TY - JOUR
T1 - Detection of excess hard X-ray emission from the optical jet galaxy NGC 1097
AU - Iyomoto, Naoko
AU - Makishima, Kazuo
AU - Fukazawa, Yasushi
AU - Tashiro, Makoto
AU - Ishisaki, Yoshitaka
AU - Nakai, Naomasa
AU - Taniguchi, Yoshiaki
PY - 1996
Y1 - 1996
N2 - Using the ASCA observatory, X-ray observations were made of the spiral galaxy NGC 1097, which exhibits four optical jets. Hard X-ray emission from a point-like source at the nucleus was detected at a 2-10 keV luminosity of 1 × 1041 erg s-1 for an assumed distance of 24 Mpc. The 2-10 keV spectrum was well fitted with a power-law of photon index ∼ 1.8. Although no X-ray variability was detected during a ∼ 40 ks pointing, the observed X-ray to optical luminosity ratio of NGC 1097 is too high for the X-ray emission to be explained by an assembly of discrete X-ray sources. From our results and optical activity, the existence of a low-luminosity active galactic nucleus (LLAGN) is strongly suggested. In the soft X-ray band (0.5-2 keV) a thin thermal emission with a temperature kT ∼ 0.6 keV was also detected, which is understood to be emission from hot gas associated with starburst activity.
AB - Using the ASCA observatory, X-ray observations were made of the spiral galaxy NGC 1097, which exhibits four optical jets. Hard X-ray emission from a point-like source at the nucleus was detected at a 2-10 keV luminosity of 1 × 1041 erg s-1 for an assumed distance of 24 Mpc. The 2-10 keV spectrum was well fitted with a power-law of photon index ∼ 1.8. Although no X-ray variability was detected during a ∼ 40 ks pointing, the observed X-ray to optical luminosity ratio of NGC 1097 is too high for the X-ray emission to be explained by an assembly of discrete X-ray sources. From our results and optical activity, the existence of a low-luminosity active galactic nucleus (LLAGN) is strongly suggested. In the soft X-ray band (0.5-2 keV) a thin thermal emission with a temperature kT ∼ 0.6 keV was also detected, which is understood to be emission from hot gas associated with starburst activity.
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U2 - 10.1093/pasj/48.2.231
DO - 10.1093/pasj/48.2.231
M3 - Article
AN - SCOPUS:0030534738
SN - 0004-6264
VL - 48
SP - 231
EP - 236
JO - Publication of the Astronomical Society of Japan
JF - Publication of the Astronomical Society of Japan
IS - 2
ER -