Large-angle observatory with energy resolution for synoptic x-ray studies (LOBSTER-SXS)

Abstract

The soft X-ray band hosts a larger, more diverse range of variable sources than any other region of the electromagnetic spectrum. They are stars, compact binaries, SMBH's, the X-ray components of Gamma-Ray Bursts, their X-ray afterglows, and soft X-ray flares from supernova. We describe a concept for a very wide field (~ 4 ster) modular hybrid X-ray telescope system that can measure positions of bursts and fast transients with as good as arc second accuracy, the precision required to identify fainter and increasingly more distant events. The dimensions and materials of all telescope modules are identical. All but two are part of a cylindrical lobster-eye telescope with flat double sided mirrors that focus in one dimension and utilize a coded mask for resolution in the other. Their positioning accuracy is about an arc minute. The two remaining modules are made from the same materials but configured as a Kirkpatrick-Baez telescope with longer focal length that focuses in two dimensions. When pointed it refines the hybrid telescope's arc minute positions to an arc second and provides larger effective area for spectral and temporal measurements. Above 10 keV the mirrors act as an imaging collimator with positioning capability. For short duration events this hybrid focusing/coded mask system is more sensitive and versatile than either a 2D coded mask or a 2D lobster-eye telescope. Very wide field X-ray telescopes have become feasible as the ability to fabricate large area arrays of CCD and CMOS detectors has improved. This instrument's function in the soft X-ray band is similar to that of Swift in hard X-ray band and there are a greater variety of fast transients in the soft X-ray band. An instrument with considerably more sensitivity than current wide field X-ray detectors would be compatible with a modest NASA Explorer mission.

Comparison of focal properties of square-channel and meridional lobster-eye lenses

“…Recent papers [2,4,5,19] propose to utilize a Schmidt-style x-ray focusing device (stacked cylindrical arrays of flat plates [20]), which operates somewhat similarly to the lobster-eye lens. Although the focusing in 2D is different, when reduced to 1D, the meridional lobster-eye lens (along its central meridion) is identical to a 1D Schmidt optic.…”

“…Deep-field x-ray telescopes have been deployed since the Einstein telescope launched in 1978 [3], and, though the angular resolution has improved, the field of view (FOV) remains limited to ≈1∕2°due to geometric constraints. Though no wide FOV x-ray imaging telescope currently exists [4], one would be extremely valuable as an all-sky monitor (ASM) for locating and identifying new galactic and extragalactic sources [2] and observing the evolution of transient sources [5].…”

X-ray monitoring for astrophysical applications

“…We tried to find a solution of this problem using 1D LE optics that creates line focus. The idea of using 1D LE optics in X-ray telescope is based on a study from Gorenstein [6]. After summing the signal in the line direction, 1D array is obtained instead of 2D image.…”

Effective algorithm for ray-tracing simulations of lobster eye and similar reflective optical systems

“…ISS-Lobster [8][9][10] and others, e.g. [11][12][13][14][15][16][17]. It is currently being used in other applications, e.g.…”