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ATEL # 1482; S.A. Grebenev (IKI, Moscow), R.A. Sunyaev (IKI, Moscow; MPA, Garching)
on 17 Apr 2008; 18:08 UT
Distributed as an Instant Email Notice (Request for Observations)
Password Certification: S.A.Grebenev (email@example.com)
Subjects: X-ray, Request for Observations, Neutron Stars, Transients
Referred to by ATEL #: 1493
We report on activity in hard X-rays of the supergiant fast X-ray transient SAX J1818.6-1703 (in't Zand et al. 1998, IAUC # 6840 ; Negueruela & Smith 2006, ATEL #831; in't Zand et al. 2006, ATEL #915). Since April 12, 2008, the IBIS/ISGRI instrument on board INTEGRAL detected several outbursts each lasted less than one day with increasing intensity. During the last outburst the 18-45 keV flux from the source reached a level of 40 mCrab. The measured light curve of the source can be found at http://hea.iki.rssi.ru/~sergei/lcurve_saxj1818.6-1703_apr2008.jpg
Similar activity of SAX J1818.6-1703 was observed with INTEGRAL only once in September 2003 (Grebenev & Sunyaev 2005, AstL 31, 672). However the source has triggered recently the BAT/SWIFT (on March 15, 2008, Barthelmy et al., GCN #7419).
We encourage follow-up observations of the source at all wavelengths.