Show simple item record

dc.contributor.authorAcero, F.en_US
dc.contributor.authorBüsching, I.en_US
dc.contributor.authorDavids, I.D.en_US
dc.contributor.authorDe Jager, O.C.en_US
dc.contributor.authorHolleran, M.
dc.contributor.authorRaubenheimer, B.C.
dc.contributor.authorVenter, C.
dc.date.accessioned2012-02-29T09:51:58Z
dc.date.available2012-02-29T09:51:58Z
dc.date.issued2010en_US
dc.identifier.citationAcero, F. et al. 2010. PKS 2005-489 at VHE: four years of monitoring with HESS and simultaneous multi-wavelength observations. Astronomy & astrophysics, 511: Article no A52. [http://www.aanda.org/]en_US
dc.identifier.issn0004-6361en_US
dc.identifier.issn1432-0746 (Online)en_US
dc.identifier.urihttp://hdl.handle.net/10394/6128
dc.identifier.urihttps://doi.org/10.1051/0004-6361/200913073
dc.description.abstractAims. Our aim is to study the very high energy (VHE; E>100 GeV) γ-ray emission from BL Lac objects and the evolution in time of their broad-band spectral energy distribution (SED). Methods. VHE observations of the high-frequency peaked BL Lac object PKS 2005-489 were made with the High Energy Stereoscopic System (HESS) from 2004 through 2007. Three simultaneous multi-wavelength campaigns at lower energies were performed during the HESS data taking, consisting of several individual pointings with the XMM-Newton and RXTE satellites. Results. A strong VHE signal, ~17σ total, from PKS 2005-489 was detected during the four years of HESS observations (90.3 h live time). The integral flux above the average analysis threshold of 400 GeV is ~3% of the flux observed from the Crab Nebula and varies weakly on time scales from days to years. The average VHE spectrum measured from ~300 GeV to ~5 TeV is characterized by a power law with a photon index, . 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 () are also observed, which appear to be mirrored in the VHE band. Conclusions. 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
dc.publisherEDP Sciencesen_US
dc.subjectgalaxies: active
dc.subjectBL Lacertae objects: individual: PKS 2005-489
dc.subjectgamma rays: galaxies
dc.subjectX-rays: individuals: PKS 2005-489
dc.titlePKS 2005-489 at VHE: four years of monitoring with HESS and simultaneous multi-wavelength observationsen_US
dc.contributor.researchID10859748 - Holleran, Mathew
dc.contributor.researchID12006653 - Venter, Christo
dc.contributor.researchID10179240 - Raubenheimer, Barend Christoffel
dc.contributor.researchID13235176 - Büsching, Ingo
dc.contributor.researchID10065857 - De Jager, Ocker Cornelis
dc.contributor.researchID13146629 - Davids, Isak Delberth


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record