Acharyya, A.Adams, C. B.Archer, A.Bangale, P.Benbow, W.Brill, A.Christiansen, J. L.Chromey, A. J.Errando, M.Falcone, A.Feng, Q.Finley, J. P.Foote, G. M.Fortson, L.Furniss, A.Gallagher, G.Hanlon, W.Hanna, D.Hervet, O.Hinrichs, C. E.Hoang, J.Holder, J.Jin, W.Johnson, M. N.Kaaret, P.Kertzman, M.Kieda, D.Kleiner, T. K.Korzoun, N.Krennrich, F.Lang, M. J.Lundy, M.Maier, G.McGrath, C. E.Millard, M. J.Millis, J.Mooney, C. L.Moriarty, P.Mukherjee, R.O'Brien, S.Ong, R. A.Pohl, M.Pueschel, E.Quinn, J.Ragan, K.Reynolds, P. T.Ribeiro, D.Roache, E.Sadeh, I.Sadun, A. C.Saha, L.Santander, M.Sembroski, G. H.Shang, R.Splettstoesser, M.Talluri, A. K.Tucci, J. V.Vassiliev, V. V.Williams, D. A.Wong, S. L.(The VERITAS Collaboration)Hovatta, TalvikkiJorstad, Svetlana G.Kiehlmann, SebastianLähteenmäki, AnneLiodakis, IoannisMarscher, Alan P.Max-Moerbeck, WalterReadhead, Anthony C. S.Reeves, RodrigoSmith, Paul S.Tornikoski, Merja2025-02-192025-02-192023-06Acharyya, A., Adams, C. B., Archer, A., Bangale, P., Benbow, W., Brill, A., Christiansen, J. L., Chromey, A. J., Errando, M., Falcone, A., Feng, Q., Finley, J. P., Foote, G. M., Fortson, L., Furniss, A., Gallagher, G., Hanlon, W., Hanna, D., Hervet, O., … Tornikoski, M. (2023). VERITAS Discovery of Very High Energy Gamma-Ray Emission from S3 1227+25 and Multiwavelength Observations. The Astrophysical Journal, 950(2), 152. https://doi.org/10.3847/1538-4357/acd2d0https://hdl.handle.net/1805/45862We report the detection of very high energy gamma-ray emission from the blazar S3 1227+25 (VER J1230+253) with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). VERITAS observations of the source were triggered by the detection of a hard-spectrum GeV flare on 2015 May 15 with the Fermi-Large Area Telescope (LAT). A combined 5 hr VERITAS exposure on May 16 and 18 resulted in a strong 13σ detection with a differential photon spectral index, Γ = 3.8 ± 0.4, and a flux level at 9% of the Crab Nebula above 120 GeV. This also triggered target-of-opportunity observations with Swift, optical photometry, polarimetry, and radio measurements, also presented in this work, in addition to the VERITAS and Fermi-LAT data. A temporal analysis of the gamma-ray flux during this period finds evidence of a shortest variability timescale of τobs = 6.2 ± 0.9 hr, indicating emission from compact regions within the jet, and the combined gamma-ray spectrum shows no strong evidence of a spectral cutoff. An investigation into correlations between the multiwavelength observations found evidence of optical and gamma-ray correlations, suggesting a single-zone model of emission. Finally, the multiwavelength spectral energy distribution is well described by a simple one-zone leptonic synchrotron self-Compton radiation model.enAttribution 4.0 Internationalgamma-rayshigh energy astrophysicsblazarsArticle