Guest, B.B.GuestSafi-Harb, S.S.Safi-HarbMacMaster, A.A.MacMasterKothes, R.R.KothesOlmi, BarbaraBarbaraOlmiAMATO, ElenaElenaAMATOBUCCIANTINI, NICCOLO'NICCOLO'BUCCIANTINIArzoumanian, Z.Z.Arzoumanian2022-03-162022-03-1620200035-8711http://hdl.handle.net/20.500.12386/31604CTB 87 (G74.9+1.2) is an evolved supernova remnant (SNR) which hosts a peculiar pulsar wind nebula (PWN). The X-ray peak is offset from that observed in radio and lies towards the edge of the radio nebula. The putative pulsar, CXOU J201609.2+371110, was first resolved with Chandra and is surrounded by a compact and a more extended X-ray nebula. Here, we use a deep XMM-Newton observation to examine the morphology and evolutionary stage of the PWN and to search for thermal emission expected from a supernova shell or reverse shock interaction with supernova ejecta. We do not find evidence of thermal X-ray emission from the SNR and place an upper limit on the electron density of 0.05 cm<SUP>-3</SUP> for a plasma temperature kT ∼ 0.8 keV. The morphology and spectral properties are consistent with a ∼20-kyr-old relic PWN expanding into a stellar wind-blown bubble. We also present the first X-ray spectral index map from the PWN and show that we can reproduce its morphology by means of 2D axisymmetric relativistic hydrodynamical simulations.STAMPAenArticle10.1093/mnras/stz32702-s2.0-85079695843http://arxiv.org/abs/1911.11829v1https://academic.oup.com/mnras/article/491/2/3013/56388802020MNRAS.491.3013GFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation::PE9_10 High energy and particle astronomy – X-rays, cosmic rays, gamma rays, neutrinos