Blazar 1ES 1959+650 shows high and hard X-ray state
ATel #1315; E. Bottacini (MPE), V. Beckmann, W. Ishibashi (ISDC), M. Ajello, J. Greiner (MPE)
on 30 Nov 2007; 13:13 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Volker Beckmann (Volker.Beckmann@obs.unige.ch)
Subjects: X-ray, Gamma Ray, AGN
Referred to by ATel #: 1317
The TeV blazar 1ES 1959+650 has been observed by INTEGRAL within the
north-ecliptic pole key program. The source was detected by IBIS/ISGRI
within revolution 625 (199 ksec: 2007-11-25T19:47 until 2007-11-28T08:43) with 5.3 sigma in the 20-40 keV energy band with a
flux of about 4 mCrab. The source was not covered by JEM-X and
OMC. The spectrum is well represented by a single power law with
photon index 1.9+-0.4 which gives a model flux of 5.6e-11
erg/cm**2/sec in the 20-100 keV band (Lx = 5.5e44 erg/sec).
Based on the model, we expect the source to have a 2-10 keV
flux of about 4e-11 erg/cm**2/sec, half the value the blazar exhibited during
the strong outburst in 2001. The spectral slope
implies that the peak of the synchrotron emission lies within or near
to the band covered by IBIS/ISGRI. Based on models of the
spectral energy distribution (Tagliaferri et al. 2003), we expect a flux
of >1e-12 photons/cm**2/sec above 1 TeV, which would make 1ES 1959+650
again detectable for e.g. MAGIC.
Time resolved analysis of the IBIS/ISGRI data shows that the flux
varied throughout the INTEGRAL observation: 2.9+-1.0 mCrab (2007-11-24T16:52 - 2007-11-26T08:43), 4.2+-1.0 mCrab
(2007-11-26T08:45 - 2007-11-27T17:23), and 2.1+-1.1 mCrab (2007-11-27T17:25 - 2007-11-29T11:43).
INTEGRAL will continue to observe the field until 2007-12-04T08:35.
