201. A study of the long term variability of RX J1856.5-3754 with XMM-Newton
- Author
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Mereghetti, S., Sartore, N., Tiengo, A., De Luca, A., Turolla, R., and Haberl, F.
- Subjects
Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report on a detailed spectral analysis of all the available XMM-Newton data of RX J1856.5-3754, the brightest and most extensively observed nearby, thermally emitting neutron star. Very small variations (~1-2%) in the single-blackbody temperature are detected, but are probably due to an instrumental effect, since they correlate with the position of the source on the detector. Restricting the analysis to a homogeneous subset of observations, with the source at the same detector position, we place strong limits on possible spectral or flux variations from March 2005 to present-day. A slightly higher temperature (kT~61.5 eV, compared to the average value kT~61 eV) was instead measured in April 2002. If this difference is not of instrumental origin, it implies a rate of variation of about 0.15 eV/yr between April 2002 and March 2005. The high-statistics spectrum from the selected observations is well fit by the sum of two blackbody models, which extrapolate to an optical flux level in agreement with the observed value., Comment: 4 pages, to appear in the proceedings of the ERPM conference, Zielona Gora, April 2012
- Published
- 2012