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@ARTICLE{Bronzini:620286,
      author       = {Bronzini, Ettore and Grandi, Paola and Torresi, Eleonora
                      and Buson, Sara},
      title        = {{F}ermi-{LAT} {D}etection of the {L}ow-luminosity {R}adio
                      {G}alaxy {NGC} 4278 during the {LHAASO} {C}ampaign},
      journal      = {The astrophysical journal / Part 2},
      volume       = {977},
      number       = {1},
      issn         = {2041-8205},
      address      = {London},
      publisher    = {Institute of Physics Publ.},
      reportid     = {PUBDB-2025-00120, arXiv:2409.17255},
      pages        = {L16},
      year         = {2024},
      note         = {submitted to ApJL on behalf of the Fermi-LAT collaboration},
      abstract     = {We present a study of the high-energy properties of the
                      compact symmetric object NGC 4278, recently associated with
                      a TeV source by the Large High Altitude Air Shower
                      Observatory (LHAASO) collaboration. We conducted a dedicated
                      analysis of a Fermi Large Area Telescope (LAT) region around
                      NGC 4278, limited to the LHAASO campaign conducted from 2021
                      March to 2022 October. A statistically significant emission
                      (∼4.3σ) was revealed, spatially consistent with the radio
                      position of NGC 4278 and the LHAASO source. The Fermi-LAT
                      source is detected above 8 GeV, exhibiting a hard spectrum
                      (photon index Γ = 1.3 ± 0.3) and a γ-ray luminosity of
                      L$_{>100 MeV}$ ≃ 4 × 10$^{41}$ erg s$^{–1}$. A
                      serendipitous Swift X-Ray Telescope (XRT) observation of NGC
                      4278 during the TeV campaign reveals the source in a high
                      state, with a flux
                      F0.5−8keV=5−2+3×10−12ergs−1cm−2, compatible with
                      the highest luminosity level observed in previous Chandra
                      pointings. The high-energy spectral energy distribution of
                      the source and the intense flux variation observed in the
                      X-ray band support a jet origin for the observed radiation.
                      We suggest that the significant enhancement of the
                      high-energy flux observed during the LHAASO campaign is due
                      to a transient, highly energetic perturbation in the jet.
                      The detection of NGC 4278 at both high and very high
                      energies opens new frontiers in studying particle
                      acceleration processes. It reveals that even compact,
                      low-power radio galaxies can exceed the sensitivity
                      thresholds of GeV and TeV instruments, becoming promising
                      targets for the upcoming Cherenkov Telescope Array
                      Observatory.},
      cin          = {$Z_GA$},
      ddc          = {520},
      cid          = {$I:(DE-H253)Z_GA-20210408$},
      pnm          = {613 - Matter and Radiation from the Universe (POF4-613) /
                      DFG project G:(GEPRIS)443220636 - FOR 5195: Relativistische
                      Jets in Aktiven Galaxien (443220636) / MessMapp - Mapping
                      Highly-Energetic Messengers throughout the Universe
                      (949555)},
      pid          = {G:(DE-HGF)POF4-613 / G:(GEPRIS)443220636 /
                      G:(EU-Grant)949555},
      experiment   = {EXP:(DE-MLZ)NOSPEC-20140101},
      typ          = {PUB:(DE-HGF)16},
      eprint       = {2409.17255},
      howpublished = {arXiv:2409.17255},
      archivePrefix = {arXiv},
      SLACcitation = {$\%\%CITATION$ = $arXiv:2409.17255;\%\%$},
      UT           = {WOS:001370971100001},
      doi          = {10.3847/2041-8213/ad93cf},
      url          = {https://bib-pubdb1.desy.de/record/620286},
}