The vanishing of the primary emission region in PKS 1510-089

Abstract

In July 2021, PKS 1510-089 exhibited a significant flux drop in the high-energy gamma-ray (by a factor 10) and optical (by a factor 5) bands and remained in this low state throughout 2022. Similarly, the optical polarization in the source vanished, resulting in the optical spectrum being fully explained through the steady flux of the accretion disk and the broad-line region. Unlike the aforementioned bands, the very-high-energy gamma-ray and X-ray fluxes did not exhibit a significant flux drop from year to year. This suggests that the steady-state very-high-energy gamma-ray and X-ray fluxes originate from a different emission region than the vanished parts of the high-energy gamma-ray and optical jet fluxes. The latter component has disappeared through either a swing of the jet away from the line-of-sight or a significant drop in the photon production efficiency of the jet close to the black hole. Either change could become visible in high-resolution radio images.

Astrophysical Journal Letters 952, L38 (2023)
ArXiv pre-print

Auxiliary informations

Aharonian et al. (H.E.S.S. Collaboration), 2023, ApJL, 952, L38
Corresponding authors: Joleen Barnard, Markus Böttcher, Hester Schutte, Michael Zacharias

Data to Figures

Figure 1: MWL light curves
H.E.S.S. light curve [DAT]
Fermi-LAT light curves [DAT]
Swift-XRT light curve [DAT]
ATOM light curve [DAT]
SALT averaged polarimetry data [DAT]

Figure 2: Averaged MWL spectral energy distributions
2021 [DAT]
2022 [DAT]

Figure 3: Year-averaged degree of polarization
2021 [DAT]
2022 [DAT]

Figure 4: Degree of polarization, individual observations in 2021
2021 April 6   (MJD 59310)   [DAT]
2021 April 9   (MJD 59313)   [DAT]
2021 April 18 (MJD 59322)   [DAT]
2021 April 21 (MJD 59325)   [DAT]
2021 May 9    (MJD 59343)   [DAT]
2021 May 14  (MJD 59348)   [DAT]
2021 June 5    (MJD 59370)    [DAT]
2021 June 10  (MJD 59375)    [DAT]

 

Collaboration Acknowledgement

The support of the Namibian authorities and of the University of Namibia in facilitating the construction and operation of H.E.S.S. is gratefully acknowledged, as is the support by the German Ministry for Education and Research (BMBF), the Max Planck Society, the German Research Foundation (DFG), the Helmholtz Association, the Alexander von Humboldt Foundation, the French Ministry of Higher Education, Research and Innovation, the Centre National de la Recherche Scientifique (CNRS/IN2P3 and CNRS/INSU), the Commissariat à l’énergie atomique et aux énergies alternatives (CEA), the U.K. Science and Technology Facilities Council (STFC), the Irish Research Council (IRC) and the Science Foundation Ireland (SFI), the Knut and Alice Wallenberg Foundation, the Polish Ministry of Education and Science, agreement no. 2021/WK/06, the South African Department of Science and Technology and National Research Foundation, the University of Namibia, the National Commission on Research, Science \& Technology of Namibia (NCRST), the Austrian Federal Ministry of Education, Science and Research and the Austrian Science Fund (FWF), the Australian Research Council (ARC), the Japan Society for the Promotion of Science, the University of Amsterdam and the Science Committee of Armenia grant 21AG-1C085. We appreciate the excellent work of the technical support staff in Berlin, Zeuthen, Heidelberg, Palaiseau, Paris, Saclay, Tübingen and in Namibia in the construction and operation of the equipment. This work benefited from services provided by the H.E.S.S. Virtual Organisation, supported by the national resource providers of the EGI Federation.

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