Wide Field X-ray Telescope

The Ultimate X-ray Survey


  1. WFXT study concept white paper submitted to Solicitation NNH11ZDA018L on 28 Oct 2011

  2. Proceedings of the WFXT Workshop (Bologna, Nov 2009) [see → Foreword by Riccardo Giacconi (Sep 2010)]

  3. Check latest talks and papers (until 2012)


The Wide Field X-Ray Telescope (WFXT) is a medium-class mission designed to be 2-orders-of-magnitude more sensitive than any previous or planned X-ray mission for large area surveys and to match in sensitivity the next generation of wide-area optical, IR and radio surveys. Using an innovative wide-field X-ray optics design, WFXT provides a field of view of 1 square degree (10x Chandra) with an angular resolution of 5′′ (Half Energy Width, HEW) nearly constant over the entire field, and a large collecting area (1 m2, >10x Chandra) over the 0.1-7 keV band. WFXT’s low-Earth orbit also minimizes the particle background. In five years of operation, WFXT will carry out three extragalactic surveys:

  1. a WIDE survey will cover most of the extragalactic sky (~20,000 deg2) at ~500 times the sensitivity, and twenty times better angular resolution of the ROSAT All Sky Survey;

  2. a MEDIUM survey will map ~3000 deg2 to deep Chandra or XMM - COSMOS sensitivity;

  3. a DEEP survey will probe ~100 deg2, or ~1000 times the area of the Chandra Deep Fields, to the deepest Chandra sensitivity.

Flux limit and sky coverage for past and planned X-ray surveys. The three WFXT surveys provide an unsurpassed combination of sensitivity and sky coverage with good angular resolution [PDF]

Description of WFXT surveys

Last update: 19 May 2019


  1. WFXT surveys will generate a legacy astrophysical data set of ~>5×105 clusters of galaxies to z~2,  >107 AGN to z > 6, and ~105 normal and starburst galaxies at z<~1

  2. The WFXT mission is scientifically broad, as the survey data will

  3. provide a description of the cosmic evolution and cycle of baryons

  4. map the large scale structure of the Universe

  5. constrain and test cosmological models and fundamental physics (e.g. the nature of Dark Matter, Dark Energy and gravity)

  6. determine the black hole accretion history to early epochs and its intimate link with galaxy formation

  7. provide an unprecedented view of nearby galaxies including our own

  8. WFXT is not only a path finder for other missions, its large collecting area allows direct physical characterization of a large fraction of sources (AGN and Clusters) via X-ray spectroscopy with no need of follow-up observations. Synergy with other missions further enhances its scientific potential and breadth

  9. Like the Sloan Digital Sky Survey, all WFXT data will become public through a series of annual data releases that will constitute a vast scientific legacy for decades

  10. See also:

  11. WFXT simulations and performance

  12. WFXT website at JHU (dismissed)

(updated on July 2010)