22 research outputs found
A Hard X-Ray View of Two Distant VHE Blazars: 1ES 1101-232 and 1ES 1553+113
TeV blazars are known as prominent nonthermal emitters across the entire
electromagnetic spectrum with their photon power peaking in the X-ray and TeV
bands. If distant, absorption of gamma-ray photons by the extragalactic
background light (EBL) alters the intrinsic TeV spectral shape, thereby
affecting the overall interpretation. Suzaku observations for two of the more
distant TeV blazars known to date, 1ES 1101-232 and 1ES 1553+113, were carried
out in 2006 May and July, respectively, including a quasi-simultaneous coverage
with the state-of-the-art Cerenkov telescope facilities. We report on the
resulting data sets with emphasis on the X-ray band and set in context to their
historical behavior. During our campaign, we did not detect any significant
X-ray or gamma-ray variability. 1ES 1101-232 was found in a quiescent state
with the lowest X-ray flux ever measured. The combined XIS and HXD PIN data for
1ES 1101-232 and 1ES 1553+113 clearly indicate spectral curvature up to the
highest hard X-ray data point (~30 keV), manifesting as softening with
increasing energy. We describe this spectral shape by either a broken power law
or a log-parabolic fit with equal statistical goodness of fits. The combined
1ES 1553+113 very high energy spectrum (90-500 GeV) did not show any
significant changes with respect to earlier observations. The resulting
contemporaneous broadband spectral energy distributions of both TeV blazars are
discussed in view of implications for intrinsic blazar parameter values, taking
into account the gamma-ray absorption in the EBL.Comment: 9 pages, 10 figure
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