Resolving the Composite Fe K-alpha Emission Line in the Galactic Black Hole Cygnus X-1 with Chandra

Abstract

We observed the Galactic black hole Cygnus X-1 with the Chandra High Energy Transmission Grating Spectrometer for 30 kiloseconds on 4 January, 2001. The source was in an intermediate state, with a flux that was approximately twice that commonly observed in its persistent low/hard state. Our best-fit model for the X-ray spectrum includes narrow Gaussian emission line (E = 6.415 +/- 0.007 keV, FWHM = 80 (+28, -19) eV, W = 16 (+3, -2) eV) and broad line (E = 5.82 (+0.06, -0.07) keV, FWHM = 1.9 (+0.5, -0.3) keV, W = 140 (+70, -40) eV) components, and a smeared edge at 7.3 +/- 0.2 keV (tau ~ 1.0). The broad line profile is not as strongly skewed as those observed in some Seyfert galaxies. We interpret these features in terms of an accretion disk with irradiation of the inner disk producing a broad Fe K-alpha emission line and edge, and irradiation of the outer disk producing a narrow Fe K-alpha emission line. The broad line is likely shaped predominantly by Doppler shifts and gravitational effects, and to a lesser degree by Compton scattering due to reflection. We discuss the underlying continuum X-ray spectrum and these line features in the context of diagnosing the accretion flow geometry in Cygnus X-1 and other Galactic black holes.

Accepted for publication in ApJ

References in corpus (11)

• XMM-EPIC observation of MCG-6-30-15: Direct evidence for the extraction of energy from aspinning black hole?
• Dynamical Evidence for a Black Hole in the Microquasar XTE J1550-564
• The Chandra HETGS and RXTE view of GRS 1915+105
• High resolution Chandra HETG and RXTE observations of GRS 1915+105 : A hot disk atmosphere & cold gas enriched in Iron and Silicon
• Coronal--Temporal Correlations in GX339-4: Hysteresis, Possible Reflection Changes, and Implications for ADAFs
• The First High Resolution X-ray Spectrum of Cyg X-1: Soft X-Ray Ionization and Absorption
• Chandra High-Resolution Spectrum of the Anomalous X-ray Pulsar 4U 0142+61
• Chandra Observations of the Anomalous X-ray Pulsar 1E 2259+58.6
• The 1998 outburst of the X-ray transient XTE J2012+381 as observed with BeppoSAX
• The Effect of Changes in the ASCA Calibration on the Fe-Kalpha Lines in Active Galaxies
• A Peculiar Flaring Episode of Cygnus X-1

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