The enhanced X-ray Timing and Polarimetry mission (eXTP) is a China-led science mission designed to study the state of matter under extreme conditions of density, gravity and magnetism. Primary goals are the determination of the equation of state of matter at supra-nuclear density, the measurement of QED effects in highly magnetized star, and the study of accretion in the strong-field regime of gravity. Primary targets include isolated and binary neutron stars, strong magnetic field systems like magnetars, and stellar-mass and supermassive black holes.
The mission carries a unique and unprecedented suite of state-of-the-art instruments enabling for the first time ever the simultaneous spectral-timing-polarimetry studies of cosmic sources in the energy range from 0.5-30 keV. Key elements of the payload are:
- The Spectroscopic Focusing Array (SFA): a set of 11 X-ray focusing instruments operating in the 0.5-10 keV energy band with a field-of-view (FoV) of 12 arcmin each and a total effective area of ∼0.9 m2 and 0.6 m2 at 2 keV and 6 keV respectively, offering <180 eV spectral resolution.
- The Polarimetry Focusing Array (PFA): a set of 2 X-ray telescopes, with total effective area of 250 cm2 at 2 keV, operating in the 2-10 keV energy range. The FoV of each telescope is 12 arcmin.
- The Large Area Detector (LAD): a deployable set of 640 Silicon Drift Detectors, achieving a total effective area of ∼3.4 m2 between 6 and 10 keV. The operational energy range is 2-30 keV, with achievable spectral resolution better than 250 eV. The LAD is a non-imaging instrument, with a collimator providing a limited FoV <1°.
- The Wide Field Monitor (WFM): a set of 3 coded mask camera pairs, with a wide FoV of 3.7 sr, equipped with Silicon Drift Detectors
operating in the energy range 2-50 keV.
Aim of our participation
The LAD and the WFM instruments (already designed during the LOFT feasibility study - ESA M3 - by an EU consortium, including ICE), will be provided by Europe, in the framework of a global EU participation in the Chinese mission eXTP supported by an ESA MoO (Mission of Opportunity). There's a relevant Spanish participation led by ICE, at the level of IP of the WFM; ICE will supply the collimator and coded masks, plus the mechanical and thermal configuration of the whole WFM, and be responsible of the Assembly, Integration, Verification and Test of the WFM cameras.
During 2016 and 2017, there has been strong work related to the fitting of LOFT instruments (LAD and WFM) into the previous XTP baseline, also helping the Chinese team to improve their previously proposed instruments (SFA and PFA). We played a significant role on the search of the best WFM configuration (3 camera pairs is the new baseline adopted) and we made crucial suggestions for the platform, in order to well accommodate all the instruments and the sunshade required for the WFM.
- Several teleconferences and meetings took place in 2016 and 2017. Talks by Hernanz: (Meeting at Fudan University in Shangai: April 2016. Meetings at IHEP in Beijing, October 2016 and March 2017)
- Preparation of the first eXTP (open) science meeting "High-throughput X-ray Astronomy in the eXTP era (February 2017, Rome); Hernanz was SOC member
- Participation in Science Working Groups (WGs): Rea in the "Strong Magnetism" WG3, Hernanz in the "Observatory Science" WG4. The former Spanish participants in the LOFT WGs (more than 30) have joined the eXTP WGs.
- Organization of a Spain-EU-China meeting at ICE (CSIC), 12-13 Dec. 2017, as well as a Spain-China meeting in CDTI (Madrid), 5 Dec. 2017
"eXTP: Enhanced X-ray Timing and Polarization mission", Zhang, S. N.; Feroci, M. et al., including Hernanz, M. Gálvez, J.L., Rea, N., Proceedings of the SPIE, Volume 9905, id. 99051Q 16 pp. (2016), https://arxiv.org/abs/1607.08823.
"The LOFT mission concept: a status update", Feroci, M.; Bozzo, E.; Brandt, S.; Hernanz, M.; van der Klis, M.; et al., including L. Alvarez, J.L. Gálvez, L. Tolos, N. Rea, D.F. Torres, Proceedings of the SPIE, Volume 9905, id. 99051R 20 pp. (2016).
"Colloquium: Measuring the neutron star equation of state using x-ray timing", Watts, A. et al., including L. Tolos, Reviews of Modern Physics, Volume 88, Issue 2, id. 021001 (2016), https://arxiv.org/abs/1602.01081.
Senior Institute members involved
, J.L. Galvez, N. Rea, L. Tolos, F. Torres