Rowell, G.Naito, T.Dazeley, S.Edwards, P.Gunji, S.Hara, T.Holder, J.Kawachi, A.Kifune, T.Matsubara, Y.Mizumoto, Y.Mori, M.Muraishi, H.Muraki, Y.Nishijima, K.Ogio, S.Patterson, J.Roberts, M.Sako, T.Sakurazawa, K.et al.2006-07-212006-07-212000Astronomy and Astrophysics (A & A), 2000; 359(1):337-3460004-6361http://hdl.handle.net/2440/12405The atmospheric Cerenkov imaging technique has been used to search for point-like and diffuse TeV gamma-ray emission from the southern supernova remnant, W28, and surrounding region. The search, made with the CANGAROO 3.8m telescope, encompasses a number of interesting features, the supernova remnant itself, the EGRET source 3EG J1800-2338, the pulsar PSR J1801-23, strong 1720 MHz OH masers and molecular clouds on the north and east boundaries of the remnant. An analysis tailored to extended and off-axis point sources was used, and no evidence for TeV gamma-ray emission from any of the features described above was found in data taken over the 1994 and 1995 seasons. Our upper limit (E>1.5 TeV) for a diffuse source of radius 0.25deg encompassing both molecular clouds was calculated at 6.64e-12 photons cm^-2 s^-1 (from 1994 data), and interpreted within the framework of a model predicting TeV gamma-rays from shocked-accelerated hadrons. Our upper limit suggests the need for some cutoff in the parent spectrum of accelerated hadrons and/or slightly steeper parent spectra than that used here (-2.1). As to the nature of 3EG J1800-2338, it possibly does not result entirely from pi-zero decay, a conclusion also consistent with its location in relation to W28.en© European Southern Observatory (ESO) 2000 Submitted to Cornell University’s online archive www.arXiv.org in 2000 by Gavin Rowell. Post-print sourced from www.arxiv.org.Journal article00010012300000884244000292-s2.0-001186805263331Rowell, G. [0000-0002-9516-1581]