Is RXJ1856.5-3754 an old neutron star?
نویسندگان
چکیده
An unusual X-ray source, RX J1856.5-3754, has recently been discovered with ROSAT: its spectrum resembles that of supersoft sources, but the very high X-ray to optical flux ratio excludes the presence of a companion star, pointing to an isolated compact object. It has been proposed that RX J1856.53754 is an old, isolated neutron star accreting from the interstellar medium. Here we present a reanalysis of the ROSAT data. TheHRI observation reveals an attitude reconstruction problem, resulting in a larger error box than previously reported. Deeper optical observations allow us to reveal a few optical counterparts inside the new error box, but the X-ray to optical flux ratio is still very high ( > ∼ 20) and none of the candidates has peculiar colors.
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