Open AccessA search for X‐ray flashes with XMM–Newton
Author(s) -
Law Nicholas M.,
Rutledge Robert E.,
Kulkarni Shrinivas R.
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.07717.x
Subject(s) - physics , rosat , astrophysics , extrapolation , sky , epic , flux (metallurgy) , observable , astronomy , photon , population , optics , galaxy , art , mathematical analysis , materials science , mathematics , literature , demography , quantum mechanics , sociology , metallurgy
We searched for X‐ray flashes (XRFs) – which we defined as ∼10‐s 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 per cent upper limit on the number of flashes per sky per year at two different incoming flash fluxes: 4.0 × 10 9 events sky −1 yr −1 for a flux of 7.1 × 10 −13 erg cm −2 s −1 and 6.8 × 10 7 events sky −1 yr −1 for 1.4 × 10 −11 erg cm −2 s −1 , both assuming a spectral power‐law photon index α= 2 . These limits are consistent with an extrapolation from the BeppoSAX /WFC XRF rate at much higher fluxes (∼ a factor of 10 5 ), assuming a homogenous population, and with a previous, more stringent limit derived from ROSAT pointed observations.