Acharyya, A.Archer, A.Bangale, P.Bartkoske, J. T.Batista, P.Baumgart, M.Benbow, W.Buckley, J. H.Falcone, A.Feng, Q.Finley, J. P.Foote, G. M.Fortson, L.Furniss, A.Gallagher, G.Hanlon, W. F.Hervet, O.Hoang, J.Holder, J.Humensky, T. B.Jin, W.Kaaret, P.Kertzman, M.Kherlakian, M.Kieda, D.O'Brien, S.Ong, R. A.Pfrang, K.Pohl, M.Pueschel, E.Quinn, J.Ragan, K.Reynolds, P. T.Roache, E.Rodd, N. L.Ryan, J. L.Sadeh, I.Saha, L.Santander, M.Sembroski, G. H.Shang, R.Splettstoesser, M.Tak, D.Tucci, J. V.Vassiliev, V. V.Williams, D. A.2025-04-222025-04-222023-03Acharyya, A., Archer, A., Bangale, P., Bartkoske, J. T., Batista, P., Baumgart, M., Benbow, W., Buckley, J. H., Falcone, A., Feng, Q., Finley, J. P., Foote, G. M., Fortson, L., Furniss, A., Gallagher, G., Hanlon, W. F., Hervet, O., Hoang, J., Holder, J., … Williams, D. A. (2023). Search for Ultraheavy Dark Matter from Observations of Dwarf Spheroidal Galaxies with VERITAS. The Astrophysical Journal, 945(2), 101. https://doi.org/10.3847/1538-4357/acbc7bhttps://hdl.handle.net/1805/47300Dark matter is a key piece of the current cosmological scenario, with weakly interacting massive particles (WIMPs) a leading dark matter candidate. WIMPs have not been detected in their conventional parameter space (100 GeV ≲Mχ ≲ 100 TeV), a mass range accessible with current Imaging Atmospheric Cherenkov Telescopes. As ultraheavy dark matter (UHDM; Mχ ≳ 100 TeV) has been suggested as an underexplored alternative to the WIMP paradigm, we search for an indirect dark matter annihilation signal in a higher mass range (up to 30 PeV) with the VERITAS γ-ray observatory. With 216 hr of observations of four dwarf spheroidal galaxies, we perform an unbinned likelihood analysis. We find no evidence of a γ-ray signal from UHDM annihilation above the background fluctuation for any individual dwarf galaxy nor for a joint-fit analysis, and consequently constrain the velocity-weighted annihilation cross section of UHDM for dark matter particle masses between 1 TeV and 30 PeV. We additionally set constraints on the allowed radius of a composite UHDM particle.enAttribution 4.0 Internationaldark matterhigh energy astrophysicsgamma-ray astronomyArticle