Transients in the Local Universe

Abstract

Two different reasons make the search for transients in the nearby Universe (d < 200 Mpc) interesting and urgent. First, there exists a large gap in the luminosity of the brightest novae (-10 mag) and that of sub-luminous supernovae (-16 mag). However, theory and reasonable speculation point to several potential classes of objects in this "gap". Such objects are best found in the Local Universe. Second, the nascent field of Gravitational Wave (GW) astronomy and the budding fields of Ultra-high energy cosmic rays, TeV photons, astrophysical neutrinos are likewise limited to the Local Universe by physical effects (GZK effect, photon pair production) or instrumental sensitivity (neutrino and GW). Unfortunately, the localization of these new telescopes is poor and precludes identification of the host galaxy (with attendant loss of distance and physical diagnostics). Both goals can be met with wide field imaging telescopes acting in concert with follow-up telescopes. Astronomers must also embark upon completing the census of galaxies in the nearby Universe.