Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Einstein Probe - a small mission to monitor and explore the dynamic
  X-ray Universe   Einstein Probe is a small mission dedicated to time-domain high-energy
astrophysics. Its primary goals are to discover high-energy transients and to
monitor variable objects in the $0.5-4~$keV X-rays, at higher sensitivity by
one order of magnitude than those of the ones currently in orbit. Its
wide-field imaging capability, featuring a large instantaneous field-of-view
($60^\circ \times60^\circ$, $\sim1.1$sr), is achieved by using established
technology of micro-pore (MPO) lobster-eye optics, thereby offering
unprecedentedly high sensitivity and large Grasp. To complement this powerful
monitoring ability, it also carries a narrow-field, sensitive follow-up X-ray
telescope based on the same MPO technology to perform follow-up observations of
newly-discovered transients. Public transient alerts will be downlinked
rapidly, so as to trigger multi-wavelength follow-up observations from the
world-wide community. Over three of its 97-minute orbits almost the entire
night sky will be sampled, with cadences ranging from 5 to 25 times per day.
The scientific objectives of the mission are: to discover otherwise quiescent
black holes over all astrophysical mass scales by detecting their rare X-ray
transient flares, particularly tidal disruption of stars by massive black holes
at galactic centers; to detect and precisely locate the electromagnetic sources
of gravitational-wave transients; to carry out systematic surveys of X-ray
transients and characterize the variability of X-ray sources. Einstein Probe
has been selected as a candidate mission of priority (no further selection
needed) in the Space Science Programme of the Chinese Academy of Sciences,
aiming for launch around 2020.

35
The categories of this paper are: mtrl-th
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph