2003/01/25 by Aya Bamba, Masaru Ueno, Katsuji Koyama +1 · 1 citation
Physics and Astronomy · #astro-ph
paper · pdf · doi:10.1086/374354
published as Astrophys.J. 589 (2003) 253-260 · 17 pages, 9 figures; to appear in ApJ
arxiv created 2003/01/25 · arxiv updated 2009/12/01
We found diffuse hard X-ray sources, G11.0+0.0, G25.5+0.0, and G26.6-0.1 in the ASCA Galactic plane survey data. The X-ray spectra are featureless with no emission line, and are fitted with both models of a thin thermal plasma in non-equilibrium ionization and a power-law function. The source distances are estimated to be 1-8 kpc, using the best-fit NH values on the assumption that the mean density in the line of sight is 1 H cm-3. The source sizes and luminosities are then 4.5-27 pc and (0.8-23)x1033 ergs/s. Although the source sizes are typical to supernova remnants (SNR) with young to intermediate ages, the X-ray luminosity, plasma temperature, and weak emission lines in the spectra are all unusual. This suggests that these objects are either shell-like SNRs dominated by X-ray synchrotron emission, like SN 1006, or, alternatively, plerionic SNRs. The total number of these classes of SNRs in our Galaxy is also estimated.