A wide field X‐ray telescope for astronomical survey purposes: from theory to practice

X-ray mirrors are usually built in the Wolter I (paraboloid-hyperboloid) configuration. This design exhibits no spherical aberration on-axis but suffers from field curvature, coma and astigmatism, therefore, the angular resolution degrades rapidly with increasing off-axis angles. Different mirror designs exist in which the primary and secondary mirror profiles are expanded as a power series in order to increase the angular resolution at large off-axis positions, at the expanses of the on-axis performances. Here we present the design and global trade off study of an X-ray mirror systems based on polynomial optics in view of the Wide Field X-ray Telescope (WFXT) mission. WFXT aims at performing an extended cosmological survey in the soft X-ray band with unprecedented flux sensitivity. To achieve these goals the angular resolution required for the mission is very demanding, ~5 arcsec mean resolution across a 1° field of view. In addition an effective area of 5-9000 cm 2 at 1 keV is needed.

[1]  J. Owens,et al.  The Soft X-ray Telescope for the SOLAR-A mission , 1991 .

[2]  Martin C. Weisskopf,et al.  Chandra X-ray Observatory (CXO): overview , 1999, Astronomical Telescopes and Instrumentation.

[3]  Paolo Conconi,et al.  X-ray optics for the WFXT telescope , 1999, Optics & Photonics.

[4]  K. Nariai,et al.  Geometrical aberration of a generalized Wolter type I telescope. , 1987, Applied optics.

[5]  H. Wolter.  Spiegelsysteme streifenden Einfalls als abbildende Optiken für Röntgenstrahlen , 1952 .

[6]  Oberto Citterio,et al.  X-ray measurements of a prototype WFXT SiC mirror at the MSFC X-Ray Calibration Facility , 1999, Optics & Photonics.

[7]  Galaxy clusters and the cosmic cycle of baryons across cosmic times , 2009, 0902.4857.

[8]  K. Shibasaki,et al.  Science of the X-ray Sun: The X-ray telescope on Solar-B , 2005 .

[9]  Patrick L. Thompson,et al.  Generalized Wolter type I design for the solar x-ray imager (SXI) , 1999, Optics & Photonics.

[10]  W. Werner,et al.  Imaging properties of Wolter I type x-ray telescopes. , 1977, Applied optics.

[11]  David L. Shealy,et al.  Astronomical Applications Of Grazing Incidence Telescopes With Polynomial Surfaces , 1979, Other Conferences.

[12]  Asher Peres,et al.  Gravitational radiation damping of nongravitational motion , 1960 .

[13]  Patrick L. Thompson,et al.  Systems engineering analysis of aplanatic Wolter type I x-ray telescopes , 2000 .

[14]  S. Borgani,et al.  X-ray Cluster Cosmology , 2009, 0903.5320.

[15]  S. Gezari,et al.  The growth and evolution of super massive black holes , 2009, 0903.5272.

[16]  K. Nariai,et al.  Geometric aberration of a generalized Wolter type I telescope. 2: Analytical study. , 1988, Applied optics.

[17]  R. Chase,et al.  Design Parameters of Paraboloid-Hyperboloid Telescopes for X-ray Astronomy. , 1972, Applied optics.

[18]  Paolo Conconi,et al.  Wide-field x-ray imaging for future missions, including XEUS , 2004, SPIE Optics + Photonics.

[19]  Giovanni Pareschi,et al.  Astronomical soft x-ray mirrors reflectivity enhancement by multilayer coatings with carbon overcoating , 2004, SPIE Astronomical Telescopes + Instrumentation.

[20]  Paolo Conconi,et al.  Optimization of grazing incidence mirrors and its application to surveying X-ray telescopes , 2001 .

[21]  James R. Lemen,et al.  The solar x-ray imager for GOES , 2004, SPIE Optics + Photonics.

[22]  Hans Wolter,et al.  Verallgemeinerte Schwarzschildsche Spiegelsysteme streifender Reflexion als Optiken für Röntgenstrahlen , 1952 .

[23]  Virendra N. Mahajan,et al.  Zernike annular polynomials for imaging systems with annular pupils , 1984 .

[24]  P. Giommi,et al.  The Swift X-Ray Telescope , 1999 .

[25]  R. Chase,et al.  Wolter-schwarzschild telescopes for x-ray astronomy. , 1973, Applied optics.

[26]  Christopher J. Burrows,et al.  Optimal grazing incidence optics and its application to wide-field X-ray imaging , 1992 .