Discovery of a New Supernova Remnant in the Direction of G69.7+1.0.pdf
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PASJ: Publ. Astron. Soc. Japan , –?? (2008)
Discovery of a New Supernova Remnant in the Direction of
G69.7+1.0
Kumi Yoshita, Emi Miyata, and Hiroshi Tsunemi
Department of Earth and Space Science, Graduate School of Science, Osaka University
1-1 Machikaneyama, Toyonaka, Osaka 560-0043
E-mail(KY): kyoshita@ess.sci.osaka-u.ac.jp
(Received 1999 December 27; accepted 2000 April 20)
Abstract
We discovered a middle-aged supernova remnant in the vicinity of G69.7+1.0 using the ASCA satellite.
G69.7+1.0 was identified in the 2.7 GHz survey and classified as a shell-type SNR with a diameter of 16′.
During the ROSAT all-sky survey, the X-ray emission was detected in the direction of G69.7+1.0. However,
it extends beyond the radio shell, and an X-ray bright region was located outside of the radio shell. A
spectral study with the ASCA and ROSAT shows a thin thermal plasma with an electron temperature
of ~ 0.4 keV. There is no significant variation of the spectral parameters over the field of view, except
for the lower column density of the eastern part. We also found a large shell structure which surrounds
the X-ray bright region in both optical and radio images. We suggest that the observed X-ray emission
is associated with the large optical and radio shell, and that they are part of a new SNR, different from
the radio SNR G69.7+1.0, which we have named AX J2001+3235 or G69.4+1.2. The large shell and the
electron temperature of ~ 0.4 keV indicate that AX J2001+3235 is an evolved SNR. From a comparison
with the column density of CTB 80 (G69.0+2.7), we estimate that the distance of the SNR is about 2.5 kpc.
Key words: ISM: individual (G69.7+1.0) — supernova remnants — X-rays: ISM
1. Introduction
Most galactic supernova remnants (SNRs) have been
discovered and classified by observations in the radio
band. Green’s present catalog (1998 September version;
Green 1998) lists 220 SNRs. These remnants are clas-
sifie
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