Einstein Probe - a small mission to monitor and explore the dynamic\n X-ray Universe

Abstract

Einstein Probe is a small mission dedicated to time-domain high-energy\nastrophysics. Its primary goals are to discover high-energy transients and to\nmonitor variable objects in the $0.5-4~$keV X-rays, at higher sensitivity by\none order of magnitude than those of the ones currently in orbit. Its\nwide-field imaging capability, featuring a large instantaneous field-of-view\n($60^\\circ \\times60^\\circ$, $\\sim1.1$sr), is achieved by using established\ntechnology of micro-pore (MPO) lobster-eye optics, thereby offering\nunprecedentedly high sensitivity and large Grasp. To complement this powerful\nmonitoring ability, it also carries a narrow-field, sensitive follow-up X-ray\ntelescope based on the same MPO technology to perform follow-up observations of\nnewly-discovered transients. Public transient alerts will be downlinked\nrapidly, so as to trigger multi-wavelength follow-up observations from the\nworld-wide community. Over three of its 97-minute orbits almost the entire\nnight sky will be sampled, with cadences ranging from 5 to 25 times per day.\nThe scientific objectives of the mission are: to discover otherwise quiescent\nblack holes over all astrophysical mass scales by detecting their rare X-ray\ntransient flares, particularly tidal disruption of stars by massive black holes\nat galactic centers; to detect and precisely locate the electromagnetic sources\nof gravitational-wave transients; to carry out systematic surveys of X-ray\ntransients and characterize the variability of X-ray sources. Einstein Probe\nhas been selected as a candidate mission of priority (no further selection\nneeded) in the Space Science Programme of the Chinese Academy of Sciences,\naiming for launch around 2020.\n