Nicholas, B.Rowell, G.2010-10-142010-10-142010Astronomy and Astrophysics: a European journal, 2010; 511(1):A52-1-A52-130004-63611432-0746http://hdl.handle.net/2440/61207VHE observations of PKS 2005-489 were made with HESS from 2004 through 2007, together with three simultaneous multi-wavelength campaigns performed with XMM-Newton and RXTE in 2004 and 2005. A strong VHE signal, ~17sigma total, is detected during the four years of HESS observations (90.3 hrs live time). The integral flux above the average analysis threshold of 400 GeV is ~3% of the Crab and varies weakly on time-scales from days to years. At X-ray energies the flux is observed to vary by more than an order of magnitude between 2004 and 2005. Strong changes in the X-ray spectrum (DeltaGamma~0.7) are also observed, which appear to be mirrored in the VHE band. The SED of PKS 2005-489, constructed for the first time with contemporaneous data on both humps, shows significant evolution. The large flux variations in the X-ray band, coupled with weak or no variations in the VHE band and a similar spectral behavior, suggest the emergence of a new, separate, harder emission component in September 2005.enCopyright © ESO, 2010. All rights reserved. Submitted to Cornell University’s online archive www.arXiv.org in 2009 by Luigi Costamante.Post-print sourced from www.arxiv.org.galaxies: activeBL Lacertae objects: individual: PKS 2005-489gamma rays: galaxiesX-rays: individuals: PKS 2005-489Cosmology and Extragalactic Astrophysics (astro-ph.CO)Journal article002009584210.1051/0004-6361/2009130730002757524000662-s2.0-7995282231535470Rowell, G. [0000-0002-9516-1581]