The enhanced X-ray Timing and Polarimetry mission
(eXTP) is a future satellite designed to study extreme states of
matter density, gravity, and magnetism. The program is to be led by
the Chinese Academy of Sciences and universities in China, with
partnerships with various European institutions. It is intended to be
launched in 2027.
eXTP will have a suite of X-ray imaging and non-image instruments. These
the Spectroscopic Focusing Array (SFA), a set of 9 X-ray telescopes
operating in the 0.5–10 keV energy band with a field-of-view (FoV)
of 12′ each with
an intended spatial resolution of 1′. The
SFA will have an effective area of ∼0.8 m2 at 2 kev and
0.5 m2 at 6 keV. SFA will be equipped with Silicon Drift
Detectors offering <180 eV spectral resolution. The optics are
Wolter-I type nested
mirrors with coated glass focal elements.
the Polarimetry Focusing Array (PFA) consists of a set of 4 X-ray
telescopes with an angular resolution of better than 30″ over a
12′ FoV, with a total effective area of 900 cm2 at 2 keV.
It will be equipped with imaging gas pixel photoelectric polarimeters.
PFA will be sensitve to energetic
photons in the energy range 2–10 keV
the Wide Field Monitor (WFM) will have 3 pairs of coded mask wide field
with position-sensitive Silicon Drift Detectors, covering in total a FoV
of 3.7 sr (roughly 70° x 70°) sensitive to photons in the range
2–50 keV and spectral resolution of ∼300 eV at 6 keV, and an
absolute timing accuracy of 1 µs. The two cameras in each pair are
sensitive to location on one dimension, and only coarsely in the orthogoal
direction, so mounted pairs are set at right
angle orientations to provide accurate 2-D targeting for the pair. The
accuracy should be 1′. The WFM will include on-board detection for
bright events to trigger Burst Alerts.
the Large Area Detector (LAD), a deployable set of 640 Silicon Drift
Detectors (SDDs) with an effective area of ∼3.4 m2 between
6 and 10 keV. LAD will be
senstive to 2–30 keV with a spectral resolution of <250 eV:
may be detectable up to 80 keV for magnetar flares and gamma-ray bursts. LAD will have 40 modules, each with 4 x 4
detectors and matching collimators, and should have a <1° FWHM
eXTP will study ultra-dense matter in neutron stars, probing and exploring
exotic matter states that exist in neutron stars because of intense
gravitational fields. It will also explore the physics of strong magnetic
fields in magnetars, accreting X-ray pulsars, and rotation-powered pulsars.
eXTP is anticipated to discover a new magnetar candidate from flaring
observations approximately once a year. The mission will also study the
accretion processing in the strong-field limit of gravity around
super-massive black holes seen at the core of active galactic nuclei.