Open AccessXMM–Newton RGS spectroscopy of LMC X‐3
Author(s) -
Page M. J.,
Soria R.,
Wu K.,
Mason K. O.,
Cordova F. A.,
Priedhorsky W. C.
Publication year - 2003
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 - 10.1046/j.1365-8711.2003.06967.x
Subject(s) - physics , astrophysics , black body radiation , ionization , spectral line , spectroscopy , lyman limit , galaxy , emission spectrum , astronomy , redshift , optics , radiation , ion , quantum mechanics , intergalactic medium
We present soft X‐ray spectroscopy of the black hole binary LMC X‐3 from the XMM–Newton Reflection Grating Spectrometer. The observations span the full range of spectral states seen in LMC X‐3. The spectra are completely dominated by continuum emission, and the neutral absorbing column measured from the O i edge ( N H = 3.8 +0.8 −0.7 × 10 20 cm −2 ) is consistent with the Galactic interstellar column density towards LMC X‐3. We find no evidence for variability of the neutral absorbing column. We also constrain the ionized column density using the upper limits to the equivalent width of the O ii –O viii K‐shell resonance lines: we find that the equivalent hydrogen column density of gas in which O is partially ionized is < 8× 10 20 cm −2 . From this upper limit we can rule out a line‐driven stellar wind as the power source for the X‐ray emission of LMC X‐3 except when it is faint. At wavelengths longward of the peak emission the spectral shape is well described by a multitemperature disc–blackbody spectrum; the power‐law component, which dominates at shorter wavelengths, does not continue longward of the disc–blackbody peak. This implies that the multitemperature disc–blackbody component supplies the seed photons that are Compton upscattered in the hot corona, consistent with the standard paradigm for black hole X‐ray binary spectral states.