Swift XRT follow-up of very high energy gamma-ray emission detected from PKS 1440-389 with H.E.S.S.
ATel #4098; W. Hofmann for the H. E. S. S. Collaboration
on 6 May 2012; 11:41 UT
Credential Certification: Berrie Giebels (berrie@poly.in2p3.fr)
Subjects: >GeV, TeV, VHE, AGN
An 8ks exposure with the Swift observatory of PKS 1440-389 was obtained on April 29,
following the H.E.S.S. detection of very high energy gamma-ray emission in the direction of
this BL Lac object (ATel #4072). This resulted in a clear detection in the quicklook data of
this object with sufficient spectral counts in the 0.3-7 keV range. The best spectral fit in
a preliminary analysis was obtained with an absorbed logparabolic model (alpha = 2.50 +/-
0.04, beta = 0.4 +/- 0.1) fixed at the Galactic absorption (NH = 7.7e20/cm^2). The
unabsorbed flux in the 0.3-10 keV, based on a fit in the 0.3-7 keV range, is 1.4e-11
erg/cm^2/s, which is compatible with the 0.1-2.4 keV flux of 6.6e-12 ergs/cm^2/s from the
Third Edition of the Roma BZCAT Multi-frequency Catalogue of Blazars (Massaro et al., 2009,
A&A, 495, 691) as well as with archival Swift observations, suggesting that the source might
not be in a high X-ray state.
The Swift team is gratefully acknowledged for accepting our observation request and their
compliance with H.E.S.S. observational constraints.
