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A Search for X-Ray Flashes with XMM-Newton

N. M. Law·R. E. Rutledge·S. R. Kulkarni
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Abstract

We searched for X-ray flashes (XRFs) -- which we defined as ~10s duration transient X-ray events observable in the 0.4-15 keV passband -- in fields observed using XMM-Newton with the EPIC/pn detector. While we find two non-Poissonian events, the astrophysical nature of the events is not confirmed in fully simultaneous observations with the EPIC/MOS detectors, and we conclude that the events are anomalous to the EPIC/pn detector. We find a 90% upper limit on the number of flashes per sky per year at two different incoming flash fluxes: 4.0x10^9 events / sky / year for a flux of 7.1x10^-13 erg / cm^2 / s and 6.8x10^7 events / sky / year for 1.4x10^-11 erg / cm^2 / s. These limits are consistent with an extrapolation from the BeppoSAX/WFC XRF rate at much higher fluxes (about a factor of 10^5), assuming an homogenous population, and with a previous, more stringent limit derived from ROSAT pointed observations.

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N. M. Law, R. E. Rutledge, S. R. Kulkarni. 2004-02-11. A Search for X-Ray Flashes with XMM-Newton. https://doi.org/10.1111/j.1365-2966.2004.07717.x

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