space and Astronautical Science, JAXA, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan)
  3. Department of Astronomy and Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210 (United States)
  4. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
Publication Date:
OSTI Identifier:
22518580
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 820; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; COSMIC RADIATION; EFFICIENCY; EMISSION SPECTRA; FILAMENTS; HYDROGEN; PROPER MOTION; SHOCK WAVES; STELLAR WINDS; SUPERNOVA REMNANTS; VELOCITY; X RADIATION