StrayCats: A catalog of NuSTAR Stray Light Observations

TL;DR

StrayCats is a comprehensive catalog of NuSTAR stray light observations, systematically identifying over 78 sources and demonstrating the scientific potential of these unique off-axis X-ray data.

Contribution

This work introduces the first extensive catalog of NuSTAR stray light observations, including identification methods and analysis techniques for high-quality science products.

Findings

Catalog includes 78 stray light sources from 436 fields

Identifies various X-ray sources including binaries and pulsars

Demonstrates scientific utility of stray light data

Abstract

We present StrayCats: a catalog of NuSTAR stray light observations of X-ray sources. Stray light observations arise for sources 1--4$^{\circ}$ away from the telescope pointing direction. At this off-axis angle, X-rays pass through a gap between optics and aperture stop and so do not interact with the X-ray optics but, instead, directly illuminate the NuSTAR focal plane. We have systematically identified and examined over 1400 potential observations resulting in a catalog of 436 telescope fields and 78 stray light sources that have been identified. The sources identified include historically known persistently bright X-ray sources, X-ray binaries in outburst, pulsars, and Type I X-ray bursters. In this paper we present an overview of the catalog and how we identified the StrayCats sources and the analysis techniques required to produce high level science products. Finally, we present a few brief examples of the science quality of these unique data.